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 Vice President Calvert Cliffs Nuclear Power Plant, LLC 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 fliesel G~enerator I .icense Amendment Reaiiest Regarding Enhancements to

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 Region 1 Administrator, NRC CCNPP Resident Inspector, 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 provided per diesel generator (DG) or per safety-related bus 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 Final Safety 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 SB 2ZA (B 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 1 E 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 11 12 21 22 previously operating I ATTACHMENT (1)RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING ENHANCEMENTS TO DIESEL GENERATOR LICENSE AMENDMENT REQUEST 1ZB 2ZA 2ZB SEQUENCER TIME IZA (BU (BUS 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 during last five 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 limiting power factor, the voltage regulators must be placed in the manual mode of operation.

This operational mode 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 increased in 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 testing practice.

Therefore, we propose to change the SR by removing the power factor numbers and the associated Note 2. The surveillance testing will be conducted at the required loads for 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 during the surveillance test but is expected to be approximately 0.9." Regarding the above statements, please provide the following information:

a. Explain why the voltage regulator needs to be in the manual mode in order to reduce the equipment risk during the surveillance test. Provide catalog cut/operational details 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 during the 2-hour period by keeping the voltage regulators in manual mode of operation, so as to limit the equipment risk to any degraded grid voltage. If yes, provide details of power 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 of Attachment I of the LAR, the licensee described the kW loading requirements for the DGfor SR 3.8.1.11.

Provide a summary of the loading calculations for each DG for 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 design finction.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 (equivalent to the newly proposed SR 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 required to 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 deviation from 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 Power Transformers ftLoad Tap Changing Equipment-Installation, Operation, and Maintenance Service InformationCOOPER POWER SYSTEMS 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 W arranty ........................

19 Exploded Views ..................

20 GENERAL The Type 550CS is an improved version of the original Type 550C load-tap-chang-ing arcing-tap-selector switch first intro-duced in 1964 for medium-size trans-formers.It offers dependable, quiet operation through a normal voltage-regulation range of plus ten percent and minus ten percent in thirty-two

%-percent steps;other regulation ranges are also available.

They meet appropriate national standards.

Load-tap-changing arcing-tap-selector switches are designed to be operated.Occasionally LTC transformers are used in applications where the LTC is not re-quired and does not operate for extended Speriods of time. In these situations, it is good operating practice to by-pass the LTC. Refer inquiries concerning by-pass Figure 1.Typical McGraw-Edison transformer with LTC equipmenL arrangements to the Service Department, McGraw-Edison Power Products, Canons-burg, PA 15317.The LTC mechanism consists of three major components:

the tap selector, the drive, and the controls.

The tap selector is located in an oil-filled compartment welded to the upper section of the trans-former tank. This compartment has an oil-tight Pennsylite*

panel isolating the tap selector from the transformer.

The drive and the controls are in an air-filled weatherproof compartment located directly beneath the tap-selector com-partment.

Part of the drive is contained in a cast-aluminum housing within the com-partment.

A universal driveshaft con-nects the drive with the tap selector through a self-compensating spring-loaded stuffing box in the selector com-partment.This Service Information bulletin covers in detail the tap selector and the drive unit; the controls are covered in S210-40-14, Controls for Power-Type Load Tap Changing Equipment.

SHIPPING The tap-selector compartment is shipped filled with either oil, dry nitrogen gas, or dry air. It is standard practice for McGraw-Edison to ship the LTC switch under the same conditions as the main transformer.

To determine the conditions under which the LTC switch has been shipped, refer to the detailed outline drawings supplied with the equipment.

These instructions do not claim to cover all details or variations in the equipment, procedure, or process described, nor to provide directions for meeting every possible contingency during installation, operation, or maintenance.

When additional information is desired to 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 Immediately upon receipt of an LTC trans-former--preferably before unloading-thoroughly inspect the exterior and the interior of the LTC and the transformer for damage, rough handling in transit, and shortage, If initial inspection reveals evidence of damage, rough handling in transit, and/or shortage, notify-and file a claim with-the carrier at once. Also notify McGraw-Edison Company, Power Systems Divi-sion, Post Office Box 440, Canonsburg, PA 15317.All leaks must be located and repaired before proceeding with the installation or storage.STORAGE If. after initial inspection, a transformer is not to be placed in the service-ready con-dition Immediately, it Is considered to be in storage.Refer to Service Information S210-05-5, Liquid-Immersed Units-installation and Maintenance Instructions.

PRELIMINARY PREPARATIONS Refer to the PRELIMINARY PREPARA-TIONS PRIOR TO FILLING Section in Service Information S210-10-1, Vacuum Filling Oil-Immersed Power Transformers.

D5RAIN AND 1 " PIPE SAMPLING PLUG VALVE Figure 2.Installation of open-breather components.

2. Check the tap selector, drive shaft, and drive box (Figure 3) to make sure they are free from foreign objects that could interfere with proper operation.

3. Remove all the blocking from the auto-matic control panel.4. Check the tap selector and the drive box for proper neutral-position relationship.

Refer to the NEUTRAL-POSITION RELATIONSHIP Section.If the proper neutral-position relation-ship is not present, notify McGraw-Edison Company. Power Systems Divi-sion, Post Office Box 440. Canonsburg, PA 15317.5. Place the handcrank on the handcrank shaft in the drive box (Figure 4).6. Handcrank the LTC through its entire range to make sure there is no me-chanical interference and operation is satisfactory.

Refer to Operation by Handcrank in the PRINCIPLES OF OPERATION Section.It is normal for the greatest in-crease in force required to move the switch to occur in moving the switch from neutral to Position 1 raise or from Position 1 raise to neutral. It is at these positions that the additional load of operating the reversing switch is picked up. Movement of the revers-ing switch also comes into play in mov-ing the switch from Position 2 raise to Position 3 raise and Position 1 lower to Position 2 lower. In these positions, the reversing switch contacts are moved from a first position to a second position on the stationary contact.B. Install the screen and retainer on the inlet breather pipe.C. Remove the 1-in. pipe plug from the topof the tap-selector compartment.

D. install the outlet breather, using a suitable thread-sealing compound (GE Glyptol 1201 or its equivalent).

Note: Switches shiipped prior to 1970 utilized a sealed compartment equipped with a 4 psi positive pressure relief de-vice. McGraw-Edison's recommenda-tion is the open-breathing system. It is possible to modify the switch compart-ments in the field to incorporate the open breathing arrangement.

Contact Service Department, McGraw-Edison Power Systems Division, Box 440, Canons-burg. PA 15317.A WARNING Before performing any work on the LTC arcing tap selector switch, drive or con-trols, observe the warnings and cautions appearing in Service Information S210-40-14 and S210-40-18

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

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

2. Open the tap-selector compartment door.3. Inspect the tap selector for physical damage.4. Inspect the tap-selector compartment for evidence of moisture.A. If there is any sign of moisture inside the compartment, determine the ex-tent and the manner by which the moisture entered and correct the condition.

B.Any moisture detected in the tap-selector compartment must be re-moved using clean, dry cloths.INSTALLATION

1. Install the open-breather system on the tap-selector compartment (Figure 2).A. Carefully remove the pipe cap from the inlet breather pipe protruding from the bottom of the compartment.

The pipe ma~y contain a small amount of oil that splashed in dur-ing manufacturing or shipping.TAP-SELECTOR COMPARTMENT OIL LEVEL GAGE ARCING SW1TCH CONTROL COMPARTMENT AUXILIARY CONTROL DEVICES (MOTOR CONTROL PANEL)DRIVE UNIT SAFETY VALVE INLET BREATHER PIPE DRIVE SHAFT AUTOMATIC CONTROL PANEL 9 Figure 3.Components of LTC mechanism.

2 S210-40-3 ft"ON POSITION-

8. Energize the motor control panel POINTER (Figure 3)./ UNIVERSAL

9. Using the manual control switch, NDICATOR DRIVE SHAFT operate the LTC electrically step-Eby-step through its entire range.LIMIT SWITCHES Refer to Operdtion by Electrical Hand Control in the PRINCIPLES OF OPERATION Section.A. Make sure the drive unit and the tap selector are stopping properly in position and the ON-POSITION POINTER is centered on the ON-POSITION INDICATOR PLATE.If not, refer to the TROUBLE-SHOOTING GUIDE.B. Make sure the operation counter is functioning properly.It not, refer to the TROUBLE-SHOOTING GUIDE.C. Check the limit-switch settings (Figure 4) by attempting to oper-HAND-CRANK ate the control beyond the limit SHAFT DRIVE MOTOR position. (The motor should not POSITION operate.)INDICATOR If the motor operates, refer to the TROUBLESHOOTING GUIDE.Figure 4. D.Check the handcrank switch by LTC drive unit. removing the crank from its holder and operating the control switch.7. Remove the handcrank from the hand- (The motor should not operate.)crank shaft; return the crank to its If the motor operates, refer to the holder. TROUBLESHOOTING GUIDE.SWR10. Test the dielectric strength and mois-S WARNIN'G ture content of the new oil before Before performing any work on the LTO filling the compartment.

arcing-tap-selector switch, drive or con- Refer to Service Information S210-trols, observe the warnings and cautions 05-3. The new oil must test at 15 ppm (wt) moisture content and 30 kV mini-mum in standard gap (ASTM D 877)or 18 kVminimum in O.040gap(ASTM D 1816).11, Close the drain-and-sampling valve, replacing the i-in. pipe plug.12. Refill the tap-selector compartment with oil to the 25 C level marked on the oil-level gage.13. Pressure test the tap-selector com-partment.Refer to the TESTING FOR LEAKS (PRESSURE TESTING) Section for recommended test procedures.

14. Operate the LTC approximately 30 operations to eliminate any air pockets that may have developed during re-filling.Refer to the Arcing-Tap Switch-Type Load Tap Changer Section in Service Information S210-10-1, Vacuum Filling Oil-Immersed Power Transformers.

If the transformer has been in storage for more than three months, operate the LTC for 10 minutes (approximately 800 operations) to re-seat, the con-tacts and eliminate any air pockets resulting from refilling.

CAUTION The drive motor is designed for inter-mittent duty. If the motor is to be operated longer than 10 minutes con-tinuously, it must be fan-cooled.

15. Energize the transformer.

appearing in Service Information S210-40-14 and S210-40-18 REVERSING ARM ASSEMBLY REVERSING SWITCH MOVABLE CONTACT STATIONARY CONTACTS POST INSULATORS MOVABLE CONTACTS REVERSING ROLLER STUB SHAFT i REVERSING FRONT INSULATING PANEL SEGMENT i INSULATING PANEL ROLLER PLATES HORIZONTAL DRIVE SHAFT INSULATING DRIVE SECTIONS SCROLL CAM VERTICAL DRIVE SHAFT Figure 5.Tap-selector assembly. (Shown In neutral position.)

3 PRINCIPLES OF OPERATION Drive Mechanism The drive with its associated motor-corntrol panel is mounted in the control compartment located below the tap-selector compartment.

