ML13197A411

Response to Request for Additional Information Regarding Enhancements to Diesel Generator License Amendment Request

ML13197A411
Person / Time
Site:	Calvert Cliffs
Issue date:	07/12/2013
From:	George Gellrich Constellation Energy Group, EDF Group, Calvert Cliffs
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML13197A411 (93)

Text

George H. Gellrich Calvert Cliffs Nuclear Power Plant, LLC Vice President 1650 Calvert Cliffs Parkway Lusby, Maryland 20657 410.495.5200 410.495.3500 Fax CENG a joint venture of Constellatinon Energy, D CALVERT CLIFFS NUCLEAR POWER PLANT July 12, 2013 U. S. Nuclear Regulatory Commission Washington, DC 20555 ATTENTION: Document Control Desk

SUBJECT:

Calvert Cliffs Nuclear Power Plant Unit Nos. 1 and 2; Docket Nos. 50-317 and 50-318 Response to Request for Additional Information Regarding Enhancements to fliesel G~enerator I .icense Amendment Reaiiest

REFERENCES:

(a) Letter from Mr. G. H. Gellrich (CCNPP) to Document Control Desk (NRC), dated October 16, 2012, License Amendment Request re:

Enhancements to Diesel Generator Surveillance Requirements (b) Letter from Ms. N. S. Morgan (NRC) to Mr. G. H. Gellrich (CCNPP),

dated June 12, 2013, Request for Additional Information Regarding Enhancements to Diesel Generator Surveillance Requirements License Amendment (TAC No. ME9832 and ME9833)

In Reference (a), Calvert Cliffs Nuclear Power Plant, LLC submitted a license amendment request to revise Surveillance Requirements 3.8.1.8, 3.8.1.11, and 3.8.2.1, and add Surveillance Requirement 3.8.1.17 to Technical Specification 3.8.1, "AC Sources-Operating." In Reference (b), the Nuclear Regulatory Commission requested additional information to support their review of Reference (a). Attachment (1) and Enclosures provide the responses to the Nuclear Regulatory Commission's request for additional information contained in Reference (b).

These responses do not change the No Significant Hazards Determination provided in Reference (a). No regulatory commitments are contained in this letter.

Document Control Desk July 12, 2013 Page 2 Should you have questions regarding this matter, please contact Mr. Douglas E. Lauver, Director-Licensing, at (410) 495-5219.

I declare under penalty of perjury that the foregoing is true and correct. Executed on July 12, 2013.

Very truly yours, GHG/PSF/bjd

Attachment:

(1) Response to Request for Additional Information Regarding Enhancements to Diesel Generator License Amendment Request

Enclosures:

1 Engineered Safety Features Actuation System Logic Diagram 2 Transformer and Tap Changer Information cc: CCNPP Project Manager, NRC CCNPP Resident Inspector, NRC Region 1 Administrator, NRC S. Gray, DNR

ATTACHMENT (1)

RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING ENHANCEMENTS TO DIESEL GENERATOR LICENSE AMENDMENT REQUEST Calvert Cliffs Nuclear Power Plant, LLC July 12,2013

ATTACHMENT (1)

RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING ENHANCEMENTS TO DIESEL GENERATOR LICENSE AMENDMENT REQUEST

RAI 1

On Page 2 of Attachment I of the LAR, in regards to SR 3.8.1.8, the licensee stated that the loads under accident and loss of offsite power (LOOP)conditions are sequentially connected to the bus by automatic load sequencers.

Provide a description of the automatic load sequencers with details such as, the number of sequencers providedper diesel generator (DG)or per safety-relatedbus and logic diagrams of the sequencers. Also, provide a table of load sequencing for the LOOP conditions for each DG (similar to Table 8-7 for accident conditions in the Calvert Cliffs Updated FinalSafety Analysis Report).

CCNPP Response 1:

There is one load sequencer per safety-related bus. The logic diagram for the Engineered Safety Features Actuation System is contained in Enclosure 1. This logic diagram includes the logic details for the accident (loss-of-coolant incident, called the LOCI sequencer) and shutdown sequencer. The accident and shutdown sequencers are one module. Different inputs will actuate different portions of the module.

If a Safety Injection Actuation Signal is present with an Undervoltage signal, then the accident function is actuated (six steps). If only an Undervoltage signal is present, then the shutdown function is actuated (three steps).

The table below shows information for the shutdown sequencer similar to the information contained on Table 8-7 in the Updated Final Safety Analysis Report for the accident sequencer.

1ZB 2ZA 2ZB SEQUENCER TIME IZA 2ZA (B SB STEP NO. (SECONDS) SERVICE (BUS 11) (BUS (BUS (BUS

14) 21) 24 0 0T57 Reactor Motor Control Centers 114 104 214 204 Turbine Bearing Oil Pump*(2) 21 IE Battery Chargers l1&14 12&13 22&23 21&24 Transformer for 208/120 Volt 11 12 21 22 Instrumentation Busses Diesel Generator Room Exhaust lB 2A 2B Fan Control Room HVAC Fans 11 12 Control Room Air Conditioning 11 12 Condenser Fans*

Emergency Core Cooling System 11 12 21 22 Pump Room Air Coolers Emergency Core Cooling System 11 12 21 22 Pump Room Exhaust Fans Boric Acid Storage Tank Heaters* Two Two Two Two Heat Tracing System* 11 12 21 22 Diesel Building IA and Auxiliaries IA Switchgear Room HVAC Fans 11 12 21 22 1E Battery Room Fans One exhaust fan and one redundant supply fan Service Water Pump, if previously 11 12 21 22 operating 1 Service water pump if not previously operating 11 12 21 22 I

ATTACHMENT (1)

RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING ENHANCEMENTS TO DIESEL GENERATOR LICENSE AMENDMENT REQUEST SEQUENCER TIME IZA 1ZB (BU 2ZA (BUS 2ZB 2ZBU STEP NO. (SECONDS) SERVICE (BUS 11) (BUS (BUS (BUS

14) 21) 24 2 10 Saltwater pumps 11 12 21 22 Switchgear Room Air Conditioner* 22 2A 20 Computer Room HVAC* 11 12 3 15 Switchgear Room Air Conditioner* 11 12 21 Instrument Air Compressor 11 12 21 22 Control Room HVAC* 11 12 3A 30 AFW Pump 13 23 (i) At time 0 seconds, the generator breaker is closed and the loads listed for the 0-second time step are energized independent of sequencer action.

(2) The loads identified with

• are process controlled. The load feeder breaker will be closed at the time listed but the equipment will not run until called for by the process signal.

(3) There are additional minor loads energized at time 0 not shown in table.

RAI_2:

In regards to SR 3.8.1.8, provide details of any load sequence times outside of the 10% time interval tolerance, which might have occurred duringlastfive years.

CCNPP Response 2:

We have reviewed the Condition Reports for the load sequencers written in the last five years. There were two Condition Reports that documented a failure of a load sequencer time step outside of the 10%

time interval tolerance in the last five years. An installed load sequencer was tested on June 23, 2013.

One of the six steps (step 2) failed to meet the acceptance criteria of 5 seconds + 10%. A replacement sequencer module was installed on June 24, 2013. One of the six steps (step 6) failed to meet the acceptance criteria of 5 seconds + 10%. A second sequencer module was installed on June 25, 2013.

This sequencer module met all of the acceptance criteria. No other failure of sequencer modules to meet the acceptance criteria has been identified in the last five years.

RAI 3

On page 3 of Attachment 1 of the LAR, in regards to SR 3.8.1.11, the licensee stated, "To perform this surveillance test at the most limitingpower factor, the voltage regulators must be placed in the manual mode of operation. This operationalmode means that the safety bus voltage now tracks with the grid voltage swings. This places equipment at greater risk for being impacted by degraded grid voltage for the duration of the surveillance test. Currently, the surveillance test is one hour in duration and the exposure time with the voltage regulators in manual is minimal. With the change to a 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> surveillance test, the exposure time with the voltage regulators in manual is significant. The probability of a grid voltage swing is increasedin a 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period It is not an optimum testingpractice. Therefore, we propose to change the SR by removing the power factor numbers and the associatedNote 2. The surveillance testing will be conducted at the requiredloadsfor a total of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> at the worst case power factor achievable with the voltage regulators in automatic mode. The achievable power factor will depend on the grid conditions duringthe surveillance test but is expected to be approximately 0.9."

Regardingthe above statements, please provide the following information:

a. Explain why the voltage regulatorneeds to be in the manual mode in order to reduce the equipment risk duringthe surveillancetest. Providecatalog cut/operationaldetails of the voltage regulator.

2

ATTACHMENT (1)

RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING ENHANCEMENTS TO DIESEL GENERATOR LICENSE AMENDMENT REQUEST

b. Explain whether the surveillance test can be performed at the power factor limits duringthe 2-hour period by keeping the voltage regulatorsin manual mode of operation,so as to limit the equipment risk to any degraded grid voltage. If yes, provide details ofpower factor test limits corresponding to the kilo-watts (kW) loading during the 2-hour test period.

CCNPP Response 3:

3a - As described below, the 13.8 kV voltage regulators need to be in the automatic mode of operation to reduce risk to safety-related equipment during Unit operation. The only way to reach the reduced power factor required by the current Technical Specification under all conditions is to place the 13.8 kV voltage regulators in manual mode, which increases risk to the associated safety-related equipment.

Calvert Cliffs' electrical distribution design includes 13.8 kV voltage regulators which control voltage on the 4 kV safety-related buses. These voltage regulators can adjust voltage, as necessary, for changes in grid voltage. Therefore, the 13.8 kV voltage regulators ensure the 4 kV safety-related bus voltages remain within acceptable values for various grid voltages. When the 13.8 kV voltage regulators are in the manual mode, the 13.8 kV voltage regulators cannot automatically correct for changes in grid voltage.

Therefore, a 4 kV safety-related bus voltage and its associated electrical distribution system can be adversely affected by grid voltage changes when its associated 13.8 kV voltage regulator is in manual.

When paralleling a DG to the grid, the DG power factor can be adjusted by either changing the DG generator voltage or the 4 kV bus voltage. To increase the DG VARs (i.e., decrease the DG power factor) the DG voltage can be increased or the 4 kV bus voltage can be decreased. Depending on the 4 kV bus voltage at the time of the test, the DG voltage regulator range may not be sufficient to achieve the required power factor. To further increase the DG VARs and decrease DG power factor, the 4 kV bus voltage could be decreased. This can be accomplished by placing the associated 13.8 kV voltage regulator in manual and "stepping" the 13.8 kV voltage regulator down one step. This decreases the 4 kV bus voltage, increases DG VARs, and decreases DG power factor. However, with the 13.8 kV voltage regulator in manual, the 4 kV bus and associated electrical distribution system can be adversely affected by changes in grid voltages.

Therefore, in order to obtain the required DG power factor, plant conditions (bus voltages, DG voltage regulator performance) may require reducing the 4 kV bus voltage. This requires placing the 13.8 kV voltage regulator in manual, which removes the automatic voltage protection to plant electrical distribution systems from grid voltage changes. As requested catalog and operational details of the transformers and tap changers are contained in Enclosure 2.

3b - The main difference between the current one hour endurance test [Surveillance Requirement (SR) 3.8.1.11] and the proposed 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> endurance test is when the test is performed. The one hour endurance test is performed during a refueling outage, during a DG testing window. The associated 4 kV bus is inoperable during this time and placing the voltage regulators in a manual mode has less impact than when the 4 kV bus is operable. The 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> endurance test is performed when the Unit is operating.

The associated 4 kV bus remains operable during the test and the impact to the stability of the operable 4 kV bus is increased when the voltage regulator is in the manual mode. The voltage regulators in automatic mode support the operation of safety-related equipment under degraded voltage conditions.

Even for a two hour period, this exposure to grid voltage changes is not acceptable.

Therefore, we are not able to guarantee that the power factor limits will be achieved during the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> endurance test.

3

ATTACHMENT (1)

RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING ENHANCEMENTS TO DIESEL GENERATOR LICENSE AMENDMENT REQUEST

RAI 4

On page 3 ofAttachment I of the LAR, the licensee describedthe kW loading requirementsfor the DGfor SR 3.8.1.11. Provide a summary of the loading calculationsfor each DGfor both accident and LOOP conditions.

CCNPP Response 4:

The table below provides the loading for each DG during accident conditions. The accidents considered were a main steam line break, a large break loss-of-coolant accident (LB LOCA) and a small break loss-of-coolant accident. For each DG, the LB LOCA was the limiting accident for DG loading. The highest loading for each DG is in bold.

Diesel Generator Accident 1st Minute Pre-RAS Post-RAS On SDC IA DG LB LOCA 3088.0 3205.9 3275.3 3184.2 1B DG LB LOCA 2309.8 2280.3 2350.6 2564.4 2A DG LB LOCA 2310.0 2357.3 2425.3 2591.3 2B DG LB LOCA 2841.3 2831.1 2902.1 2699.6 RAS - Recirculation Actuation Signal. For a LB LOCA, this is assumed to occur at 30 minutes into the accident.

The table below provides the loading for each DG during loss of offsite power (LOOP) conditions. The highest loading for each DG is in bold.

Diesel Accident I"Minute 1-10 10-75 75 Minutes- On SDC Generator Minutes Minutes 4 Hours 1A DG LOOP 2058.7 2799.6 3495.9 3148.9 3027.7 1B DG LOOP 1282.6 1983.2 2359.3 2140.4 2388.1 2A DG LOOP 1310.5 2054.9 2296.4 2076.8 2427.4 2B DG LOOP 1830.2 2450.4 2771.8 2539.5 2474.5

RAI 5

The proposed changes to SR 3.8.1.11 relating to the 2-hour and 22-hour tests, states that, "These test phases may be performed in either order."

Explain how performing the 2-hour test after the 22-hour test demonstrates the capability of the DG to perform its designfinction.

CCNPP Response 5:

As can be seen in the response to RAI 4, sometimes the DG loading is higher at the end of an event rather than the beginning of an event. Therefore, a higher test load at the end of an endurance run can more closely model the bus loading that could be experienced.

Additionally, DG loading includes a prclubricating and warm-up period and a gradual loading period as described in the Technical Specification Bases. It takes approximately 15 to 30 minutes to load a DG to its test band. During the test, no adjustments are made at the lower load which would affect the ability of the DG to operate at the higher load. Therefore, since time to load is not critical, and the ability to 4

ATTACHMENT (1)

RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING ENHANCEMENTS TO DIESEL GENERATOR LICENSE AMENDMENT REQUEST increase to the higher load later is not affected, operating at the lower load first does not affect the higher load test. Also note that wear and tear on the DG may be reduced if operated at the lower load first, thereby reducing the need for tear-down maintenance of the DG.

RAI 6

Provide the operating modes of the plant that the newly proposed SR 3.8.1.17 will be permitted to be performed.

CCNPP Response 6:

New SR 3.8.1.17 will be performed in Modes 5, 6, and defueled.

RAI 7

According to the Standard Technical Specification (STS), NUREG-1432, Revision 4, in Section 3.8.2, "AC Sources - Shutdown, "SR 3.8.2.1; SR 3.8.1. 11 (equivalentto the newly proposedSR 3.8.1.17) is not in the list of SRs which are not applicable,but rather is in the list of SRs in the "NOTE", which are not requiredto be performed. The NRC stafffinds that the exemption for not performing the newly proposed SR 3.8.1.17 should be covered in the "NOTE".

Please explain the deviationfrom the STS.

CCNPP Response 7:

This deviation from the Improved Technical Specifications is based on plant specific criteria approved during the Improved Technical Specifications conversion. Specifically, the new SR 3.8.17 tests the DG automatic start in response to an undervoltage signal [provided by Diesel Generator (DG)-Loss of Voltage Start (LOVS), Technical Specification 3.3.6]. The DG-LOVS is not required to be Operable in Modes 5 and 6, or during movement of irradiated fuel assemblies. As described in Reference 1, the undervoltage instrumentation is only required in Modes 1 through 3. This is consistent with the discussion provided in our application for a license amendment (Reference 2). That letter states that a DG is required during shutdown and refueling to ensure adequate AC electrical power is available to mitigate events such as a fuel handling incident or a loss of shutdown cooling. Due to the reduced pressure and temperature conditions of the Reactor Coolant System during shutdown conditions, these events develop more slowly and the results are less severe than the events which occur at full power. Thus, additional time is available for the operator to evaluate plant conditions and respond by manually operating the engineered safety feature components (including a DG) as required to successfully mitigate the consequences of the event. These discussions support the exclusion of undervoltage signals in Modes 5 and 6, and during movement of irradiated fuel assemblies.

Technical Specification SR 3.0.1 requires that SRs be met during the Modes or other specified conditions in the Applicability, unless otherwise stated. Failure to meet a SR, whether the failure is experienced during the performance of the SR or between performances of the SR, is a failure to meet the Limiting Condition for Operation. New SR 3.8.1.17 includes the requirement to auto start the DG from a standby condition on a loss of offsite power signal. This requires that the DG-LOVS system be Operable. The DG-LOVS system operability is contained in Technical Specification 3.3.6. The Applicability of Technical Specification 3.3.6 is Modes 1 through 4. The DG-LOVS system is not required to be Operable in Modes 5, 6 or during movement of irradiated fuel assemblies. Therefore, it can be taken out of service in these Modes. When it is taken out of service, the requirements of SR 3.8.1.17 are not met, 5

ATTACHMENT (1)

RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING ENHANCEMENTS TO DIESEL GENERATOR LICENSE AMENDMENT REQUEST and the Limiting Condition for Operation is not met. This leads to the need to exempt SR 3.8.1.17 from the list of SRs requirements.

This position is consistent with the current list of SRs exempt in SR 3.8.2.1.

REFERENCES

1. Letter from D. G. McDonald (NRC) to R. E. Denton (CCNPP), dated September 27, 1994, Issuance of Amendments for Calvert Cliffs Nuclear Power Plant, Unit No. I (TAC No. M88168) and Unit No. 2 (TAC No. M88169)

2. Letter from R. E. Denton (CCNPP) to Document Control Desk (NRC), dated November 2, 1993, License Amendment Request: Emergency Diesel Generator Testing 6

ENCLOSURE 1 ENGINEERED SAFETY FEATURES ACTUATION SYSTEM LOGIC DIAGRAM Calvert Cliffs Nuclear Power Plant, LLC July 12, 2013

ENCLOSURE 2 TRANSFORMER AND TAP CHANGER INFORMATION Calvert Cliffs Nuclear Power Plant, LLC July 12,2013

______ _____ ____/5n -o/;--. /o;,3 Service Information

• i COOPER POWER SYSTEMS Power Transformers ftLoad Tap Changing Equipment-Installation, Operation, and Maintenance S210-40-3 Applicable to Type 550C and in particular to Type 550CS Load Tap Changers.

CONTENTS General .......... ........ 1 Shipping .................... 1 Initial Inspection ................. 2 Storage ........................ 2 Preliminary Preparation .......... 2 Installation ...................... 2 Principles of Operation ............ 4 Drive Mechanism .............. 4 Tap Selector ................... 5 Automatic Operation By Voltage-Regulation Relay 6 Operation By Electrical Hand Control ................ 6 Operation By Hand Crank ........ 6 Maintenance .................... 6 Testing For Leaks .............. 8 Neutral-Position Relationship ..... 9 Maximum Raise And Lower Positions .................... 10 Contacts ........................ 12 Contact Erosion Guide .......... 12 Contact Replacement Criteria ..... 12 Movable Arcing Contacts ...... 12 Stationary Arcing Contacts ..... 12 Reversing Movable Contacts .. 13 Reversing Stationary Contacts ................ 13 Trouble-Shooting Guide ........... 14 Replacement Parts ............... 19 Warranty ........................ 19 Exploded Views .................. 20 Figure 1.

Typical McGraw-Edison transformer with LTC equipmenL GENERAL arrangements to the Service Department, This Service Information bulletin The Type 550CS is an improved version McGraw-Edison Power Products, Canons- covers in detail the tap selector and the of the original Type 550C load-tap-chang- burg, PA 15317. drive unit; the controls are covered in ing arcing-tap-selector switch first intro- The LTC mechanism consists of three S210-40-14, Controls for Power-Type duced in 1964 for medium-size trans- major components: the tap selector, the Load Tap Changing Equipment.

formers. drive, and the controls. The tap selector It offers dependable, quiet operation is located in an oil-filled compartment SHIPPING through a normal voltage-regulation welded to the upper section of the trans- The tap-selector compartment is shipped range of plus ten percent and minus former tank. This compartment has an oil- filled with either oil, dry nitrogen gas, or ten percent in thirty-two %-percent steps; tight Pennsylite* panel isolating the tap dry air. It is standard practice for McGraw-other regulation ranges are also available. selector from the transformer. The drive Edison to ship the LTC switch under the They meet appropriate national standards. and the controls are in an air-filled same conditions as the main transformer.

Load-tap-changing arcing-tap-selector weatherproof compartment located To determine the conditions under which switches are designed to be operated. directly beneath the tap-selector com- the LTC switch has been shipped, refer to Occasionally LTC transformers are used partment. Part of the drive is contained in the detailed outline drawings supplied in applications where the LTC is not re- a cast-aluminum housing within the com- with the equipment.

quired and does not operate for extended partment. A universal driveshaft con-Speriods of time. In these situations, it is nects the drive with the tap selector good operating practice to by-pass the through a self-compensating spring-LTC. Refer inquiries concerning by-pass loaded stuffing box in the selector com-partment.

These instructionsdo not claim to cover all details or variationsin the equipment,procedure,or process described,nor to providedirections for meeting every possible contingencyduringinstallation,operation,ormaintenance.When additionalinformation is desiredto satisfy a problem not covered sufficiently for the user's purpose, please contact your Cooper Power Systems sales engineer.

September 1989

• Supersedes 6/85 I

INITIAL INSPECTION 2. Check the tap selector, drive shaft, and Immediately upon receipt of an LTC trans- drive box (Figure 3) to make sure they former--preferably before unloading- are free from foreign objects that could thoroughly inspect the exterior and the interfere with proper operation.

interior of the LTC and the transformer 3. Remove all the blocking from the auto-for damage, rough handling in transit, and matic control panel.

shortage, 4. Check the tap selector and the drive box If initial inspection reveals evidence of for proper neutral-position relationship.

damage, rough handling in transit, and/or Refer to the NEUTRAL-POSITION shortage, notify-and file a claim with- RELATIONSHIP Section.

the carrier at once. Also notify McGraw- If the proper neutral-position relation-Edison Company, Power Systems Divi- ship is not present, notify McGraw-sion, Post Office Box 440, Canonsburg, Edison Company. Power Systems Divi-PA 15317. sion, Post Office Box 440. Canonsburg, D5RAIN AND PA 15317.

All leaks must be located and repaired 1 " PIPE SAMPLING before proceeding with the installation 5. Place the handcrank on the handcrank PLUG VALVE or storage. shaft in the drive box (Figure 4).

Figure 2. 6. Handcrank the LTC through its entire STORAGE Installation of range to make sure there is no me-If. after initial inspection, a transformer is open-breather components. chanical interference and operation is not to be placed in the service-ready con- satisfactory.

dition Immediately, it Is considered to be B. Install the screen and retainer on the Refer to Operationby Handcrankin the in storage. inlet breather pipe. PRINCIPLESOF OPERATION Section.

