ML13197A411

Calvert Cliffs, Units 1 & 2, 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:	Gellrich G H Constellation Energy Group, EDF Group, Calvert Cliffs
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML13197A411 (93)

Text

George H. GellrichVice President Calvert Cliffs Nuclear Power Plant, LLC1650 Calvert Cliffs ParkwayLusby, Maryland 20657410.495.5200 410.495.3500 FaxCENGa joint venture ofConstellatinon Energy, DCALVERT CLIFFSNUCLEAR POWER PLANTJuly 12, 2013U. S. Nuclear Regulatory Commission Washington, DC 20555ATTENTION:

Document Control Desk

SUBJECT:

Calvert Cliffs Nuclear Power PlantUnit Nos. 1 and 2; Docket Nos. 50-317 and 50-318Response to Request for Additional Information fliesel G~enerator I .icense Amendment ReaiiestRegarding 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 LicenseAmendment (TAC No. ME9832 and ME9833)In Reference (a), Calvert Cliffs Nuclear Power Plant, LLC submitted a license amendment request torevise 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), theNuclear Regulatory Commission requested additional information to support their review ofReference (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). Noregulatory commitments are contained in this letter.

Document Control DeskJuly 12, 2013Page 2Should 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 toDiesel Generator License Amendment Request

Enclosures:

1 Engineered Safety Features Actuation System Logic Diagram2 Transformer and Tap Changer Information cc: CCNPP Project Manager, NRCRegion 1 Administrator, NRCCCNPP Resident Inspector, NRCS. Gray, DNR ATTACHMENT (1)RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING ENHANCEMENTS TO DIESEL GENERATOR LICENSEAMENDMENT REQUESTCalvert Cliffs Nuclear Power Plant, LLCJuly 12,2013 ATTACHMENT (1)RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING ENHANCEMENTS TO DIESEL GENERATOR LICENSE AMENDMENT REQUESTRAI 1:On Page 2 of Attachment I of the LAR, in regards to SR 3.8.1.8, the licensee stated that the loads underaccident 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 foraccident 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 FeaturesActuation System is contained in Enclosure

1. This logic diagram includes the logic details for theaccident (loss-of-coolant

incident, called the LOCI sequencer) and shutdown sequencer.

The accidentand 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 isactuated (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 onTable 8-7 in the Updated Final Safety Analysis Report for the accident sequencer.

1ZB 2ZA 2ZBSEQUENCER TIME IZA SB 2ZA (BSTEP NO. (SECONDS)

SERVICE (BUS 11) (BUS (BUS (BUS14) 21) 240 0T57 Reactor Motor Control Centers 114 104 214 204Turbine Bearing Oil Pump*(2) 21IE Battery Chargers l1&14 12&13 22&23 21&24Transformer for 208/120 Volt 11 12 21 22Instrumentation BussesDiesel Generator Room Exhaust lB 2A 2BFanControl Room HVAC Fans 11 12Control Room Air Conditioning 11 12Condenser Fans*Emergency Core Cooling System 11 12 21 22Pump Room Air CoolersEmergency Core Cooling System 11 12 21 22Pump Room Exhaust FansBoric Acid Storage Tank Heaters*

Two Two Two TwoHeat Tracing System* 11 12 21 22Diesel Building IA and Auxiliaries IASwitchgear Room HVAC Fans 11 12 21 221 E Battery Room Fans One exhaust fan and one redundant supplyfanService Water Pump, if previously 11 12 21 22operating 1 Service water pump if not 11 12 21 22previously operating I

ATTACHMENT (1)RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING ENHANCEMENTS TO DIESEL GENERATOR LICENSE AMENDMENT REQUEST1ZB 2ZA 2ZBSEQUENCER TIME IZA (BU (BUS 2ZBUSTEP NO. (SECONDS)

SERVICE (BUS 11) (BUS (BUS (BUS14) 21) 242 10 Saltwater pumps 11 12 21 22Switchgear Room Air Conditioner*

222A 20 Computer Room HVAC* 11 123 15 Switchgear Room Air Conditioner*

11 12 21Instrument Air Compressor 11 12 21 22Control Room HVAC* 11 123A 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 butthe 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 intervaltolerance, 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. Therewere 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 theacceptance 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 meetthe 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 thissurveillance test at the most limiting power factor, the voltage regulators must be placed in the manualmode of operation.

This operational mode means that the safety bus voltage now tracks with the gridvoltage swings. This places equipment at greater risk for being impacted by degraded grid voltage forthe duration of the surveillance test. Currently, the surveillance test is one hour in duration and theexposure 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. Thesurveillance 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 powerfactor achievable with the voltage regulators in automatic mode. The achievable power factor willdepend 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 REQUESTb. Explain whether the surveillance test can be performed at the power factor limits during the 2-hourperiod 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 toreduce risk to safety-related equipment during Unit operation.

The only way to reach the reduced powerfactor required by the current Technical Specification under all conditions is to place the 13.8 kV voltageregulators 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 onthe 4 kV safety-related buses. These voltage regulators can adjust voltage, as necessary, for changes ingrid voltage.

Therefore, the 13.8 kV voltage regulators ensure the 4 kV safety-related bus voltagesremain within acceptable values for various grid voltages.