Mechanical fea-tures of the drive unit are shown in Figure 4.The drive, enclosed in an air-filled, cast-aluminum housing, is equipped with self-lubricating bearings; the gearing is coated with silicone grease during assembly to protect against rust. The limit switches and seal-in switch are mounted on the drive box.A mechanical stop located inside the drive housing prevents operation of the tap selector beyond the limit positions when hand cranking, or in the event of electrical limit-switch failure.The LTC is driven by a 115-Vac, 60-Hz, single-phase, capacitor-start, capacitor-run motor with positive stopping of the drive being achieved by dc braking of the motor. It is important that the motor has a well-regulated voltage supply (mea-sured at the motor).CAUTION The drive motor is designed for inter-mittent duty. It the motor is to be operated longer than ten minutes con-tinuously, it must be fan cooled.Numerals in parentheses in the following discussion refer to Figure 6.The motor (75), through a spur gear reduction (101 and 99). drives the spur gears(103 and 109). The hand-crank shaft (100) is attached to spur gear (103). Spur gear (92) drives the universal shaft (38)through a pair of miter gears (91 and 47).Shaft (81) extends through the rear of the drive housing and has mounted on it the seal-in switch operating cam (78). The motion of this shaft is transmitted through a pair of miter gears(78 and 77)and worm-gear assembly (49 and 69) to the position indicator and limit-switch arm (58).Upon energization of the motor, the ap-proximate time required to complete one tap change for a 32-step switch is one second. For a 16-step switch the time of the change is approximately doubled.Located on the universal driveshaft coupling (36) at the top of the drive hous-ing (43) is an ON-POSITION pointer.Normally, at the completion of each tap change this pointer should be centered on the ON-POSITION plate which is attached to the drive housing (see Checks and Adjustments Nos. I and 2 in the TROUBLESHOOTING GUIDE Section).The pointer being anywhere between the indicating ends of the ON POSITION plate indicates that the tap-selector contacts are fully in contact.A CAUTION Before dismantling the drive box, the LTC mechanism must be in the neutral position (see Neutral-Position Relation-ship in TROUBLESHOOTING GUIDE Section).

Incorrect timing within the drive box or between drive and tap selector can cause transformer failure.If trouble is suspected within the drive housing, the McGraw-Edison Power Sys-tems Division transformer service section 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 i The tap selector is an arcing-tap-switch type load tap changer. The selector is mounted on a Pennsylite insulating panel which is oil-tight and isolates the main transformer compartment from the tap-selector compartment.

The insulating panel will withstand full vacuum and serves as the terminal board for the taps from the transformer winding and the leads from the preventive-autotransformer.

& CAUTION Do not operate the LTC switch when the transformer is under full vacuum condition.

The tap-selector compartment is open-breathing.

The purpose of an open-breathing system is to exhaust the gases formed by breakdown of the oil by con-tact arcing. These gases can have a plat-ing effect on copper and copper alloy surfaces which increases contact resis-tance. The compartment is also equipped with a safety valve (Figure 2) to exhaust any excessive pressure build up.Note: Switches shipped prior to 1970 utilized a sealed compartment equipped with a 4 psi positive pressure relief device. Experience and verifying tests revealed that a hard black resis-tive coating could form on copper and copper-bearing alloy surfaces from polymerization of acetylene.

Acetylene is always produced with arcing in oil. McGraw-Edison's recommenda-tion is the open-breather system to eliminate as much of the acetylene as possible.

It is possible to modify the switch compartments in the field to incorporate the open breathing arrangement.

Contact the Service Department, McGraw-Edison Power Systems Division, Canonsburg, Pennsylvania 15317.Numerals in parentheses in the following discussion refer to Figure 7.The universal driveshaft enters the tap-selector compartment through a self-compensating, spring-loaded stuffing box. The motion of the universal drive-shaft is transmitted through an insulating coupling (5) to the center phase of the tap selector through a pair of miter gears (21).one of which is attached to the scroll-cam shaft. Motion is transmitted to the two end phases through horizontal insulating shafts (5 and 20). Operation of the end phases is identical to that of the center phase described below.The motion of the universal driveshaft transmitted to the scroll-cam shaft causes the scroll cam (16) to rotate 180 degrees in the case of a 32-step switch, and 360 degrees in the case of 16-step switch.Every 180-degree movement of the scroll cam operates one of two roller plates (57 and 62) which are located on opposite sides of the scroll cam. Attached to each roller plate and operating con-centrically are the movable-arcing-con-tact shafts (39 and 37), with movable-arcing-contact assemblies attached to insulating supports.The movable arcing contacts (36)operate in different planes. The scroll cam, in moving 180 degrees, moves one or the other roller plate, causing the movable arcing contact to be moved from one stationary arcing contact (25) to the one adjacent.

At the end of this move-ment, the dwell section of the scroll cam is positioned between two adjacent rollers of each roller plate and, because the arcing contact shafts are attached to the roller plates, they are thus locked in position.In the case of a 32-step switch, the movable arcing contacts are positioned on the same stationary contact or adjacent stationery contacts for each tap change.In a 16-step switch, the movable arcing contacts are both positioned on the same stationary contact for each tap change.The reversing switch changes winding connections for raise or lower regulation.

The reversing switch for each phase.operated as the selector switches pass through neutral position, is actuated by a roller projecting from the face of the rear roller plate.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[A WARNING Before performing any work on the LTC arcing-tap-selector switch, drive, or con-trols, observe the warnings and cautions appearing in Service Information S210-40-14 and S210-40-18.

& WARNING The three revolutions of the hand-crank MUST be accomplished in 3 seconds and the switch MUST be hand cranked steadily IN ONE DIRECTION ONLY until the ON-POSITION POINTER is cen-tered over the ON-POSITION plate. If the above instructions are not followed, transformer failure can occur.For automatic operation of the mecha-nism, the control instruments, voltage-regulating relay, and line-drop compensa-tor must be adjusted for the specific requirements of the system. Refer to ADJUSTMENTS Section in S210-40-14, Controls for Power-Type Load-Tap-Changing Equipment.

With all controls properly set, the load-tap-changing mechanism will operate automatically, giving the proper correc-tion in secondary voltage as required by the setting of the voltage-regulating relay and line-drop compensator.

Operation by Electrical Hand Control For operation of the mechanism by hand control. refer to S210-40-14, "Controls for Power-Type Load-Tap-Changing Equip-ment." With the controls properly set, operate the control switch to either RAISE or LOWER as desired.Operation by Handcrank A WARNZNt~A. For each tap change, in the case of a 16-step switch, six revolutions of the handcrank are required.

Crank clock-wise to lower and counterclockwise to raise voltage.A WARNING The six revolutions of the handcrank MUST be accomplished in 6 seconds and the swich MUST be hand cranked steadily IN ONE DIRECTION ONLY until the on-position pointer is centered over the ON-POSITION plate. If the above in-structions are not followed, transformer failure can occur.A WARNING McGraw-Edison DOES NOT recom-mend hand cranking the LTC mech-anism while the transformer is energized.

However, if IN AN EMERGENCY SITUATION you choose to hand crank the LTC mechanism while the transformer is ENERGIZED, the following procedure MUST be ad-hered to. otherwise transformer failure can occur, 1. Place the LTC motor breaker, located on the motor control panel, and the relay breaker, located on the automatic control panel, in the OFF positions.

2. Remove the handcrank.

The removal of the handcrank opens the handcrank switch in the motor circuit and de-energizes the motor.NOTE: A handcrank stop prevents the operator from hand cranking the tap changer through a limit.3. For each tap change, in the case of a 32-step switch, three revolutions.

of the handcrank are required.

Crank clockwise to lower and counterclock-wise to raise voltage.5. After the tap change is complete, remove and replace the handcrank in its holder thus closing the handerank switch.6. Place the LTC motor breaker and re-lay breaker back in the ON position enabling the LTC switch to be oper-ated electrically.

When it is desired to operate the LTC mechanism by handcrank for preven-tive maintenance with the transformer DEENERGIZED, the procedure is iden-tical to that described for "operation by handcrank while the transformer is energized" EXCEPT for the following:

1. The time required to complete a tap change is not limited.2. The restriction for hand cranking in one direction only no longer applies.MAINTENANCE Periodic preventive maintenance in-spection of the LTC mechanism is re-quired. Generally, the interval between inspections is determined by the amount of contact erosion based on the number of tap changes as shown on the opera-tion counter. The interval between inspec-tions of like LTC mechanisms will vary considerably depending on individual conditions.

For normal utility systems it is recommended that a thorough inspec-tion of the mechanism be made at the end of the first year of operation and that subsequent inspections be based on the amount of contact erosion and number of tap changes noted at the end of the first year.1. Deenergize the transformer.

The transformer must be deenergized before performing any maintenance in-spection or work on an LTC. Inspecting or working on an LTC mechanism while the transformer is energized may result in bodily injury.2. Energize the control circuit and operate the mechanism by electrical hand control step by step through the entire range.A. Observing the position indicator and ON-POSITION pointer, make sure the drive unit is stopping properly on position.If not, refer to Checks and Ad-justments Nos. 1 and 2 in the TROUBLESHOOTING GUIDE Section.B. Check that the operation counter is functioning.

If not, refer to the TROUBLE-SHOOTING GUIDE Section.C. Check the limit-switch settings by attempting to operate the control beyond the limit position.

The motor should not operate.If the motor operates, refer to the TROUBLESHOOTING GUIDE Section.D. Check the handcrank switch by _____removing the handcrank from its holder and operating the control switch. The motor should not oper-ate.It the motor operates, roetr to Checks and Adjustments No. 5 in the TROUBLESHOOTING GUIDE Section.3. Set the LTC mechanism in the neutral position by operating by electrical hand control until the position indi-cator on the drive unit indicates neu-tral (N). See Neutral-Position Rela-tionship Section.4. Remove the 1-in. pipe plug from the drain-and-sampling valve.5. Open the drain-and-sampling valve: drain the oil from the tap-selector compartment.

Refer to S210-10-1, Vacuum Filling Oil Immersed Power Transformers.

6. Open the tap-selector compartment door.7. Inspect the tap selector for physical damage or evidence of moisture.A. If there is any sign of moisture in-side the tap-selector compart-ment, determine the extent and the manner by which the moisture entered.Refer to the TESTING FOR LEAKS (PRESSURE TESTING)Section.B. Any moisture detected in the tap-selector compartment must be re-moved using clean, dry cloths.a S210-40-3 8. Inspect stuffing box (Figure 17, Item S27) for evidence of oil leakage.A. If there is any sign of oil leakage, determine the extent and the cause and correct, Refer to the TROUBLESHOOT-ING GUIDE Section.*9. Check external shaft assembly (Fig-ure 17, Item 25) for freedom of move-ment by sliding the shaft up and down slightly to make sure there is no bind-ing in stuffing box (27).It there is binding in the stuffing box, refer to the TROUBLESHOOTING GUIDE Section.10. Thoroughly flush and, using clean, dry cloths, remove all carbonization which may be deposited on insulat-ing surfaces.

We recommend flushing with transformer oil but do not object to the use of oil-base solvents.11. Close the drain-and-sampling valve, replacing the 1-in. pipe plug.12. Place the LTC motor breaker (on the motor control panel) and the relay breaker (on the automatic control panel) in the OFF position.13. Remove the handcrank from its holder.Removal of the handcrank opens the handcrank switch in the motor circuit and deenergizes the motor. A hand-crank stop prevents the operator S from handcranking the tap selector through a limit.14. Place the handcrank on the hand-crank shaft in the drive box.15. Inspect the arcing contacts (Figure 12 and 13) for arc erosion.In an arcing-tap-switch-type LTC mechanism, the tap selector performs a dual function:

Tap selection and preventive-auto (switching-reactor) switching.