Refer to Service Information S210-05-5, C. Remove the 1-in. pipe plug from the It is normal for the greatest in-Liquid-Immersed Units-installation and topof the tap-selector compartment. crease in force required to move the Maintenance Instructions. D. install the outlet breather, using a switch to occur in moving the switch suitable thread-sealing compound from neutral to Position 1 raise or from PRELIMINARY PREPARATIONS (GE Glyptol 1201 or its equivalent). Position 1 raise to neutral. It is at these Refer to the PRELIMINARY PREPARA- Note: Switches shiipped prior to 1970 positions that the additional load of TIONS PRIOR TO FILLING Section in utilized a sealed compartment equipped operating the reversing switch is with a 4 psi positive pressure relief de- picked up. Movement of the revers-Service Information S210-10-1, Vacuum vice. McGraw-Edison's recommenda- ing switch also comes into play in mov-Filling Oil-ImmersedPowerTransformers. tion is the open-breathing system. It is ing the switch from Position 2 raise to possible to modify the switch compart- Position 3 raise and Position 1 lower A WARNING ments in the field to incorporate the open to Position 2 lower. In these positions, Before performing any work on the LTC breathing arrangement. Contact Service Department, McGraw-Edison Power the reversing switch contacts are arcing tap selector switch, drive or con- moved from a first position to a second trols, observe the warnings and cautions Systems Division, Box 440, Canons-burg. PA 15317. position on the stationary contact.

appearing in Service Information S210-40-14 and S210-40-18 TAP-SELECTOR COMPARTMENT SAFETY VALVE INLET BREATHER PIPE

1. Vent nitrogen gas or drain oil from the tap-selector compartment.

A. Remove the 1-in.pipe plug from the OIL LEVEL drain-and-sampling valve; drain the GAGE oil from the compartment.

2. Open the tap-selector compartment ARCING door.

3. Inspect the tap selector for physical SW1TCH damage.

4. Inspect the tap-selector compartment for evidence of moisture.

A. If there isany sign of moisture inside the compartment, determine the ex-tent and the manner by which the CONTROL moisture entered and correct the COMPARTMENT condition. DRIVE B.Any moisture detected in the tap- SHAFT AUXILIARY selector compartment must be re- CONTROL moved using clean, dry cloths. DEVICES (MOTOR CONTROL INSTALLATION PANEL)

1. Install the open-breather system on the AUTOMATIC CONTROL tap-selector compartment (Figure 2).

A.Carefully remove the pipe cap from the inlet breather pipe protruding from the bottom of the compartment. DRIVE UNIT PANEL 9

The pipe ma~y contain a small amount of oil that splashed in dur-ing manufacturing or shipping. Figure 3.

Components of LTC mechanism.

2

S210-40-3 "ON POSITION- 8. Energize the motor control panel (wt) moisture content and30kV mini-POINTER (Figure 3). mum in standardgap (ASTM D 877) ft *'ONPOSITION" NDICATOR

/ UNIVERSAL DRIVE SHAFT Eby-step

9. Using the manual control switch, operate the LTC electrically step-through its entire range. 11, or 18 kVminimum in O.040gap(ASTM D 1816).

Close the drain-and-sampling valve, LIMIT SWITCHES Refer to Operdtion by Electrical replacing the i-in. pipe plug.

Hand Control in the PRINCIPLES 12. Refill the tap-selector compartment OF OPERATION Section. with oil to the 25 C level marked on A. Make sure the drive unit and the the oil-level gage.

tap selector are stopping properly 13. Pressure test the tap-selector com-in position and the ON-POSITION partment.

POINTER is centered on the ON- Refer to the TESTING FOR LEAKS POSITION INDICATOR PLATE. (PRESSURE TESTING) Section for If not, refer to the TROUBLE- recommended test procedures.

SHOOTING GUIDE. 14. Operate the LTC approximately 30 B. Make sure the operation counter operations to eliminate any air pockets is functioning properly. that may have developed during re-It not, refer to the TROUBLE- filling.

SHOOTING GUIDE. Refer to the Arcing-Tap Switch-Type C. Check the limit-switch settings Load Tap ChangerSection in Service (Figure 4) by attempting to oper- InformationS210-10-1, Vacuum Filling HAND-CRANK ate the control beyond the limit Oil-Immersed Power Transformers.If SHAFT DRIVE MOTOR position. (The motor should not the transformer has been in storage POSITION operate.) for more than three months, operate INDICATOR If the motor operates, refer to the the LTC for 10 minutes (approximately TROUBLESHOOTING GUIDE. 800 operations) to re-seat, the con-Figure 4. D.Check the handcrank switch by tacts and eliminate any air pockets LTC drive unit. removing the crank from its holder resulting from refilling.

and operating the control switch.

7. Remove the handcrank from the hand- (The motor should not operate.) CAUTION crank shaft; return the crank to its If the motor operates, refer to the The drive motor is designed for inter-holder. TROUBLESHOOTING GUIDE. mittent duty. If the motor is to be SWR10. Test the dielectric strength and mois- operated longer than 10 minutes con-S WARNIN'G ture content of the new oil before tinuously, it must be fan-cooled.

Before performing any work on the LTO filling the compartment.

arcing-tap-selector switch, drive or con- Refer to Service Information S210- 15. Energize the transformer.

trols, observe the warnings and cautions 05-3. The new oil must test at 15 ppm appearing in Service Information S210-40-14 and S210-40-18 REVERSING STUB SHAFT REVERSING FRONT INSULATING PANEL ARM ASSEMBLY i SEGMENT i

• -.PENNSYLITE*

INSULATING REVERSING SWITCH PANEL MOVABLE CONTACT STATIONARY CONTACTS ROLLER PLATES POST INSULATORS MOVABLE CONTACTS REVERSING HORIZONTAL ROLLER DRIVE SHAFT INSULATING DRIVE SECTIONS SCROLL CAM VERTICAL DRIVE SHAFT Figure 5.

Tap-selector assembly. (Shown In neutral position.)

3

PRINCIPLES OF OPERATION Located on the universal driveshaft A* CAUTION Drive Mechanism The drive motor is designed for inter- coupling (36) at the top of the drive hous-The drive with its associated motor- ing (43) is an ON-POSITION pointer.

mittent duty. It the motor is to be Normally, at the completion of each tap corntrol panel is mounted in the control operated longer than ten minutes con-compartment located below the tap- tinuously, it must be fan cooled. change this pointer should be centered selector compartment. Mechanical fea- on the ON-POSITION plate which is tures of the drive unit are shown in attached to the drive housing (see Checks Numerals in parentheses in the following and Adjustments Nos. I and 2 in the Figure 4. discussion refer to Figure 6.

The drive, enclosed in an air-filled, cast- TROUBLESHOOTING GUIDE Section).

The motor (75), through a spur gear aluminum housing, is equipped with self- The pointer being anywhere between the reduction (101 and 99). drives the spur indicating ends of the ON POSITION plate lubricating bearings; the gearing is coated gears(103 and 109). The hand-crank shaft with silicone grease during assembly to indicates that the tap-selector contacts (100) is attached to spur gear (103). Spur are fully in contact.

protect against rust. The limit switches gear (92) drives the universal shaft (38) and seal-in switch are mounted on the through a pair of miter gears (91 and 47).

drive box. Shaft (81) extends through the rear of the A CAUTION A mechanical stop located inside the Before dismantling the drive box, the drive housing and has mounted on it the drive housing prevents operation of the LTC mechanism must be in the neutral seal-in switch operating cam (78). The tap selector beyond the limit positions position (see Neutral-Position Relation-motion of this shaft is transmitted through when hand cranking, or in the event of ship in TROUBLESHOOTING GUIDE a pair of miter gears(78 and 77)and worm-electrical limit-switch failure. Section). Incorrect timing within the gear assembly (49 and 69) to the position The LTC is driven by a 115-Vac, 60-Hz, drive box or between drive and tap indicator and limit-switch arm (58).

single-phase, capacitor-start, capacitor- selector can cause transformer failure.

Upon energization of the motor, the ap-run motor with positive stopping of the proximate time required to complete one drive being achieved by dc braking of the If trouble is suspected within the drive tap change for a 32-step switch is one motor. It is important that the motor has housing, the McGraw-Edison Power Sys-second. For a 16-step switch the time of a well-regulated voltage supply (mea- tems Division transformer service section the change is approximately doubled.

sured at the motor). should be consulted before repair or ad-justment is attempted.

SEAL-IN SWITCH (9

ft 101 9

Figure 6.

Exploded view of LTC drive unit. (For complete parts list, refer to Figure 17 and accompanying table.)

4

____ ____ ___S210-40--3 Tap Selector arcing in oil. McGraw-Edison's recommenda- centrically are the movable-arcing-con-i The tap selector is an arcing-tap-switch tion is the open-breather system to eliminate tact shafts (39 and 37), with movable-type load tap changer. The selector is as much of the acetylene as possible. It is arcing-contact assemblies attached to possible to modify the switch compartments mounted on a Pennsylite insulating panel in the field to incorporate the open breathing insulating supports.

which is oil-tight and isolates the main arrangement. The movable arcing contacts (36) transformer compartment from the tap- Contact the Service Department, McGraw- operate in different planes. The scroll selector compartment. The insulating Edison Power Systems Division, Canonsburg, cam, in moving 180 degrees, moves one panel will withstand full vacuum and Pennsylvania 15317. or the other roller plate, causing the serves as the terminal board for the taps movable arcing contact to be moved from from the transformer winding and the leads Numerals in parentheses in the following one stationary arcing contact (25) to the from the preventive-autotransformer. discussion refer to Figure 7.

one adjacent. At the end of this move-The universal driveshaft enters the tap-ment, the dwell section of the scroll cam selector compartment through a self- is positioned between

& CAUTION two adjacent rollers compensating, spring-loaded stuffing Do not operate the LTC switch when box. The motion of the universal drive-of each roller plate and, because the the transformer is under full vacuum shaft is transmitted through an insulating arcing contact shafts are attached to the condition. roller plates, they are thus locked in coupling (5) to the center phase of the tap position.

The tap-selector compartment is open- selector through a pair of miter gears (21). In the case of a 32-step switch, the breathing. The purpose of an open- one of which is attached to the scroll-cam movable arcing contacts are positioned breathing system is to exhaust the gases shaft. Motion is transmitted to the two on the same stationary contact or adjacent formed by breakdown of the oil by con- end phases through horizontal insulating stationery contacts for each tap change.

tact arcing. These gases can have a plat- shafts (5 and 20). Operation of the end In a 16-step switch, the movable arcing ing effect on copper and copper alloy phases is identical to that of the center contacts are both positioned on the same phase described below.

surfaces which increases contact resis- stationary contact for each tap change.

The motion of the universal driveshaft tance. The compartment is also equipped transmitted The reversing switch changes winding with a safety valve (Figure 2) to exhaust to the scroll-cam shaft causes connections for raise or lower regulation.

the scroll cam (16) to rotate 180 degrees any excessive pressure build up. The reversing switch for each phase.

Note: Switches shipped prior to 1970 utilized in the case of a 32-step switch, and 360 operated as the selector switches pass a sealed compartment equipped with a 4 psi degrees in the case of 16-step switch.

through neutral position, is actuated by a positive pressure relief device. Experience and Every 180-degree movement of the roller projecting from the face of the rear verifying tests revealed that a hard black resis- scroll cam operates one of two roller roller plate.

tive coating could form on copper and copper- plates (57 and 62) which are located on bearing alloy surfaces from polymerization of opposite sides of the scroll cam. Attached acetylene. Acetylene is always produced with to each roller plate and operating con-

/62 Figure 7.

Exploded view of tap-selector unit. (For complete parts list refer to Figure 18 and accompanying table.)

5

Automatic Operation by Voltage-Regulating Relay & WARNING A WARNZNt~

The three revolutions of the hand-crank The transformer must be deenergized MUST be accomplished in 3 seconds before performing any maintenance in-Before performing any work on the LTC spection or work on an LTC. Inspecting and the switch MUST be hand cranked arcing-tap-selector switch, drive, or con- steadily IN ONE DIRECTION ONLY until or working on an LTC mechanism while

[Atrols,WARNING observe the warnings and cautions the ON-POSITION POINTER is cen- the transformer is energized may result appearing in Service Information S210- tered over the ON-POSITION plate. If in bodily injury.

40-14 and S210-40-18. the above instructions are not followed, transformer failure can occur. 2. Energize the control circuit and For automatic operation of the mecha- operate the mechanism by electrical nism, the control instruments, voltage- hand control step by step through regulating relay, and line-drop compensa- A. For each tap change, in the case of a the entire range.

tor must be adjusted for the specific 16-step switch, six revolutions of the A. Observing the position indicator requirements of the system. Refer to handcrank are required. Crank clock- and ON-POSITION pointer, make ADJUSTMENTS Section in S210-40-14, wise to lower and counterclockwise sure the drive unit is stopping Controls for Power-Type Load-Tap- to raise voltage. properly on position.

Changing Equipment. If not, refer to Checks and Ad-With all controls properly set, the load- A WARNING justments Nos. 1 and 2 in the tap-changing mechanism will operate The six revolutions of the handcrank TROUBLESHOOTING GUIDE automatically, giving the proper correc- MUST be accomplished in 6 seconds Section.

tion in secondary voltage as required by and the swich MUST be hand cranked B. Check that the operation counter is the setting of the voltage-regulating relay steadily IN ONE DIRECTION ONLY until functioning.

and line-drop compensator. the on-position pointer is centered over If not, refer to the TROUBLE-the ON-POSITION plate. Ifthe above in- SHOOTING GUIDE Section.

Operation by Electrical Hand structions are not followed, transformer C. Check the limit-switch settings by Control failure can occur. attempting to operate the control For operation of the mechanism by hand beyond the limit position. The control. refer to S210-40-14, "Controlsfor 5. After the tap change is complete, motor should not operate.

Power-Type Load-Tap-ChangingEquip- remove and replace the handcrank in If the motor operates, refer to the ment." With the controls properly set, its holder thus closing the handerank TROUBLESHOOTING GUIDE operate the control switch to either RAISE switch. Section.

or LOWER as desired. 6. Place the LTC motor breaker and re- D. Check the handcrank switch by _____

lay breaker back in the ON position removing the handcrank from its Operation by Handcrank enabling the LTC switch to be oper- holder and operating the control ated electrically. switch. The motor should not oper-A WARNING ate.

McGraw-Edison DOES NOT recom- When it is desired to operate the LTC It the motor operates, roetr to mend hand cranking the LTC mech- mechanism by handcrank for preven- Checks and Adjustments No. 5 in anism while the transformer is tive maintenance with the transformer the TROUBLESHOOTING energized. However, if IN AN DEENERGIZED, the procedure is iden- GUIDE Section.

EMERGENCY SITUATION you choose tical to that described for "operation by 3. Set the LTC mechanism in the neutral to hand crank the LTC mechanism handcrank while the transformer is position by operating by electrical while the transformer is ENERGIZED, energized" EXCEPT for the following: hand control until the position indi-the following procedure MUST be ad- 1. The time required to complete a tap cator on the drive unit indicates neu-hered to. otherwise transformer failure change is not limited. tral (N). See Neutral-Position Rela-can occur, 2. The restriction for hand cranking in tionship Section.

one direction only no longer applies. 4. Remove the 1-in. pipe plug from the

1. Place the LTC motor breaker, located drain-and-sampling valve.

on the motor control panel, and the MAINTENANCE 5. Open the drain-and-sampling valve:

relay breaker, located on the automatic Periodic preventive maintenance in- drain the oil from the tap-selector control panel, in the OFF positions. spection of the LTC mechanism is re- compartment.

2. Remove the handcrank. The removal quired. Generally, the interval between Refer to S210-10-1, Vacuum Filling of the handcrank opens the handcrank inspections is determined by the amount Oil Immersed Power Transformers.

switch in the motor circuit and de- of contact erosion based on the number 6. Open the tap-selector compartment energizes the motor. of tap changes as shown on the opera- door.

NOTE: A handcrank stop prevents the tion counter. The interval between inspec- 7. Inspect the tap selector for physical operator from hand cranking the tap changer through a limit. tions of like LTC mechanisms will vary damage or evidence of moisture.

3. For each tap change, in the case of a considerably depending on individual A. If there is any sign of moisture in-32-step switch, three revolutions. of conditions. For normal utility systems it side the tap-selector compart-the handcrank are required. Crank is recommended that a thorough inspec- ment, determine the extent and clockwise to lower and counterclock- tion of the mechanism be made at the the manner by which the moisture wise to raise voltage. end of the first year of operation and entered.

that subsequent inspections be based on Refer to the TESTING FOR the amount of contact erosion and LEAKS (PRESSURE TESTING) number of tap changes noted at the end Section.

of the first year. B. Any moisture detected in the tap-

1. Deenergize the transformer. selector compartment must be re-moved using clean, dry cloths.

a

S210-40-3

8. Inspect stuffing box (Figure 17, Item Contact assemblies are factory-set on the silver plating can occur, the S27) for evidence of oil leakage. and designed to produce a 10-12 stationary contacts must be re-A. If there is any sign of oil leakage, lb force per contact point. placed.

determine the extent and the To replace the movable arcing NOTE: The silver-plated main dial sta-cause and correct, contacts: tionary arcing contacts are directly Refer to the TROUBLESHOOT- (1) Handcrank the movable con- interchangeable with all previous ING GUIDE Section. model 550C.

tacts to a convenient position

• 9. Check external shaft assembly (Fig- between the stationary arcing To replace the stationary arcing ure 17, Item 25) for freedom of move- contacts or remove the sta- contacts:

(1) Remove the eroded contacts.

ment by sliding the shaft up and down tionary arcing contacts on one slightly to make sure there is no bind- tap position and handcrank the (2) Thoroughly clean all oxidation movable contacts to that posi- from the ends of the stationary ing in stuffing box (27).

It there is binding in the stuffing box, tion. contact spacer tubes and refer to the TROUBLESHOOTING (2) Remove the eroded main mov- mounting supports.

Scotch-Brite No. 44 7 or No. 448 GUIDE Section. able arcing contacts.

is recommended for cleaning

10. Thoroughly flush and, using clean, (3) Install the new movable arcing dry cloths, remove all carbonization contacts, using flatwashers, copper surfaces.

which may be deposited on insulat- locknuts, and shouldered (3) Install the new stationary arcing ing surfaces. We recommend flushing mounting bolts, positioning the contacts, holding them against with transformer oil but do not object bolt heads next to the thrust the mounting bolts toward the to the use of oil-base solvents. piece as shown in Figure 15. outside of the stationary con-

11. Close the drain-and-sampling valve, tact bolt circle to establish proper alignment. See Fig-replacing the 1-in. pipe plug. CAUTION ure 16.

12. Place the LTC motor breaker (on the When installing main movable arcing 16. Inspect the non-arcing reversing mov-motor control panel) and the relay contacts, it is essential that zero pres- able contacts (Figure 16) for mechani-breaker (on the automatic control sure be maintained in the main trans- cal wear.

panel) in the OFF position. former tank to establish proper align- NOTE: Earlier models shipped prior to

13. Remove the handcrank from its holder. ment with the main stationary arcing February 1975 utilized a reversing switch Removal of the handcrank opens the contacts. design which because of the timing with handcrank switch in the motor circuit Do not overtighten the mounting the main dial would have arcing occurring and deenergizes the motor. A hand- bolts. Overtightening these bolts will on reversing stationary contact No. 1. At crank stop prevents the operator crack the main insulating arm in the that time the reversing stationary contacts S from handcranking the tap selector area of the bolt holes. were tipped with a copper tungsten mate-through a limit. rial to withstand the effects of arcing. The

14. Place the handcrank on the hand- NOTE: Mounting bolts are shouldered, so that, movable contact tips which engage the when properly assembled as shown in Figure stationary contacts were also of a copper crank shaft in the drive box. tungsten or silver tungsten material. The

15. Inspect the arcing contacts (Figure 15, the thrust piece will move between the bolt heads and the main insulating arm to com- slot in the reversing segment was a 12 and 13) for arc erosion. straight slot as shown in Figure 16.

In an arcing-tap-switch-type LTC pensate for misalignment of the stationary and In 1975 we began using a reversing mechanism, the tap selector performs the movable arcing contacts.

segment as shown in Figure 16 with an (4)Handcrank the LTC slowly a dual function: Tap selection and through its entire range around offset slot to delay the reversing movable preventive-auto (switching-reactor) contact coming off the stationary contact the dial to make sure there is allowing the main dial contacts to interrupt switching. Since the tap-selector also clearance between the lower switches the preventive auto, the tap the current eliminating the arcing on re-spring pins and the slipring and versing stationary contact No. 1. This per-selector contacts are subject to arc the upper spring pin and the mitted the use of silverplated stationary erosion. Arc-resistant materials are stationarycontact while on con- contacts and coin silver movable contacts.

used in both the movable and the tact and while sweeping to When updating the reversing switches of stationary contacts. Erosion rates and adjacent contacts. older units you must replace the reversing patterns are functions of the tap volt- (5) Return the LTC to the neutral stationary contacts, reversing neutral age, the load current, and the preven- position.

stationary contact, movable contact as-tive-auto design. sembly and reversing insulating arm Refer to the NEUTRAL-POSI- assembly. See Figure 5.

Figure 14 shows typical contact TION RELATIONSHIP Section.

erosion patterns. The stationary arc- The reversing movable contacts ing contacts normally erode more B. Inspect the stationary arcing con- are subject to mechanical wear, not slowly than the movable arcing con- tacts (Figure 13) for arc erosion. arc erosion. When the initial gap be-using a small inspection mirror to tween the movable contacts wears to tacts because many tap positions thoroughly examine the backs of (stationary arcing contacts) are en- 9/32 in., the contacts should be re-the contacts. placed. The contact assemblies are countered by the movable arcing The point of replacement of sta-contacts during their service life. factory-set and designed to produce tionary arcing contacts is shown on a 10-12 lb force per contact point.

A. Inspect the movable arcing con-the right in Figure 14. To replace the reversing movable tacts (Figure 12) for arc erosion. Stationary arcing contacts are sil-The point of replacement of mov- contacts:

ver plated to reduce the possibility A. Handcrank the LTC so that the re-able arcing contacts is shown on the left in Figure 14. of high-resistance oxidation which versing movable contacts are mid-impedes current flow, adding to way between the reversing station-If contacts are not replaced at this point, thermal instability at the con- thermal instability at the point of ary contacts.

tact interface will result, followed contact. When the arcing tips S. Remove the.worn reversing mov-by thermal failure of the contact. erode to the point where burning able contacts.

C. Install the new reversing movable contacts.

7

D. Handcrank the LTC slowly through Testing for Leaks A CAUTION at least two positions on either side (Pressure Testing)

When installing reversing movable of neutral to make sure there is A pressure test of the tap selector cornt-contacts, it is essential that zero pres- clearance between the reversing partment is recommended any time a gas-sure be maintained in the main trans- stationary contacts and the upper keted device is removed or replaced former tank to establish proper align- spring pin of the reversing mov- which may leak oil out of or moisture into ment with the stationary contacts. able contacts. the switch compartment. Either one of the E. Return the LTC to the neutral posi- following methods is recommended:

(1) Make sure the centerlines of tion.

Method 1 the reversing stationary con- Refer to the NEUTRAL-POSITION With the transformer deenergized, the tap tact, the reversing movable con- RELATIONSHIP Section. selector compartment door sealed and tact assembly (thrust piece), 18. Make sure all fasteners, lockstrips, the inlet and outlet of the open breather and the reversing neutral sta- and electrical connections are tight system sealed:

tionary contact coincide (Fig- and secure. 1. Fill the tap-selector compartment with ure 16). 19. Handcrank the LTC step-by-step oil.

(2) Handcrank the LTC slowly through its entire range to make sure 2. Hold the oil under 5 psi max pressure through at least three posi- there is no mechanical interference for several hours.

tions on either side of neutral and that all the new contacts have Monitor the pressure closely because to make sure there is clear- been properly installed. a change in ambient temperature can anoe between the lower sprng 20. Return the LTC to the neutral posi- easily cause a drastic change in pres-pins of the movable contact tion. sure.

assembly and the reversing Refer to the NEUTRAL-POSITION 3. Dust blue chalk powder on areas of neutral stationary contact and RELATIONSHIP Section. suspected leakage.

the upper spring pins of the 21. If the same oil is to be returned to The chalk will turn dark when wet with movable contact assembly and the tap-selector compartment, filter oil.

the stationary contacts. and test the oil.