When the 13.8 kV voltage regulators are in themanual 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 beadversely 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 DGgenerator 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 busvoltage at the time of the test, the DG voltage regulator range may not be sufficient to achieve therequired power factor. To further increase the DG VARs and decrease DG power factor, the 4 kV busvoltage could be decreased.

This can be accomplished by placing the associated 13.8 kV voltageregulator in manual and "stepping" the 13.8 kV voltage regulator down one step. This decreases the 4 kVbus voltage, increases DG VARs, and decreases DG power factor. However, with the 13.8 kV voltageregulator in manual, the 4 kV bus and associated electrical distribution system can be adversely affectedby changes in grid voltages.

Therefore, in order to obtain the required DG power factor, plant conditions (bus voltages, DG voltageregulator performance) may require reducing the 4 kV bus voltage.

This requires placing the 13.8 kVvoltage 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 thetransformers 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 hourendurance test is performed during a refueling outage, during a DG testing window. The associated 4 kVbus is inoperable during this time and placing the voltage regulators in a manual mode has less impactthan 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 4kV bus is increased when the voltage regulator is in the manual mode. The voltage regulators inautomatic 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 hourendurance test.3 ATTACHMENT (1)RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING ENHANCEMENTS TO DIESEL GENERATOR LICENSE AMENDMENT REQUESTRAI 4:On page 3 of Attachment I of the LAR, the licensee described the kW loading requirements for the DGforSR 3.8.1.11.

Provide a summary of the loading calculations for each DG for both accident and LOOPconditions.

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 highestloading for each DG is in bold.Diesel Generator Accident 1st Minute Pre-RAS Post-RAS On SDCIA DG LB LOCA 3088.0 3205.9 3275.3 3184.21B DG LB LOCA 2309.8 2280.3 2350.6 2564.42A DG LB LOCA 2310.0 2357.3 2425.3 2591.32B DG LB LOCA 2841.3 2831.1 2902.1 2699.6RAS -Recirculation Actuation Signal. For a LB LOCA, this is assumed to occur at 30 minutes into theaccident.

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

Thehighest loading for each DG is in bold.Diesel Accident I" Minute 1-10 10-75 75 Minutes-On SDCGenerator Minutes Minutes 4 Hours1A DG LOOP 2058.7 2799.6 3495.9 3148.9 3027.71B DG LOOP 1282.6 1983.2 2359.3 2140.4 2388.12A DG LOOP 1310.5 2054.9 2296.4 2076.8 2427.42B DG LOOP 1830.2 2450.4 2771.8 2539.5 2474.5RAI 5:The proposed changes to SR 3.8.1.11 relating to the 2-hour and 22-hour tests, states that, "These testphases may be performed in either order."Explain how performing the 2-hour test after the 22-hour test demonstrates the capability of the DG toperform 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 ratherthan the beginning of an event. Therefore, a higher test load at the end of an endurance run can moreclosely model the bus loading that could be experienced.

Additionally, DG loading includes a prclubricating and warm-up period and a gradual loading period asdescribed in the Technical Specification Bases. It takes approximately 15 to 30 minutes to load a DG toits test band. During the test, no adjustments are made at the lower load which would affect the ability ofthe DG to operate at the higher load. Therefore, since time to load is not critical, and the ability to4 ATTACHMENT (1)RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING ENHANCEMENTS TO DIESEL GENERATOR LICENSE AMENDMENT REQUESTincrease to the higher load later is not affected, operating at the lower load first does not affect the higherload 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 beperformed.

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 notin the list of SRs which are not applicable, but rather is in the list of SRs in the "NOTE", which are notrequired to be performed.

The NRC stafffinds that the exemption for not performing the newly proposedSR 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 approvedduring the Improved Technical Specifications conversion.

Specifically, the new SR 3.8.17 tests the DGautomatic start in response to an undervoltage signal [provided by Diesel Generator (DG)-Loss of VoltageStart (LOVS), Technical Specification 3.3.6]. The DG-LOVS is not required to be Operable in Modes 5and 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 inour application for a license amendment (Reference 2). That letter states that a DG is required duringshutdown and refueling to ensure adequate AC electrical power is available to mitigate events such as afuel 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 slowlyand the results are less severe than the events which occur at full power. Thus, additional time isavailable 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 theevent. These discussions support the exclusion of undervoltage signals in Modes 5 and 6, and duringmovement 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 LimitingCondition for Operation.

New SR 3.8.1.17 includes the requirement to auto start the DG from a standbycondition on a loss of offsite power signal. This requires that the DG-LOVS system be Operable.

TheDG-LOVS system operability is contained in Technical Specification 3.3.6. The Applicability ofTechnical Specification 3.3.6 is Modes 1 through 4. The DG-LOVS system is not required to beOperable in Modes 5, 6 or during movement of irradiated fuel assemblies.

Therefore, it can be taken outof 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 REQUESTand the Limiting Condition for Operation is not met. This leads to the need to exempt SR 3.8.1.17 fromthe 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, Issuanceof Amendments for Calvert Cliffs Nuclear Power Plant, Unit No. I (TAC No. M88168) and UnitNo. 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 Testing6 ENCLOSURE 1ENGINEERED SAFETY FEATURES ACTUATION SYSTEM LOGICDIAGRAMCalvert Cliffs Nuclear Power Plant, LLCJuly 12, 2013

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

______ _____ ____/5n -o/;--. /o;,3Power Transformers ftLoad Tap Changing Equipment-Installation, Operation, and Maintenance Service InformationCOOPER POWER SYSTEMSS210-40-3 Applicable to Type 550C and in particular to Type 550CS Load Tap Changers.