Since the tap-selector also switches the preventive auto, the tap selector contacts are subject to arc erosion. Arc-resistant materials are used in both the movable and the stationary contacts.

Erosion rates and patterns are functions of the tap volt-age, the load current, and the preven-tive-auto design.Figure 14 shows typical contact erosion patterns.

The stationary arc-ing contacts normally erode more slowly than the movable arcing con-tacts because many tap positions (stationary arcing contacts) are en-countered by the movable arcing contacts during their service life.A. Inspect the movable arcing con-tacts (Figure 12) for arc erosion.The point of replacement of mov-able arcing contacts is shown on the left in Figure 14.If contacts are not replaced at this point, thermal instability at the con-tact interface will result, followed by thermal failure of the contact.Contact assemblies are factory-set and designed to produce a 10-12 lb force per contact point.To replace the movable arcing contacts: (1) Handcrank the movable con-tacts to a convenient position between the stationary arcing contacts or remove the sta-tionary arcing contacts on one tap position and handcrank the movable contacts to that posi-tion.(2) Remove the eroded main mov-able arcing contacts.(3) Install the new movable arcing contacts, using flatwashers, locknuts, and shouldered mounting bolts, positioning the bolt heads next to the thrust piece as shown in Figure 15.CAUTION When installing main movable arcing contacts, it is essential that zero pres-sure be maintained in the main trans-former tank to establish proper align-ment with the main stationary arcing contacts.Do not overtighten the mounting bolts. Overtightening these bolts will crack the main insulating arm in the area of the bolt holes.NOTE: Mounting bolts are shouldered, so that, when properly assembled as shown in Figure 15, the thrust piece will move between the bolt heads and the main insulating arm to com-pensate for misalignment of the stationary and the movable arcing contacts.(4)Handcrank the LTC slowly through its entire range around the dial to make sure there is clearance between the lower spring pins and the slipring and the upper spring pin and the stationarycontact while on con-tact and while sweeping to adjacent contacts.(5) Return the LTC to the neutral position.Refer to the NEUTRAL-POSI-TION RELATIONSHIP Section.B. Inspect the stationary arcing con-tacts (Figure 13) for arc erosion.using a small inspection mirror to thoroughly examine the backs of the contacts.The point of replacement of sta-tionary arcing contacts is shown on the right in Figure 14.Stationary arcing contacts are sil-ver plated to reduce the possibility of high-resistance oxidation which impedes current flow, adding to thermal instability at the point of contact. When the arcing tips erode to the point where burning on the silver plating can occur, the stationary contacts must be re-placed.NOTE: The silver-plated main dial sta-tionary arcing contacts are directly interchangeable with all previous model 550C.To replace the stationary arcing contacts: (1) Remove the eroded contacts.(2) Thoroughly clean all oxidation from the ends of the stationary contact spacer tubes and mounting supports.Scotch-Brite No. 44 7 or No. 448 is recommended for cleaning copper surfaces.(3) Install the new stationary arcing contacts, holding them against the mounting bolts toward the outside of the stationary con-tact bolt circle to establish proper alignment.

See Fig-ure 16.16. Inspect the non-arcing reversing mov-able contacts (Figure 16) for mechani-cal wear.NOTE: Earlier models shipped prior to February 1975 utilized a reversing switch design which because of the timing with the main dial would have arcing occurring on reversing stationary contact No. 1. At that time the reversing stationary contacts were tipped with a copper tungsten mate-rial to withstand the effects of arcing. The movable contact tips which engage the stationary contacts were also of a copper tungsten or silver tungsten material.

The slot in the reversing segment was a straight slot as shown in Figure 16.In 1975 we began using a reversing segment as shown in Figure 16 with an offset slot to delay the reversing movable contact coming off the stationary contact allowing the main dial contacts to interrupt the current eliminating the arcing on re-versing stationary contact No. 1. This per-mitted the use of silverplated stationary contacts and coin silver movable contacts.When updating the reversing switches of older units you must replace the reversing stationary contacts, reversing neutral stationary contact, movable contact as-sembly and reversing insulating arm assembly.

See Figure 5.The reversing movable contacts are subject to mechanical wear, not arc erosion. When the initial gap be-tween the movable contacts wears to 9/32 in., the contacts should be re-placed. The contact assemblies are factory-set and designed to produce a 10-12 lb force per contact point.To replace the reversing movable contacts: A. Handcrank the LTC so that the re-versing movable contacts are mid-way between the reversing station-ary contacts.S. Remove the.worn reversing mov-able contacts.C. Install the new reversing movable contacts.7 A CAUTION When installing reversing movable contacts, it is essential that zero pres-sure be maintained in the main trans-former tank to establish proper align-ment with the stationary contacts.(1) Make sure the centerlines of the reversing stationary con-tact, the reversing movable con-tact assembly (thrust piece), and the reversing neutral sta-tionary contact coincide (Fig-ure 16).(2) Handcrank the LTC slowly through at least three posi-tions on either side of neutral to make sure there is clear-anoe between the lower sprng pins of the movable contact assembly and the reversing neutral stationary contact and the upper spring pins of the movable contact assembly and the stationary contacts.Make sure that the reversing insulating arm is not rubbing on the face o the reversing neutral stationary contact.(3) Return the LTC to the neutral position.Refer to the NEUTRAL-POS!-

T/ON RELATIONSHIP Section.17. Inspect the non-arcing reversing sta-tionary contacts (Figure 16) for me-chanical wear.The reversing stationary contacts are silverplated to reduce the possibility of high-resistance oxidation which impedes current flow, adding to ther-mal instability at the point of contact.The reversing stationary contacts are subject to mechanical wear, not arc erosion. When the silver plating has worn off in the path of the reversing movable contacts, the stationary con-tacts should be replaced.To replace the reversing stationary contacts: A. Handcrank the LTC so that the re-versing movable contacts are mid-way between the stationary con-tacts.B. Remove the worn reversing sta-tionary contacts.C. Install the new reversing stationary contacts.D. Handcrank the LTC slowly through at least two positions on either side of neutral to make sure there is clearance between the reversing stationary contacts and the upper spring pin of the reversing mov-able contacts.E. Return the LTC to the neutral posi-tion.Refer to the NEUTRAL-POSITION RELATIONSHIP Section.18. Make sure all fasteners, lockstrips, and electrical connections are tight and secure.19. Handcrank the LTC step-by-step through its entire range to make sure there is no mechanical interference and that all the new contacts have been properly installed.

20. Return the LTC to the neutral posi-tion.Refer to the NEUTRAL-POSITION RELATIONSHIP Section.21. If the same oil is to be returned to the tap-selector compartment, filter and test the oil.The oil must test 26 kV minimum in standard gap (ASTM D 877) and 25 ppm (wt) maximum moisture content.22. Close the tap-selector compartment door.23. Refill the tap-selector compartment with oil to the 25 C level marked on the oil-level gage.Refer to S210-10-1, Vacuum Filling Oil-Immersed Power Transformers.

24. Pressure test the tap selector com-partment.Although each LTC mechanism is subjected to pressure tests for leaks before leaving the factory and pres-sure testing is recommended again before the open-breathing system is installed and prior to placing the unit in service for the first time, another pressure test is recommended prior to placing the unit in service after performing maintenance.

Refer to the TESTING FOR LEAKS (PRESSURE TESTING) Section for recommended test procedures.

25. Operate the LTC for 10 minutes (ap-proximately 800 operations) to seat the contacts and eliminate any air pockets resulting from the oil filling.Refer to the Arcing-Tap-Switch-Type Load Tap Changer Section in Service Information S210-10-1, Vacuum Fill-ing Oil-Immersed Power Trans-formers.Testing for Leaks (Pressure Testing)A pressure test of the tap selector cornt-partment is recommended any time a gas-keted device is removed or replaced which may leak oil out of or moisture into the switch compartment.

Either one of the following methods is recommended:

Method 1 With the transformer deenergized, the tap selector compartment door sealed and the inlet and outlet of the open breather system sealed: 1. Fill the tap-selector compartment with oil.2. Hold the oil under 5 psi max pressure for several hours.Monitor the pressure closely because a change in ambient temperature can easily cause a drastic change in pres-sure.3. Dust blue chalk powder on areas of suspected leakage.The chalk will turn dark when wet with oil.Method 2 With the transformer deenergized, the tap selector compartment door sealed, and the inlet and outlet of the open breather system sealed: 1. Maintain a nitrogen pressure of ap-proximately 4 psi.2. Paint a soap-bubble solution such as glycerine and liquid soap on the welded and gasketed joints to disclose leaks.Alternative to painting with a soap-bubble solution.

Seal the unit under the gas test pressure for a period of hours while monitoring for loss of pressure.PRESSURE TEST OF TAP SELECTOR PANEL A pressure test of the tap selector panel to check the integrity of all the gaskets forming seals between the tap selector compartment and the transformer is rec-ommended any time a gasket is replaced or the oil level in the LTC compartment increases with no apparent reason.With the transformer de-energized and the selector compartment drained and opened: 1. Wipe down selector panel with clean dry cloths.2. Apply 3 psi min., 5 psi max. pressure to the transformer tank.3. Check for oil seepage at gasketed points.& CAUTION When installing reversing stationary contacts, it is essential that zero pres-sure be maintained in the main trans-former tank to establish proper align-ment with the reversing movable con-tacts.& CAUTION The drive motor is designed for inter-mittent duty. If the motor is to be oper-ated longer than 10 minutes continu-ously, it must be fan-cooled.

26. Energize the transformer.

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

Whnevetran-omponRelationsheLTC i CAUTION The main movable arcing contacts of the Whenever any component of the Incorrect timing within the drive box 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, contacts an 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 a when 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 are on the stationary contact.ON POSITION 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. 10 MAIN MOVAOLE ARCING CONTACTS MAIN STATIONARY ARCING CONTACT NO. 2 REVERSING ROLLER ATTACHED YO REAR ROLLER PLATE REVERSING STATIONARY CONTACT NO.1/ MAIN STATIONARY ARCING CONTACT NO. 9 REAR INDEXING ROLLER PLATE (ACTUATES FRONT MAIN MOVABLE ARCING CONTACTS -Z-)FRONT INDEXING ROLLER PLAE (ACTUATES REAR MAIN MOVABLE ARCIN CONTACTS "Y) SCROLL CAM REAR MAIN MOVABLE ARCING CONTACTS "Y" REAR COLLECTOR'RING "Y" F F S i'=RONT COLLECTOR lING "Z'WITCH MOUNTING PANEL SOLATING SWITCH FROM lAIN TRANSFORMER MAIN AND REVERSING MOVABLE CONTACTS OF ARCING TAP SHOWN IN NEUTRAL POSITION..................

...... --I ,t h RELATIVE POSITION OF DRIVE SHAFT SPLINE TO CENTERLINE 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 Figure 10 for 16-step switch, Figure 11 for from the neutral position to either maxi- 32-step switch). The mechanical stop will mum position.