Make sure that the reversing The oil must test 26 kV minimum in Method 2 insulating arm is not rubbing on standard gap (ASTM D 877) and 25 With the transformer deenergized, the tap the face o the reversing neutral ppm (wt) maximum moisturecontent. selector compartment door sealed, and stationary contact. 22. Close the tap-selector compartment the inlet and outlet of the open breather (3) Return the LTC to the neutral door. system sealed:

23. Refill the tap-selector compartment 1. Maintain a nitrogen pressure of ap-position.

Refer to the NEUTRAL-POS!- with oil to the 25 C level marked on proximately 4 psi.

T/ON RELATIONSHIP Section. the oil-level gage. 2. Paint a soap-bubble solution such as Refer to S210-10-1, Vacuum Filling glycerine and liquid soap on the

17. Inspect the non-arcing reversing sta- Oil-ImmersedPower Transformers. welded and gasketed joints to disclose tionary contacts (Figure 16) for me- 24. Pressure test the tap selector com- leaks.

chanical wear. partment. Alternative to painting with a soap-The reversing stationary contacts are Although each LTC mechanism is bubble solution. Seal the unit under silverplated to reduce the possibility subjected to pressure tests for leaks the gas test pressure for a period of of high-resistance oxidation which before leaving the factory and pres- hours while monitoring for loss of impedes current flow, adding to ther- sure testing is recommended again pressure.

mal instability at the point of contact. before the open-breathing system is The reversing stationary contacts are PRESSURE TEST OF installed and prior to placing the unit TAP SELECTOR PANEL subject to mechanical wear, not arc in service for the first time, another erosion. When the silver plating has A pressure test of the tap selector panel pressure test is recommended prior to check the integrity of all the gaskets worn off in the path of the reversing to placing the unit in service after forming seals between the tap selector movable contacts, the stationary con-performing maintenance. compartment and the transformer is rec-tacts should be replaced. Refer to the TESTING FOR LEAKS To replace the reversing stationary ommended any time a gasket is replaced (PRESSURE TESTING) Section for or the oil level in the LTC compartment contacts: recommendedtest procedures.

A. Handcrank the LTC so that the re- increases with no apparent reason.

25. Operate the LTC for 10 minutes (ap- With the transformer de-energized and versing movable contacts are mid- proximately 800 operations) to seat way between the stationary con- the selector compartment drained and the contacts and eliminate any air opened:

tacts. pockets resulting from the oil filling.

B. Remove the worn reversing sta- 1. Wipe down selector panel with clean Refer to the Arcing-Tap-Switch-Type dry cloths.

tionary contacts. Load Tap ChangerSection in Service C. Install the new reversing stationary 2. Apply 3 psi min., 5 psi max. pressure Information S210-10-1, Vacuum Fill- to the transformer tank.

contacts. ing Oil-Immersed Power Trans- 3. Check for oil seepage at gasketed formers. points.

& CAUTION When installing reversing stationary & CAUTION contacts, it is essential that zero pres- The drive motor is designed for inter-sure be maintained in the main trans- mittent duty. If the motor is to be oper-former tank to establish proper align- ated longer than 10 minutes continu-ment with the reversing movable con- ously, it must be fan-cooled.

tacts.

26. Energize the transformer.

a

S210-40-3 Neutral-Position Relationship A position relationships are established.

Whnevetran-Whenever anyomponRelationsheLTC component of the i CAUTION Incorrect timing within the drive box The main movable arcing contacts of the selectorswitch are centered on stationary mechanism is disassembled or re- or between drive and tap selector can contact N and the reversing switch mov-assembled, the mechanism must be in cause transformer failure, contactsan revonstion cotact the correct neutral-position relationship. . able contacts are on stationary contact eremoving any component. This 10. The reversing roller must be in the Before re component t his neutral-position relationship is slot of the segment and set 20 degrees match mark the component and its tablished when a the position indicator is to the right of the vertical centerline as mating part so that they can be re- on N (neutral) and the ON-POSITION viewed facing the front of the arcing tap assembled in proper alignment. POINTER of the drive mechanism is cen- switch.

tered on the ON POSITION plate. Refer to Figure 8. The following other neutral-The On-Position Pointer must be cen-tered on the On-Position Plate. The On-Position Pointer being anywhere between the arrows of the On-Position Plate indi-cates that the selector movable contacts ON POSITION are on the stationary contact.

POINTER PIN ON POSITION-PLATE "MECHANICAL---- lX~ ,,,

STOP SECTION (INTEGRAL TO DRIVE HOUSING)

MECHANICAL STOP P STOPSECTION GEAR ON GEAR SECTION 'C-C' NEUTRAL POSITION RELATIONSHIP OF MECHANICAL STOP PINION AND MECHANICAL STOP GEAR REVERSING STATIONARY CONTACT NO.1 REVERSING STATIONARY CONTACT NO. 10 / MAIN STATIONARY ARCING CONTACT NO. 9 REAR MAIN MOVABLE MAIN MOVAOLE ARCING ARCING CONTACTS "Y" CONTACTS REAR INDEXING ROLLER PLATE (ACTUATES FRONT MAIN STATIONARY MAIN MOVABLE ARCING ARCING CONTACT CONTACTS -Z-)

REAR COLLECTOR NO. 2 FRONT INDEXING ROLLER

'RING "Y" PLAE (ACTUATES REAR REVERSING ROLLER MAIN MOVABLE ARCIN CONTACTS "Y) 1I*

ATTACHED YO REAR ROLLER PLATE SCROLL CAM FRONT COLLECTOR FlING "Z'

--I ,t h SWITCH MOUNTING PANEL i'=

SOLATING SWITCH FROM

...... lAIN TRANSFORMER MAIN AND REVERSING MOVABLE RELATIVE POSITION OF DRIVE CONTACTS OF ARCING TAP SHOWN SHAFT SPLINE TO CENTERLINE IN NEUTRAL POSITION IN NEUTRAL POSITION WITH CURVED INDEXING SECTION OF SCROLL CAM CENTERED ON TOP Figure 8.

Neutral-position relationship of tap selector and drive unit 9

Maximum Raise and Lower the limit switch slightly before the seal-in change in the position of the movable arc-Positions switch (see switch-sequencing charts; ing contacts. Refer to Figure 9.

There are 48 full turns of the handcrank from the neutral position to either maxi-mum position. In the maximum position, Figure 10 for 16-step switch, Figure 11 for 32-step switch). The mechanical stop will become engaged during the 49th turn of o

the limit switch and seal-in switch open: the handcrank; however, there will be no REVERSING SWITCH MOVABLE REVERSING SWITCH MOVABLE CONTACTS ON REVERSING CONTACTS ON REVERSING STATIONARY CONTACT NO. 10 STATIONARY CONTACT NO. 1 BOTH MAIN MOVABLE

'ARCING CONTACTS CENTERED ON MAIN STATIONARY ARCING CONTACT NO. 2 BOTH MAIN MOVABLE ARCING CONTACTS CENTERED ON MAIN STATIONARY ARCING CONTACT NO, 9

'REVERSING ROLLER ARCING TAP SWITCH SHOWN IN MAXIMUM ARCING TAP SWITCH SHOWN IN MAXIMUM LOWER POSITION (16 LQ(TYP ALL THREE PHASES) RAISE POSITION (16 R) (TYP ALL THREE PHASES)

STOP SECTION STOP SECTION IN DRIVE IN DRIVE HOUSING HOUSING STOP SECTIi ON GEAR MECHANICAL STOP POSITION INDICATOR MECHANICAL STOP IN POSITION INDICATOR IN DRIVE UNIT SHOWN SHOWN IN MAX. LOWER DRIVE UNIT SHOWN SHOWN IN MAX. RAISE ENGAGED. SWITCH IN POSITION (16 L) ENGAGED. SWITCH IN POSITION (16 R)

MAX. LOWER POSITION (16 L) MAX. RAISE POSITION (16 R)

MAXIMUM LOWER POSITION MAXIMUM RAISE POSITION Figure 9.

Maximum-position retationship.

S21 0-40-3 Y

LOWER c RI- RAISE POSITION F DESIGNATIONS 1

2 II 3 I iim I

i 9

I mi~ miiinimi~

10 I

11 I

12 I 13 1

14 I

15 I

16 1

F i7 RAISE LIMIT SWITCH r

~II 760 +/-100' 1 I im Iinin mi~i -A I I I 750 +/-100 LOWER LIMIT SWITCH SEAL-IN

?r¶1i1,,r 4SWITCH I I I 20I - ° I I I NOTES: 3. One complete turn of handcrank

1. Sequence expressed in degrees rota- rotates main drive shaft 60°.

tion of main drive shaft. 4. Solid lines indicate span of contact

2. 3600 rotation of main drive shaft is closure, contacts are open at other required for one tap change. positions.

Figure 10.

Switch sequencing chart for 16-step switch.

-J LOWR . RAISE POSITION z DESIGNATION 2 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 N 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 1 _ 1 1] 1I 1 1 1 1 1I 1 I___I I I I L I I I I I I I RAISE UMIT SWITCH LOWER LIMIT SWITCH th750 +/ I111 1

SEAL IN-IYTTIJ [ - WI 1 NOTES:

1. Sequence expressed in degrees rota- 3. One complete turn of hand crank tion of main drive shaft. rotates main drive shaft 600

2. 18su rotation of main drive shaft is 4. Solid lines indicate span of contact required for one tap change. closure, contacts are open at other positions.

Figure 11.

Switch sequencing chart for 32-step switch~.

I1

0l Figure 12.

Movable arcing contact.

LOCKNUT SPACER (BETWEEN SHOULDER WASHER SOLT AND INSULATING NOTE: WASHER MUST ARM) (ITEM 72. FIGURE 181 BE PLACED BETWEEN NUT AND INSULATING ARM MAIN STATIONARY ARCING CONTACT FIgure 13. CONTACT SPACER Stationary arcing contact. TUBE MOVABLE ARCING STATIONARY ARCING CONTACT CONTACT MAIN MOVABLE ARCING CONTACTS NEW CLEARANCE SILVER PLATING UPPER SPRING PIN ARCING INSERT THRUST PIECE MOVABLE ARCING CONTACT BOLTS MOUNTING (NOTE ARC EROSION LAT LOCATIONS OF SOLT HEADS)

INTERMEDIATE LOWER SPRING PIN CLEARANCE MAIN INSULATING ARM ARC EROSION HAS PRO-GRESSED TO A POINT WHERE BURNING CAN OCCUR ON THE SILVER PLATING REPLACEMENT /MAIN RPCMN TRANSFORMER

~/'MINIMUM V's,,* IfM N I U

-. SLIP R IN G CENTERLINES OF COMPLETE ASSEMBLY LJAJ PENNSYLITE INSULATING PANEL Figure 14.

Typical 550CS Figure 15.

contact erosion patterns. Movable arcing, stationary arcing, and slip ring assembly.

12

S210-40-3 CENTERLINE OF REVERSING83

• STATIONARY CONTACT.

REVERSING MOVABLE CONTACT ASSEMBLY (THRUST PIECE).

AND REVERSING NEUTRAL STATIONARY CONTACT

!o\ S

/o\

t S*

SLOT REVERSING ' SLOT SEGMENT Modified reversing Original reversing NEUTRAL STATIONARY SUP RING segment segment (with offset slot) (with straight slot) o'-

MAIN DIAL STATIONARY CONTACT STATIONARY CONTACT MOUNTING BOLT -- . ý /

MAIN DIAL STATIONARY CONTACT APPLY PRESSURE SNOTE: TWISTED CONTACTS CAN INTERFERE WITH THE MOVABLE NOTE: WHEN ASSEMBLING MAIN DIAL STATIONARY CONTACT SPRING PINS. CONTACTS MAINTAIN PRESSURE AGAINST THE CONTACT MOUNTING BOLTS TO ESTABLISH PROPER CONTACT ALIGNMENT.

Figure 16.

Reversing movable and revesring stationary contact assembly.

13

TROUBLESHOOTING GUIDE If any difficulty is experienced with the & WARNING operation of the LTC switch, it is important to note and record the following informa-tion for reference.

Before performing any work on the LTC arcing tap selector switch, drive, or con-trols, observe the warnings and cautions 0

1. The position of the switch at time of appearing in Service Information S210-incident. 40-14 and S210-40-18.

A. By position indicator.

B. By ON-POSITION pointer (see Fig-ure 8). Normally the ON-POSITION pointer is centered on the ON-POSITION plate at the completion of a tap change.

2. The direction the switch was moving at time of incident.

3. Was switch on automatic or manual control?

4. Check the motor supply voltage. The voltage should be 115 volts, measured at terminals 55 and 57 or 56 and 57 at the terminal block mounted on the side of the drive box. (See Figure 17).

5. The transformer serial number from the transformer nameplate.

TROUBLESHOOTING GUIDE Problem Concition Solution Improper manual operation Tap changer does not respond to of LTQ. Raise-Lower switch.

Tap changer operates in one direc-Refer to the Troubleshooting Guide in Service Information S210-40-14 Load-0 tion only or operates erratically. Tap-ChangingControls.

Tap changer makes more than one step at a time.

Improper automatic operation Tap changer runs to full boost posi-of LTC. tion, but operates properly manually.

Refer to the Troubleshooting Guide in Se-T Tap changer runs to full buck position, vice Information S210-40-18 Load-Tap-but operates properly manually. Changing Controls Tap changer overruns position and/or hunts.

Switch failure to complete a tap change. Motor breaker did not trip. 1. Check for loss of control power.

2. Check for improper operation of seat-in switch. Refer to LTC tap sequencing chart Figure 10 for 16-step unit and Figure 11 for 32-step unit.

3. Check for incorrect or defective motor breaker. Refer to chart.

4. Check controls-refer to Service Infor-mation S210-40-18.

(continued next page) (continued next page) 0 14

S210-40-3 TROUBLESHOOTING GUIDE (Continued)

Problem Condition Solution Switch failure to complete a tap change. Motor breaker did not trip. 5. Check relays (continued) (continued) a. For freedom of operation.

b. Forloosescrewsfastening relaycom-ponents. If loose screws are found, remove screws one at a time and reinstall with loctite.

c. For foreign material lodged in con-tacts.

d. For deteriorated contacts-consider length of service and effect of en-vironment.

e.Check motor windings and capaci-tors-refer to chart (Figure 17).

Switch failure to complete a tap change. Motor breaker did trip. 1. Check time of operation of the motor.

The motor is designed for intermittent duty, and should not be operated in excess of ten minutes without forced cooling.

2. Check for switch binding Check the main drive shaft at the point it exits the drive control com-partment to be certain there is no Interference between the main drive shaft rain shield and the compart-ment. If there is interference move the drive box assembly.

3. Check motor. windings, capacitor and breaker. Refer to chart Figure 17.

4. If binding or jamming is suspected in the tap selector switch, deenergize the transformer, drain and open the switch compartment to inspect the switch.

5. Check the movable contacts for jam-ming.

a. Check that the movable contact spring pins, both main dial and re-versing switches are not rubbing on the stationary contacts or slip rings.

It is suggested that an inspection mirror be used.

NOTE: The switch must be operated to position 3 raise and 2 lower to properly Check the reversing switch.

b. Check that all stationary contacts.

both main dial and reversing switch are properly positioned relative to the center of the contact circle.

(Refer to Figure 16).

NOTE: This condition can occur at the time the tap leads are connected to the contact studs on the transformer side.

twisting the entire contact assembly it the contact assembly is not properly sup-ported on the switch side, A similar condition can alsooccur at the lime replacement stationary contacts are installed if they are not held against the contact mounting bolts toward the out-side of the stationary contact bolt circle to establish proper alignment. Refer to (continued next page) (continued next page) Figure 16.

15

TROUBLESHOOTING GUIDE (Continued)

Problem I Condition Solution Switch failure to complete a tap change. Motor breaker did trip. c. Check that the main dial and revers-(continued) (continued) ing switch movable contacts are in alignment with the stationary con-tacts. Hand crank the switch while observing the contact alignment with an inspection mirror.

d. Check the reversing switch for tight-ness at the reversing pivot shaft.

NOTE: Units shipped prior to August.

1982 do not have tapered roller bearings supporting the reversing pivot shaft. In particular, these units should be checked to ensure there Is no galling of metal be-tween the reversing segment and scroll cam mounting bracket casting. Also check for galling between the reversing arm assembly and scroll cam mounting bracket casting. If it is necessary to re-move the reversing segment to verify a galling condilion or to correct the condi-tion by polishing, be sure to mark the reversing segment and pivot shaft so they can be reassembled exactly as removed.

e.Check the main dial contacts, both stationary and movable for any un-usual or blunt erosion pattern that could make it difficult for the mov-able contact to slide onto the station-ary contact. Replace the contacts.

NOTE: This type of blunt erosion pattern results when the movable contact stope off the stationary contact but close enough to arc.

f. Check the clearance between the rear insulating arm and rear slip ring.

With zero pressure maintained in the transformer tank and only the head of oil acting on the insulating panel, the clearance should be approxi-mately Yainch.

NOTE: For procedure to obtain this di-mension contact McGraw-Edison Co.

Service Department, P.O. Box 440, Canonsburg, Pa. 15317.

g. Check the main drive shaft through the stuffing box for binding by sliding the drive shaft up and down slightly.

If there is binding of the shaft or oil leakage in the stuffing box use following procedure.

Numerals in parentheses refer to Fig-ure 17.

1. Remove input shaft assembly (5):

a. Disengage snapring (1) from ex-ternal shaft assembly (25), mark the snapring groove on shaft (25), and slide the snapring toward the cou-pling ball.

b.Remove rollpin (26) from drive-shaft subassembly (36).

c. Slide external shaft (25) down to-ward drive box (82) until input shaft (25) can be removed.

(continued next page) (continued next page) 116

S210-40-3 TROUBLESHOOTING GUIDE (Continued)

Problem Condition Solution Switch failure to complete a tap change. Motor breaker did trip. 2. Match-mark the components of the (continued) (continued) upper universal coupling end of drive-shaft subassembly (36) and the shaft so that components can be reassem-bled in exactly the same place if they come apart

3. Match-mark components of follower assembly (33) and stuffing box (27) so that components can be reassem-bled in exactly the same place.

4. Loosen bolts (35) securing follower assembly (33) to stuffing box (27),

S. Remove external shaft assembly (251 and washer (14).

6. Remove bolts (35) and lockwashers (34) that secure follower assembly (33) to stuffing box (27).

7. Using a blunt instrument, carefully (to avoid damaging the packing) remove the stuffing box components.

a. Female packing (32).

b.V packing (31).

c. Male packing (30).

d. Washers (14).

e. Spring washers (29),

8. Polish external shaft assembly (25) to remove any burrs or-sharp edges.

9. Check the inside of stuffing box (27) for burrs and sharp edges. polish to remove any found.

10. Be certain that the bearing in the stuffing box is not extending into the stuffing box. Ream the bearing with with a 0.877 dia straight reamer.

11. Lightly lubricate external shaft as-sembly (25), mate packing (30), V packing (31), and female packing (32) with petrolatum (vaseline).

12. Place washer (14) on external shaft assembly (25).

13. Reinstall external shaft assembly (25) in stuffing box (27).

14. Reinstall spring washers{29). washers (14). male packing (30). V packing (31), and female packing (32) on ex-ternal shaft assembly (25) in the se-quence shown in Figure 17.

CAUTION When placing packing on the external shaft assembly, handle the packing with extreme care to avoid damaging I the packing.

(continued next page) (continued next page) 17

III I IIIII[I I ,, , , ,I ,I I TROUBLESHOOTING GUIDE (Continued)

Problem Condition Solution Switch failure to complete a tap change. Motor breaker did trip. 15. Reinstall follower assembly (33),

(continued) (continued) using bolts (35) and lockwashers (34),

but do not tighten the bolts.

16. Align follower assembly (33) and stuffing box (27), matching the marks made when disassembling.

17. Tighten bolts (35) securing follower assembly (33) to stuffing box (27).

A CAUTION While tightening the bolts, rotate and move external shaft assembly (24) up and down to prevent binding when the bolts are secured.

18. Slide external shaft assembly (25) into driveshaft subassembly (36) until input shaft assembly (5) can be rein-stalled.

19. Reinstall input shaft assembly (5).

20. Align the holes in external shaft assembly (25) and drive shaft sub-assembly(36) and reinstall rollpin (26).

21. Reengage snapring (1) in the same groove on external shaft assembly (25) from which it was removed.

22. Make sure all fasteners, lockstrips.

and electrical connections are tight and secure.

Operation counter. Operation counter not functioning Check the counter terminations and properly. associated circuitry Drive runs into mechanical stop. Motor operates beyond maximum Make sure the maximum position limit position. switch is open just prior to the LTC reach-ing the maximum position.

a. Check for a faulty limit switch

b. Using an Allen wrench, adjust the switch internally for proper operation.

Handcrank switch. Motor operates when the handcrank Make sure the handcrank switch opens is removed from its holder. when the crank is removed from the holder.

a. Check for a faulty handcrank switch.

b. Check the switch for sticking or me-chanical obstruction.

Seal-in switch. Drive box pointer is not centered 1. Check for a faulty seat-in switch.

on ON-POSITION plate. 2. Loosen the two mounting bolts and realign the seal-in switch.

NOTE- For setting seal-in switch refer to LTC lap sequencing chart-Figure 10 for 16-step switch and Figure 11 for 32-step switch.

0i 18

. . ... ....... . .......... . ......... 210-40-3 REPLACEMENT PARTS Limited Parts Warranty (Refer to Figures 17 and 18.) McGraw-Edison warrants to the original Few spare parts are required for the LTC purchaser that type 550CS load tap mechanism: however, it is recommended changers shipped after August 1, 1982 that a few select parts be kept on hand are free of defective workmanship and for prompt replacement if needed. The materials, This warranty commences on parts recommended for spares are indi- the date of arrival at destination and cated in the replacement parts list. covers any defects and malfunctions of Each replacement parts list is keyed the load tap changer except those caused to the related exploded view drawing and by improper installation, improper main-the item numbers correspond to the ex- tenance, improper operation, customer-ploded view callout numbers. furnished materials, alterations executed To ensure prompt receipt of the correct by customer or vandalism.

part the following informaton must be sup- Type 550CS LTC Parts are warranted as plied to McGraw-Edison when ordering. follows:

1. The transformer serial number and the Silver Contacts-five years or 75.000 op-type of LTC switch. This information is erations, point of re-specified on the transformer nameplate. placement as described NOTE: Specification of type of LTC switch in figure 14 S210-40-3; on the transformer nameplate began in cost prorated per % of 1972. time or operation.

2. Specify the bulletin number and date, Mechanism- 500,000 operations.

figure, item number, description, and Control-five years.

quantity required.

Example:

To order item 54 on the Drive unit.

Transformer Serial

1. C- Type 550CS LTC S210-40-3, September 1982 Figure 17 Item 54-Limit Switch-2 each.

19

This drive mechanism for ille types 550G and 550CS are identical. However, molor, capacitor and motor-breaker packages have c*hanged as shown in the following tablo.

Motor-. Motor Braking Winding Motor MotorSuppller Capacitor BMoteer Year 1967 and Model Number Ohio Motor Model 915-23X-4909 Size (mfd) 100 Size (amps) 6 Fuse (amps)

Resistance (ohms - 10%)

2.5 Drawing Number B219444 0

See Custom Motor Design Schematic 1982(2) Model 615-01-0602 100 6 Drawing 2.8 SLB00012A Custom Motor Design For 1983(2) Model 700-01-0606 100 7 Particular 2.6 SL800028A Unit Century Elec 1988(2) 8-168935-01 175 7 0.9 SLB0281 A (1) Supplier discontinued manufacture of these models.