CONTENTSGeneral ..........

........

1Shipping

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

1Initial Inspection

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

2Storage ........................

2Preliminary Preparation

..........

2Installation

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

2Principles of Operation

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

4Drive Mechanism

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

4Tap Selector

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

5Automatic Operation ByVoltage-Regulation Relay 6Operation By Electrical Hand Control ................

6Operation By Hand Crank ........

6Maintenance

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

6Testing For Leaks ..............

8Neutral-Position Relationship

..... 9Maximum Raise And LowerPositions

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

10Contacts

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

12Contact Erosion Guide ..........

12Contact Replacement Criteria

..... 12Movable Arcing Contacts

...... 12Stationary Arcing Contacts

..... 12Reversing Movable Contacts

.. 13Reversing Stationary Contacts

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

13Trouble-Shooting Guide ...........

14Replacement Parts ...............

19W arranty ........................

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

20GENERALThe Type 550CS is an improved versionof 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 minusten 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 usedin applications where the LTC is not re-quired and does not operate for extendedSperiods of time. In these situations, it isgood operating practice to by-pass theLTC. Refer inquiries concerning by-passFigure 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 threemajor components:

the tap selector, thedrive, and the controls.

The tap selectoris 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 tapselector from the transformer.

The driveand the controls are in an air-filled weatherproof compartment locateddirectly beneath the tap-selector com-partment.

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

A universal driveshaft con-nects the drive with the tap selectorthrough a self-compensating spring-loaded stuffing box in the selector com-partment.

This Service Information bulletincovers in detail the tap selector and thedrive unit; the controls are covered inS210-40-14, Controls for Power-Type Load Tap Changing Equipment.

SHIPPINGThe tap-selector compartment is shippedfilled with either oil, dry nitrogen gas, ordry air. It is standard practice for McGraw-Edison to ship the LTC switch under thesame conditions as the main transformer.

To determine the conditions under whichthe LTC switch has been shipped, refer tothe detailed outline drawings suppliedwith the equipment.

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

When additional information is desired to satisfy a problem notcovered sufficiently for the user's purpose, please contact your Cooper Power Systems sales engineer.

September 1989

• Supersedes 6/85I INITIAL INSPECTION Immediately upon receipt of an LTC trans-former--preferably before unloading-thoroughly inspect the exterior and theinterior of the LTC and the transformer for damage, rough handling in transit, andshortage, If initial inspection reveals evidence ofdamage, rough handling in transit, and/orshortage, 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 repairedbefore proceeding with the installation or storage.STORAGEIf. after initial inspection, a transformer isnot to be placed in the service-ready con-dition Immediately, it Is considered to bein storage.Refer to Service Information S210-05-5, Liquid-Immersed Units-installation andMaintenance Instructions.

PRELIMINARY PREPARATIONS Refer to the PRELIMINARY PREPARA-TIONS PRIOR TO FILLING Section inService Information S210-10-1, VacuumFilling Oil-Immersed Power Transformers.

D5RAIN AND1 " PIPE SAMPLINGPLUG VALVEFigure 2.Installation ofopen-breather components.

2. Check the tap selector, drive shaft, anddrive box (Figure 3) to make sure theyare free from foreign objects that couldinterfere with proper operation.

3. Remove all the blocking from the auto-matic control panel.4. Check the tap selector and the drive boxfor 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 entirerange to make sure there is no me-chanical interference and operation issatisfactory.

Refer to Operation by Handcrank in thePRINCIPLES OF OPERATION Section.It is normal for the greatest in-crease in force required to move theswitch to occur in moving the switchfrom neutral to Position 1 raise or fromPosition 1 raise to neutral.

It is at thesepositions that the additional load ofoperating the reversing switch ispicked up. Movement of the revers-ing switch also comes into play in mov-ing the switch from Position 2 raise toPosition 3 raise and Position 1 lowerto Position 2 lower. In these positions, the reversing switch contacts aremoved from a first position to a secondposition on the stationary contact.B. Install the screen and retainer on theinlet breather pipe.C. Remove the 1-in. pipe plug from thetopof the tap-selector compartment.

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

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

Contact ServiceDepartment, McGraw-Edison PowerSystems Division, Box 440, Canons-burg. PA 15317.A WARNINGBefore performing any work on the LTCarcing tap selector switch, drive or con-trols, observe the warnings and cautionsappearing in Service Information S210-40-14 and S210-40-18

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

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

2. Open the tap-selector compartment door.3. Inspect the tap selector for physicaldamage.4. Inspect the tap-selector compartment for evidence of moisture.

A. If there is any sign of moisture insidethe compartment, determine the ex-tent and the manner by which themoisture entered and correct thecondition.

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 thetap-selector compartment (Figure 2).A. Carefully remove the pipe cap fromthe inlet breather pipe protruding from the bottom of the compartment.

The pipe ma~y contain a smallamount of oil that splashed in dur-ing manufacturing or shipping.