In the maximum position, become engaged during the 49th turn of the limit switch and seal-in switch open: the handcrank; however, there will be no o REVERSING SWITCH MOVABLE CONTACTS ON REVERSING STATIONARY CONTACT NO. 10 REVERSING SWITCH MOVABLE CONTACTS ON REVERSING 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 LOWER POSITION (16 LQ (TYP ALL THREE PHASES)ARCING TAP SWITCH SHOWN IN MAXIMUM RAISE POSITION (16 R) (TYP ALL THREE PHASES)STOP SECTION IN DRIVE HOUSING STOP SECTION IN DRIVE HOUSING STOP SECTIi ON GEAR MECHANICAL STOP IN DRIVE UNIT SHOWN ENGAGED. SWITCH IN MAX. LOWER POSITION (16 L)POSITION INDICATOR SHOWN IN MAX. LOWER POSITION (16 L)MECHANICAL STOP IN DRIVE UNIT SHOWN ENGAGED. SWITCH IN MAX. RAISE POSITION (16 R)POSITION INDICATOR SHOWN IN 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 i 2 3 I I 9 10 11 I I I 12 I 13 1 14 15 16 I I 1 II iim i mi~ miiinimi~~II 1 im inin 750 +/-100 -A I I mi~i 7 F RAISE LIMIT SWITCH LOWER LIMIT SWITCH r 760 +/-100'I I I SEAL-IN?r¶1i1,,r 4 SWITCH I I I 20I -°I I I NOTES: 1. Sequence expressed in degrees rota-tion of main drive shaft.2. 3600 rotation of main drive shaft is required for one tap change.3. One complete turn of handcrank rotates main drive shaft 60°.4. Solid lines indicate span of contact closure, contacts are open at other positions.

Figure 10.Switch sequencing chart for 1 6-step switch.16-J LOWR .RAISE z POSITION DESIGNATION 2 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 ] I 1 1 1 1 1 1 I 1 1 1 I___ I I I I L I I I I I I I RAISE UMIT SWITCH LOWER LIMIT SWITCH th750 +/-10-I111 SEAL IN-WI IYTTIJ [ -1 1 NOTES: 1. Sequence expressed in degrees rota-tion of main drive shaft.2. 18su rotation of main drive shaft is required for one tap change.3. One complete turn of hand crank rotates main drive shaft 600 4. Solid lines indicate span of contact 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 MOUNTING BOLTS (NOTE INTERMEDIATE ARC EROSION LOCATIONS LAT OF SOLT HEADS)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 TRANSFORMERIfM N I U SLIP R IN G~/'MINIMUM

-.CENTERLINES OF COMPLETE ASSEMBLY PENNSYLITE INSULATING LJAJ 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 S t !o\ /o\SLOT REVERSING

' SLOT SEGMENT Modified reversing Original reversing segment segment (with offset slot) (with straight slot)NEUTRAL STATIONARY SUP RING o'-MAIN DIAL STATIONARY CONTACT SNOTE: TWISTED CONTACTS CAN INTERFERE WITH THE MOVABLE CONTACT SPRING PINS.Figure 16.Reversing movable and revesring stationary contact assembly.MAIN DIAL STATIONARY CONTACT STATIONARY CONTACT MOUNTING BOLT -- .ý /APPLY PRESSURE NOTE: WHEN ASSEMBLING MAIN DIAL STATIONARY CONTACTS MAINTAIN PRESSURE AGAINST THE CONTACT MOUNTING BOLTS TO ESTABLISH PROPER CONTACT ALIGNMENT.

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

1. The position of the switch at time of incident.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.

& WARNING Before performing any work on the LTC arcing tap selector switch, drive, or con-trols, observe the warnings and cautions appearing in Service Information S210-40-14 and S210-40-18.

0 TROUBLESHOOTING GUIDE Problem Concition Solution Improper manual operation Tap changer does not respond to of LTQ. Raise-Lower switch.Refer to the Troubleshooting Guide in Tap changer operates in one direc- Service Information S210-40-14 Load-tion only or operates erratically.

Tap-Changing Controls.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 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. For loosescrewsfastening 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.(continued next page)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 Figure 16.(continued next page)15 TROUBLESHOOTING GUIDE (Continued)

Problem I Condition Solution Switch failure to complete a tap change. Motor breaker did trip.(continued) (continued)

c. Check that the main dial and revers-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 Ya inch.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.(continued)(continued next page)Motor breaker did trip.(continued)

2. Match-mark the components of the 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 the packing.I (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

.. ..... ....... ...........

..........2 1 0 -4 0 -3 REPLACEMENT PARTS (Refer to Figures 17 and 18.)Few spare parts are required for the LTC mechanism:

however, it is recommended that a few select parts be kept on hand for prompt replacement if needed. The parts recommended for spares are indi-cated in the replacement parts list.Each replacement parts list is keyed to the related exploded view drawing and the item numbers correspond to the ex-ploded view callout numbers.To ensure prompt receipt of the correct part the following informaton must be sup-plied to McGraw-Edison when ordering.1. The transformer serial number and the type of LTC switch. This information is specified on the transformer nameplate.

NOTE: Specification of type of LTC switch on the transformer nameplate began in 1972.2. Specify the bulletin number and date, figure, item number, description, and quantity required.Example: To order item 54 on the Drive unit.Transformer Serial#C- Type 550CS LTC S210-40-3, September 1982 Figure 17 Item 54-Limit Switch-2 each.Limited Parts Warranty McGraw-Edison warrants to the original purchaser that type 550CS load tap changers shipped after August 1, 1982 are free of defective workmanship and materials, This warranty commences on the date of arrival at destination and covers any defects and malfunctions of the load tap changer except those caused by improper installation, improper main-tenance, improper operation, customer-furnished materials, alterations executed by customer or vandalism.

Type 550CS LTC Parts are warranted as follows: Silver Contacts-five years or 75.000 op-erations, point of re-placement as described in figure 14 S210-40-3; cost prorated per % of time or operation.

Mechanism-500,000 operations.

Control-five years.19 This drive mechanism for ille types 550G and 550CS are identical.

However, molor, capacitor and motor-breaker packages have as shown in the following tablo.Motor-. Motor MotorSuppller Capacitor BMoteer Braking Winding Motor Year and Model Number Size Size Fuse Resistance Drawing (mfd) (amps) (amps) (ohms -10%) Number Ohio Motor 1967 Model 915-23X-4909 100 6 2.5 B219444 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 Century Elec Unit 1988(2) 8-168935-01 175 7 0.9 SLB0281 A 0 (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 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 ,.tý 64 53 116 s 104 117 q 119- OWARNING 120 m McGra-Edson OCa3 not recom-mend hand c*Afk, ,ng wnile the Ileansfor'er IS energizecs See instruction book TO c hange 0O31-NiOn during main.tenancC nPiano-crank until Ihe on 0o0ition Dointe, is cenlered o0der the LO on-Dos'lion plate Figure 17.Exploded view of LTC drive unit.28-e 29~141)30-0 3 1 3- 4 o 11 11 20 S210-40-3'4 Parts List--LTC Drive Unit (Figure 17)Item DItem Item No. Description INo Description NO. Description 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 Snap Ring Washer Drive Shaft Coupling Insulating Drive Shaft Assy.Coupling Drive Shaft Gear Bearing Assy. (X)Lockwasher Gear Support Cam Mounting Brkt.Cam Spacer Washers Cam Drive Shaft Bearing Assy. (X)Bolt Insulating Drive Shaft Assy.Gear Inner Race & Needle Bearing Washer Input Shaft Input Shaft Roll Pin Stuffing Box Bearing Wave Washer Male Adapter Packing Female Adapter Follower Assy.Lockwasher Bolt Drive Shaft Assy 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 Roll Pin Drive Shaft Bolt Lockwasher Snap Ring Washer Drive Shaft Support Screw"On Position" Plate Spline Tube Drive Gear Roll Pin Gear Worm Shaft Bolt Mounting Bracket Spacer Limit Switch (2 req'd)Screw Worm Gear Shaft Roll Pin Limit Switch Cam Indicator Mounting Bracket Spring Roll Pin Dial Plate Spacer Pointer Pointer Spacer Pointer Roll Pin Worm Roll Pin Brass Tube Gear Shaft Shaft Support Bolt Motor Gasket Miter Gear Seal-In Cam Assy.79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 9B 99 100 101 102 103 104 105 106 107 108 109 110 ill 112 113 114 115 116 117 118 119 120 Screw Seal-In Switch (1 req'd)Spur Gear Shaft Drive Box Terminal Block Screw Geneva Pinion 6 Spacer Spur Gear Spline Tube Assy.Washer Spur Gear Drive Gear Spur Gear Washer Lock Strip Snap Ring Roller Assy.Pin Roll Pin Motor Pinion Spur Gear Shaft Spur Gear Washer Spur Gear Spur Gear Shaft Geneva Segment Spacer Spur Gear Spline Tube Spur Gear Spur Gear Drive Box Cover Bolt Screw Caution Plate Caution Plate Bolt Rubber Washer Rubber Washer Washer Locknut i 2 g D ___p Caution.8efw>e dsnm.9nh1nJ d~,ve bo LTC n hgmso n'., be 4. NEUTRAL POSMTON e. ,nst,uctobn book.IlneofreCl llmvng wIhmf drtve bo- 01 belween Wt~e Jnd Seleelor Sf lttCS ran Cauee K) 0 Nx) lap selectors shipped atter August 1 1982 are provided with bearing assemblies items 9 and 18.2t-j 21

/Typical assembly.TERMINAL 1 9 Figure 18.Exploded view ol tap selector.22 S210-40-3 Parts List--Tap Selector (Figure 18)Recoin-Iter mended RoNo Description lStock Recom-S Nut Jam Nut Belleville Washer Spanner Nut Collar Collar Locknut Washer Gasket Panel Insulating Tube Pins Gasket (A)Collar Stationary Contact Support Reversing Stationary Contact Lock Strip Shoulder Stud Bolt Snap Ring Insulating Tube Pin Collar Stationary Contact Support Ring Pin Gasket (B)Collar Rear Slip Ring Nut Washer Main Movable Contact Assy.Rear Shaft Assy.Less Contact Assy.Bolt Front Shaft Assy.Less Contact Assy.Bolt Lock Strip Front Slip Ring Bolt Spacer Reversing Movable Contact Assy Reversing Assy.Less Contact Assy.Insulating Tube Collar ended Item tock No. Description 54 49 Support Stud 50 Front Insulating Panel 51 52 Scroll Cam Mounting Bracket 53 Roll Pin 54 Reversing Segment 55 Bolt 56 Thrust Bearing Assy.(X)57 Rear Roller Plate Assy.58 Snap Ring 59 Collar 60 Roll Pin 61 Shaft Support 62 Front Roller Plate Assy.63 Snap Ring r64 Lock Strip 65 Bolt.66 Lock Strip 67 Stud Assy.68 Connection Bar 69 Bolt 70 Nut 71 Shoulder Bolt 72 Spacer 73 Washer 74 Belleville Washer 75 Thrust Bearing Assy.(X)76 Bearing Assy. (X)0-20 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.., 1 i1 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 S210-40-14 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, CAUTION Incorrect supply voltage could dam-age drive, motor or controls.

Refer to wiring schematics which accom-pany each transformer.

T_BREAKER NORMA# CONTROL SWITCH4ES TEST I REACTANCE~

REMOTE MANUAL RAISE TERMINALS LuV9SE AL AUTO OwER Figure 1.Automatic control panel.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 secondary which operates in the 1 tO-130-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 instructions do nor claim to cover all details or variations in the equipment, procedure, or process descrbed, nor to provide direcions for meeting every possible contngency during installation, operation, or maintenance.