(2)This motor, capacitor and breaker package can replace all preceding packages providing proper modiflication is made to the motor control circui*ry.

II a change In motor package Is deemed necessary be sure to furnIsh the transformer serrial number (see transformer namdplale) to the Service Department. McGraw-Edison Power Products, Canonsburg, PA 16317. F N- 12 8

1 1y~

48,, 61 P37

,.t

ý64 53 28-e 29~

116s 104 141) 117 q 30-0 119- OWARNING 11 120 m McGra-Edson 31 OCa3 not recom-mend hand c*Afk,

,ng wnile the Ileansfor'er IS energizecs See instruction book 11 3- 4 TO change 0O31-NiOnduring main.

tenancC nPiano-crank until Ihe on 0o0ition Dointe, is cenlered o0der the LO on-Dos'lion plate o

Figure 17.

Exploded view of LTC drive unit.

20

S210-40-3 4

Parts List--LTC Drive Unit (Figure 17)

Item DItem Item No. Description INo Description NO. Description 1 Snap Ring 37 Roll Pin 79 Screw 2 Washer 38 Drive Shaft 80 Seal-In Switch 3 Drive Shaft 39 Bolt (1 req'd) 4 Coupling 40 Lockwasher 81 Spur Gear Shaft 5 Insulating Drive Shaft Assy. 41 Snap Ring 82 Drive Box 6 Coupling 42 Washer 83 Terminal Block 7 Drive Shaft 43 Drive Shaft Support 84 Screw 8 Gear 44 Screw 85 Geneva Pinion 9 Bearing Assy. (X) 45 "On Position" Plate 86 6 Spacer 10 Lockwasher 46 Spline Tube 87 Spur Gear 11 Gear Support 47 Drive Gear 88 Spline Tube Assy.

12 Cam Mounting Brkt. 48 Roll Pin 89 Washer 13 Cam Spacer 49 Gear 90 Spur Gear 14 Washers 50 Worm Shaft 91 Drive Gear 15 51 Bolt 92 Spur Gear 16 Cam 52 Mounting Bracket 93 Washer 17 Drive Shaft 53 Spacer 94 Lock Strip 18 Bearing Assy. (X) 54 Limit Switch (2 req'd) 95 Snap Ring 19 Bolt 55 Screw 96 Roller Assy.

20 Insulating Drive Shaft Assy. 56 Worm Gear Shaft 97 Pin 21 Gear 57 Roll Pin 9B Roll Pin 22 Inner Race &Needle Bearing 58 Limit Switch Cam 99 Motor Pinion 23 Washer 59 Indicator Mounting Bracket 100 Spur Gear Shaft 24 Input Shaft 60 Spring 101 Spur Gear 25 Input Shaft 61 Roll Pin 102 Washer 26 Roll Pin 62 Dial Plate 103 Spur Gear 27 Stuffing Box 63 Spacer 104 Spur Gear Shaft 28 Bearing 64 Pointer 105 Geneva Segment 29 Wave Washer 65 Pointer 106 Spacer 30 Male Adapter 66 Spacer 107 Spur Gear 31 Packing 67 Pointer 108 Spline Tube 32 Female Adapter 68 Roll Pin 109 Spur Gear 33 Follower Assy. 69 Worm 110 Spur Gear 34 Lockwasher 70 Roll Pin ill Drive Box Cover 35 Bolt 71 Brass Tube 112 Bolt 36 Drive Shaft Assy 72 Gear Shaft 113 Screw 73 Shaft Support 114 Caution Plate D ___p 74 Bolt 115 Caution Plate Caution. 75 Motor 116 Bolt 8efw>e dsnm.9nh1nJd~,ve bo LTC n hgmso n'.,

76 Gasket 117 Rubber Washer be 4. NEUTRAL POSMTON 77 Miter Gear 118 Rubber Washer

e. ,nst,uctobn book.

IlneofreCl llmvng wIhmf drtve 78 Seal-In Cam Assy. 119 Washer ig 2 bo- 01 belween Wt~e Jnd Seleelor Sf lttCS ran Cauee 120 Locknut -j Nx)lap selectors shipped atter August 1 1982 are provided with bearing assemblies items 9 and 18.

K) 0 2t 21

/Typical assembly.

TERMINAL 1 9

Figure 18.

Exploded view ol tap selector.

22

S210-40-3 Parts List--Tap Selector (Figure 18)

Recoin- Recom-RoNo Description mended lStock ended Item Iter S tock No. Description Nut 54 49 Support Stud Jam Nut 50 Front Insulating Panel Belleville Washer 51 Spanner Nut Ring 52 Scroll Cam Collar Mounting Bracket Collar Pin 53 Roll Pin Locknut Gasket (B) 54 Reversing Segment Washer Collar 55 Bolt Gasket Rear Slip Ring 56 Thrust Bearing Assy.(X)

Panel Nut 57 Rear Roller Plate Insulating Tube Washer Assy.

Pins Main Movable 58 Snap Ring Gasket (A) Contact Assy. 59 Collar Collar Rear Shaft Assy. 60 Roll Pin Stationary Contact Less Contact Assy. 61 Shaft Support Support Bolt 62 Front Roller Plate Reversing Stationary Front Shaft Assy. Assy.

Contact Less Contact Assy. 63 Snap Ring Lock Strip Bolt r64 Lock Strip Shoulder Stud Lock Strip 65 Bolt Bolt Front Slip Ring .66 Lock Strip Snap Ring Bolt 67 Stud Assy.

Insulating Tube Spacer 68 Connection Bar Pin Reversing Movable 69 Bolt Collar Contact Assy 70 Nut Stationary Contact Reversing Assy. 71 Shoulder Bolt Support Less Contact Assy. 72 Spacer Insulating Tube 73 Washer 0-20 Collar 74 Belleville Washer 75 Thrust Bearing Assy.(X) 76 Bearing Assy. (X)

Buna-N synthetic rubber gaskets can be obtained ftrm E. F. Houghton &Co. (compound IOV70-VIX-SYN., series AN-6227) or Parker Seal Co. (compound N2 19-70).

tA) Recommended size is 2% inch O.D., 11%ID.. and IN, inch dia.

11) Recommended size is 1"N inch O.., 1i1 inch I.D.. and % inch dia.

(X) Tap selectors shipped after August 1. 1982 are provided with bearing assemblies items 56. 75, and 76.

70 61

,63 23

/S70/5J--02 10a4- Service Information COOPER P~WER SYSTEMS Power Transformers W Load-Tap-Changing Automatic Controls S210-40-14 CONTENTS GENERAL ............................ 1 Automatic Control Panel ............... 2 Manual Operation .................... 2 Autiomatic Operation .................. 2 Components ....................... 3 Setting ................. ........... 4 Une-Drop Compensator ............... 5 Voltage Sensor ...................... 6 Troublehooting Guide For New Equipment ................. 8 Urmited Parts Warranty ................ 11 GENERAL The LTC control is divided into two basic components-the automatic control de-scribed in Service Information S210-40-14 and the tap changer motor control de-scribed in S210-40-18.

The automatic control panel is shown in Figure 1. Service Information S210 14 and S210-40-18 describes the standard features for automatic control of Mcgraw Edison load tap changing transformers.

To operate the load tap changer, the wiring schematics that accompany each transformer must be consulted before making the power supply connections, T_

BREAKER CAUTION Incorrect supply voltage could dam-NORMA# CONTROL SWITCH4ES TEST age drive, motor or controls. Refer I REACTANCE~ REMOTE MANUAL RAISE TERMINALS to wiring schematics which accom-pany each transformer.

LuV9SE AL AUTO OwER To operate the load tap changer in the automatic mode, it is necessary to connect a potential transformer between the regu-lated lineaand the automatic voltage sens-ing circuit. The potential transformer (nor-mally supplied by the user) must have a Figure 1. secondary which operates in the 1tO-130-Automatic control panel. volt range. Proper polarity relationship must be maintained between the potential transformer and the internal, load-sensi-tive, line-drop compensator current trans-lormer. Refer to the schematic drawings that accompany the transformer before connecting the potential source to the input connections. To energize the voltage sensing circuit, place the CONTROL CIR-CUlT BREAKER in the ON position.

These instructionsdo nor claim to cover all detailsor variationsin the equipment,procedure, or process descrbed, nor to provide direcions for meeting every possible contngency during installation, operation, or maintenance. When additionalinformation is desired to satisfy a problem not covered sufficiently for the user's purpose, please contact yourCooper Power Systems sales engineer.

May 1989

• Supercedes 6/86 I

CHASSIS-FRONT VIEW CONTROL PANEL-REAR VIEW Figure 2.

Typical automatic control panel wiring.

AUTOMATIC CONTROL PANEL When more than one lap change is neces- 2. Loosen the four locking screws on the,,d The automatic control panel includes sary. holding the RAISE-LOWER switch in knobs above the control switches. ___

solid-state voltage sensing and timing the appropriate position until just before 3. Place the AUTO-MANUAL switch in -

devices used in conjunction with mechan- the tap changer reaches the desired tap the MANUAL position and the REMOTE-ical output relays to initiate the operation position causes the tap changer to operate LOCAL swilch in the LOCAL position.

of the lap changer motor operating panel. in a sequential mode. Releasing the RAISE- 4. Set the TEST RHEOSTAT control at The voltage sensing device is factory cali- LOWER switch and allowing it to return to zero (0).

brated. The specific voltage level and the OFF (center) position permits a short 5. Set the VOLTAGE LEVEL control to bandwidth adjustments are obtainable by time delay and enforces motor brake the desired voltage.

using calibrated control knobs which can operation. 6. Set the BANDWIDTH control to the be locked in place..Unless otherwise spec- NOTE: The manual operation of the load tap preselected value-ified, the controls are designed for 60-Hz, changer isnot affected by or related toany of 7. Set the LINE-DROP COMPENSATOR ac operation with an accuracy classof bet- the other components on the automatic con- (LDC on control panel). REACTANCE trol panel. and RESISTANCE controls at zero (0).

ter than Class 1. Except for the motor breaker, all of the controls for both manual Automatic Operation (Alter the calibration check, these and automatic operations are mounted on Before attempting to place the load tap controls should be set at the calculated the front of the automatic control panel. levels.)

changer in the automatic mode oi operation, The motor breaker is located on the motor 8. Place the MOTOR BREAKER on the the motor control power and the automatic operating panel. motor operating panel in the ON posi-voltage sensor potential source must be con-tion. See S210-40-18.

nected and energized. (Refer to the wiring 9. If the voltage level and bandwidth are schematic for each specific transformer). to be checked with a voltmeter, con-Manual Operation To place the load-tap-changing equip- nect the meter to TEST TERMINALS G The bottom section of the automatic control ment in the automatic mode, all related and A.

panel contains four toggle switches, three control settings must be predetermined 10. Place the CONTROL CIRCUIT of which are used to select and direct man- and selected. BREAKER in the ON position. Wait ual or automatic control of the load tap Individual circuits and controls relating approximately 15 minutes beforepro-changer (Figures 1 and 2). With the RE- to the automatic operation are covered in ceeding, to allow warm-up.

MOTE-LOCAL switch in the LOCAL posi- the COMPONENTS for automatic control It the vollage level and bandwidth are tion and the MANUAL-AUTO switch inthe panel section. To clarify the automatic not going to be checked with a volt-MANUAL position, the load tap changer operating procedure, a control setting meter, operate Ihe load tap changer can be operated in the manual mode by checklist follows: in the manual mode until the LOWER4 actuating the momentary RAISE-LOWER 1. Place the CONTROL CIRCUIT test light in energized-then proceed Wo switch in the desired direction. BREAKER (8-90) Figure 2 in the OFF to checking the bandwidth as out-position. lined in 11 E.

2

S210-40-14

11. If the voltage level and bandwidth are F Secure BAND LEVEL and BAND- 7. CONTROL SWITCHES. Three control going to be checked with a voltmeter. WIDTH controls by tightening their switches mounted in the lower section the TEST RHIEOSTAt control can be locking screws. of the automatic control panel provide a used to advantage: G. Check operation of time-delay re- selection of the following operations A. Operate the load tapchangerin the lays by rotating the TEST RHEO- and modes of the load lap changer:

manual mode until the voltmeter STAT control and noting the time remote. local, automatic, manual, raise.

reads as close as possible to the differential between the test light off. and lower.

desired band center , 3 volts. ignition and dimming, (Output relay A. To operate the load tap changer B. Place the MOTOR BREAKER in the closure causes test light to atten- from within the cabinet in either the OFF position and pull the dual fuse uate.) Each time-delay relay is fac- automatic or manual mode. the holder (located on the motor oper- tory set for a 30-second time delay. REMOTE-LOCAL switch must be in ating panel) out of its retaining See instructions for rime-delay the LOCAL position. To operate the block. SeeS210-40-18. relays undet COMPONENTS for load tap changer from a remote C. Set the TEST RHEOSTAT control automatic control panel before point, the REMOTE-LOCAL switch to a value which equals the voltage changing the setting. must be in the REMOTE position.

increment above the desired band H. Return the TEST RHEOSTAT con- Auxiliary auto-manual and raise-center obtained in Step 11 A. trol to zero (0) and secure its lock- lower switches must be supplied by Example: ing screw. the user when operating from a To obtain a desired band center of 120 I, Set the appropriate LINE-DROP remote point.

volts: COMPENSATOR setting. (See Step 8. To operate the load tap changer (1) Operate the load tap changer in the Sand instructions under Line-Drop from within the cabinet in the manual manual mode until the voItmeler Compensator.) Secure the LOC mode or to deactivate local auto-reads as close as possible to the RESISTANCE knob locking screw, matic operation, place the AUTO-desired band center +3 volts. J. Replace the dual fuse holder and MANUAL switch in the MANUAL a, Nearest voltage obtainable is move the MOTOR BREAKER to the position. To operate the load tap 123.5 volts. ON position. changer in the local automatic mode,

b. Therefore. 123.5 - 120 -- 3.5 volts, K. After completing the preceeding place the AUTO-MANUAL switch in (2) Place the MOTOR BREAKER in the steps, move the AUTO-MANUAL the AUTO position, OFF position and putl the dual fuse switch to the AUTO position and C. The RAISE-LOWER switch is used holder out o1 its retaining block. the load tap changer will respond to to operate the load tap changer in (3) Set TEST RHEOSTAT control for the automatic control mode. the local manual mode. The switch is 3.5 volts. equipped with a center OFF and two Components D. It necessary, adjusl the VOLTAGE momentary ON positions. Making

1. CONTROL CIRCUIT BREAKER. A

.EVEL qgntrQl VnI!j neither the momentary contact in the up direc-single-pole. tip-ffee breaker provides RAISE nor the LOWER test light is tion for RAISE or down for LOWER ON-OFF. short-circuit and overload lit. For the most accurate setting. will cause the load tap changer to protection for the control panel.

center the control between the two move one step at a time. Ifmore than

2. TEST TERMINALS. Two test terminals points where the RAISE and LOWER one tap change is required. holding facilitate connecting a voltmeter during lest lights are lit. the momentary contact in the desired calibration tests.

NOTE, Al the lime the band level and direction will permit sequential the bandwidth are being adjusted. the 3. VOLTAGE-REGULATING RELAY. A operation.

make and break points of both the solid-state, adjustable voltage sensor

8. TIME-DELAY RELAYS, Two adjustable raise and the lower Circuits dilter by permits the selection of a band level time-delay relays (one for RAISE. one approximately 0.5 volt. This ditleren- between 105 and 135 volts. The BAND-for LOWER) are in the circuit between hal is a seat-in feature furnished to WIDTH control permits the selection of the voltage-regulating relay and the tap assure the positive making of the con- a bandwidth of from 1.5 to 7.5 volts.

tacts at the extremities of the band- changer motor control. These relays

4. TEST LIGHTS. Two test lights incor-width. provide a selection of time delays from porated in the time-delay circuits pro-E. Check the bandwidth by rotating to to 90 seconds. Unless otherwise vide a visual indication of the conduction the TEST RHEOSTAT control in specified, the relays are factory-set for occurring within the voltage regulating both directions and observing the 30 seconds, relay.

dial voltage differential between the To change the setting, insert a small S. LINE-DROP COMPENSATOR. The line-points where the RAISE and LOWER screwdriver (preferably a '.-in.-diameter drop compensator, complete with test lights come on. handle) in the potentiometer screwdriver reverse-reactance switch, variable-Example (continued from 11C): slot and rotate clockwise to increase or reactance and variable-resistance con-

• Assume BANDWIDTH control counterclockwise to decrease the lime trols, facilitates the regulation of the has been preset to 3 volts. delay. Changing of potentiometer settings leeder at a point remote from the trans-

" Voltnteter (if used) reads 123.5 will show resistance to movement because former and provides for reverse react-volts. of a mechanical drag which has been ance paralleling.

" TEST RHEOSTAT control set at placed on the shaft to prevent accidental

6. TEST RHEOSTAT. The fine-adjustment 3.5 volts. movement. Total rotation is about 300 test rheostat facilitates the determina-

" BAND LEVEL control set at 120 degrees and can be observed by relating tion of the bandwidth even though a volts. the slot position relative to the graduations variable external power source may not

" Rotate surrounding the shaft (Figure 3).

in bothTEST RHEOSTATcontrot directions: LOWER test be available.

light comes on at two volts:

&t CAUTION RAISE lest light comes on at five To prevent potentiometer damage, do volts. not use a large screwdriver or force the

• Therefore. 5 - 2 = 3 volts band- settings at the extreme ends of the width. range.

3

NOTE: Potentiometer must be securely CIRtC UIT mounted Hold potentiometer while tighten-ing mounting nut. Bottom section ol shaft lock must be locked against potentiometer mounting nut, Top section of shaft lock is to SHAFT be pulled snug enough to make it necessary LOCKING to use a small screwdriver to adjuSt the DEVICE potentiometer. (Screwdriver--Stanley 1010 or equivalent). TOP SEC TION-SHAFT LOCK

'POT SHAFT VIEW A-A TIME DELAY LED MOUNTED ON SAME SIDE AS FOIL Legend LED Light emitting diode (TEST LIGHT)

R1 5600. 1/2W R2 1.5KO. 1/2 W R3 100KO. 1/2 W R4 Pol. 2.5M" C1 100 MFD. 25V 0 400V. 1A CIRCUIT BOARD Figure 3.

Physical representation of time-delay relay circuit board.

Time-delay settings can be measured without operating the tapchanger. Put the auto-manual switCh in the MANUAL posi-POT TRANSF BY OTHERS 1R 02 = 03 T1I 40 02 TDC 03 tion and observe the time interval between ZE-- j-vM>

the light ignition and the point when the light goes dim due to the closing of the output relay.

Setting 8.88/5 0-0.2 When setting from an independent source, AMPRCTS the automatic control panel should be energized by a variable source connected toTerminals 10 and G, Figures 2 and 4.

A CAUTION Make sure that the normal potential source is not connected to I0-G before connecting an external source. If the external power source is grounded, the source and ground terminals on the panel must be phased out or the inter-nal ground on the control panel must be removed. (Refer to wiring diagram for ground connections.) Before ener-gizing the independent power source.

pull the dual fuse holder on the motor operating panel and make sure that 90 Solid-state voltage sensor both the CONTROL and MOTOR TR Time-delay RAISE TL TIme-delay LOWER BREAKERS are in the OFF position. 8-90 Control breaker RCTB 8.66/5-0,2-amp CT RCTA 0.2-O.O1-amp CT APT Aux pwr transformer ARA Arrester Figure 4.

Automatic voltage regulation scheme.

4

S21 0-40-14

1. Connect an ac voltmeter to TEST It reverse reactance compensation is current transformer. The second-TERMINALS G and A. required, move the NORMAL REACT- aries are so interconnected that. with

2. Loosen the four locking screws on the ANCE-REVERSE REACTANCE swilch rated Current flowing in each prim-knobs above the control switches. on the front panel to the REVERSE REACT- ary. 10 ma will flow in the line-drop

3. Place the AUTO-MANUAL switch in ANCE position. compensatorcircuit This 10-ma cur-the MANUAL position and the REMOTE- To determine proper settings required rent will be properly phased for use LOCAL switch in the LOCAL position. for the line-drop compensator, it is neces- of a line-to-line potential transformer

4. Set the TEST RHEOSTAT control at sary to understand the principle of line- which is connected as shown on the zero (0). drop compensation. The principle involved load tap changing schematic dia-

5. Set the VOLTAGE LEVEL control for consists of connecting a resistance-react- gram.

the desired level. ance network in series with the voltage- 2. Calculate line resistance and reactance.

6. Set the BANDWIDTH control for the regulating relay input. Current from an 3. Calculate line-drop in resistance volts total desired bandwidth. internal current transformer is passed and reactance volts as the products of

7. Set all three LINE-DROP COMPEN- through the compensator, producing a Step 1 times Step 2.

SATOR controls at zero (0). voltage drop which is opposed to the ap- 4. Divide the values obtained in Step 3 by

8. Place the CONTROL CIRCUIT plied potential. the potential transformer ratio.

BREAKER in the ON position. Since the current is proportional to the 5. Set the dials of the line-drop compen-

9. Adjust the source voltage until neither feeder current and, if the resistance and sator equal to the values obtained in test light is energized. Wait approxi- the reactance of the compensator are pro- Step 4. The dials, calibrated in volts, are mately 15 minutes before proceeding. portional to those of the feeder from the labeled RESISTANCE and REACT-

10. To check band level and bandwidth. transformer to the desired point, the volt- ANCE VOLTS, adjust the source voltage and record age at the voltage-regulating relay input Example: Consider a delta-connected the voltmeter readings at the levels will drop by an amount proportional to the transformer supplying one mile of where the raise-lower test lights are feeder voltage drop to that point. This will feeder to a point for which resistance energized. If required, the VOLTAGE cause the load tap changing mechanism and reactance compensation are re-LEVEL and BANDWIDTH controls can to adjust its voltage to maintain a constant, quired. The line is a 2 0. 20-in. equiva-be adjusted slightly to obtain the exact selected voltage at the predetermined lent spacing line which has a resistance bandwidth and level desired. point. of 0.41 ohm and a reactance of 0.60 NOTE. At the time Ihe band level and the The remote point, often called the load ohm per mile.

bandwidth are being adjusted. the make center. should be selected with great care. If the currenttransformerfor the line-and break points o0both the RAISE and It may be an actual point on the feeder the LOWER circuits differ by approxi- drop compensator has a primary rating where the main trunk branches out in a o1300 amps. the feeder line currentwill mately 0.5 volt. This ditferential prod uces a seal-in leature to assure the positive star-shaped pattern in the center of the be -,/3times 300 or 520 amps.

making of the contacts at the extremities feeder's territory. it may also be a fictitious The line drop will be 520 times 0. 41 or o0 the bandwvidth. point recurrent about the middle of each 213 volts resistance and 520 times 0.60

11. After having obtained the exact band feeder branch so that it represents an or 312 volts reactance.

level and bandwidth required, secure average condition existing over a wide If a 20:1 potential transformeris used the TEST RHEOSTAT. BAND LEVEL. area, to step the Output voltage down for use and BANDWIDTH control knobs by The line-drop compensator circuit with the voltage-regulating relay. the tightening the locking screws. employed by McGraw-Edison is designed line-drop compensator settings would

12. Check TIME-DELAY relay settings by to operate at 10 ma and has been equipped be 213 divided by 20 or 10.7 volts re-adjusting the source voltage and re- with an intermediate current step of 0.2 sistance and 312 divided by 20 or 15.6 cording the time differential between amp to accommodate provisions for the volts reactance. The nearest dial set-test light ignition and dimming. (Out- circulating current method of paralleling tings on the line-drop compensator put relay closure causes test light to with existing load tapchanging equipment. would be 11 resistance and 16 react-attenuate.) Each time-delay relay is To determine the settings for the line- ance. Generally. it is desirable to com-factory set for 30-second time-delay. drop compensator: pensate for the drop in distribution See instructions for time-delay relays 1. Determine the feeder line current that transformers and secondary service.

under COMPONENTS on automatic will provide 10 ma to flow in the line- Increase these calculated values ac-control panel before changing settings. drop compensator circuit. For the var- cordingly to compensate for this addi-

13. Set the LDC REACTANCE and RE- ious winding outputs described below. tional drop.

SISTANCE controls for the calculated see the connection diagram nameplate values. (See Line-Drop Compensator A. For wye-connected output windings & WARNING section for calculating procedures.) with one current transformer for line-If any work is to be done on the line-Secure the LDC RESISTANCE control drop compensation, this value will be drop compensator portion of the knob locking screw. the primary current rating of the current transformer for line-drop com- control circuit while the transformer pensation. is energized, care must be exer-Line-Drop Compensator cised so that the secondary circuits The line-drop compensator is supplied B, Fordelta-connected output windings.

with one resistance control and two react- this value will be V-3 times the pri- of the current transformers are not ance controls, furnishing resistance and mary rated current of the current accidentally opened. The current reactance compensation up to 24 volts in transformer for line-drop compen- transformers must be short-circuited either, or both, elements. The resistance sation, at the short-circuiting device in the compensation is continuously variable C, For wye-connected output windings drive-and-control compartment be-from 0 to 24 volts; the reactance compen- with two current transformers for fore any work begins.

sation is variable in both 1- and 5-volt steps line-drop compensation (each hav- Accidental opening of the current to a total of 24 volts. ing a secondary rating of 5.0 amps). transformer circuits will cause a the feeder line current will be equal dangerously high voltage to appear to the primary current rating of either across the opened circuit.