TAP-SELECTOR COMPARTMENT OILLEVELGAGEARCINGSW1TCHCONTROLCOMPARTMENT AUXILIARY CONTROLDEVICES(MOTORCONTROLPANEL)DRIVE UNITSAFETY VALVEINLET BREATHER PIPEDRIVESHAFTAUTOMATIC CONTROLPANEL9Figure 3.Components of LTC mechanism.

2 S210-40-3 ft"ON POSITION-

8. Energize the motor control panelPOINTER (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 thetap selector are stopping properlyin 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 counteris 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 limitSHAFT DRIVE MOTOR position.

(The motor should notPOSITION operate.)

INDICATOR If the motor operates, refer to theTROUBLESHOOTING GUIDE.Figure 4. D.Check the handcrank switch byLTC drive unit. removing the crank from its holderand 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 theholder. TROUBLESHOOTING GUIDE.SWR10. Test the dielectric strength and mois-S WARNIN'G ture content of the new oil beforeBefore 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 onthe oil-level gage.13. Pressure test the tap-selector com-partment.

Refer to the TESTING FOR LEAKS(PRESSURE TESTING)

Section forrecommended test procedures.

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

Ifthe transformer has been in storagefor more than three months, operatethe LTC for 10 minutes (approximately 800 operations) to re-seat, the con-tacts and eliminate any air pocketsresulting from refilling.

CAUTIONThe drive motor is designed for inter-mittent duty. If the motor is to beoperated 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 ASSEMBLYREVERSING SWITCHMOVABLE CONTACTSTATIONARY CONTACTSPOST INSULATORS MOVABLECONTACTSREVERSING ROLLERSTUB SHAFT iREVERSING FRONT INSULATING PANELSEGMENT i INSULATING PANELROLLER PLATESHORIZONTAL DRIVE SHAFTINSULATING DRIVE SECTIONSSCROLL CAM VERTICAL DRIVE SHAFTFigure 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 controlcompartment located below the tap-selector compartment.

Mechanical fea-tures of the drive unit are shown inFigure 4.The drive, enclosed in an air-filled, cast-aluminum

housing, is equipped with self-lubricating bearings; the gearing is coatedwith silicone grease during assembly toprotect against rust. The limit switchesand seal-in switch are mounted on thedrive box.A mechanical stop located inside thedrive housing prevents operation of thetap selector beyond the limit positions when hand cranking, or in the event ofelectrical limit-switch failure.The LTC is driven by a 115-Vac, 60-Hz,single-phase, capacitor-start, capacitor-run motor with positive stopping of thedrive being achieved by dc braking of themotor. It is important that the motor hasa well-regulated voltage supply (mea-sured at the motor).CAUTIONThe drive motor is designed for inter-mittent duty. It the motor is to beoperated 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 gearreduction (101 and 99). drives the spurgears(103 and 109). The hand-crank shaft(100) is attached to spur gear (103). Spurgear (92) drives the universal shaft (38)through a pair of miter gears (91 and 47).Shaft (81) extends through the rear of thedrive housing and has mounted on it theseal-in switch operating cam (78). Themotion of this shaft is transmitted througha pair of miter gears(78 and 77)and worm-gear assembly (49 and 69) to the positionindicator and limit-switch arm (58).Upon energization of the motor, the ap-proximate time required to complete onetap change for a 32-step switch is onesecond. For a 16-step switch the time ofthe 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 tapchange this pointer should be centeredon the ON-POSITION plate which isattached to the drive housing (see Checksand Adjustments Nos. I and 2 in theTROUBLESHOOTING GUIDE Section).

The pointer being anywhere between theindicating ends of the ON POSITION plateindicates that the tap-selector contactsare fully in contact.A CAUTIONBefore dismantling the drive box, theLTC mechanism must be in the neutralposition (see Neutral-Position Relation-ship in TROUBLESHOOTING GUIDESection).

Incorrect timing within thedrive box or between drive and tapselector can cause transformer failure.If trouble is suspected within the drivehousing, the McGraw-Edison Power Sys-tems Division transformer service sectionshould be consulted before repair or ad-justment is attempted.

SEAL-IN SWITCH(9ft1019Figure 6.Exploded view of LTC drive unit. (For complete parts list, refer to Figure 17 and accompanying table.)4

____ ____ ___ ____ ____ ___S210-40--3 Tap Selectori The tap selector is an arcing-tap-switch type load tap changer.

The selector ismounted on a Pennsylite insulating panelwhich is oil-tight and isolates the maintransformer compartment from the tap-selector compartment.

The insulating panel will withstand full vacuum andserves as the terminal board for the tapsfrom the transformer winding and the leadsfrom the preventive-autotransformer.

& CAUTIONDo not operate the LTC switch whenthe transformer is under full vacuumcondition.

The tap-selector compartment is open-breathing.