When additional information is desired to satisfy a problem not covered sufficiently for the user's purpose, please contact your Cooper 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 The automatic control panel includes solid-state voltage sensing and timing devices used in conjunction with mechan-ical output relays to initiate the operation of the lap changer motor operating panel.The voltage sensing device is factory cali-brated. The specific voltage level and bandwidth adjustments are obtainable by using calibrated control knobs which can be locked in place..Unless otherwise spec-ified, the controls are designed for 60-Hz, ac operation with an accuracy classof bet-ter than Class 1. Except for the motor breaker, all of the controls for both manual and automatic operations are mounted on the front of the automatic control panel.The motor breaker is located on the motor operating panel.Manual Operation The bottom section of the automatic control panel contains four toggle switches, three of which are used to select and direct man-ual or automatic control of the load tap changer (Figures 1 and 2). With the RE-MOTE-LOCAL switch in the LOCAL posi-tion and the MANUAL-AUTO switch in the MANUAL position, the load tap changer can be operated in the manual mode by actuating the momentary RAISE-LOWER switch in the desired direction.

When more than one lap change is neces-sary. holding the RAISE-LOWER switch in the appropriate position until just before the tap changer reaches the desired tap position causes the tap changer to operate in a sequential mode. Releasing the RAISE-LOWER switch and allowing it to return to the OFF (center) position permits a short time delay and enforces motor brake operation.

NOTE: The manual operation of the load tap changer isnot affected by or related toany of the other components on the automatic con-trol panel.Automatic Operation Before attempting to place the load tap changer in the automatic mode oi operation, the motor control power and the automatic voltage sensor potential source must be con-nected and energized. (Refer to the wiring schematic for each specific transformer).

To place the load-tap-changing equip-ment in the automatic mode, all related control settings must be predetermined and selected.Individual circuits and controls relating to the automatic operation are covered in the COMPONENTS for automatic control panel section. To clarify the automatic operating procedure, a control setting checklist follows: 1. Place the CONTROL CIRCUIT BREAKER (8-90) Figure 2 in the OFF position.2. Loosen the four locking screws on the,,d knobs above the control switches.

___3. Place the AUTO-MANUAL switch in -the MANUAL position and the REMOTE-LOCAL swilch in the LOCAL position.4. Set the TEST RHEOSTAT control at zero (0).5. Set the VOLTAGE LEVEL control to the desired voltage.6. Set the BANDWIDTH control to the preselected value-7. Set the LINE-DROP COMPENSATOR (LDC on control panel). REACTANCE and RESISTANCE controls at zero (0).(Alter the calibration check, these controls should be set at the calculated levels.)8. Place the MOTOR BREAKER on the motor operating panel in the ON posi-tion. See S210-40-18.

9. If the voltage level and bandwidth are to be checked with a voltmeter, con-nect the meter to TEST TERMINALS G and A.10. Place the CONTROL CIRCUIT BREAKER in the ON position.

Wait approximately 15 minutes before pro-ceeding, to allow warm-up.I t the vollage level and bandwidth are not going to be checked with a volt-meter, operate Ihe load tap changer in the manual mode until the LOWER4 test light in energized-then proceed Wo to checking the bandwidth as out-lined in 11 E.2 S210-40-14

11. If the voltage level and bandwidth are going to be checked with a voltmeter.

the TEST RHIEOSTAt control can be used to advantage:

A. Operate the load tapchangerin the manual mode until the voltmeter reads as close as possible to the desired band center , 3 volts.B. Place the MOTOR BREAKER in the OFF position and pull the dual fuse holder (located on the motor oper-ating panel) out of its retaining block. SeeS210-40-18.

C. Set the TEST RHEOSTAT control to a value which equals the voltage increment above the desired band center obtained in Step 11 A.Example: To obtain a desired band center of 120 volts: (1) Operate the load tap changer in the manual mode until the voItmeler reads as close as possible to the desired band center +3 volts.a, Nearest voltage obtainable is 123.5 volts.b. Therefore.

123.5 -120 -- 3.5 volts, (2) Place the MOTOR BREAKER in the OFF position and putl the dual fuse holder out o1 its retaining block.(3) Set TEST RHEOSTAT control for 3.5 volts.D. It necessary, adjusl the VOLTAGE.EVEL qgntrQl VnI!j neither the RAISE nor the LOWER test light is lit. For the most accurate setting.center the control between the two points where the RAISE and LOWER lest lights are lit.NOTE, Al the lime the band level and the bandwidth are being adjusted.

the make and break points of both the raise and the lower Circuits dilter by approximately 0.5 volt. This ditleren-hal is a seat-in feature furnished to assure the positive making of the con-tacts at the extremities of the band-width.E. Check the bandwidth by rotating the TEST RHEOSTAT control in both directions and observing the dial voltage differential between the points where the RAISE and LOWER test lights come on.Example (continued from 11 C):*Assume BANDWIDTH control has been preset to 3 volts." Voltnteter (if used) reads 123.5 volts." TEST RHEOSTAT control set at 3.5 volts." BAND LEVEL control set at 120 volts." Rotate TEST RHEOSTATcontrot in both directions:

LOWER test light comes on at two volts: RAISE lest light comes on at five volts.* Therefore.

5 -2 = 3 volts band-width.F Secure BAND LEVEL and BAND-WIDTH controls by tightening their locking screws.G. Check operation of time-delay re-lays by rotating the TEST RHEO-STAT control and noting the time differential between the test light ignition and dimming, (Output relay closure causes test light to atten-uate.) Each time-delay relay is fac-tory set for a 30-second time delay.See instructions for rime-delay relays undet COMPONENTS for automatic control panel before changing the setting.H. Return the TEST RHEOSTAT con-trol to zero (0) and secure its lock-ing screw.I, Set the appropriate LINE-DROP COMPENSATOR setting. (See Step Sand instructions under Line-Drop Compensator.)

Secure the LOC RESISTANCE knob locking screw, J. Replace the dual fuse holder and move the MOTOR BREAKER to the ON position.K. After completing the preceeding steps, move the AUTO-MANUAL switch to the AUTO position and the load tap changer will respond to the automatic control mode.Components

1. CONTROL CIRCUIT BREAKER. A single-pole.

tip-ffee breaker provides ON-OFF. short-circuit and overload protection for the control panel.2. TEST TERMINALS.

Two test terminals facilitate connecting a voltmeter during calibration tests.3. VOLTAGE-REGULATING RELAY. A solid-state, adjustable voltage sensor permits the selection of a band level between 105 and 135 volts. The BAND-WIDTH control permits the selection of a bandwidth of from 1.5 to 7.5 volts.4. TEST LIGHTS. Two test lights incor-porated in the time-delay circuits pro-vide a visual indication of the conduction occurring within the voltage regulating relay.S. LINE-DROP COMPENSATOR.

The line-drop compensator, complete with reverse-reactance switch, variable-reactance and variable-resistance con-trols, facilitates the regulation of the leeder at a point remote from the trans-former and provides for reverse react-ance paralleling.

6. TEST RHEOSTAT.

The fine-adjustment test rheostat facilitates the determina-tion of the bandwidth even though a variable external power source may not be available.

7. CONTROL SWITCHES.

Three control switches mounted in the lower section of the automatic control panel provide a selection of the following operations and modes of the load lap changer: remote. local, automatic, manual, raise.off. and lower.A. To operate the load tap changer from within the cabinet in either the automatic or manual mode. the REMOTE-LOCAL switch must be in the LOCAL position.

To operate the load tap changer from a remote point, the REMOTE-LOCAL switch must be in the REMOTE position.Auxiliary auto-manual and raise-lower switches must be supplied by the user when operating from a remote point.8. To operate the load tap changer from within the cabinet in the manual mode or to deactivate local auto-matic operation, place the AUTO-MANUAL switch in the MANUAL position.

To operate the load tap changer in the local automatic mode, place the AUTO-MANUAL switch in the AUTO position, C. The RAISE-LOWER switch is used to operate the load tap changer in the local manual mode. The switch is equipped with a center OFF and two momentary ON positions.

Making momentary contact in the up direc-tion for RAISE or down for LOWER will cause the load tap changer to move one step at a time. If more than one tap change is required.

holding the momentary contact in the desired direction will permit sequential operation.

8. TIME-DELAY RELAYS, Two adjustable time-delay relays (one for RAISE. one for LOWER) are in the circuit between the voltage-regulating relay and the tap changer motor control. These relays provide a selection of time delays from to to 90 seconds. Unless otherwise specified, the relays are factory-set for 30 seconds, To change the setting, insert a small screwdriver (preferably a '.-in.-diameter handle) in the potentiometer screwdriver slot and rotate clockwise to increase or counterclockwise to decrease the lime delay. Changing of potentiometer settings will show resistance to movement because of a mechanical drag which has been placed on the shaft to prevent accidental movement.

Total rotation is about 300 degrees and can be observed by relating the slot position relative to the graduations surrounding the shaft (Figure 3).&t CAUTION To prevent potentiometer damage, do not use a large screwdriver or force the settings at the extreme ends of the range.3 NOTE: Potentiometer must be securely 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 be pulled snug enough to make it necessary to use a small screwdriver to adjuSt the potentiometer. (Screwdriver--Stanley 1010 or equivalent).

CIRtC UIT SHAFT LOCKING DEVICE 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-tion and observe the time interval between the light ignition and the point when the light goes dim due to the closing of the output relay.Setting When setting from an independent source, the automatic control panel should be energized by a variable source connected toTerminals 10 and G, Figures 2 and 4.POT TRANSF BY OTHERS 1R 02 = 03 T1I 02 TDC 03 ZE-- j-vM>40 8.88/5 0-0.2 AMP RCTS 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 both the CONTROL and MOTOR BREAKERS are in the OFF position.90 Solid-state voltage sensor TR Time-delay RAISE TL TIme-delay LOWER 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 TERMINALS G and A.2. Loosen the four locking screws on the knobs above the control switches.3. Place the AUTO-MANUAL switch in the MANUAL position and the REMOTE-LOCAL switch in the LOCAL position.4. Set the TEST RHEOSTAT control at zero (0).5. Set the VOLTAGE LEVEL control for the desired level.6. Set the BANDWIDTH control for the total desired bandwidth.

7. Set all three LINE-DROP COMPEN-SATOR controls at zero (0).8. Place the CONTROL CIRCUIT BREAKER in the ON position.9. Adjust the source voltage until neither test light is energized.

Wait approxi-mately 15 minutes before proceeding.

10. To check band level and bandwidth.

adjust the source voltage and record the voltmeter readings at the levels where the raise-lower test lights are energized.

If required, the VOLTAGE LEVEL and BANDWIDTH controls can be adjusted slightly to obtain the exact bandwidth and level desired.NOTE. At the time Ihe band level and the bandwidth are being adjusted.

the make and break points o0 both the RAISE and the LOWER circuits differ by approxi-mately 0.5 volt. This ditferential prod uces a seal-in leature to assure the positive making of the contacts at the extremities o0 the bandwvidth.

11. After having obtained the exact band level and bandwidth required, secure the TEST RHEOSTAT.

BAND LEVEL.and BANDWIDTH control knobs by tightening the locking screws.12. Check TIME-DELAY relay settings by adjusting the source voltage and re-cording the time differential between test light ignition and dimming. (Out-put relay closure causes test light to attenuate.)