S

Voltage Sensor Operational amplifier OP1 compares the level control. Trimming (calibrating) re-The solid-state vdltage sensing relay in- voltages across R8 and Z3. If the Z3 volt- Sislor R30 is used to match individual volt-corporated in this automatic control cir- age exceeds the R8 voltage. OP1 output age sensors to the preselected voltage lev-cuit utilizes a temperature-compensated. swings positive causing the OP2 output to els for which the band-level control has cascaded Zener diode reference voltage go positive and furnish the turn on gate been calibrated. Compensating resistor (Eacross Z3) compared to a portion of the voltage for SCRi. It the R8 voltage ex- R9 is a factory-set potentiometer used to input voltage (E across RB) to furnish the ceeds the Z3 voltage. OPt output swings compensate forsmall value changes in Z3.

intelligence required to select one of three negative causing the OP3 output to go R5. R6. R7. and R8 and still permit setting possible relay output modes. positive and furnish the gate voltage for the sensor null input voltage within the Conduction through silicon-controlled SCR2. A rheostat (bandwidth control) permissible range, A 24-volt input to Ter-Rectifier #1 (SCR 1) indicatesthat the input connected between T5 and T6 desensi- minals T3 and T4 furnishes the power voltage T I-T2 is not of sufficient magni- tizes OP1 input, thereby providing a vari- supply for the OP amps and the regulated tude to provide a voltage across R8 which able band between the voltage level inputs reference voltage.

equals the reference voltage across Z3. which cause OP1 output to change. Re- The schematic diagram, parts layout, Conduction through silicon-controlled sistor R11 fixes the minimum bandwidth and component identification are shown Rectifier #2 (SCR2) indicates that input obtainable. ResistorsR t 7and R22 furnish in Figures 5 and 6.

voltage T1-T2 exceeds the magnitude a small feedback voltage to OP2 and OP3 required to produce a voltage across RB after their output swings to provide a hys-which equals the Z3 reference voltage. A teresis action (seal-in feature) to the Out-lack of conduction through either SCR1 or put circuits. Resistor R29 is a shunt re-SCR2indicates that the input voltage Tl- sistor selected to bring the sensing-circuit T2 is at the proper level to produce a match input current to a value which permits the between the voltages across R8 and Z3. use of a standard rheostat for the voltage E1 7<1 3-C

,TopX l) VIEW 4

OPt, OP2. OP3 CONNECTION DETAIL Figure 5.

Schematic of voltage sensor.

6

S210-40-14 Hem i Value 8 'IB 2 ............ -........... . . Bridge rectifier R i* . .. . . .. . .. . .. . .. . .. . .. . . I.. .. ... I(0). 'bW R 2 ....... °........................ 2000* 2.5W 2KM. 1,5W A3 . .R. R 5........ .................... 3300), 1.5W t1 ,R4

. .. .. ...... ... ... ... ... ... .... 470. '/?W R6, R7.............................. 13KG, 3W R 8 .. . . . . .. ... . .. .. . .. .. .. . .. ... .. 4,7KG. 3W R ll .. . . . . . .. .. . .. . . .... .. . .. . .. .. Pot, 10KO n il ........... ....... .. ...... .. .. 500O, '/AW 81 R . ............................ 1200. Y*W 82KO. 'kW R 14, A 15. Il18. R919, R 20. R23. R 26 ...... 10K. %W R16. R21. R24. A2? ..................

4.7K". 1W A122 .............................. 39KG. "*W 8 29 .............................. 33K-50K (selected)

Pot. 5KG R W ........................ ....... 20 MFD. 75V CI, ............................... 2OMFD, 250V C2 t r ug . .. 1.................... 5 MFD. NP, 25V 0.1 MFO, 200V ZP8 Z2 ............................ 400V. IA 12V. 1W Z3 . .......................... .... 8 4V (temperature compensaled)

OP1. OP2. OP3 .......

SCRI . SCR2 ....................... OP amps Silicon controlled reclifier Figure 6.

Physical representation of voltage sensor circuit board.

7

TROUBLESHOOTING GUIDE For Equipment Built After 111182 AUTOMATIC OPERATION OF LOAD TAP CHANGER Trouble Solution Tap changer runs to full boost position, 1. Check for open circuit in VOLTAGE SENSOR circuit by checking volt-but operates properly manually, age between terminals T1 &T2 on voltage sensor card. Shouldbe approximately 80 Vac. (See VOL TAGE SENSOR TROUBLESHOOTING Refer to Service Information S210-40-18. GUIDE).

2. Check for open circuit in TEST RHEOSTAT, VOLTAGE LEVEL, LDC resistance controls, R1-R2 winding on LDC reactor, etc.

3. Check for defective voltage sensor. (See VOLTAGE SENSOR TROUBLE-SHOOTING GUIDE).

4. Check for sticking relay on RAISE time-delay relay circuit board.

Tap changer runs to full buck position 1. Check for high input voltage by checking voltage at the test terminals.

but operates properly manually. 2. Check for defective voltage sensor. (See VOLTAGE SENSOR TROUBLE-Refer to Service Information S210-40-18.

Tap changer overruns position and/or SHOOTING GUIDE).

3. Check for sticking relay on LOWER time-delay relay circuit board.

1. Check manual operation for overrun. If LTC overruns, see section 4D hunts. covering manual operation.

2. Check time-delay relay dropout time.

Relays should drop out within one second after test light goes out.

Refer to Service Information S210-40-18. 3. Check BANDWIDTH. Should be at least 1.25+ volts for 32 step opera-tion and 2.5+ volts for 16 step operation when connected for indepen-dent operation. Add minimum of .25 to .5 volts respectively for current balance parallel operation.

4. If using current balance type paralleling check connections for crossed wires and proper polarity.

5. If using current balance type paralleling, check sensitivity of setting.

The LDC reactor provides 3 levels of sensitivity. Use 300 turn connec-tions (600-900 terminals) for narrow bandwidth. 600 turn connections (0-600 terminals) for medium bandwidth or 900 turn connection (0-900 terminals) for wide bandwidth setting.

Tap changer operates properly manually 1. Check positions and integrity of automatic control panel CONTROL but will not operate automatically. SWITCHES and CONTROL CIRCUIT BREAKER.

2. Check potential source of terminals 10 & G (See Figure 2).

Refer to Service Information S210-40-18. 3. Check for open circuit in sensor auxiliary power source by checking voltage between terminals Ta and T4 on voltage sensor card. Should be approximately 24 Vac. If "0" volts check 11 to G and 12 to G. Should be approximately 120 Vac (SeeFigure2).

4. Check for open circuit in time delay relay source by checking voltage between terminal D4 on the delay relay cards and T7 on the voltage sensor card. Should be approximately 12 Vac. I1no voltage appears check voltages from 14 and 15 to 8 at terminal strip on cabinet back-wall. Should be 12 Vac. (See Figure2).

5. Check for open circuit in BANDWIDTH CONTROL and associated wiring. (See Figure 2).

6. Check for detective VOLTAGE SENSOR. (See VOLTAGE SENSOR TROUBLESHOOTING GUIDE).

LINE DROP COMPENSATOR Trouble Solution Both reactance and resistance compen- I, Check external current transformer and potential transformer wiring.

sation work backwards. (Polarity must be as shown on wiring diagrams which were furnished with the transformer.)

2. Check auxiliary current transformer wiring. (RCT-A and RCT-B located on LTC control box backwall.) (Polarity must be as shown on wiring diagrams furnished with the transformer.)

Resistance compensation works 1. Check load power faclor. If load power factor is leading, increase in properly, reactance compensation works load should cause negative reactance action.

backwards. 2. Check wiring of RI and R2 leads on LDC reactor and wiring of REVERSE REACTANCE switch. (Polarity must be as shown on wiring diagrams furnished with transformer.)

8

S210-40-14 TROUBLESHOOTING GUIDE (Continued)

For Equipment Built After 111182 W VOLTAGE SENSOR Make certain that the theory of voltage sensor and automatic operation is understood. Read voltage sensor operation, page 6, and automatic operation, page 2.

Trouble I Solution RAISE test light energized all of the 1. Check for open R30, R5, R6, R7, B2. Dl, D2, and/or Z3.

time; LOWER test light will not light 2. Check for defective OP1.

3. Check C2 and/or B2 for short.

LOWER test light energized all of the 1. Check for open R8, R9. R29, and/or Zi.

time; RAISE test light will not light. 2. Check for defective OPI.

3. Check Z2 and/or Z3 for short.

Neither test light can be energized. 1. Check for defective auxiliary power transformer.

2. Check for open B1, R1, and/or R2.

3. Check BI and/or C1 for short.

4. Check for defective OP1.

5. Check for open BANDWIDTH control.

Both tests lights energized. 1. Usually due to a failure in either the RAISE or the LOWER side of the circuit board when the input is calling for the opposite mode of opera-tion. (See the RAISE and LOWER troubleshooting solutions above.)

2. If the recheck of the RAISE and LOWER troubleshooting solutions indi-cates that both RAISE and LOWER circuits are defective, check for multiple failures of SCRi and SCR2. OP2 and OP3, or a combination of the two failures.

VOLTAGE SENSOR VOLTAGE READINGS The following readings are given as a A The Voltage Chart readings should guide to use when troubleshooting a volt- CAUTION appear on the voltage sensor circuit board age sensor. All readings are taken using a If an external source is used, discon- with a sinusoidal power source of 120 Vac, high-impedance voltmeter (preferably dig- nect the normal source and make cer- 60 Hz, applied to terminals 10 and G, the ital) with the voltage sensor mounted in tain that the source ground lead is BANDWIDTH, TEST RHEOSTAT, and the control panel under conditions speci- connected to G. L D.C. control knobs in their fully counter-fied. All readings are dc unless otherwise clockwise positions, and with the VOLT-specified, Top and bottom voltage ref- 8. Set the VOLTAGE LEVEL control at a AGE LEVEL control set in a position where erences relate to the physical locations on point where both test lights are deen- both test lights are deenergized (120 Vac).

the voitage sensor circuit board. ergized. If this is not possible or, if the NOTE: With the translormer energized and VOLTAGE LEVEL control setting is the normal potential transformer connected more than 5 volts different than the to Terminals l0 and Gin the LTC control box. voltmeter reading, set the VOLTAGE

1. Place the AUTO-MANUAL control LEVEL control at the voltmeter reading, switch in the MANUAL position.

2. Place the LOCAL-REMOTE control VOLTAGE CHART switch in the LOCAL position. Terminal 1 to Terminal 2 ...................................... 80 Vac +/-1

3. Set the TEST RHEOSTAT and BAND- Terminal 3 to Terminal 4 ...................................... 24 Vac i1 WITH controls at zero (0). Line A (-) to Line 0 (-) ....................................... 24 volts +/-10%

4. Set all three LDC controls at zero (0). Bottom (.,) Z3 to Top (-) Z3 .................................. 8,4 volts *-5%

5. Connect a voltmeter to TEST TERMI- Top (*) R8 to Bottom (-) R8 ....... ....................... Z3 Reading +/-.2 NALS G and A. Top (.) R13 to Bottom (-) R8 .................................. 11 volts +/-1

6. Place the CONTROLCIRCUIT BREAKER Bottom (t) R23 to Bottom (-) R21 .............................. 1 volt +/-1.5 in the ON position. Top (+) R26 to Bottom (-) R21 ................................. t volt 11.5

7. Using the RAISE-LOWER control, run Increase VOLTAGE LEVEL control setting by 5 volts (RAISE test light energized) the LTC to the position that gives a reading as close to 120 Vac as system Top (4) R13 to Bottom (-) R8 .................................. 1 volt +/-1.5 conditions permit. Bottom (*) R23 to Bottom (-) R2t .............................. 22 volts +/-2 NOTE: If it is necessary to use an Outside Top (+) R26 to Bottom (-) R21 ................................. 1 volt t1.5 source, connect a variable 120 Vac. 60-Hz.

sinusoidal wavelorm powersource to LTC Decrease VOLTAGE LEVEL control setting by 10 volts (LOWER test light energized) control box Terminals 10 and G. Set ine source level at 120 Vac. Top 1+) R13 to Bottom ('-I R8 22 volts +/-

Bottom f') R23 to Bottom (-) R21 .............................. 1 volt +/-1.5 Top ( R26 -) to Bottom (-) R21 .. ............................ 22volts +/-12 9

TROUBLESHOOTING GUIDE (Continued)

For Equipment Built After 111182 VOLTAGE READINGS Condition Voltmeter Readings and Troubleshooting Procedure Neither test light can be energizeed. 1. Check the voltage from Terminal 3 to Terminal 4 on the voltage sensor.

Voltage should be 24 Vac +/- 5%.

A. If the voltage from Terminal 3 to Terminal 4 is 0, check the auxiliary power transformer and connections.

B. If the voltage from Terminal 3 to Terminal 4 is very low, check B8 and C1 for a short.

C. If the voltage from Terminal 3 to Terminal 4 is 24 Vac +/- 5%, check the voltage from the top (+) of Zi to the bottom (-) of Z2.

Voltage should be 24 volts +/- 10%.

If the voltage from Zi to Z2 is 0 or low, check R1, R2, and B1 for an open circuit and check C1 and Z2 for a short.

RAISE test light energized all of the 1. With the LOWER test light energized, check the voltage from bottom time-LOWER test light operates (+) of R23 to top (-) of R20.

properly. A. If the voltage is 1 to 3 volts, check SCRI and C4 for a short.

B. If the voltage is high, check OP2.

RAISE test light energized all of the 1. Check the voltage from the bottom (+) of Z3 to the top (-) of Z3.

time-LOWER test light will not operate. Voltage should be 8.4 volts +_5%.

&If the voltage is high, check for an open Z3.

2. Check the voltage from the top (+) of R8 to the bottom (-) of A8.

Voltage should be approximately equal to Z3 voltage.

A. When R8 voltage equals Z3 voltage, check the voltage from top (+)

of R13 to bottom (-) of R8.

Voltage should be 11 to 12 volts.

• If the voltage stays low regardless of the change in differential between R8 and Z3 voltage, replace OP1.

B. If R8 voltage is 0. check for an open R30, R5, A6, R7, D1, D2 or B2 and check B2, C2, and R9 for a short.

C. Check combined resistance of R8 and R9.

Combined resistance should be 2400 to 3000 ohms.

NOTE: The resistance of R9 is factory set. Do not change this setting. See 4

BIAS POTENTIOMETER SETTING section, page 16.

(1) If the resistance is low, check for a shorted R8 and/or R9.

LOWER test light energized all of the 1. With the RAISE light energized, check the voltage from the top (+) of time-RAISE test light operatesproperly. R26 to the top (-) of R20.

A. If 1 to 3 volts, check SCR2 and C5 for shorts.

B. If the voltage is high, check OP3.

LOWER test light energized all of the 1. Check the voltage from the bottom (+) of Z3 to the top (-) of Z3.

lime-RAISE test light will not operate. Voltage should be 8.4 volts +/-5%.

&If the voltage is low, check for an open ZI or R4 and shorted Z2 or Z3.

2. Check the voltage from top (+) of R8 to the bottom (-) of R8.

Voltage should be approximately equal to Z3 voltage.

A. When R8 voltage equals Z3 voltage, check voltage from top (+) of R13 to bottom (-) of R8.

Voltage should be 11 to 12 volts.

If voltage stays high regardless of change in differential between R8 and Z3 voltage, replace OP1.

B. If voltage is high, check combined resistance of R8 and R9.

Combined resistance should be 2400 to 3000 ohms.

NOTE: The resistance of R9 is factory set. Do not change this setting: see

- BIAS POTENTIOMETER SETTING section, page 16.

(1) I1resistance is high, check for an open RB or R9.

(2) If R8 and R9 resistance is correct, check for an open R29.

Both test lights energized all of the time. 1. Check for any combination: Defective OP2. OP3, shorted SCR1, SCR2, C4, C5.

Voltage sensor operates test light pro- 1. Check for poor contact in R9 and/or R30.

perly, but voltage level setting drifts NOTE: Do not change these settings before reading sections covering BIAS andlor is off by more than two volts. POTENTIOMETER and CALIBRATION POTENTIOMETER settings.

2. Check for open 829. R8. and/or R9.

3. Check for detective Z3. and/or OPI.

4. Check for poor contact in the VOLTAGE LEVEL. TEST RHEOSTAT, and/or BANDWIDTH controls.

10

S210-40-14 TROUBLESHOOTING GUIDE (Continued)

For Equipment Built After 111182 BIAS POTENTIOMETER SETTING CALIBRATION RESISTOR SETTING LIMITED PARTS WARRANTY Bias potentiometer R9 has been factory If necessary to reset calibration resistor McGraw-Edison warrants to the original set and sealed. It should not be necessary R30: purchaser that load tap changing equip-to change its setting unless it becomes 1. Set all controls except the BAND LEVEL ment controls shipped after August 1, 1982 defective or it is necessary to replace R6. control in their fully counterclockwise are free of defective workmanship and R7. R8, or Z3. To reset R9: positions. materials for a period of five years. This

1. Set all control knobsexcept the VOLT- 2. Connect a high-impedance voltmeter limited parts warranty commences on the AGE LEVELcontrol at their fully coun- (preferably digital) to TEST TERMINALS date of arrival at destination and covers any terclockwise positions. A and G. defects and malfunctions of the load tap

2. Set VOLTAGE LEVEL cont.., at 120 3. Connect a 120-volt,. +/-1 Vac. 60-Hz sinu- changer controls except those caused by volts. soidal waveform voltage source to LTC improper installation, improper mainte-

3. Turn calibration potentiometer P30 control box Terminals 10 and G. nance, improper operation, customer fur-(on the lefthand edge of the voltage NOTE: This can be done from the normal nished materials, alterations executed by sensor circuit board) to its fully coun- source with the transformer energized or customer or vandalism.

terclockwise position. from an external source.

4. Place bias potentiometer R9 in its $ully clockwise position. & CAUTION

5. Connect a high-impedance voltmeter If an external source is used, discon-(preferably digital) to voltage sensor nect the normal source and make cer-Terminals 1 and 2. tain that the source ground lead is con-

6. Connect a 114-volt +/-1 Vac, 60-Hz, sinu- nected to G.

soidal waveform voltage source to LTC control box Terminals 10 and G. 4. Energize the power source and set the NOT E: This can be done from the normal VOLTAGE LEVEL control to the setting power source with the transformer ener- that corresponds to the voltmeter read-gized or from an external source. ing - 0.6 volts.

Example: Voltmeter reading is 119.5 CAUTION volts + 0.6 = 120.1 Vac; therefore, the

&x If an external source is used, discon- VOLTAGE LEVEL control should be set nect the normal source and make cer- at 120.1 volts.

tain that the source ground lead is con- 5. If the LOWER test light is energized.

nected to G. slowly turn calibration resistor R30 clockwise until the LOWER test light

7. Energize the power source and, if goes out and the RAISE test light just necessary, adjust the VOLTAGE comes on.

LEVEL control until the voltmeter 6. If the RAISE test light is energized.

reads 75 Vac +/-0.2 volts. slowly turn calibration resistor R30 5, Slowly turn R9 counterclockwise until counterclockwise until the RAISE test the RAISE test light is just energized. light goes out and then clockwise until

9. Seal the bias potentiometer setting the RAISE light just comes on.

with a hot iron or cement.

10. Reset calibration resistor R30 in accordance with the instructions In the CALIBRATION RESISTOR SETTING section.

11

+ COOPER POWER SYSTEMS P.O. Box 440, Canonsburg, PA 153*

TAPCHANGER CONTROL M-oo67E

" Adaptable to any LTC Transformer-Old or New

" Meets ANSI Class 1 (1%) Accuracy Requirement

.

• Fully Transient Protected

• Now in Use by Leading Manufacturers as Standard Equipment 0

I,

INPUTS Power. A two wire input, requiring less than 3 W at 90 to 140 V ac, provides all power requirements. The unit should be powered from a potential transformer or from the voltage to be controlled.

Line Current: Line drop compensation is provided by a C.T. input with a 0.2 A nominal full scale rating.

The burden imposed by this input on the current source is 0.03 VA. A Beckwith Electric model M-0121 (5 A to 0.2 A) or M-0169 (5 A or 8.66 A to 0.2 A) Auxiliary Current Transformer is available when required.

Circulating Cunrent; Parallel operation of transformers is provided by a second C.T. input with a 0.2 A nominal full scale rating. The burden imposed by this input on the current source is 0.005 VA. A paralleling input with a 02 A full scale rating gives approximately 24 V correction at approximately 90W for parallel operation with other transformers.

OUTPUTS Two outputs drive a raise and lower motor starter relay. The starters may be any voltage up to 240 V ac. The output contacts are rated at 2.5 A inrush current and will handle a NEMA size I starter or smaller.

CONTROLS VOLTAGE CENTER OF BAND: The center of the control band may be set to any voltage from 105 to 135 V ac. The scale calibration accuracy is +/-0.5 V at 120 V ac.

TOTAL BANDWIDTH: The bandwidth control can be adjusted from 1.0 to 6.0 V. The scale calibration accuracy is +/-0.3 V.

TIME: The timer is adjustable from 0 to 120 sec. with a scale calibration accuracy of +/-10% of setting or +/-2 sec.,

whichever is greater. The timer starts when the voltage goes outside the band and resets within a few milliseconds upon return to the band or when reset by an external contact in the Non-Sequential mode.

LINE DROP COMPENSATOR: The resistance compensation provides 24 V compensation for 0.2 A input in phase with the input voltage. The reactance compensation provides 24 V compensation for 0.2 amps input at a phase angle of +/-90W as chosen by the DIRECT/REVERSE switch. The magnitude and angle of each circuit is individually set by a pair of trimpots to any accuracy limited only by the instruments used in setting. The factory setting of magnitude will be within +/-5% and the phase angles within +/-2%. The voltage and two current circuits are isolated from each other and do not interact.

TESTIOPERATE: When this switch is in the TEST position, the Line Drop Compensator is deactivated and the voltage may be raised and lowered by means of an uncalibrated voltage control. An external voltmeter with a burden of 500 £t per V or higher can be connected to test the band limits by observing when the RAISE and LOWER LEDs light. No special test voltage source required.