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

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

It ispossible 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 stuffingbox. The motion of the universal drive-shaft is transmitted through an insulating coupling (5) to the center phase of the tapselector through a pair of miter gears (21).one of which is attached to the scroll-cam shaft. Motion is transmitted to the twoend phases through horizontal insulating shafts (5 and 20). Operation of the endphases is identical to that of the centerphase described below.The motion of the universal driveshaft transmitted to the scroll-cam shaft causesthe scroll cam (16) to rotate 180 degreesin the case of a 32-step switch, and 360degrees in the case of 16-step switch.Every 180-degree movement of thescroll cam operates one of two rollerplates (57 and 62) which are located onopposite sides of the scroll cam. Attachedto each roller plate and operating con-centrically are the movable-arcing-con-tact shafts (39 and 37), with movable-arcing-contact assemblies attached toinsulating supports.

The movable arcing contacts (36)operate in different planes. The scrollcam, in moving 180 degrees, moves oneor the other roller plate, causing themovable arcing contact to be moved fromone stationary arcing contact (25) to theone adjacent.

At the end of this move-ment, the dwell section of the scroll camis positioned between two adjacent rollersof each roller plate and, because thearcing contact shafts are attached to theroller plates, they are thus locked inposition.

In the case of a 32-step switch, themovable arcing contacts are positioned on the same stationary contact or adjacentstationery contacts for each tap change.In a 16-step switch, the movable arcingcontacts are both positioned on the samestationary contact for each tap change.The reversing switch changes windingconnections for raise or lower regulation.

The reversing switch for each phase.operated as the selector switches passthrough neutral position, is actuated by aroller projecting from the face of the rearroller plate.62/Figure 7.Exploded view of tap-selector unit. (For complete parts list refer to Figure 18 and accompanying table.)5 Automatic Operation byVoltage-Regulating Relay[A WARNINGBefore performing any work on the LTCarcing-tap-selector switch, drive, or con-trols, observe the warnings and cautionsappearing in Service Information S210-40-14 and S210-40-18.

& WARNINGThe three revolutions of the hand-crank MUST be accomplished in 3 secondsand the switch MUST be hand crankedsteadily IN ONE DIRECTION ONLY untilthe ON-POSITION POINTER is cen-tered over the ON-POSITION plate. Ifthe 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 specificrequirements of the system. Refer toADJUSTMENTS Section in S210-40-14, Controls for Power-Type Load-Tap-Changing Equipment.

With all controls properly set, the load-tap-changing mechanism will operateautomatically, giving the proper correc-tion in secondary voltage as required bythe setting of the voltage-regulating relayand line-drop compensator.

Operation by Electrical HandControlFor operation of the mechanism by handcontrol.

refer to S210-40-14, "Controls forPower-Type Load-Tap-Changing Equip-ment." With the controls properly set,operate the control switch to either RAISEor LOWER as desired.Operation by Handcrank A WARNZNt~A. For each tap change, in the case of a16-step switch, six revolutions of thehandcrank are required.

Crank clock-wise to lower and counterclockwise to raise voltage.A WARNINGThe six revolutions of the handcrank MUST be accomplished in 6 secondsand the swich MUST be hand crankedsteadily IN ONE DIRECTION ONLY untilthe on-position pointer is centered overthe ON-POSITION plate. If the above in-structions are not followed, transformer failure can occur.A WARNINGMcGraw-Edison DOES NOT recom-mend hand cranking the LTC mech-anism while the transformer isenergized.

However, if IN ANEMERGENCY SITUATION you chooseto hand crank the LTC mechanism while the transformer is ENERGIZED, the following procedure MUST be ad-hered to. otherwise transformer failurecan occur,1. Place the LTC motor breaker, locatedon the motor control panel, and therelay breaker, located on the automatic control panel, in the OFF positions.

2. Remove the handcrank.

The removalof the handcrank opens the handcrank switch in the motor circuit and de-energizes the motor.NOTE: A handcrank stop prevents theoperator from hand cranking the tapchanger through a limit.3. For each tap change, in the case of a32-step switch, three revolutions.

ofthe handcrank are required.

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

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

1. The time required to complete a tapchange is not limited.2. The restriction for hand cranking inone direction only no longer applies.MAINTENANCE Periodic preventive maintenance in-spection of the LTC mechanism is re-quired. Generally, the interval betweeninspections is determined by the amountof contact erosion based on the numberof tap changes as shown on the opera-tion counter.

The interval between inspec-tions of like LTC mechanisms will varyconsiderably depending on individual conditions.

For normal utility systems itis recommended that a thorough inspec-tion of the mechanism be made at theend of the first year of operation andthat subsequent inspections be based onthe amount of contact erosion andnumber of tap changes noted at the endof 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 whilethe transformer is energized may resultin bodily injury.2. Energize the control circuit andoperate the mechanism by electrical hand control step by step throughthe entire range.A. Observing the position indicator and ON-POSITION

pointer, makesure the drive unit is stoppingproperly on position.

If not, refer to Checks and Ad-justments Nos. 1 and 2 in theTROUBLESHOOTING GUIDESection.B. Check that the operation counter isfunctioning.

If not, refer to the TROUBLE-SHOOTING GUIDE Section.C. Check the limit-switch settings byattempting to operate the controlbeyond the limit position.

Themotor should not operate.If the motor operates, refer to theTROUBLESHOOTING GUIDESection.D. Check the handcrank switch by _____removing the handcrank from itsholder and operating the controlswitch. The motor should not oper-ate.It the motor operates, roetr toChecks and Adjustments No. 5 inthe TROUBLESHOOTING GUIDE Section.3. Set the LTC mechanism in the neutralposition 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 thedrain-and-sampling valve.5. Open the drain-and-sampling valve:drain the oil from the tap-selector compartment.