Each time-delay relay is factory set for 30-second time-delay.

See instructions for time-delay relays under COMPONENTS on automatic control panel before changing settings.13. Set the LDC REACTANCE and RE-SISTANCE controls for the calculated values. (See Line-Drop Compensator section for calculating procedures.)

Secure the LDC RESISTANCE control knob locking screw.Line-Drop Compensator The line-drop compensator is supplied with one resistance control and two react-ance controls, furnishing resistance and reactance compensation up to 24 volts in either, or both, elements.

The resistance compensation is continuously variable from 0 to 24 volts; the reactance compen-sation is variable in both 1- and 5-volt steps to a total of 24 volts.It reverse reactance compensation is required, move the NORMAL REACT-ANCE-REVERSE REACTANCE swilch on the front panel to the REVERSE REACT-ANCE position.To determine proper settings required for the line-drop compensator, it is neces-sary to understand the principle of line-drop compensation.

The principle involved consists of connecting a resistance-react-ance network in series with the voltage-regulating relay input. Current from an internal current transformer is passed through the compensator, producing a voltage drop which is opposed to the ap-plied potential.

Since the current is proportional to the feeder current and, if the resistance and the reactance of the compensator are pro-portional to those of the feeder from the transformer to the desired point, the volt-age at the voltage-regulating relay input will drop by an amount proportional to the feeder voltage drop to that point. This will cause the load tap changing mechanism to adjust its voltage to maintain a constant, selected voltage at the predetermined point.The remote point, often called the load center. should be selected with great care.It may be an actual point on the feeder where the main trunk branches out in a star-shaped pattern in the center of the feeder's territory.

it may also be a fictitious point recurrent about the middle of each feeder branch so that it represents an average condition existing over a wide area, The line-drop compensator circuit employed by McGraw-Edison is designed to operate at 10 ma and has been equipped with an intermediate current step of 0.2 amp to accommodate provisions for the circulating current method of paralleling with existing load tapchanging equipment.

To determine the settings for the line-drop compensator:

1. Determine the feeder line current that will provide 10 ma to flow in the line-drop compensator circuit. For the var-ious winding outputs described below.see the connection diagram nameplate A. For wye-connected output windings with one current transformer for line-drop compensation, this value will be the primary current rating of the current transformer for line-drop com-pensation.

B, Fordelta-connected output windings.this value will be V-3 times the pri-mary rated current of the current transformer for line-drop compen-sation, C, For wye-connected output windings with two current transformers for line-drop compensation (each hav-ing a secondary rating of 5.0 amps).the feeder line current will be equal to the primary current rating of either current transformer.

The second-aries are so interconnected that. with rated Current flowing in each prim-ary. 10 ma will flow in the line-drop compensatorcircuit This 10-ma cur-rent will be properly phased for use of a line-to-line potential transformer which is connected as shown on the load tap changing schematic dia-gram.2. Calculate line resistance and reactance.

3. Calculate line-drop in resistance volts and reactance volts as the products of Step 1 times Step 2.4. Divide the values obtained in Step 3 by the potential transformer ratio.5. Set the dials of the line-drop compen-sator equal to the values obtained in Step 4. The dials, calibrated in volts, are labeled RESISTANCE and REACT-ANCE VOLTS, Example: Consider a delta-connected transformer supplying one mile of feeder to a point for which resistance and reactance compensation are re-quired. The line is a 2 0. 20-in. equiva-lent spacing line which has a resistance of 0.41 ohm and a reactance of 0.60 ohm per mile.If the current transformer for the line-drop compensator has a primary rating o1300 amps. the feeder line current will be -,/3times 300 or 520 amps.The line drop will be 520 times 0. 41 or 213 volts resistance and 520 times 0.60 or 312 volts reactance.

If a 20:1 potential transformer is used to step the Output voltage down for use with the voltage-regulating relay. the line-drop compensator settings would be 213 divided by 20 or 10.7 volts re-sistance and 312 divided by 20 or 15.6 volts reactance.

The nearest dial set-tings on the line-drop compensator would be 11 resistance and 16 react-ance. Generally.

it is desirable to com-pensate for the drop in distribution transformers and secondary service.Increase these calculated values ac-cordingly to compensate for this addi-tional drop.& WARNING If any work is to be done on the line-drop compensator portion of the control circuit while the transformer is energized, care must be exer-cised so that the secondary circuits of the current transformers are not accidentally opened. The current transformers must be short-circuited at the short-circuiting device in the drive-and-control compartment be-fore any work begins.Accidental opening of the current transformer circuits will cause a dangerously high voltage to appear across the opened circuit.S Voltage Sensor The solid-state vdltage sensing relay in-corporated in this automatic control cir-cuit utilizes a temperature-compensated.

cascaded Zener diode reference voltage (E across Z3) compared to a portion of the input voltage (E across RB) to furnish the intelligence required to select one of three possible relay output modes.Conduction through silicon-controlled Rectifier

1. 1 (SCR 1) indicatesthat the input voltage T I -T2 is not of sufficient magni-tude to provide a voltage across R8 which equals the reference voltage across Z3.Conduction through silicon-controlled Rectifier

1. 2 (SCR2) indicates that input voltage T1-T2 exceeds the magnitude required to produce a voltage across RB which equals the Z3 reference voltage. A lack of conduction through either SCR1 or SCR2indicates that the input voltage Tl-T2 is at the proper level to produce a match between the voltages across R8 and Z3.Operational amplifier OP1 compares the voltages across R8 and Z3. If the Z3 volt-age exceeds the R8 voltage. OP1 output swings positive causing the OP2 output to go positive and furnish the turn on gate voltage for SCRi. It the R8 voltage ex-ceeds the Z3 voltage. OPt output swings negative causing the OP3 output to go positive and furnish the gate voltage for SCR2. A rheostat (bandwidth control)connected between T5 and T6 desensi-tizes OP1 input, thereby providing a vari-able band between the voltage level inputs which cause OP1 output to change. Re-sistor R11 fixes the minimum bandwidth obtainable.

ResistorsR t 7and R22 furnish a small feedback voltage to OP2 and OP3 after their output swings to provide a hys-teresis action (seal-in feature) to the Out-put circuits.

Resistor R29 is a shunt re-sistor selected to bring the sensing-circuit input current to a value which permits the use of a standard rheostat for the voltage level control. Trimming (calibrating) re-Sislor R30 is used to match individual volt-age sensors to the preselected voltage lev-els for which the band-level control has been calibrated.

Compensating resistor R9 is a factory-set potentiometer used to compensate forsmall value changes in Z3.R5. R6. R7. and R8 and still permit setting the sensor null input voltage within the permissible range, A 24-volt input to Ter-minals T3 and T4 furnishes the power supply for the OP amps and the regulated reference voltage.The schematic diagram, parts layout, and component identification are shown in Figures 5 and 6.E1 ,TopX l) VIEW 7<1 3-C 4 OPt, OP2. OP3 CONNECTION DETAIL Figure 5.Schematic of voltage sensor.6 S210-40-14 Hem i Value 8 'IB 2 ............

-...........

..R ... .... ... ... ... ... ... ..I. ... ...R 2 ....... °........................

A3 ..R .R 5........

....................

t1 ,R4 ... .. ...... ... ... ... ... ... ....R6, R7..............................

R 8 .. ...... ... ... .. ... .. .. ... ... ..R ll .. ....... .. ... ...... .. ... ... ..n il ...........

....... .. ...... .. ..81 R .............................

R 14, A 15. Il18. R919, R 20. R23. R 26 ......R16. R21. R24. A2? ..................

A122 ..............................

8 29 ..............................

R W ........................

.......CI, ...............................

C2 t r ug 1 .. .....................

ZP8 Z2 ............................

Z 3 ...........................

....OP1. OP2. OP3 .......SCRI .SCR2 .......................

Bridge rectifier I(0). 'bW2.5W 2KM. 1,5W 3300), 1.5W 470. '/?W 13KG, 3W 4,7KG. 3W Pot, 10KO 500O, '/AW 1200. Y*W 82KO. 'kW 10K. %W 4.7K". 1W 39KG. "*W 33K-50K (selected)

Pot. 5KG 20 MFD. 75V 2OMFD, 250V 5 MFD. NP, 25V 0. 1 MFO, 200V 400V. IA 12V. 1W 8 4V (temperature compensaled)

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.

SHOOTING GUIDE).3. Check for sticking relay on LOWER time-delay relay circuit board.Tap changer overruns position and/or 1. Check manual operation for overrun. If LTC overruns, see section 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 T 4 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. I1 no 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 4D 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 .. ............................

22 volts +/-12 9 TROUBLESHOOTING GUIDE (Continued)

For Equipment Built After 111182 VOLTAGE READINGS Condition Neither test light can be energize Voltmeter Readings and Troubleshooting Procedure ed. 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 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 operates properly.

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) I1 resistance 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.4 10 S210-40-14 TROUBLESHOOTING GUIDE (Continued)

For Equipment Built After 111182 BIAS POTENTIOMETER SETTING Bias potentiometer R9 has been factory set and sealed. It should not be necessary to change its setting unless it becomes defective or it is necessary to replace R6.R7. R8, or Z3. To reset R9: 1. Set all control knobsexcept the VOLT-AGE LEVELcontrol at their fully coun-terclockwise positions.

2. Set VOLTAGE LEVEL cont.., at 120 volts.3. Turn calibration potentiometer P30 (on the lefthand edge of the voltage sensor circuit board) to its fully coun-terclockwise position.4. Place bias potentiometer R9 in its $ully clockwise position.5. Connect a high-impedance voltmeter (preferably digital) to voltage sensor Terminals 1 and 2.6. Connect a 114-volt +/-1 Vac, 60-Hz, sinu-soidal waveform voltage source to LTC control box Terminals 10 and G.NOT E: This can be done from the normal power source with the transformer ener-gized or from an external source.CALIBRATION RESISTOR SETTING If necessary to reset calibration resistor R30: 1. Set all controls except the BAND LEVEL control in their fully counterclockwise positions.

2. Connect a high-impedance voltmeter (preferably digital) to TEST TERMINALS A and G.3. Connect a 120-volt,.

+/-1 Vac. 60-Hz sinu-soidal waveform voltage source to LTC control box Terminals 10 and G.NOTE: This can be done from the normal source with the transformer energized or from an external source.& CAUTION If an external source is used, discon-nect the normal source and make cer-tain that the source ground lead is con-nected to G.LIMITED PARTS WARRANTY McGraw-Edison warrants to the original purchaser that load tap changing equip-ment controls shipped after August 1, 1982 are free of defective workmanship and materials for a period of five years. This limited parts warranty commences on the date of arrival at destination and covers any defects and malfunctions of the load tap changer controls except those caused by improper installation, improper mainte-nance, improper operation, customer fur-nished materials, alterations executed by customer or vandalism.

&x CAUTION If an external source is used, discon-.nect the normal source and make cer-tain that the source ground lead is con-nected to G.7. Energize the power source and, if necessary, adjust the VOLTAGE LEVEL control until the voltmeter reads 75 Vac +/-0.2 volts.5, Slowly turn R9 counterclockwise until the RAISE test light is just energized.