LED INDICATORS The RAISE and LOWER LEDs light to indicate a voltage outside the band and a forthcoming tapchanger operation as soon as the timer times out. With a slowly varying input, operation of the LEDs and initiation of timing is very sharp with 0.2 V hysteresis. The LEDs have an expected life of 25 years.

I, II

. I MODES OF OPERATION

. Either of the following modes are available as determined by presence or absence of a cam switch which is closed while the LTC is in transition.

Non-Sequential Mode: The timer resets after a tapchange, regardless of voltage.

Sequential Mode: The timer resets only after the sensed voltage is back within the control band.

LOW VOLTAGE PROTECTION Outputs are blocked from operating at input voltages below approximately 60 V ac. A proper raise output will be obtained down to this threshold.

RESPONSE

The M-0067E will respond to 5/8% voltage change in 0.2 sec. ensuring freedom from hunting on minimum bandwidth.

STANDARDS The unit meets the requirements of accuracy class 1 as defined in ANSI standards C97.12.30-1977 paragraph 93 and C57.15-4.2 when tested according to C57.15-1986 paragraph 9.4.1.

OPTIONS Voltage Setpoint

• 1. Single-step voltage reduction: The addition of an external resistor lowers the voltage setpoint.

2. Voltage reduction resistors: Resistors for a maximum of two preselected steps of voltage reduction will be mounted on the printed circuit board at the factory.

3. Instantaneous (non-time delayed) voltage reduction: Circuitry is added at the factory.

50 Hz Operating Frequency This option is available for use in countries outside the continental United States and Canada. The unit will be shipped with the standard 60 Hz operating frequency unless otherwise specified.

TRANSIENT PROTECTION Input and output circuits are protected against system transients. The M-0067E will pass all requirements of ANSI/IEEE C37.90.1-1989 defining oscillatory surge withstand capability. All inputs and outputs will withstand 1500 V ac to chassis or instrument ground for one minute. Voltage inputs are electrically isolated from each other, from other circuits, and from ground.

MOUNTING

1. Standard vertical

2. Horizontal

3. 19" rack mount 0

!Iii *.

ENVIRONMENTAL Temperature: The voltage band limits will vary no more than 0.5 V from -500 to +800 C. The timer will vary no more than +/-10% of setting or +/-2 sec., whichever is greater.

Humidity: Stated accuracies are maintained at up to 95% relative humidity (non-condensing).

Fungus Resistance: A conformal printed circuit board coating inhibits fungus growth.

PHYSICAL Size and Mounting: Overall dimensions are 6-3/8" x 16-1/2" (16.2 cmx 41.9 cm); requires a panel cutout of 5-7/8" x 15-1/8" (14.9 cm x 38.4 cm).

Approximate Weight: 6 lbs (2.7 kg).

Approximate Shipping Weight: 9 lb (4.1 kg).

PATENTS U.S. Patent 3,721,894; Canadian Patent 985,368; British Patent 1,432,607; Swedish Patent 7,301,667-7; and other foreign patents applied for.

WARRANTY The M--0067E Tapchanger Control is covered by a two year warranty from date of shipment.

IV.

NOTICE Any illustrations and descriptions by Beckwith Electric Co., Inc. are for the sole purpose of identification.

THE DRAWINGS AND/OR SPECIFICATIONS ENCLOSED HEREIN ARE THE PROPRIETARY PROPERTY OF BECKWITH ELECTRIC CO., INC. AND ARE ISSUED IN STRICT CONFIDENCE; THEREFORE, SHALL NOT BE USED AS A BASIS OF REPRODUCTION OF THE APPARATUS DESCRIBED THEREIN WITHOUT PRIOR WRITTEN PERMISSION OF BECKWITH ELECTRIC CO.,

INC.

NO ILLUSTRATION OR DESCRIPTION CONTAINED HEREIN SHALL BE CONSTRUED AS AN EXPRESS WARRANTY OF AFFIRMATION, PROMISE, DESCRIPTION OR SAMPLE AND ANY AND ALL SUCH EXPRESS WARRANTIES ARE SPECIFICALLY EXCLUDED NOR SHALL SUCH ILLUSTRATION OR DESCRIPTION IMPLY A WARRANTY THAT THE PRODUCT' IS MERCHANTABLE OR FIT FOR A PARTICULAR PURPOSE.

THERE SHALL BE NO WARRANTIES WHICH EXTEND BEYOND TIIOSE CONTAINED IN THE BECKWITH ELECTRIC CO., INC. TERMS OF SALE.

All rights reserved by Beckwith Electric Co., Inc. No reproduction may be made without prior written approval of the Company.

0 051 V.

S WARNING DANGEROUS VOLTAGES, CAPABLE OFCAUSINGDEATH OR SERIOUS INJURY, ARE PRESENT ON THE EXTERNAL TERMINALS AND INSIDE THIS EQUIPMENT. USE EXTREME CAUTION AND FOLLOW ALL SAFETY RULES WHEN HANDLING, TESTING OR ADJUSTING THE EQUIPMENT.

HOWEVER, THESE INTERNAL VOLTAGE LEVELS ARE NO GREATER THAN THE VOLTAGES APPLIED TO THE EXTERNAL TERMINALS.

0 PERSONNEL SAFETY PRECAUTIONS The following general rules and other specific warnings throughout the manual must be followed during application, test or repair of this equipment. Failure to do so will violate standards for safety in the design, manufacture and intended use of the product.

Qualified personnel should be the only ones who operate and maintain this equipment. Beckwith Electric Co., Inc. assumes no liability for the customer's failure to comply with these requirements.

ALWAYS GROUND THE EQUIPMENT To avoid possible shock hazard, the chassis must be connected to an electrical ground. When servicing equipment in a test area, the chassis must be attached to a separate ground since it is not grounded by external connections.

DO NOT OPERATE INAN EXPLOSIVE ENVIRONMENT Do not operate this equipment in the presence of flammable or explosive gases or fumes. To do so would risk a possible fire or explosion.

KEEP AWAY FROM LIVE CIRCUITS Operating personnel must not remove the cover or expose the printed circuit board while power is applied. In no case may Scomponentsbe replawe with power applied. In someinstances, dangerous voltages mayexist even when power is disconnected.

To avoid electrical shock, always disconnect power and discharge circuits before working on the unit.

EXERCISE CARE DURING INSTALLATION, OPERATION AND MAINTENANCE PROCEDURES The equipment described in this manual contains voltages high enough to cause serious injury or death. Only qualified personnel should install, operate, test and maintain this equipment, Be sure that all personnel safety procedures are carefully followed.

Exercise due care when operating or servicing alone.

DO NOT MODIFY EQUIPMENT Do not perform any unauthorized modifications on this instrument. Return of the unit to a Beckwith Electric repair facility is preferred. If authorized modifications are to be attempted, be sure to follow replacement procedures carefully to assure that safety features are maintained.

A PRODUCT CAUTIONS Before attempting any test, calibration or maintenance procedure, personnel must be completely familiar with the particular circuitry of this unit and have an adequate understanding of field effect devices. If a component is found to be defective, always follow replacement procedurescarefully to assure safety features are maintained. Always replace components with those of equal or better quality as shown in the Parts List of the Instruction Book.

AVOID STATIC CHARGE If this unit contains MOS circuitry, it can be damaged by improper test or rework procedures. Care should be taken to avoid static charge on work surfaces and service personnel.

• USE CAUTION WHEN MEASURING RESISTANCES Any attempt to measure resistances between points on the printed circuit board, unless otherwise noted in the Instruction Book, is likely to cause damage to the unit. 051 vi

TABLE OF CONTENTS M-0067E TAPCHANGER CONTROL instruction Book Introduction ..................................................................................................................................... 1 Block Diagram ........................................................................ Figure 1 ......................... 2 Principles of Operation ........................................................................................................... 3 Line Drop Com pensation ................................................................................................... 3 Voltage Sensing ..................................................................................................................... 4 Timer and Output ................................................................................................................... 4 Stability ............................................................................................................................... 5 Application ....................................................................................................................................... 6 General ................................................................................................................................ 6 Parallel Operation ....................................................................................................... 6 External Connections ................................................................. Figure 2 .......................... 7 Options .................................................................................................................................. 8 Voltage Reduction ................................................................... Figure 3 .......................... 9 Use of the M-0329 LTC Backup Control with the M--0067E Tapchanger Control ........................................................................................... 9 Schem atic ........................................................................................... Figure 4 ............................. 10 Installation .................................................................................................................................... 12 Lightning Protection ............................................................................................................ 12 M ounting and Outline Dimensions ............................................ Figure 5 ......................... 13 Horizontal M ounting Configuration ......................................... Figure 6a ......................... 14 19" Rack M ount Configuration .................................................. Figure 6b ........................ 14 M-0329 Interconnection with Beckwith M-0067 Tapchanger Control ................................................................. Figure 7 ......................... 15 Adjustm ent ..................................................................................................................................... 16 Checkout Procedure ....................................................................................................................... 17 Settings ............................................................................................................................... 17 Power .................................................................................................................................. 17 Test Circuit ........................................... ........................................ 17 Component Location ................................................................. Figure 8 ......................... 18 M aintenance .................................................................................................................................. 19 How to Avoid Damaging Your Control Through Testing ................................................ 20 Test Procedure ............................................................................................................................. 21 Equipment Required ............................................................................................................. 21 Hints in M easurements .................................................................................................... 21 Removing the Printed Circuit Board ...................................... 21 W aveshape ............................................................................. Figure 9 ......................... 22 Power Supply ...................................................................................................................... 22 Voltage and Bandwidth .................................................................................................. 23 Timer ................................................................................................................................... 23 Resistance Compensation ................................................................................................ 23 VI','

Reactance Compensation ...................................................................................................... 23 Paralleling Com pensation ............................................................................................. 23 Typical Voltages ............................................................................................................................ 24 Parts List ......................................................................................................................................... 25 Optional Components ..................................................................................................... 29 Single or M ulti-Step Voltage Reduction Option .............................................................. 29 Instantaneous Voltage Reduction Option ......................................................................... 29 50 Hz Operating Frequency Option ................................................................................. 29 Patent, W arranty and Indemnification ...................................................................................... 30 In our efforts to provide accurate and informative technical literature, suggestions to improve the

.Department, clarity or to correct errors will receive immediate attention. Please contact the Marketing Services specifying the publication and page number.

Vil l}I

I INTRODUCTION The M-0067 is a solid-state control that makes novel use of the latest electronic techniques to achieve a highly stable and reliable transformer or regulator control. The Block Diagram is shown in Figure 1. The M-0067 control is suitable for use on existing LTC transformers, single-phase regulators or induction voltage regulators, as well as new transformers.

All components are mounted on a single printed circuit board which in turn is mounted on a metal panel. The panel can be easily removed, leaving a completely functional circuit board with both sides exposed for ease in servicing. The panel mounting space is consistent with a three-unit drawout case.

A self-checking feature permits checking calibration with only an accurate ac voltmeter.

All dials are accurately calibrated with only one knob used for each function. Calibration of each function is independent of all others.

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I~~i 0

I I

00 FIGURE 1 Block Diagram PRINCIPLES OF OPERATION U NOTE. It will help in following the Schematic shown in Figure 4 to know that generally dc voltages are positive at the top and negative at the bottom. Information generally flows from left to right.

LINE DROP COMPENSATION This uses a number of unique circuits to give improved performance at lower cost and with almost no heat rise.

The voltage is scaled down 10:1 by T4 so that 12 V ac on the secondary represents 120 V ac. By bringing the P.T.

voltage to a 95% tap for test, both a raised and lowered voltage can be produced across the entire primary by adjustment of R3. This permits checking both band limits without using a separate test voltage source.

Transformer TI and associated network produces a voltage across R5 of 2.4 V ac for 0.2 A in its primary.

Capacitor C19 corrects for transformer inductance causing the voltage across R5 to be exactly in phase with the current. Resistor R2 is the main burden, and trimmer R4 adjusts the half-scale point of the resistance control R5 to be exactly correct.

Transformer T2 and associated network produces a voltage across R9 of 2.4 V ac for 0.2 A in its primary. Switch S2 provides direct or reversed polarity for this reactance compensation voltage.

Winductance.

The pi network consisting of C2, R7 and C5 provides exactly 9Q0 phase shift, including effects of transformer Trimmer R7, therefore, adjusts the angle of the voltage across R9 to be exactly 90* out of phase with

'12 primary current. Trimmer R8 adjusts the magnitude to the correct value at half scale on reactance control R9.

Capacitors are used in the reactance network since they provide nearly perfect linearity with current level and at lower cost than inductances. A reversal of T2 polarity brings the phasing to the correct point, making the capacitive burden look like an inductive burden.

Transformer T3 with C3 and C4 produce a secondary voltage, approximately 90' out of phase with the primary current, for use in parallel operation of transformers. This angle is actually 84' and is not compensated to precisely 90 since this is not required for proper paralleling. Again, reversal of polarity through TP3 makes its capacitive burden look like an inductive burden.

Summing amplifier Q1 has a current summin-g input at pin 2 0-). Current is fed to this point through resistors R13, RIO, R11 and R12. It is the nature of QI that current cannot enter the device but that, instead, the Q1 output will serve itself so that the sum of the four currents flows through R16. When the sum of the input voltages is positive, Q1 output will be a negative voltage in precise proportion to the sum (at the juncture of D4, R18 and feedback resistor R1 6). When the sum of the input is negative, the feedback is blocked by D4 so that the summing input actually moves negative and Q1 switches positive to saturation. This forms an effective half-wave rectifier yet without the temperature-sensitive drop of 1)4 giving an error.

The resistor capacitance network following Q1 gives a dc voltage proportional to the sum. Components R17, R18 and C6 are chosen to make this dc voltage proportional to the rms content of the input regardless of considerable distortion. This provides proper compensation when very nonlinear loads such as arc furnaces distort the current waveshape.

Resistors R20, R66 and R67 together with capacitors C8, C17 and C18 form a twin T-filter which removes the 40* ripple voltage without introducing a time delay which could cause the transformer to hunt when set for a I

narrow bandwidth. When the bandwidth is so narrow that it can be matched by only one tap position, it is essential to detect the voltage in time to stop the tapchangeron that one tap; otherwise the operation will oscillate continuously, never stopping within the band.

VOLTAGE SENSING Power transformer T5 and full-wave rectifiers D5 and D6 provide an unregulated 24 V for noncritical circuits and as relay potential.

Integrated circuit regulator Q2 provides a very stable dc reference source for voltage determination and timing.

Full-wave rectifiers D13, D18 and associated network provides negative voltages regulated by zener diodes D14 and D15.

Integrated operational amplifier circuits Q3 and Q4 are used as threshold detectors. Their outputs switch as the dc voltage "E," proportional to the compensated ac input, goes outside a band of reference voltages.

Zener diode D7 maintains a constant voltage across the band width determining circuit so that the bandwidth is independent of voltage control R26. The zener diode D7, and the fact that R27 equals R30, assures that the bandwidth will vary around a bandcenter value determined by R26 alone.

Resistors R34 and R35 provide approximately 0.2 V hysteresis at the band edges. This results in very sharp band edge operation, energizing the motor starter without chattering.

TIMER AND OUTPUT A precise and stable timer is formed by charging C12 through R43 to a point where operational-amplifier Q6 switches. The second input to Q6 is by timing control R40. Resistor R45 provides a snap action when the threshold is reached.

RAISE and LOWER LEDs I1and 12 operate when either threshold detector Q3 or Q4 operate. Until the timer times out, the LED current is shunted to -6 V by diodes D11 and D12. When the timer does time out, the current from either 11 or 12 is passed to the base of Q9 or Q7, thereby turning it on. This transistor operates relay K1 or K2 which causes a raise or lower operation.

Transistor Q5 shorts the timing capacitor, thereby cutting off either relay whenever the voltage goes back within the band. This occurs in 1/2 cycle or less, assuring that the tapchanger will stop in the band whenever minimum bandwidth is being used.

The timing capacitor can also be discharged by closing a contact from terminals 3 to 10. If tied to a cam switch, closed off normal, non-sequential operation is obtained where the timer starts following each tapchanger step regardless of the voltage.

STABILITY Excellent stability is achieved from -50P to +800 C (-58* to 1760 F). This is accomplished by using circuits and components each having inherent stability. In units with serial numbers up to 5000, it was necessary to include a varistor to correct for a final +/-1/2%of temperature drift. Units serial 5000 and greater have this temperature correction eliminated.

This excellent stability is essential when transformers are used in parallel with very narrow bandwidth. If the controls were to drift apart in voltage setting, first one transformer would operate to bring the voltage within its band and then the other. This would occur after each timer times out and would continue until the circulating current stopped the action. Minimum circulating current is thus not obtained.

The design uses operational amplifier integrated circuits which have variations in manufacture, temperature and life measured in terms of less than 10 mV. These are used with voltages in the order of 10 V, well within their rating but far above the levels of undesired variations. In addition, an integrated circuit voltage regulator establishes a highly stable reference to compare with the rectified ac voltage.

Highly stable metal film resistors and wirewound potentiometers are used throughout the design. These are used as voltage dividers in such a way that the essential divided voltage is independent of the small variation of resistance with temperature.

Light emitting diodes assure trouble-free, long life with little deterioration due to age and no effect from vibration.

All active semiconductors are hermetically sealed so that moisture cannot change their characteristics.

The circuit involving Q1 is a novel combination of summing amplifier and compensated half-wave rectifier. This eliminates all interaction between the several inputs to the compensator. It also includes half-wave rectifier D4 inside a high gain feed-back path to eliminate the effect of the voltage drop across D4 which varies with temperature.

The ac voltage and current compensation voltages are scaled down 10:1 to values more appropriate for use with integrated circuits. This and other techniques reduce the power input within the band to about 1 W which reduces warmup drift to a minimum by the simple fact that the temperature rise due to operation is very small.

Accurate timing is achieved by use of a stable resistor and capacitor, and by measuring the charging time to a stable dc voltage using an operational amplifier to compare these voltages to within a few millivolts. Through use of simple logic circuits, a single timer is used for either raise or lower.

High temperature, low leakage electrolytic capacitors are used where necessary to minimize total drift with usage and variations in ambient temperature.

0 APPLICATION GENERAL External connections are shown in Figure 2. 3oth power (I to 3 W) and voltage sensing are obtained from a potential device having a nominal 120 V ac output. Normally, this is line-to-neutral potential although line-to-line potential can also be used if special attention is paid when using line drop compensation. Load current must be reduced by suitable auxiliary current transformers to 0.2 A full scale before connecting to the M-0067 input.

The Beckwith Electric M-0121 Current Transformer (SA to 0.2 A) can be used with the M-0067 when there is no additional burden present. The M-0169 Current Transformer (8.66 A or 5 A to 0.2 A) is for use in high burden current circuits, such as are found in paralleling schemes. Outputs are protected against overvoltage.

In general, the tapchanger motor must be operated from a different transformer than that used to measure potential. If this is not done, hunting at the upper band edge may result. As soon as the motor starts and before it is sealed in, the motor current can drop the voltage within the band and reset the control. Some motor seal-in schemes are fast enough to prevent this but others are not.

PARALLEL OPERATION A number of problems of distinct origin may be hard to distinguish because they all result in hunting of transformers in parallel. The net result is excessive operations as noted on the counter. In order to prevent these operations, it is essential that the various causesbe carefully distinguished and eliminated to the extent provided by adherence to ANSI Class I standards.

Due to the necessity of tapping the transformer winding to the nearest turn, a change may be as much as 3/4%

or 1 V. The tapchanger will have only one chance to stop within a 1 V band, and the control timer must reset before a second change is initiated. If not, the tapchanger will move up two steps, reset, time out, move down two steps, time out and continue this indefinitely. The M-0067 has been designed with a sufficiently fast response to avoid this problem.

Another problem is that the industry standard for 1% accuracy may typically be fulfilled by*l /2% temperature variation and +1/2% due to other errors. It is quite possible for one control to drift +1/2% and another -1/2%

with temperature. This means the minimum practical bandwidth for parallel operation is 2% or 2.4 V, assuming no error was made in setting the controls.

The adjustment error can be reduced by using the same voltmeter with great precision in setting the voltage at center of band of units being paralleled. If the Beckwith control is used with a control of poor stability, even wider bandwidth must be used to compensate for the poor stability of the other control.

A further problem in paralleling can arise if one control is of a different design and if line drop compensation is used. The line drop compensator of the M-0067 has rather exact 00 resistance compensation and 90* reactance compensation. Other controls of older vintage have been found to have reactance compensation of 60r to 700, rather than 90r as it should be. Due to these imperfections, the line drop compensator of other controls may not track the rather exact line drop compensator of the M-0067. This may cause hunting to occur at load levels different than those existing when the controls were initially adjusted.

.- a-Current Withstand; Eiher input AMP MAX TIME 5 2 sec Tapchanger 4 3sec Control Termir tals S.3 4 sec 5 sac POLARITY 2.9 0.4 2 hoJurs Potential If Desired Transformer Instantaneous Voltage Reduction Connections n5A Line Current POLARI Cam Swilch Contact, Closed while LTC Is In transition for non-sequenlial 2 Circulating operation. K1' n 5A Current I

K2 Current Inputs are 0.2 A

• Full Scale*. Add 5/0.2 A 120/240 V Current Transformers Ifrequired Motor Starter Relay Cam Switch Contact, Closed "

while LTC Is in transition for non-sequential operation External Resistor A%

Close one Contact at a K3 time for various steps of T Voltage Reduction, as Indicated on ODlions Par

• .l NOTE: For Instantaneous Voltage Reduction, use additional contact from the KI and K2 relays.

• WARNING: Open C.T. secondary will result in high voltage at C.T. terminals.

Death, severe injury or damage to equipment can occur.

Do not operate with C.T. secondary open. Short circuit or apply burden at C.T. secondary during operation.

0 FIGURE 2 External Connections An additional problem in paralleling may occur if the transformers themselves have widely different imped-ances. This will cause current in the circulating current circuit, even with transformers on the same tap. In order to eliminate hunting, it is now necessary to desensitize the circulating current circuit so that no tapchange results from this minimal circulating current.

This can be accomplished by changingR12 (normally 270 K). The sensitivity is inversely proportional to the size of R12, i.e., inserting R12 equal to 540 K would give a sensitivity of 12 V/0.2 A rather than the standard 24 V/0.2 A. This resistor is mounted on turrets to permit unsoldering without removing the panel.

k CAUTION: Use a small iron and minimal heat In changing this component. Refer to the TEST PROCEDURE section for the proper equipment required.

The need to change R12 is eliminated if the Beckwith Electric M-0115 Parallel Balancing Module is used since it contains a sensitivity control. Refer to the Instruction Book on the M-01 15 for details.

In another case, the standard sensitivity may not be sufficient. This is the case where the impedance of an overcurrent relay in the circulating current circuit is so high as to reduce the current from the C.T. below the value which should flow. Here a lower than normal R12 value can be used to increase the sensitivity and compensate for the high relay impedance.

This problem is best avoided by using a Beckwith Electric M-0127 10-100 mA ac Overcurrent Relay. The input impedance of approximately 100 D avoids saturation of the source current transformer.

These difficulties have led some utilities to decide against using the circulating current method of paralleling.

Field experience with the Beckwith Electric controls proves that the operation will be stable over long periods and with no readjustment if the above points are carefully considered.

OPTIONS VOLTAGE REDUCTION The voltage setpoint may be reduced by closing the external dry contacts one at a time from terminal 11 or 12 to

13. These contact closures may typically be remotely-controlled by supervisory control.

A CAUTION: Leads between contacts and the M-0067 terminals must be kept short and within the control cabinet in order to avoid circuit damage or misoperation.