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

6. Open the tap-selector compartment door.7. Inspect the tap selector for physicaldamage or evidence of moisture.

A. If there is any sign of moisture in-side the tap-selector compart-ment, determine the extent andthe manner by which the moistureentered.Refer to the TESTING FORLEAKS (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, ItemS27) for evidence of oil leakage.A. If there is any sign of oil leakage,determine the extent and thecause 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 downslightly 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 flushingwith transformer oil but do not objectto 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 themotor control panel) and the relaybreaker (on the automatic controlpanel) in the OFF position.

13. Remove the handcrank from its holder.Removal of the handcrank opens thehandcrank switch in the motor circuitand deenergizes the motor. A hand-crank stop prevents the operatorS from handcranking the tap selectorthrough a limit.14. Place the handcrank on the hand-crank shaft in the drive box.15. Inspect the arcing contacts (Figure12 and 13) for arc erosion.In an arcing-tap-switch-type LTCmechanism, the tap selector performsa dual function:

Tap selection andpreventive-auto (switching-reactor) switching.

Since the tap-selector alsoswitches the preventive auto, the tapselector contacts are subject to arcerosion.

Arc-resistant materials areused in both the movable and thestationary contacts.

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

The stationary arc-ing contacts normally erode moreslowly than the movable arcing con-tacts because many tap positions (stationary arcing contacts) are en-countered by the movable arcingcontacts 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 onthe left in Figure 14.If contacts are not replaced at thispoint, thermal instability at the con-tact interface will result, followedby thermal failure of the contact.Contact assemblies are factory-set and designed to produce a 10-12lb force per contact point.To replace the movable arcingcontacts:

(1) Handcrank the movable con-tacts to a convenient positionbetween the stationary arcingcontacts or remove the sta-tionary arcing contacts on onetap position and handcrank themovable contacts to that posi-tion.(2) Remove the eroded main mov-able arcing contacts.

(3) Install the new movable arcingcontacts, using flatwashers,

locknuts, and shouldered mounting bolts, positioning thebolt heads next to the thrustpiece as shown in Figure 15.CAUTIONWhen installing main movable arcingcontacts, it is essential that zero pres-sure be maintained in the main trans-former tank to establish proper align-ment with the main stationary arcingcontacts.

Do not overtighten the mountingbolts. Overtightening these bolts willcrack the main insulating arm in thearea of the bolt holes.NOTE: Mounting bolts are shouldered, so that,when properly assembled as shown in Figure15, the thrust piece will move between thebolt heads and the main insulating arm to com-pensate for misalignment of the stationary andthe movable arcing contacts.

(4)Handcrank the LTC slowlythrough its entire range aroundthe dial to make sure there isclearance between the lowerspring pins and the slipring andthe upper spring pin and thestationarycontact while on con-tact and while sweeping toadjacent contacts.

(5) Return the LTC to the neutralposition.

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 tothoroughly examine the backs ofthe contacts.

The point of replacement of sta-tionary arcing contacts is shown onthe right in Figure 14.Stationary arcing contacts are sil-ver plated to reduce the possibility of high-resistance oxidation whichimpedes current flow, adding tothermal instability at the point ofcontact.

When the arcing tipserode to the point where burningon the silver plating can occur, thestationary contacts must be re-placed.NOTE: The silver-plated main dial sta-tionary arcing contacts are directlyinterchangeable with all previousmodel 550C.To replace the stationary arcingcontacts:

(1) Remove the eroded contacts.

(2) Thoroughly clean all oxidation from the ends of the stationary contact spacer tubes andmounting supports.

Scotch-Brite No. 44 7 or No. 448is recommended for cleaningcopper surfaces.

(3) Install the new stationary arcingcontacts, holding them againstthe mounting bolts toward theoutside 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 toFebruary 1975 utilized a reversing switchdesign which because of the timing withthe main dial would have arcing occurring on reversing stationary contact No. 1. Atthat time the reversing stationary contactswere tipped with a copper tungsten mate-rial to withstand the effects of arcing. Themovable contact tips which engage thestationary contacts were also of a coppertungsten or silver tungsten material.

Theslot in the reversing segment was astraight slot as shown in Figure 16.In 1975 we began using a reversing segment as shown in Figure 16 with anoffset slot to delay the reversing movablecontact coming off the stationary contactallowing 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 ofolder units you must replace the reversing stationary

contacts, reversing neutralstationary

contact, movable contact as-sembly and reversing insulating armassembly.

See Figure 5.The reversing movable contactsare subject to mechanical wear, notarc erosion.

When the initial gap be-tween the movable contacts wears to9/32 in., the contacts should be re-placed. The contact assemblies arefactory-set and designed to producea 10-12 lb force per contact point.To replace the reversing movablecontacts:

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 movablecontacts.

7 A CAUTIONWhen installing reversing movablecontacts, 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 ofthe 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 slowlythrough at least three posi-tions on either side of neutralto make sure there is clear-anoe between the lower sprngpins of the movable contactassembly and the reversing neutral stationary contact andthe upper spring pins of themovable contact assembly andthe stationary contacts.