9. Seal the bias potentiometer setting with a hot iron or cement.10. Reset calibration resistor R30 in accordance with the instructions In the CALIBRATION RESISTOR SETTING section.4. Energize the power source and set the VOLTAGE LEVEL control to the setting that corresponds to the voltmeter read-ing -0.6 volts.Example: Voltmeter reading is 119.5 volts + 0.6 = 120.1 Vac; therefore, the VOLTAGE LEVEL control should be set at 120.1 volts.5. If the LOWER test light is energized.

slowly turn calibration resistor R30 clockwise until the LOWER test light goes out and the RAISE test light just comes on.6. If the RAISE test light is energized.

slowly turn calibration resistor R30 counterclockwise until the RAISE test light goes out and then clockwise until the RAISE light just comes on.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 IN AN 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

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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 Tim er ...................................................................................................................................

23 Resistance Compensation

................................................................................................

23 VI','

Reactance Compensation

......................................................................................................

23 Paralleling Com pensation

.............................................................................................

23 Typical Voltages ............................................................................................................................

24 Parts List .........................................................................................................................................

25 Optional Components

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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 clarity or to correct errors will receive immediate attention.

Please contact the Marketing Services.Department, 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.U 0m v~w 0 cc~7 I'I~~i 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.The pi network consisting of C2, R7 and C5 provides exactly 9Q0 phase shift, including effects of transformer Winductance.

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 theripple 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 I1 and 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 4 3sec S.3 4 sec 2.9 5 sac 0.4 2 hoJurs Tapchanger Control Termir POLARITY Potential If Desired Transformer Line Current POLARI n5A n 2 5A I tals Instantaneous Voltage Reduction Connections Cam Swilch Contact, Closed while LTC Is In transition for non-sequenlial operation.

K1'K2 Circulating Current Current Inputs are 0.2 A*Full Scale*. Add 5/0.2 A Current Transformers If required 120/240 V 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 Voltage Reduction, as T 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.

FIGURE 2 External Connections 0

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 O)LL C/)0 1.'0 40 NL 10 1 2 3 4 9 6 7 8 9 10 11 12 t.3 14 15 3 V E 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 complete ordering information.

0

• C27 & C28 installed for 50 Hz System RESISTANCE VALUE FACTORY SELECTED 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.

C3) c C0)0 A~ III ( CAP__ ____I___0 _ _ _ __.__o_ __ _ _ _ _ _o LL C 00 0 ~C4:: Nb E (j)PLa, I 0 RGURE 5 Mounting and Outilne Dfrmensions hAICHANGER CONTROL RiErS! (gffiECT M-0067E R I Mxwn 00 IN~u*~ CLM.ELECTRIC:[>

LINE DROP COMPENSATOR 0 QTOT 00 LOWER 0 T Terminal Blocks FIGURE 6a Horizontal Mounting Configuration WfW4CANGER CONTROL "WUC OO LaaR N-M067E Terminal Blocks 4 Rack Units (7 inches)FIGURE 6b 19" Rack Mount Configuration MOTOR SUPPLY TAPCHANGER CONTROL M-0329 90 M-0067E 8 BLK RAISE 9 8LK 00 _L F-ý 1 LOWER 90 B.U.I SLimit switcher, auxiliary contacts as required in motor control circuits.4 84R -Raise Motor Auxiliary Relay 84L -Lower Motor Auxiliary RelayFIGURE 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 a il LL II, I I--a *le t m FIGURE 8 Component Location Eg...low i

• 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.

It is suggested that each knob be moved rapidly back and forth a dozen times or so during routine maintenance.once 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 V dc (Trimmer R23 should vary this voltage)D14 (Anode) toO0 V -12 Vdc D14 (Cathode stripe) toO0 V -6 Vdc-22--

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 X knob 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 X knob at 24 V, and the R knob at 0, apply 0.1 A capacitive current (9 0 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 0V 0V 0V 0V 12V 12 V 0V 0V 0V 0V 0V TO 20 V 12V-6V-12 V TP-2 R46-R48 Junction R46-R48 Junction R47-R49 Junction R36-R38 Junction R41-C26 Junction CONDITION VOLTAGE Voltage 120 V ac, S1 on OPERATE 243 V dc Ac Ripple, above condition 1.0 V pp Ac Ripple 0.01 V pp Ac Ripple 0.06 V pp Ac Ripple 0.2 V pp Voltage 105 V ac -7.0 V dc Voltage 120 V ac -8.2 V dc Voltage 135 V ac -9.1 V dc 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 R26 cw, R29 ccw +3.2 V dc R26 ccw, R29 ccw +5.1 V dc R26 cw, R29 ccw +3.4 V dc Voltage in band -4.0 V dc RAISE LED on +8.7 V dc Above condition after timing +8.9 V dc Voltage in band -4.1 V dc LOWER LED on +8.7 V dc Above condition after timing +8.9 V dc Voltage in band 0 V dc Voltage out of band +0.6 V dc Voltage in band +0.6 V dc 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*

C1 C2,C3,C4 C5 C6 C7 C8 C9 c00 Cll,C22,C23 C12 000-00850 010-00529 000-W0501 000-00617 010-400527 000-40626 000-00903 000-O0902 000-00533 P.C. Board, P-0273 Not Used Capacitor, Polyester Film, 1 jiF+/-10%, 200 V Capacitor, Mylar, 0.47 p.F +/-10%, 200 V Capacitor, Tantalum, 3.9 IjF +/-10%, 35 V Capacitor, Electrolytic,50 jiF +75%/-10%, 50 V Capacitor, Mylar, 0.068 I+/-F +/-10%, 100 V Capacitor, Electrolytic, 150 ;iF +75%/-10%, 75 V Capacitor, Ceramic Disc, 100 pF +/-10%, 1 kV Capacitor, Ceramic Disc, 680 pF +/-_10%, 1 kV Capacitor, Tantalum, 150 pF+/-10%, 15 V 0 COMPONENT BECO DESCRIPTION DESIGNATION NUMBER_C13,C14,C1 6 C15 C17,C18 C19 C20 C21 C24 C25 C26 C27,C28 D1,D2,D5,D6,D13,D18 D3,D19 D4,D9-D12,D16 D7 D8 D14,D15 D17 D20,D2-Z D21 Fl, F2 11J12 K1,K2 QI,Q3,Q4,Q6 Q2 000-00418 010-M0526 010-00531 000-40918 000-00913 000-00914 000-00545 400-00211 400-00030 400-00200 40O-00035 400-00001 400-00043 400-00078 400-00021 420-00720 400-00722 420-00118*

400-00600 400--"603 Not Used Capacitor, Electrolytic, 170 +/-F +75%/-10%, 50 V Capacitor, Mylar, 0.033 4xF +/-10%, 100V Capacitor, Mylar, 0.1 ptF +/-10%, 200 V Not Used Capacitor, Ceramic Disc, 0.0047 gFF+/-20%, 1 kV Capacitor, Ceramic Disc, 0.001 ;+/-F, I kV Capacitor, Ceramic Disc, 0.1 iF +/-20%, 50 V Capacitor, Solid Tantalum, 2.7 gF +/-10%, 15 V Refer to OPTIONAL COMPONENTS Diode, Rectifier, 600 V, G.E. 1N5061 Diode, Zener, 15 V +/-5%, 400 mW, 1N965B Diode, 1N662/B692X13-4 Diode, Reference, 6.2 V +/-5%, 400 mW, 1N823A, Not Used Diode, Zener, 6.2 V +/-5%, 400 mW, 1N753A/IN5234B Diode, Zener, 33 V +10%, 5 W, 1N5364A Diode, Zener, 15 V +/-5%, 5 W, 1N5352 Diode, Zener, 12 V +/-5%, 5 W, 1N5349 Microfuse, Plug-in, 1/4 A, Littelfuse 273.250 Diode, Light Emitting, HP HLMP-3316 Relay, AZ, 420-07-4H Integrated Circuit, Op Amp, UA741, TO- 99 Integrated Circuit, Regulator, UA723, TO -100 e COMPONENT r BECO DESCRIPTION DESIGNATION NUMBER i ii ...... .. Vi Q5,Q7-29,Ql3 400-00300 Transistor, NPN Signal, 2N1711 Q1O-Q12 Q14-Q22 Q23 RI R2 R3 R4,R$R5,R9,R40 R6 R7 RIO R11 R12 R13 R14 RIS R16 R17 R18 R19 R20, R67 R21 R22 400-00728 400-00733 290-00I52*

360-00045*

360-00032 360-00042 360-00042 290-00274 290-00364 330-00647 330-00643 200-00102 330-00638 320-00466 320-00381 200-=0222 200-00823 200-00100 Not Used Varistor, 275 V, G.E. V275LA2 Varistor, 460 V, G.E. V460LB20 Not Used Resistor, Metal Film, 1.5 K +/-2%Potentiometer, 5 K, 2 W, U-0048-1 Trimmer, Cermet, 10 K +/-20%, Bourns 3386P-1-103 Potentiometer, 50 KY, 2 W, U-0048-2 Not Used Trimmer, Cermet, 2 K +/-20%, Bourns 3386P-1-202 Resistor, Metal Film, 270 K +/-2%Resistor, Metal Film, 357 K +/-2%Resistor, Metal Film, 301 K+/-1%, 1/4 W Resistor, Metal Film, 274 K +/-1%, 1/4 W, RN60E Not Used Resistor, Carbon, 1 K +/-5%Resistor, Metal Film, 243 K +/-1%, 1/4 W, RN60E Resistor, Metal Film, 4.75 K +/-1%, RN65D Resistor, Metal Film, 681 Q +/-1%, RN65D Resistor, Carbon, 2.2 K +/-5%Resistor, Carbon, 82 K +/-5%Resistor, Carbon, 10 ohms +/-5%Resistor, Metal Film, +/-1% 1/4 W, Factory Select, RN60E, U-0038 COMPONENT 1 ECO DESCRIPTION DESIGNATION NUMBER D R23,R28,R31 R24 R25 R26,R29 R27,R30 R32 R33,R70,R73 R34 R35 R36 R37 R38,R48,R49 R39 R41 R42,R44,R65,R72 R43 R45 R46, R47 R50-R54 R55 R56-R63 R64 R66 R68 R69 360-00034 330-00469 330-00393 360-00047*

330-00460 200-00101 200-00684 200-"0155 200-00683 200-00682 360004 200-00223 200-00103 290-00434 20"-00226 200-00182 200-00331 200-W0104 200-00273 290-00202 Trimmer, Cermet, 200 ohms +/-20%, Bourns 3386P-1-201 Resistor, 5.11 K +/-1%, 1/4 W, RN60E Resistor, 909 ohms +/-1%, 1/4 W, RN60E Potentiometer, 500 ohms, 4 W, U-0031-1 Resistor, 4.12 K +/-1%, 1/4 W, RN60E Not Used Resistor, Carbon, 100 ohms +/-5%Resistor, Carbon, 680 K +/-5%Resistor, Carbon, 1.5 M +/-5%Resistor, Carbon, 68 K +/-5%Refer to OPTIONAL COMPONENTS Resistor, Carbon, 6.8 K +/-5%Trimmer, Cermet, 20 K +/-20%, Bourns 3386P-1-203 Resistor, Carbon, 22 K +/-5%Resistor, Carbon, 10 K +/-5%Resistor, Metal Film, 430 K +/-2%Resistor, Carbon, 22 M +/-5%Resistor, Carbon, 1.8 K +/-5%Not Used Resistor, Carbon, 330 ohms +/-5%Not Used Resistor, Carbon, 100 K +/-5%Resistor, Carbon, 27 K +/-5%Not Used Resistor, Metal Film, 2 K +/-2%-28--

0 COMPONENT BECO DESCIPTION 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 C28 REV 0 000-00716 000-00859 Capacitor, Polyester, .18 gF +/-10%, 50 V Capacitor, Polyester, .39 jIF +/-10%, 50 V 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,,,,/5~7/5~ c9~/a ~Service Information 15-7/ 01;ý - Powe Trasfor ersCOOPER POWER SYSTEMS Power Transformers cooGFU , McGraw-Edison@

Load Tap Changer Motor Control S210-40-1 8 Maintenance Instructions CONTENTS o0 Introduction

...................................