Approximate values of resistance for various amounts of voltage reduction may be obtained from Figure 3. The resistors for two preselected steps of voltage reduction will be mounted on the printed circuit board. Please indicate the desired percentage(s) of voltage reduction (based on 120 V) on the OPTIONS page when ordering the unit. Resistors R74 and R75 will be factory selected and installed to provide the desired voltage reduction. If no voltage reduction is specified on the option sheet, R74 and R75 will not be installed at the factory. If more than two steps of voltage reduction are required, additional voltage reduction resistors may be added externally to the unit in series with terminals 11 and 12.

INSTANTANEOUS (NON-TIME DELAYED) VOLTAGE REDUCTION To implement this option, a 2.2 K +/-10%, 1/2 W carbon resistor is substituted at the factory for R37. When ordering the M-0067, please indicate if this option is desired by checking the appropriate entry on the OPTIONS page.

21

'0 1.

O)LL C/) 40 NL 3

0 10 1 2 3 V

4 9 6 E 7 8 9 10 11 12 t.3 14 15 VOLTS REDUCTION ON 120 V BASE FIGURE 3 Voltage Reduction The external circuitry required is shown in Figure 2. When voltage reduction is required, the contacts from terminal 10 to terminal 13 dose, forcing the timer to instantaneously time out. Subsequent tap changes will occur with no time delay. Meanwhile, the normally closed contacts will open to keep the cam switch from resetting the timer if the control has been wired for nonsequential operation. If the control is being used in the sequential mode of operation, these normally closed contacts are unnecessary.

A CAUTION: Leads between contacts and the M-0067 terminals must be kept short and within the control cabinet in order to avoid circuit damage or misoperation.

USE OF THE M-0329 LTC BACKUP CONTROL WITH THE M-0067 TAPCHANGER CONTROL The M-0329 is a single-phase, solid-state backup control that has three main functions:

I. Prevent a defective tapchanger control from running the voltage outside the upper and lower limits.

2. Prevent the line drop compensator from raising the voltage too high under full load or overload conditions.

3. Lower the voltage if the regulated voltage goes above the Block Raise setpoint by a fixed bandwidth.

The Block Raise and Block Lower voltage levels are set by accurately calibrated dials; four per-unit values are available for the fixed bandwidth.

The M-0329 Instruction Book is available on request and gives added details. Since the M-0329 voltage and the fixed bandwidth value must be specified at the time of purchase, please refer to the M-0329 Instruction Book for 0 complete ordering information.

RESISTANCE VALUE FACTORY SELECTED

• C27 & C28 installed for 50 Hz System FIGURE 4 Schematic 0

INSTALLATION The mounting and outline dimensions are shown in Figure 5 and 6b. The M-0067E is also available in horizontal and rack mount configurations as shown in Figure 6a and 6b. The horizontal configuration uses the same mounting dimensions as the vertical configuration shown in Figure 5.

Since the compensated voltage is not available from the Beckwith Electric Tapchanger Control, the M-0329LTC Backup Control must be connected as a two terminal device to the potential transformer. Figure 7 shows the typical interconnection of the two devices with motor auxiliary relays.

Before energizing a new transformer or a modified old transformer make certain of the following7 LIGHTNING PROTECTION It has been determined that transient voltages in excess of 1500 V ac rms can exist on the "ground"lead normally tied to tenninal 3 and that these excessive voltages were causing occasional failure. In the '"S version of the M-0067 units, these voltages are suppressed by a string of varistors which still permit the unit to pass a 1500 V ac hi-pot test, all terminals to ground.

If possible, the potential transformer should be grounded at the control with a lead no longer than 6" from the M-0067 terminal 3 to ground (such as one of the M-0067 mounting screws). This will give the best protection from lightning damage to the control.

Multiple P.T. grounds far apart must be avoided, however, since a varying difference in ground potential could add or subtract from the effective potential and cause a variation in the voltage setpoint.

A CAUTION- The Meter Circuit is protected by a 0.25 A Axial Lead Picofuse (F2). Any external device, e.g. a voltmeter, connected to TB1-2 must not draw more than 0.25 A to ensure F2 will not be blown. Refer to the TEST CIRCUIT section for instructions on using T71-2 for external voltage monitoring. This fuse can be replaced by unsoldering the old fuse and replacing with an equivalent fuse. Consult the PARTS LIST and Component Location, Figure 8 for the fuse type and location. Spare fuses are supplied with new M-0067E units, and additional fuses can be obtained from the manufacturers or from Beckwith Electric Co.

Units returned with only a blown fuse are not covered by warranty, and a nominal repair charge will be made for replacement of the fuse.

Please check the fuse before returning the M-0067forrepair, In order to avoid unnecessary repair charge.

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PLa, I 0 RGURE 5 Mounting and Outilne Dfrmensions 0 QTOT hAICHANGER CONTROL RiErS! (gffiECT 00 LOWER M-0067E R I Mxwn CLM.

00 IN~u*~

ELECTRIC:[> LINE DROP COMPENSATOR 0

T Terminal Blocks FIGURE 6a Horizontal Mounting Configuration WfW4CANGER CONTROL OO "WUC LaaR 4 Rack Units (7 inches)

N-M067E Terminal Blocks FIGURE 6b 19" Rack Mount Configuration MOTOR SUPPLY TAPCHANGER CONTROL M-0329 90 M-0067E 8 BLK RAISE 9 8LK L F-ý 1 LOWER 90 B.U.I 00 _

SLimit switcher, auxiliary contacts as required in motor control circuits.

4 84R - Raise Motor Auxiliary Relay 84L - Lower Motor Auxiliary Relay 0* FIGURE 7 M-0329 interconnection with Beckwlth M-0067 TapchangerControl I

ADJUSTMENT The BANDCENTER and BANDWIDTH controls of the LTC Backup Control should be set so that the Block Lower limit is a small amount, (approximately 2 V), below the lower band limit of the Tapchanger Control, and the Block Raise limit is a similar amount above the upper limit if line drop compensation is not used.

If line drop compensation is used, the Block Raise limit should be set at the maximum voltage desired from the transformer.

If line drop compensation is used, the Backup Control Block Raise limit should be set higher than the highest voltage expected from the transformer under full load.

The M-0329 LTC Backup Control also includes a First Customer Protection function that regulates the maximum voltage from the transformer. This "LOWER" function operates slightly above the Block Raise limit and is connected to force the tapchanger to lower the voltage if this maximum limit is exceeded.

Figure 7 shows the interconnection of the Tapchanger Control and LTC Backup Control The Instruction Book on the M-0329 LTC Backup Control is available on request and gives added details.

Ideally, the UNE DROP COMPENSATOR should be set for the impedance from the transformer to the load center.

The problem is that this load center varies with distribution of load and is seldom, if ever known.

A balance of high and low voltage at full load can be achieved by using the M-0329 LTC Backup Control with the M-0067Tapchanger Control. Connections for this combination are shown in Figure 7. With this combination, the LDC is set at a value surely greater than the impedance to the load center. The M-0329 lower output contact will operate to limit the voltage to the nearest load when the transformer load is greater than approximately 80%

load.

See the M-0329 Instruction Book for further details.

CHECKOUT PROCEDURE SE'IrNGS Before power is applied to the transformer, adjust the VOLTAGECENTER OF BAND, TOTAL BANDWIDTH, TIME and R and X LINE DROP COMPENSATOR knobs to the desired setting. Remove wires from terminals 7,8 and 9 and place lead from terminal 4 temporarily on terminal 3.

POWER Make certain by measurement, if possible, that the potential to be applied to terminals I through 3 is nominal 120 V ac. Apply this power but not the motor power. Turn the TEST/OPERATE switch to TEST, connect a voltmeter from 2 to 3, vary the TEST knob and determine that the RAISE and LOWER LEDs operate on either side of the voltage setting. With an LED lit, determine that the corresponding relay operates after the set time. Disconnect the P.T. voltage.

Connect the lead for terminal 7 to the lead for terminal 8 with a clip lead. Apply motor voltage. Ascertain that the motor runs in the Raise direction. Remove power and connect the lead for terminal 8 to the lead for terminal 9.

Reapply motor power and ascertain that the motor runs in the Lower direction. Disconnect power and reconnect leads to terminals 7,8 and 9.

Apply both P.T. and motor voltages. Using the TEST knob, exercise the entire control and tapchanger switch by getting a Raise light and determining that the switch raises after an appropriate time for the timer to time out.

W Repeat with a setting that gives a Lower light.

With some load on the transformer, measure the current in the wire from terminal 4. This should be 0.2 A multiplied by the fraction of full load on the transformer. If correct, reconnect the lead to terminal 4. If the transformer is energized when making this connection, be sure to first short the C.T secondary.

TEST CIRCUIT This circuit permits checking the band limits as well as the operation of the tapchanger. Voltmeter terminals are ordinarily provided external to this control and tied to terminals 2 and 3 of the control. Connect a voltmeter of not less than 500 fQ per V to these terminals. With the TESTIOPERATE switch on TEST, vary the TEST knob and read the voltage where the band edge LEDs just light. By waiting for the timer to time out with one of the LEDs lit, operation of the tapchanger can be checked. In making this check, the potential must be approximately equal to the setting of the VOLTAGE knob asit would be in practice (but might not be in a laboratory test setup). The circuit depends on the voltmeter burden to lower the voltage. If the voltmeter burden is more than 500 0 per V, connect a 50 K resistor across the voltmeter terminals or from 2 to 3 of the M-0067 control. If the voltmeter burden is appreciably less than 500 D per V, the TEST knob will be inaccurate and damage could result to the unit.

0 WARNING: Some motors must be stopped in order to startin the properdirection. With such motors, never set the timer less than the lime it takes the motor to stop. In such a case a setting of 15 seconds or more is safe.

.0 Tests indicate all M-0067E units will pass the Surge Withstand Capability (SWC) test per ANSI standard C37.90.1-1989. Since serial number 5500, all units have been tested per this standard before shipment il LL II a

II,

- -a

• le t m Location Eg..

lowi 8 Component FIGURE

• MAINTENANCE Due to the extremely sophisticated nature of the circuitry in the M-0067, field repair is not recommended. All units are fully calibrated at the factory prior to shipment; there is not need to re-calibrate a unit prior to initial installation. Calibration is only required after a component is replaced. In the event that a unit does not operate properly, it should be established that the problem is caused by malfunction of a Beckwith unit and not caused by an external fault or wiring error. Once this is assured, the entire unit should be returned toBeckwith Electric.

Pack the unit carefully (in the original carton if possible), assuring that there is adequate packing material to protect the contents.

0 NOTE: Any equipment returned for repair must be sent with transportation charges prepaid. The equipment must remain the property of the user. The warranty is void if the value of the unit is invoiced to Beckwith Electric at the time of return or If the unit is returned with transportation charges collect.

If under warranty, units will be repaired rapidly and returned at no cost and with return transportation paid if the fault is found to be due to workmanship or failure of material. If a unit is under warranty and express shipment for return of the repaired unit is requested, shipping charges will be billed at the current rate. If the fault is due to abuse or misuse, or if the unit is out of warranty, a modest charge will be made. Repair can normally be expected to take two weeks, plus shipping time. If faster service is required, it should be requested at the time of return.

0 E NOTE: Units returned with only a blown fuse are not covered by warranty and a nominal repair charge will be made for replacement of the fuse. Please check the fuses before returning the M-0067 for repair in order to avoid unnecessary repair charges.

To help in analyzing the problem, a complete description of the malfunction and conditions leading to the failure should be included with the unit.

However, if you choose to repair the unit, it is necessary to be completely familiar with the circuitry involved, and have an adequate understanding of field effect devices. Be sure to carefully read the WARNING page at the beginning of this manual.

If Fl blows, it is surely due to the failure of another component, which should be identified and replaced together with the fuse.

It is suggested that first a visual inspection be made for any component that does not appear normal or appears to have overheated. Analysis of the circuit will then often lead to the cause of the failure and components that need to be replaced.

If no obvious problems exist, it is suggested that the TEST PROCEDURES be followed until a portion of a circuit is detected which does not perform as expected or until a calibration point is found which will not meet requirements. These procedures should lead to a determination of the defective component.

.once It is suggested that each knob be moved rapidly back and forth a dozen times or so during routine maintenance or twice a year. This will remove dirt or oxidation from the contacting elements within the control so as to assure trouble-free operation.

HOW TO AVOID DAMAGING YOUR CONTROL THROUGH TESTING This solid-state control is in many ways more rugged, less affected by changes in temperature, and less sensitive to shock and vibration than the earlier electromechanical controls. It is possible to damage the circuits, however, by introduction of excessive voltage through improper test procedures. Therefore, a series of don'ts:

1. Don't hi-pot one terminal at a time to ground. When this is done to TBI-10, TB1-11, TB1-12 or TB1-13; excessive 60 Hz currents may flow through the stray capacity of the circuit to the panel and damage semiconductors.

2. Don't make measurements from "hot" 120 V ac to terminals TB1-10, TB1-11, TB1-12, TB1-13 or to any points within the circuit. In particular, a low impedance ac voltmeter will introduce sufficient current into these terminals to damage semiconductors.

3. Don't apply the SWC Test (ANSI C37.90.1-1989) to terminals TB1-10, TBl-11, TB3-12 or TB1-13. To do so may cause damage to Q3 and Q4.

A CAUTION: In testing the unit, make certain that the motor starterand motor operate off a supply other than the test supply for the unit. If this is not done, the current drawn by the motor and starter may drop the voltage back within the band when checking the Lower operation. This will cause an oscillation which must be correctly attributed to the test circuit and Is not an Indication of improper operation of the control.

Any attempt to measure resistance between points on the printed circuit board may cause damage to the unit.

TEST PROCEDURE Please refer to the WARNING page at the beginning of this manual before proceeding.

EQUIPMENT REQUIRED

1. Regulated 60 Hz source with variable amplitude from 60 to 140 V rms.

2. 200 mA, 60 Hz current source with phase angle settings of 0( to +900.

3. High impedance true rms digital voltmeter with accuracy on ac of at least +/-0.1% of reading.

4. Solder sucking syringe or solder wick.

5. Soldering iron-Weller Controlled Output Soldering Station Model MTCPC, 60 W, 120 V, 50/60 Hz or equivalent with grounded tip.

6. An accurate stopwatch or timing device.

HINTS IN MEASUREMENS WIf possible, use a regulated ac voltage supply; however, this should not be the saturable core type regulator which has a severely distorted output.

In setting up the resistive current, use of a 100 ohm non-inductive 25 W resistor and 25 ohm potentiometer in series is suggested. The potentiometer should be at least 2 W and preferably carbon-ceramic construction. This will assure in-phase current and smooth current adjustment.

In checking the voltage and bandwidth controls, move the test voltage slowly to allow the output of the C6-C-C8 filter network to catch up.

In checking the line drop compensator, polarity must be observed, otherwise a 180' error will occur. See Figure 4 Schematic for standard polarity marking.

REMOVING THE PRINTED CIRBCUIT BOARD The circuit board and panel can be easily separated leaving a completely functional circuit. To do this, remove the knobs using a small screwdriver. Remove the nuts securing the switches and knobs. Remove all screws showing on the outside of the panel. Remove the panel. Any component can now be easily changed.

U NOTE. The M-0067 printed circuit board is coated with a moisture resistant conformal coating. This coating must be removed from areas where components are to be replaced.

Carefully scrape away the coating surrounding the component using a small, sharp knife, being careful not to damage the printed circuit board.

0 To replace a component, dip out the old component and discard. Remove the clipped wire using the solder wick or syringe. Be sure to leave the holes clear to facilitate insertion of the new component.

A CAUTION: Do not attempt to melt the solder and push the component through the hole as the component lead is likely to catch the edge of the foil and lift it off the board.

In replacing integrated circuits, make sure to insert the new unit into the transipad so that the tab fits into the slot.

Once this is done, there is only one correct way to insert the combination into the printed circuit board.

To reassemble the unit, place the panel over the controls and secure with the screws previously removed.

Replace the TEST knob nut and knob. Turn the knob shafts counter-clockwise and replace the pointer knobs with the pointer at the minimum calibration point. Before tightening the setscrew, back out the locking knob and temporarily place a thin cardboard spacer under the knob so as to space it about 0.010' away from the panel.

I NOTEh The set screws securing the knobs may "seize" and be difficult to remove. If so, apply a drop of penetrating oil and try again.

WMAE-SHAPE With 120 V ac from TBi-I to TBI-3, the waveshape from TPI to TP2 (high) should be as follows:

Very Fine Vertical Line Figure 9 Waveslape If the waveshape is found to differ, then QI or a closely associated component may be defective.

POWER SUPPLY Connect 120 V ac from TBI-l to 'rBl-3. Check to see that the following dc voltages are obtained.

Across C9 24 V dc Unregulated Across D3 15 Vdc R21-R33 junction to 0 V 12 Vdc (Trimmer R23 should vary this voltage)

D14 (Anode) toO0 V -12 Vdc D14 (Cathode stripe) toO0 V -6 Vdc

VOLTAGE AND BANDWIDTH W Place theTEST/OPERATE switch in theTEST position. Connect an accurate ac voltmeter from TB1-2 to T13-3. Vary the uncalibrated TEST knob and see that the RAISE and LOWER LEDs light at correct voltages with some dead band where both are extinguished.

Set theTOTAL BANDWIDTH knob to 2.0 and adjust trimmer R28 to give 2 V bandwidth. Set the VOLTAGE CENTER OF BAND dial to 125 and the TOTAL BANWIDTH knob to 1.0. Adjust R23 so that 25 V is in the center of the band as indicated by the RAISE and LOWER LEDs. Set the VOLTAGE CENTER OF BAND knob to 110 and adjust R31 so that 110 V is in the center of the band. Recheck 125 V and the bandwidth; these cahlbrations should not have changed.

Note that the TEST knob (R3) will only raise the voltage 5% from the P.T. voltage. The higher the voltmeter current, the more the voltage will be lowered.

TIMER Connect a reversing type motor starter from TB1-7 and TB1-9 to the low side of a 120 V ac supply. This source need not be regulated, and may be the same source that is used for calibration procedures. Connect the high side of this supply to TB1-8. If a motor starter is not available, two 60 W light bulbs may be connected from TBI1-7 and TB1-9 to the low side of the ac supply.

Set the TIME knob to 0. The appropriate lamps or portion of the motor starter should operate immediately after the RAISE or LOWER LED comes on as the test voltage is moved suddenly out of the dead band.

Set the TIME knob on 40. The output device should now operate 40 seconds after the voltage is moved suddenly out of the band. If not, adjust trimmer R39 to give the proper 40 seconds time. This procedure can be shortened by quickly adjusting R39. The device will then time out a bit later, and at least close to the desired 40 seconds on the first try.

RESISTANCE COMPENSATION Set the VOLTAGE CENTER OF BAND knob on 120. Connect a separate variable ac voltage from the output of a phase shifter through a 600 0, 10 W non-inductive resistor and ac ammeter from TB1-4 to TB1-3. Set the UNE DROP COMPENSATOR X knob on zero and the R knob on 12. Set the current to 0.2 A, angle to 00. Adjust R4 so that with current present, the voltage at the center of band is increased precisely 12 V. Note that the voltage on TB11-2 is not affected by this current but that the setpoint rises 12 V.

REACTANCE COMPENSATION Set the VOLTAGE CENTER OF BAND knob to 120.0 V rms. Set the UNE DROP COMPENSATOR switch on DIRECT, with the Xknob at 24 V, and the R knob at 0. Apply 0.1 A in-phase current; adjust R7 for 0.6 V decrease in bandcenter to 119A V.

With the Xknob at 24 V, and the R knob at 0, apply 0.1 A capacitive current (90 0 leading). Adjust R8 for 108 V bandeenter with the UNE DROP COMPENSATOR switch on DIRECT and 132 V bandcenter with the UNE DROP COMPENSATOR switch on REVERSE.

PARALLELING COMPENSATION

.Switch connections from TB1-4 and T131-3 toTBI-6 and T11-5 respectively. Set the current at 0.1 A and its phase angle 900 lagging. The center of band should now be close to 132 V.

TYPICAL VOLTAGES Using Simpson Model 270 Meter and Oscilloscope of I M.I input impedance.

FROM TO CONDITION VOLTAGE 0V 20 V Voltage 120 V ac, S1 on OPERATE 243 V dc Ac Ripple, above condition 1.0 V pp 0V 12V Ac Ripple 0.01 V pp 0V -6V Ac Ripple 0.06 V pp 0V -12 V Ac Ripple 0.2 V pp 12V Voltage 105 V ac -7.0 V dc Voltage 120 V ac -8.2 V dc Voltage 135 V ac -9.1 V dc 12 V TP-2 Voltage swing from +12 R (Regulated Voltage)

(for waveshape, see TEST PROCEDURE section)

Voltage 105 V ac +1.0 V dc to

-13.0 V dc Voltage 120 V ac +1.0 V dc to

-15.0 V dc Voltage 135 V ac +1.0 V dc to

-17.0 V dc 0V R46-R48 R26 cw, R29 ccw +3.2 V dc Junction R26 ccw, R29 ccw +5.1 V dc R26 cw, R29 ccw +3.4 V dc 0V R46-R48 Voltage in band -4.0 V dc Junction RAISE LED on +8.7 V dc Above condition after timing +8.9 V dc 0V R47-R49 Voltage in band -4.1 V dc Junction LOWER LED on +8.7 V dc Above condition after timing +8.9 V dc 0V R36-R38 Voltage in band 0 V dc Junction Voltage out of band +0.6 V dc 0V R41-C26 Voltage in band +0.6 V dc Junction Voltage out of band OV dc PARTS LIST M-0067E Tapchanger Control This list includes all electrical and mechanical parts which could conceivably either require replacement or be lost. The COMPONENT DESIGNATION is the same as that appearing on schematics or referred to in Instruction Books.

The BECO NUMBER refers to an index maintained by the company. This lists the currently available device which may be substituted even though the device originally supplied is obsolete and no longer available.

Parts marked by an asterisk* are not available from other sources. Either the original component or a current substitute will be carried in stock by Beckwith Electric.

Parts not marked with an asterisk are normally available from an electronics components house. Those parts or a current substitute will normally be available from Beckwith Electric stock.

In either case, when partsare ordered from Beckwith Electric, we willbe responsible for supplying thecurrent replacement in the shortest possible time.

Sufficient detailed description is also given to permit purchasing from an electronics parts house, providing the part is of equal or better quality to insure reliable operation. This may require some interpretation of specifications which may be avoided by direct purchase from Beckwith Electric using the BECO NUMBER.

Note that in a few instances, components are selected in final test. Procedures described in the TEST PROCEDURES Section must be followed in replacing these components.

, All resistors are 1/2 W unless noted.