Make sure that the reversing insulating arm is not rubbing onthe face o the reversing neutralstationary contact.(3) Return the LTC to the neutralposition.

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 aresilverplated to reduce the possibility of high-resistance oxidation whichimpedes current flow, adding to ther-mal instability at the point of contact.The reversing stationary contacts aresubject to mechanical wear, not arcerosion.

When the silver plating hasworn 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 throughat least two positions on either sideof neutral to make sure there isclearance between the reversing stationary contacts and the upperspring 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 tightand secure.19. Handcrank the LTC step-by-step through its entire range to make surethere is no mechanical interference and that all the new contacts havebeen 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 tothe tap-selector compartment, filterand test the oil.The oil must test 26 kV minimum instandard gap (ASTM D 877) and 25ppm (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 onthe oil-level gage.Refer to S210-10-1, Vacuum FillingOil-Immersed Power Transformers.

24. Pressure test the tap selector com-partment.

Although each LTC mechanism issubjected to pressure tests for leaksbefore leaving the factory and pres-sure testing is recommended againbefore the open-breathing system isinstalled and prior to placing the unitin service for the first time, anotherpressure test is recommended priorto placing the unit in service afterperforming maintenance.

Refer to the TESTING FOR LEAKS(PRESSURE TESTING)

Section forrecommended test procedures.

25. Operate the LTC for 10 minutes (ap-proximately 800 operations) to seatthe contacts and eliminate any airpockets resulting from the oil filling.Refer to the Arcing-Tap-Switch-Type Load Tap Changer Section in ServiceInformation 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 replacedwhich may leak oil out of or moisture intothe switch compartment.

Either one of thefollowing methods is recommended:

Method 1With the transformer deenergized, the tapselector compartment door sealed andthe inlet and outlet of the open breathersystem sealed:1. Fill the tap-selector compartment withoil.2. Hold the oil under 5 psi max pressurefor several hours.Monitor the pressure closely becausea change in ambient temperature caneasily cause a drastic change in pres-sure.3. Dust blue chalk powder on areas ofsuspected leakage.The chalk will turn dark when wet withoil.Method 2With the transformer deenergized, the tapselector compartment door sealed, andthe inlet and outlet of the open breathersystem sealed:1. Maintain a nitrogen pressure of ap-proximately 4 psi.2. Paint a soap-bubble solution such asglycerine and liquid soap on thewelded and gasketed joints to discloseleaks.Alternative to painting with a soap-bubble solution.

Seal the unit underthe gas test pressure for a period ofhours while monitoring for loss ofpressure.

PRESSURE TEST OFTAP SELECTOR PANELA pressure test of the tap selector panelto check the integrity of all the gasketsforming seals between the tap selectorcompartment and the transformer is rec-ommended any time a gasket is replacedor the oil level in the LTC compartment increases with no apparent reason.With the transformer de-energized andthe selector compartment drained andopened:1. Wipe down selector panel with cleandry cloths.2. Apply 3 psi min., 5 psi max. pressureto the transformer tank.3. Check for oil seepage at gasketedpoints.& CAUTIONWhen 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.& CAUTIONThe 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 theWhenever 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 cotactthe correct neutral-position relationship.

.able contacts are on stationary contacteremoving any component.

This 10. The reversing roller must be in theBefore re component t his neutral-position relationship is slot of the segment and set 20 degreesmatch mark the component and its tablished a when the position indicator is to the right of the vertical centerline asmating part so that they can be re- on N (neutral) and the ON-POSITION viewed facing the front of the arcing tapassembled in proper alignment.

POINTER of the drive mechanism is cen- switch.tered on the ON POSITION plate. Referto 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 betweenthe arrows of the On-Position Plate indi-cates that the selector movable contactsare on the stationary contact.ON POSITIONPOINTERPINON POSITION-PLATE"MECHANICAL----

lX~ ,,,STOP SECTION(INTEGRAL TODRIVE HOUSING)MECHANICAL STOP P STOPSECTION GEAR ON GEARSECTION 'C-C'NEUTRAL POSITION RELATIONSHIP OF MECHANICAL STOP PINION ANDMECHANICAL STOP GEARREVERSING STATIONARY CONTACT NO. 10MAIN MOVAOLE ARCINGCONTACTSMAIN STATIONARY ARCING CONTACTNO. 2REVERSING ROLLERATTACHED YOREAR ROLLER PLATEREVERSING STATIONARY CONTACT NO.1/ MAIN STATIONARY ARCING CONTACT NO. 9REAR INDEXING ROLLERPLATE (ACTUATES FRONTMAIN MOVABLE ARCINGCONTACTS

-Z-)FRONT INDEXING ROLLERPLAE (ACTUATES REARMAIN MOVABLE ARCINCONTACTS "Y) SCROLLCAMREAR MAIN MOVABLEARCING CONTACTS "Y"REAR COLLECTOR

'RING "Y"FFSi'=RONT COLLECTOR lING "Z'WITCH MOUNTING PANELSOLATING SWITCH FROMlAIN TRANSFORMER MAIN AND REVERSING MOVABLECONTACTS OF ARCING TAP SHOWNIN NEUTRAL POSITION..................