1 Safety Advisory .....................................................

2 Motor Control ..........................................................

2 nE. 12 Operation by Electrical Hand Control ........................

2 Components

...........................................................

2 1. Motor Reversing Contractors

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2 2. Motor Braking Contractor

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2 I 3. Sequential Tim ing Relay .......................................

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

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

2 6. M otor B reaker .......................................................

2 7. Operation Counter .........................................

3 8. Fuses ....................................................................

3 8 4 L 84 R 9. Heater Switch ..................................................

3 D j 10. Convenience Outlet .........................................

3 [ j 11. Motor Capacitor

.............................................

3 W iring .....................................................................

3 <Maintenance

..................................................................

3 PULL-OUT FUSE BLOCK z Troubleshooting

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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 &?mechanisms.

The motor control panel is shown in Figure 1. 084B WARNING YOU MUST HAVE TRAINING IN THE 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 instructions donotclaimto coveralldetails orvariationsin theequipment, procedures, or processes described, norto provide directions formeeting every possible contingency during installation, operation, or maintenance.

When additional information is desired, please contact your Cooper Power Systems Representative.

March 1991

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

-. 2 SAFETY ADVISORY 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.& DANGER IMMEDIATE HAZARDS WHICH WILL RESULT IN DEATH OR SEVERE PERSONAL INJURY OR SUB-STANTIAL PROPERTY DAMAGE, IF PROPER PRE-CAUTIONS ARE NOT TAKEN.OPERATION BY ELECTRICAL HAND CONTROL zI &WARNING DO NOT OPERATE EQUIPMENT UNLESS IT IS COM-PLETELY AND PROPERLY ASSEMBLED.

LI\ WARNING Un vrlgfr! Cru"m~' I l ovv" Io.nr '.UULV RESULT IN DEATH OR SEVERE PERSONAL INJURY OR SUBSTANTIAL PROPERTY DAMAGE, IF PROPER PRECAUTIONS ARE NOT TAKEN.I & CAUTION HAZARDS OR UNSAFE PRACTICES WHICH COULD RESULT IN MINOR PERSONAL INJURY OR PROD-UCT OR PROPERTY DAMAGE, IF PROPER PRE-CAUTIONS ARE NOT TAKEN.NOTICE SITUATION WHICH COULD RESULT IN PRODUCT OR-PROPERTY DAMAGE WITH NO PROBABILITY OF PERSONAL INJURY, IF PROPER PRECAUTIONS ARE NOT TAKEN.MOTOR CONTROL Motor control systems for Load Tap Changer transformers may be electrically hand controlled or automatically initi-ated, with control facilities specified to meet operating requirements.

The motor control circuit uses electromechanical contactors and relays which are both mechanically and electrically interlocked to insure positive operation of the Load Tap Changer motor.McGraw-Edison utilizes two similar, but slightly differ-ent, motor control panels: 1) To control a 115 volt, single phase, 60 Hertz reversible motor, 2) To control a 230 volt, single phase, 60 Hertz reversible motor.Operating the Load Tap Changer from one operating position to another requires a single electrical control signal to initialize the motor control system. This electrical control signal or momentary contact must be closed from 0.10 to 0.25 second duration, to ensure proper operation of the motor control system. The LTC drive mechanism then completes the tap change without any interruption.

Automatic braking following a tap change is accom-plished bythe trouble-free DC braking method (DC voltage is applied to the motor windings in parallel), incorporating an auxiliary step-down transformer and a full wave rectifier.

Current limiting time delay fuse(s) protect the LTC supply circuitand a fuse protects the DC braking circuit. A breaker is provided for protection of the LTC drive mechanism motor.Hand-operated control switches are normally provided in the control cabinet so that the Load Tap Changer mecha-nism may be operated during installation or periods of preventive maintenance.

All control circuits must be ener-gized and functioning properly.

The Load Tap Changer switching mechanism may be energized and carrying load.COMPONENTS The actual components furnished on any specific unit, along with their ratings, may be determined by reading the 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-in 9 The motor control panel is usually equipped with the following components:

1. Motor Reversing Contactors (84R and 84L)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 base and are electrically and mechanically interlocked with each other. Each contactor is also equipped with additional contacts to provide electrical interlocking between the LTC motor AC running and DC braking circuits.2. Motor Braking Contactor (84D)This contactor controls the application of the DC volt-age to the LTC motor windings in parallel, and is part of the automatic DC braking circuit. The duration of this application is controlled by the DC braking timing relay (62A). This contactor is equipped with additional con-tacts to provide electrical interlocking between the motor DC braking and AC running circuits.3. Sequential Timing Relay (33A)This relay provides an immediate seal-in of a single electrical control signal to initialize a tap change op-eration. It also provides a controlled time delay at the completion of the braking cycle to assure positive operation of the Load Tap Changer.4. DC Power Source This source is derived from a circuit consisting of a fuse, an auxiliary step-down transformer (T84), and a full wave rectifier (two diodes, D84A & D84B, on a heat sink). The transformer connections are determined by the motor used with the Load Tap Changer drive mechanism.

5. DC Braking Timing Relay (62A)This timing relay determines the duration of the DC braking action. The relay is equipped with a normally open contact which closes immediately when the relay is energized by the operation of either the 84R or 84L contactor.

The 62A contact stays closed for approxi-mately two seconds after the 84R or 84L contactor has been released, to energize the motor braking contactor (84D).6. 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. FusesCAUTION DO NOT REMOVE ANY FUSE UNDER LOAD. FUSE BLOCKS ARE FOR DISCONNECT USE ONLY.WIRING ACAUTION DO NOT TOUCH BARE WIRES,-UVE PARTS, OR TERMINALS, TO PREVENT ELECTRICAL SHOCK HAZARD Separate fuses protect the control circuits, DC braking circuit, and auxiliary circuits.

A fuse has been provided in the 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 application.

Many units are furnished with special equipment.

Consult the wiring diagrams furnished with each specific unit for customer conforming variations.

The LTC Schematic drawings which accompany each unit must be consulted before making the power supply connections.

I & -CAUTION INCORRECTSUPPLY VOLTAGE MAY DAMAGETHE CONTROLS.

REFER TO LTC SCHEMATIC DRAW-INGS.I NOTICE THE PULL-OUT FUSE BLOCK (FBA) USED IN THE MOTOR CONTROL AND SOURCE CIRCUITS HAS BEEN FURNISHED AS A SAFETY FEATURE. THIS FUSE BLOCK SHOULD BE PULLED OPEN TO PROVIDE A VISUAL DISCONNECT WHEN SERVIC-ING THE CONTROL CIRCUITS, MOTOR CIRCUITS, LTC DRIVE MECHANISM OR LTC SWITCH.IA 9. Heater Switch (43H)This ON-OFF switch controls the space heater(s) located in the cabinet. It is recommended that the heater(s) be left on at all times to prevent moisture condensation and attendant corrosion.

//i CAUTION MAINTENANCE

& WARNING DISCONNECT AND GROUND ALL ELECTRICAL POWER SOURCES, TO PREVENT ELECTRICAL I SHOCK HAZARD.& WARNING GROUND AND SHORT CIRCUIT ALL CURRENT TRANSFORMERS, TO PREVENT HIGH VOLTAGE SHOCK HAZARD.Maintenance and repairs must be done by authorized personnel only. Read, understand and obey all Safety Advisories, before doing any repairs, maintenance, or changing the features and accessories of this equipment.

During the performance of established maintenance procedures, annually, and every 100,000 tap changes the LTC Motor Control Panel, its components and wiring must be cleaned of all accumulated dust, dirt, and foreign debris. Make certain all electrical connections are clean and securely tightened.

Inspect for worn, cracked, frayed or otherwise damaged components and wires. Keep all fasteners tight. Keep all adjustments according to factory specifications Immediately notify Cooper Power Systems upon the detection of probable defective parts. Failure to perform these minimal procedures could void the limited warranty.ENERGIZE HEATERS DURING STORAGE TO PRE-VENT MOISTURE CONDENSATION AND ATTEN-DANT CORROSION.

PROVIDE TEMPORARY HEATER POWER IF PERMANENT POWER IS NOT AVAILABLE.

10. Convenience Outlet (DO)This NEMA 5-15R separately fused duplex outlet may be used for portable lights and small power hand tools.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.

& CAUTION SHORT CIRCUIT CAPACITOR TERMINALS, TO PREVENT ELECTRICAL SHOCK HAZARD.a 3 TROUBLESHOOTING (FOR EQUIPMENT BUILT AFTER 1/1/82)Electrical Operation of Load Tap Changer Motor Control 1. Load Tap Changer does not respond to RAISE-LOWER switch.a. Check AUTO-MANUAL, REMOTE-LOCAL, RAISE-LOWER switches and their wiring for open circuit.b. Check fuses and motor breaker. Read specific LTC schematic drawings for proper ratings. If braking fuse is open, check diodes (D84A and D84B) for short circuit. If a diode shorting problem persists, check timing of 62A relay. Check station service supply for transient problems.c. Check position of handcrank. (Must be in storage position.)

d. Check 84R and 84L contacts and 840 contacts.e. Check mechanical stop switch (if supplied).

It must be closed.f. If reversing contactor operates and motor breaker does not trip, check motor, capacitor, reversing contactor contacts, and associated wiring for open circuit condition.

g. If reversing contactor operates and motor breaker trips; check motor, motor capacitor, and associ-ated wiring for short circuit condition.

Check for mechanical binding in Load Tap Changer mecha-nism. (Read LTC Maintenance and Operating In-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.3. Load Tap Changer over-runs (makes additional uninitiated steps). Refer to Service Information instruc-tions covering specific LTC mechanisms.

a. Check seal-in switch (33/1) setting. Refer to instruc-tions for LTC switch.b. Check 84R and 84L contactors for binding and erratic operation.

c. Check DC brakin.g circuit (84D contactor, 62A timing relay, rectifier diodes, 84R-84L contacts, braking transformer).

4. Load Tap Changer stops off position.

Refer to Ser-vice Information instructions covering specific LTC mechanisms.

a. Check seal-in switch (3311) setting. Refer to instruc-tions for LTC switch.b. Check operation of 33A relay.c. Check 84R and 84L contactors.

d. Check all wiring associated with the 84R and 84L contacts, the tap changer motor and the power supply.e. Check 84D contactor for erratic operation.

f. Check handcrank switch (89C) and mechanical stop switch (39) for erratic operation.

g. Check for mechanical binding in the Load Tap Changer mechanism, Read LTC Maintenance and Instruction Manual.COOPER POWER SYSTEMS Mcmaw.EdlsonO Power Products Post Office Box 440 Canonsburg, PA 15317 to 4