COMPONENT BECO DECITO DESIGNATION NUMBER DIESCRIPTION 450-00036* P.C. Board, P-0273 C1 Not Used C2,C3,C4 000-00850 Capacitor, Polyester Film, 1 jiF+/-10%, 200 V C5 010-00529 Capacitor, Mylar, 0.47 p.F +/-10%, 200 V C6 000-W0501 Capacitor, Tantalum, 3.9 IjF +/-10%, 35 V C7 000-00617 Capacitor, Electrolytic,50 jiF +75%/-10%, 50 V C8 010-400527 Capacitor, Mylar, 0.068 I+/-F +/-10%, 100 V C9 000-40626 Capacitor, Electrolytic, 150 ;iF +75%/-10%, 75 V c00 000-00903 Capacitor, Ceramic Disc, 100 pF +/-10%, 1 kV Cll,C22,C23 000-O0902 Capacitor, Ceramic Disc, 680 pF +/-_10%, 1 kV 0 C12 000-00533 Capacitor, Tantalum, 150 pF+/-10%, 15 V COMPONENT BECO DESCRIPTION DESIGNATION NUMBER_

C13,C14,C1 6 Not Used C15 000-00418 Capacitor, Electrolytic, 170 +/-F +75%/-10%, 50 V C17,C18 010-M0526 Capacitor, Mylar, 0.033 4xF +/-10%, 100V C19 010-00531 Capacitor, Mylar, 0.1 ptF +/-10%, 200 V C20 Not Used C21 000-40918 Capacitor, Ceramic Disc, 0.0047 gFF+/-20%, 1 kV C24 000-00913 Capacitor, Ceramic Disc, 0.001 ;+/-F, I kV C25 000-00914 Capacitor, Ceramic Disc, 0.1 iF +/-20%, 50 V C26 000-00545 Capacitor, Solid Tantalum, 2.7 gF +/-10%, 15 V C27,C28 Refer to OPTIONAL COMPONENTS D1,D2,D5,D6,D13,D18 400-00211 Diode, Rectifier, 600 V, G.E. 1N5061 D3,D19 400-00030 Diode, Zener, 15 V +/-5%, 400 mW, 1N965B D4,D9-D12,D16 400-00200 Diode, 1N662/B692X13-4 D7 40O-00035 Diode, Reference, 6.2 V +/-5%, 400 mW, 1N823A, D8 Not Used D14,D15 400-00001 Diode, Zener, 6.2 V +/-5%, 400 mW, 1N753A/IN5234B D17 400-00043 Diode, Zener, 33 V +10%, 5 W, 1N5364A D20,D2-Z 400-00078 Diode, Zener, 15 V +/-5%, 5 W, 1N5352 D21 400-00021 Diode, Zener, 12 V +/-5%, 5 W, 1N5349 Fl, F2 420-00720 Microfuse, Plug-in, 1/4 A, Littelfuse 273.250 11J12 400-00722 Diode, Light Emitting, HP HLMP-3316 K1,K2 420-00118* Relay, AZ, 420-07-4H QI,Q3,Q4,Q6 400-00600 Integrated Circuit, Op Amp, UA741, TO- 99 Q2 400--"603 Integrated Circuit, Regulator, UA723, TO - 100 e COMPONENT DESIGNATION r BECO NUMBER DESCRIPTION i ...... ..

ii Vi Q5,Q7-29,Ql3 400-00300 Transistor, NPN Signal, 2N1711 Q1O-Q12 Not Used Q14-Q22 400-00728 Varistor, 275 V, G.E. V275LA2 Q23 400-00733 Varistor, 460 V, G.E. V460LB20 RI Not Used R2 290-00I52* Resistor, Metal Film, 1.5 K +/-2%

R3 360-00045* Potentiometer, 5 K, 2 W, U-0048-1 R4,R$ 360-00032 Trimmer, Cermet, 10 K +/-20%, Bourns 3386P-1-103 R5,R9,R40 360-00042 Potentiometer, 50 KY, 2 W, U-0048-2 R6 Not Used R7 360-00042 RIO Trimmer, Cermet, 2 K +/-20%, Bourns 3386P-1-202 290-00274 Resistor, Metal Film, 270 K +/-2%

R11 290-00364 Resistor, Metal Film, 357 K +/-2%

R12 330-00647 Resistor, Metal Film, 301 K+/-1%, 1/4 W R13 330-00643 Resistor, Metal Film, 274 K +/-1%, 1/4 W, RN60E R14 Not Used RIS 200-00102 Resistor, Carbon, 1 K +/-5%

R16 330-00638 Resistor, Metal Film, 243 K +/-1%, 1/4 W, RN60E R17 320-00466 Resistor, Metal Film, 4.75 K +/-1%, RN65D R18 320-00381 Resistor, Metal Film, 681 Q +/-1%, RN65D R19 200-=0222 Resistor, Carbon, 2.2 K +/-5%

R20, R67 200-00823 Resistor, Carbon, 82 K +/-5%

R21 200-00100 Resistor, Carbon, 10 ohms +/-5%

R22 Resistor, Metal Film, +/-1% 1/4 W, Factory Select, RN60E, U-0038 COMPONENT 1 ECO DESCRIPTION DESIGNATION NUMBER D R23,R28,R31 360-00034 Trimmer, Cermet, 200 ohms +/-20%, Bourns 3386P-1-201 R24 330-00469 Resistor, 5.11 K +/-1%, 1/4 W, RN60E R25 330-00393 Resistor, 909 ohms +/-1%, 1/4 W, RN60E R26,R29 360-00047* Potentiometer, 500 ohms, 4 W, U-0031-1 R27,R30 330-00460 Resistor, 4.12 K +/-1%, 1/4 W, RN60E R32 Not Used R33,R70,R73 200-00101 Resistor, Carbon, 100 ohms +/-5%

R34 200-00684 Resistor, Carbon, 680 K +/-5%

R35 200-"0155 Resistor, Carbon, 1.5 M +/-5%

R36 200-00683 Resistor, Carbon, 68 K +/-5%

R37 Refer to OPTIONAL COMPONENTS R38,R48,R49 200-00682 Resistor, Carbon, 6.8 K +/-5%

R39 360004 Trimmer, Cermet, 20 K +/-20%, Bourns 3386P-1-203 R41 200-00223 Resistor, Carbon, 22 K +/-5%

R42,R44,R65,R72 200-00103 Resistor, Carbon, 10 K +/-5%

R43 290-00434 Resistor, Metal Film, 430 K +/-2%

R45 20"-00226 Resistor, Carbon, 22 M +/-5%

R46, R47 200-00182 Resistor, Carbon, 1.8 K +/-5%

R50-R54 Not Used R55 200-00331 Resistor, Carbon, 330 ohms +/-5%

R56-R63 Not Used R64 200-W0104 Resistor, Carbon, 100 K +/-5%

R66 200-00273 Resistor, Carbon, 27 K +/-5%

R68 Not Used R69 290-00202 Resistor, Metal Film, 2 K +/-2%

COMPONENT BECO DESCIPTION 0 DESIGNATION NUMBER D R71 240-00151 Resistor, Carbon, 150 ohms +/-10%, 2 W S1, S2 430-00054 Switch, DPDT Toggle, U-0079 T1-T3 410-00023* Transformer, Current, U-0025 T4 410-00022* Transformer, Sensing, U-0027 T5 410-00017 Transformer, Power, U-0029 TBI 420-00012 Terminal Block, Cinch-Jones 12-140-Y REV V OPTIONAL COMPONENTS Single or Multi-Step Voltage Reduction Option R74 and/or R75 j Factory select (based on reduction specified)

REV A Instantaneous Voltage Reduction Option R37 200-00222 Resistor, Carbon, 2.2K +/-5%

REV A 50 Hz Operating Frequency Option Vtt C27 000-00716 Capacitor, Polyester, .18 gF +/-10%, 50 V C28 000-00859 Capacitor, Polyester, .39 jIF +/-10%, 50 V REV 0 0

C PATENT The units described in this manual are protected by U.S. Patent 3,721,894; and Canaidan Patent 985,368; British Patent 1,432607, Swedish Patent 7,301677-7; and other foreign patents applied for.

Buyer shall hold harmless and indemnify the Seller, its directors, officers, agents, and employees from any and all costs and expense, damage or loss, resulting from any alleged infringement of United States Letters Patent or rights accruing therefrom or trademarks whether federal, state, or common law, arising from the Seller's compliance with Buyer's designs, specifications, or instructions.

WARRANTY Seller hereby warrants that the goods which are the subject matter of this contract will be manufactured In a good workmanlike manner and all materials used therein will be new and reasonably suitable for the equipment. Seller warrants that if, during a period of two years from date of shipment of the equipment, the equipment rendered shall be found bythe Buyer to be faulty or shall failto perform in accordance withSeller's specifications of the product, Seller shall at his expense correct the same, provided however that Buyer shall ship the equipment prepaid to Seller's facility. The Seller's responsibility hereunder shall be limited to the replacement value of the equipment furnished under this contract.

The foregoing shall constitute the exclusiveremedyof the Buyerand the sole liabilityof the sellerand is in lieu of all other warranties, whether written, oral, implied or statutory, except as to the title of the Seller to the equipment furnished. No implied statutory warranty of merchantability or of fitness for a particular purpose shall apply. Seller does not warrant any product or services of others which Buyer has designated.

SELLER MAKES NO WARRANTIES EXPRESSED OR IMPLIED OTHER THAN THOSE SET OUT ABOVE. SELLER SPECIFICALLY EXCLUDES THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THERE ARE NO WARRANTIES WHICH EXTEND BEYOND THE DESCRIPTION CONTAINED HEREIN. IN NO EVENT SHALL SELLER BE LIABLE FOR CONSEQUENTIAL, EXEMPLARY, OR PUNITIVE DAMACES OF WHATEVER NATURE.

Any equipment returned for repair must be sent with transportation charges prepaid. The equipment must remain the property of the Buyer. The aforementioned warranties arevoid if the value of the unit is invoiced to the Seller at the time of return.

INDEMNIFICATION The Seller shall not be liable for any property damages whatsoever or claims of any kind whether based on contract, warranty, tort including negligence or otherwise, or for any loss or damage arising out of, connected with, or resulting from this contract, or from the performance or breach thereof, or from all services covered by or furnished under this contract.

In no event shallthe Sellerbe liableforspecial, incldental, exemplaryorconsequential damages including, but not limited to loss of profits or revenue, loss of use of the equipment or any associated equipment, cost of capital, cost of purchased power, cost of substitute equipment, facilities or services, downtime costs, or claims or damages of customers or employees of the Buyer for such damages, regardless of whether said claim or damages Is based on contract, warranty, tort including negligence or otherwise.

Under no circumstances shall the Seller be liable for any personal injury whatsoever.

It Is agreed that when the equipment furnished hereunder or any services furnished hereunder are to be used or performed in connection with any nuclear installation, facility, or activity, Seller shall have no liability for any nuclear damage, personal injury, property damage, or nuclear contamination to any property located at or near the site of the nuclear facility. Buyer agrees to Indemnify and hold harmless the Seller against any and all liability associated therewith whatsoever whether based on contract, tort, or otherwise. Nuclear installation or facility means any nuclear reactor and includes the site on which any of the foregoing is located, all operations conducted on such site and all premises used for such operations. It is the intention of the parties that this is a complete indemnification and hold harmless agreement in regard to all claims arising from nuclear operations of Buyer.

067

°%C S

• 0 iII

• BECKWITH ELECTRIC CO., INC.

Mailing Address P.O. Box 2999 Largo, Florida 34649-2999 Shipping Address 6190 - 118th Avenue North Largo, Florida 34643 (813) 535-3408

© 1993 Beckwith Electric Printed in the U.S.A. 6/93

- c,,,,

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/5~7/5~ ~Service Information Power Transformers Powe Trasfor ersCOOPER 15-7/ 5*- 01;ý - lO-c**,i°~,,t,cooGFU , POWER SYSTEMS McGraw-Edison@ Load Tap Changer Motor Control S210-40-1 8 Maintenance Instructions CONTENTS o0 Introduction ................................... 1 2

Safety Advisory .....................................................

Motor Control ..........................................................

Operation by Electrical Hand Control ........................

Components ...........................................................

2 2

2 nE. 12

1. Motor Reversing Contractors .......................... 2

2. Motor Braking Contractor .....................................

3. Sequential Tim ing Relay .......................................

2 2

I

4. DC Power Source ........................................... 2

5. DC Braking Tim ing Relay ..................................... 2

6. Motor B reaker ....................................................... 2

7. Operation Counter ......................................... 3

8. Fuses .................................................................... 3 84 L 84 R

9. Heater Switch .................................................. 3 D j

10. Convenience Outlet .........................................

11. Motor Capacitor .............................................

3 3

[ j W iring ..................................................................... 3 <

Maintenance .................................................................. 3 PULL-OUT FUSE BLOCK z Troubleshooting ..................................................... 4

• 1. Load Tap Changer does not respond to RAISE-LOWER switch .................. 4 FBA F-

2. Load Tap Changer operates in one direction only ................................................. 4 84D

3. Load Tap Changer over-runs ............................... 4

4. Load Tap Changer stops off position ................... 4 INTRODUCTION FUSES The Load Tap Changer (LTC) Controls are divided into four basic components: 1) Drive Mechanism, 2) Motor Control,

3) Automatic Regulation (when required), 4) Vacuum Inter-rupter Monitoring System (when applicable). Service Infor- D84A mation S210-40-18 describes the standard features for the &

LTC motor control of McGraw-Edison load tap changing &?

084B mechanisms. The motor control panel is shown in Figure 1.

WARNING YOU MUST HAVE TRAINING INTHE OPERATION OF THIS EQUIPMENT BEFORE USING IT. YOU MUST FBB ALSO READ, UNDERSTAND AND OBEY ALL SAFETY ADVISORIES. l T84

,o LLi Figure 1.

s o Motor Control Panel These instructionsdonotclaimtocoveralldetailsorvariationsintheequipment,procedures,orprocessesdescribed,nortoprovide directionsformeeting every possible contingency during installation,operation,or maintenance. When additionalinformation is desired,please contactyour CooperPower Systems Representative.

March 1991

• Supercedes 9/90 * © 1991 Cooper Power Systems. Inc. 1 Printed in U.S.A.

-. 2 SAFETY ADVISORY OPERATION BY ELECTRICAL HAND CONTROL This Safety Advisory is intended to identify the potential hazards and consequences to anyone who comes in contact with their contents. The supportive wording is expected to elicit a safe response from adults.

zI WARNING DO NOT OPERATE EQUIPMENT UNLESS IT IS COM-PLETELY AND PROPERLY ASSEMBLED.

& DANGER Hand-operated control switches are normally provided in IMMEDIATE HAZARDS WHICH WILL RESULT IN the control cabinet so that the Load Tap Changer mecha-DEATH OR SEVERE PERSONAL INJURY OR SUB- nism may be operated during installation or periods of STANTIAL PROPERTY DAMAGE, IF PROPER PRE- preventive maintenance. All control circuits must be ener-CAUTIONS ARE NOT TAKEN. gized and functioning properly. The Load Tap Changer switching mechanism may be energized and carrying load.

LI\ WARNING I'IA.JMLU*I Un vrlgfr! Cru"m~' I l Io.nr ovv"'.UULV COMPONENTS RESULT INDEATH OR SEVERE PERSONAL INJURY The actual components furnished on any specific unit, OR SUBSTANTIAL PROPERTY DAMAGE, IF PROPER along with their ratings, may be determined by reading the PRECAUTIONS ARE NOT TAKEN. parts description contained on the LTC Schematic draw-ings issued with that particular unit. The connections to these components are also shown on these same draw-I& CAUTION in9The motor control panel is usually equipped with the HAZARDS OR UNSAFE PRACTICES WHICH COULD RESULT IN MINOR PERSONAL INJURY OR PROD- following components:

UCT OR PROPERTY DAMAGE, IF PROPER PRE- 1. Motor Reversing Contactors (84R and 84L)

CAUTIONS ARE NOT TAKEN. These contactors control the application of AC voltage to the LTC motor windings when a tap change is initialized. These contactors are mounted on a common NOTICE base and are electrically and mechanically interlocked SITUATION WHICH COULD RESULT IN PRODUCT with each other. Each contactor is also equipped with OR-PROPERTY DAMAGE WITH NO PROBABILITY additional contacts to provide electrical interlocking OF PERSONAL INJURY, IF PROPER PRECAUTIONS between the LTC motor AC running and DC braking ARE NOT TAKEN. circuits.

2. Motor Braking Contactor (84D)

This contactor controls the application of the DC volt-MOTOR CONTROL age to the LTC motor windings in parallel, and is part of Motor control systems for Load Tap Changer transformers the automatic DC braking circuit. The duration of this may be electrically hand controlled or automatically initi- application is controlled by the DC braking timing relay ated, with control facilities specified to meet operating (62A). This contactor is equipped with additional con-requirements. tacts to provide electrical interlocking between the motor DC braking and AC running circuits.

The motor control circuit uses electromechanical 3. Sequential Timing Relay (33A) contactors and relays which are both mechanically and This relay provides an immediate seal-in of a single electrically interlocked to insure positive operation of the electrical control signal to initialize a tap change op-Load Tap Changer motor. eration. It also provides a controlled time delay at the McGraw-Edison utilizes two similar, but slightly differ-ent, motor control panels: 1) To control a 115 volt, single completion of the braking cycle to assure positive phase, 60 Hertz reversible motor, 2) To control a 230 volt, operation of the Load Tap Changer.

single phase, 60 Hertz reversible motor. 4. DC Power Source Operating the Load Tap Changer from one operating This source is derived from a circuit consisting of a position to another requires a single electrical control fuse, an auxiliary step-down transformer (T84), and a signal to initialize the motor control system. This electrical full wave rectifier (two diodes, D84A & D84B, on a heat control signal or momentary contact must be closed from sink). The transformer connections are determined by 0.10 to 0.25 second duration, to ensure proper operation the motor used with the Load Tap Changer drive mechanism.

of the motor control system. The LTC drive mechanism 5. DC Braking Timing Relay (62A) then completes the tap change without any interruption. This timing relay determines the duration of the DC Automatic braking following a tap change is accom-plished bythe trouble-free DC braking method (DC voltage braking action. The relay is equipped with a normally is applied to the motor windings in parallel), incorporating open contact which closes immediately when the relay an auxiliary step-down transformer and a full wave rectifier. is energized by the operation of either the 84R or 84L contactor. The 62A contact stays closed for approxi-Current limiting time delay fuse(s) protect the LTC supply mately two seconds after the 84R or 84L contactor has circuitand a fuse protects the DC braking circuit. A breaker been released, to energize the motor braking contactor is provided for protection of the LTC drive mechanism motor. 6. (84D).

Motor Breaker (8-84)

The motor breaker is provided and wired for motor protection only. The number of poles and current rating of the breaker are determined by the Load Tap Changer mechanism motor requirements.

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. 7. Operation Counter (OC)

The operation counter keeps an accumulative total of the number of electrically controlled (motor driven) tap change operations of the LTC mechanism.

8. Fuses WIRING ACAUTION DO NOT TOUCH BARE WIRES,-UVE PARTS, OR TERMINALS, TO PREVENT ELECTRICAL SHOCK Zi* CAUTION HAZARD DO NOT REMOVE ANY FUSE UNDER LOAD. FUSE Many units are furnished with special equipment. Consult BLOCKS ARE FOR DISCONNECT USE ONLY. the wiring diagrams furnished with each specific unit for customer conforming variations. The LTC Schematic Separate fuses protect the control circuits, DC braking drawings which accompany each unit must be consulted circuit, and auxiliary circuits. A fuse has been provided before making the power supply connections.

inthe motor control circuitto prevent electrical operation of the LTC mechanism in the event of DC braking circuit failure. All of the fuses are 250 volt cartridge type; however, the ampere rating and type depend on the I& - CAUTION INCORRECTSUPPLY VOLTAGE MAY DAMAGETHE application. CONTROLS. REFER TO LTC SCHEMATIC DRAW-INGS. I NOTICE MAINTENANCE THE PULL-OUT FUSE BLOCK (FBA) USED IN THE MOTOR CONTROL AND SOURCE CIRCUITS HAS BEEN FURNISHED AS A SAFETY FEATURE. THIS & WARNING FUSE BLOCK SHOULD BE PULLED OPEN TO PROVIDE A VISUAL DISCONNECT WHEN SERVIC- DISCONNECT AND GROUND ALL ELECTRICAL ING THE CONTROL CIRCUITS, MOTOR CIRCUITS, POWER SOURCES, TO PREVENT ELECTRICAL LTC DRIVE MECHANISM OR LTC SWITCH. I SHOCK HAZARD.

IA & WARNING GROUND AND SHORT CIRCUIT ALL CURRENT TRANSFORMERS, TO PREVENT HIGH VOLTAGE SHOCK HAZARD.

9. Heater Switch (43H)

This ON-OFF switch controls the space heater(s) located Maintenance and repairs must be done by authorized in the cabinet. It is recommended that the heater(s) be personnel only. Read, understand and obey all Safety left on at all times to prevent moisture condensation and Advisories, before doing any repairs, maintenance, or attendant corrosion. changing the features and accessories of this equipment.

During the performance of established maintenance procedures, annually, and every 100,000 tap changes the

//i CAUTION LTC Motor Control Panel, its components and wiring must ENERGIZE HEATERS DURING STORAGE TO PRE- be cleaned of all accumulated dust, dirt, and foreign VENT MOISTURE CONDENSATION AND ATTEN- debris. Make certain all electrical connections are clean DANT CORROSION. PROVIDE TEMPORARY and securely tightened. Inspect for worn, cracked, frayed HEATER POWER IF PERMANENT POWER IS NOT or otherwise damaged components and wires. Keep all AVAILABLE. fasteners tight. Keep all adjustments according to factory specifications Immediately notify Cooper Power Systems upon the

10. Convenience Outlet (DO) detection of probable defective parts. Failure to perform This NEMA 5-15R separately fused duplex outlet may be used for portable lights and small power hand tools. these minimal procedures could void the limited warranty.

11. Motor Capacitor (C84)

This capacitor is used to both start and run the LTC motor. Its voltage rating and capacitance value are determined by the LTC drive mechanism motor re-quirements.

a & CAUTION SHORT CIRCUIT CAPACITOR TERMINALS, TO PREVENT ELECTRICAL SHOCK HAZARD.

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TROUBLESHOOTING 3. Load Tap Changer over-runs (makes additional (FOR EQUIPMENT BUILT AFTER 1/1/82) uninitiated steps). Refer to Service Information instruc-Electrical Operation of Load Tap Changer Motor Control tions covering specific LTC mechanisms.

1. Load Tap Changer does not respond to RAISE- a. Check seal-in switch (33/1) setting. Refer to instruc-LOWER switch. tions for LTC switch.

a. Check AUTO-MANUAL, REMOTE-LOCAL, RAISE- b. Check 84R and 84L contactors for binding and LOWER switches and their wiring for open circuit. erratic operation.

b. Check fuses and motor breaker. Read specific LTC c. Check DC brakin.g circuit (84D contactor, 62A schematic drawings for proper ratings. If braking timing relay, rectifier diodes, 84R-84L contacts, fuse is open, check diodes (D84A and D84B) for braking transformer).

short circuit. If a diode shorting problem persists, check timing of 62A relay. Check station service 4. Load Tap Changer stops off position. Refer to Ser-supply for transient problems. vice Information instructions covering specific LTC

c. Check position of handcrank. (Must be in storage mechanisms.

position.) a. Check seal-in switch (3311) setting. Refer to instruc-

d. Check 84R and 84L contacts and 840 contacts. tions for LTC switch.

e. Check mechanical stop switch (if supplied). Itmust b. Check operation of 33A relay.

be closed. c. Check 84R and 84L contactors.

f. If reversing contactor operates and motor breaker d. Check all wiring associated with the 84R and 84L does not trip, check motor, capacitor, reversing contacts, the tap changer motor and the power contactor contacts, and associated wiring for open supply.

circuit condition. e. Check 84D contactor for erratic operation.

g. If reversing contactor operates and motor breaker f. Check handcrank switch (89C) and mechanical trips; check motor, motor capacitor, and associ- stop switch (39) for erratic operation.

ated wiring for short circuit condition. Check for g. Check for mechanical binding in the Load Tap mechanical binding in Load Tap Changer mecha- Changer mechanism, Read LTC Maintenance and nism. (Read LTC Maintenance and Operating In- Instruction Manual.

structions.)

2. Load Tap Changer operates in one direction only.

a. Check 84R-84L contactor for mechanical binding, open contact and open coil.

b. Check for open-limit switch (84LS/R1 and 84LS/

L1). They are normally closed.

c. Check RAISE-LOWER switch and associated wir-ing for open circuit condition.

d. Check wires for loose connections or open circuit.

F* COOPER POWER SYSTEMS Mcmaw.EdlsonO Power Products Post Office Box 440 to Canonsburg, PA 15317 4