...... --I ,t hRELATIVE POSITION OF DRIVESHAFT SPLINE TO CENTERLINE IN NEUTRAL POSITION WITHCURVED INDEXING SECTION OFSCROLL CAM CENTERED ON TOPFigure 8.Neutral-position relationship of tap selector and drive unit9 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 forfrom the neutral position to either maxi- 32-step switch).

The mechanical stop willmum position.

In the maximum position, become engaged during the 49th turn ofthe limit switch and seal-in switch open: the handcrank;

however, there will be nooREVERSING SWITCH MOVABLECONTACTS ON REVERSING STATIONARY CONTACT NO. 10REVERSING SWITCH MOVABLECONTACTS ON REVERSING STATIONARY CONTACT NO. 1BOTH MAIN MOVABLE'ARCING CONTACTSCENTERED ON MAINSTATIONARY ARCINGCONTACT NO. 2BOTH MAINMOVABLE ARCINGCONTACTS CENTEREDON MAIN STATIONARY ARCING CONTACTNO, 9'REVERSING ROLLERARCING TAP SWITCH SHOWN IN MAXIMUMLOWER POSITION (16 LQ (TYP ALL THREE PHASES)ARCING TAP SWITCH SHOWN IN MAXIMUMRAISE POSITION (16 R) (TYP ALL THREE PHASES)STOP SECTIONIN DRIVEHOUSINGSTOP SECTIONIN DRIVEHOUSINGSTOP SECTIiON GEARMECHANICAL STOPIN DRIVE UNIT SHOWNENGAGED.

SWITCH INMAX. LOWER POSITION (16 L)POSITION INDICATOR SHOWN IN MAX. LOWERPOSITION (16 L)MECHANICAL STOP INDRIVE UNIT SHOWNENGAGED.

SWITCH INMAX. RAISE POSITION(16 R)POSITION INDICATOR SHOWN IN MAX. RAISEPOSITION (16 R)MAXIMUM LOWER POSITIONMAXIMUM RAISE POSITIONFigure 9.Maximum-position retationship.

S21 0-40-3YLOWER cRI- RAISEPOSITION F DESIGNATIONS 1i2 3 II9 10 11I I I12I13114 15 16I I 1II iim i mi~ miiinimi~

~II 1 im inin 750 +/-100 -AI I mi~i7F RAISE LIMITSWITCHLOWER LIMITSWITCHr760 +/-100'I I ISEAL-IN?r¶1i1,,r 4 SWITCHIII20I -°I I INOTES:1. Sequence expressed in degrees rota-tion of main drive shaft.2. 3600 rotation of main drive shaft isrequired for one tap change.3. One complete turn of handcrank rotates main drive shaft 60°.4. Solid lines indicate span of contactclosure, contacts are open at otherpositions.

Figure 10.Switch sequencing chart for 1 6-step switch.16-JLOWR .RAISEzPOSITION DESIGNATION 215 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 15 161 _ 1 ] I 1 1 1 1 1 1 I 1 1 1 I___ I I I I L I I I I I I IRAISE UMITSWITCHLOWER LIMITSWITCHth750 +/-10-I111SEAL IN-WI IYTTIJ [ -1 1NOTES:1. Sequence expressed in degrees rota-tion of main drive shaft.2. 18su rotation of main drive shaft isrequired for one tap change.3. One complete turn of hand crankrotates main drive shaft 6004. Solid lines indicate span of contactclosure, contacts are open at otherpositions.

Figure 11.Switch sequencing chart for 32-step switch~.I1 0lFigure 12.Movable arcing contact.LOCKNUTSPACER (BETWEEN SHOULDER WASHERSOLT AND INSULATING NOTE: WASHER MUSTARM) (ITEM 72. FIGURE 181 BE PLACED BETWEENNUT AND INSULATING ARMMAIN STATIONARY ARCING CONTACTFIgure 13. CONTACT SPACERStationary arcing contact.

TUBEMOVABLE ARCING STATIONARY ARCINGCONTACT CONTACT MAIN MOVABLEARCING CONTACTSNEW CLEARANCE SILVER PLATING UPPER SPRINGPINARCING INSERT THRUST PIECE MOVABLE ARCINGCONTACT MOUNTINGBOLTS (NOTEINTERMEDIATE ARC EROSION LOCATIONS LAT OF SOLT HEADS)LOWER SPRING PINCLEARANCE MAIN INSULATING ARMARC EROSION HAS PRO-GRESSED TO A POINT WHEREBURNING CAN OCCUR ONTHE SILVER PLATINGREPLACEMENT

/MAINRPCMN TRANSFORMERIfM N I U SLIP R IN G~/'MINIMUM

-.CENTERLINES OFCOMPLETE ASSEMBLYPENNSYLITE INSULATING LJAJ PANELFigure 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 CONTACTASSEMBLY (THRUST PIECE).AND REVERSING NEUTRALSTATIONARY CONTACTS t !o\ /o\SLOT REVERSING

' SLOTSEGMENTModified reversing Original reversing segment segment(with offset slot) (with straight slot)NEUTRAL STATIONARY SUP RINGo'-MAIN DIAL STATIONARY CONTACTSNOTE: TWISTED CONTACTS CANINTERFERE WITH THE MOVABLECONTACT SPRING PINS.Figure 16.Reversing movable and revesring stationary contact assembly.

MAIN DIAL STATIONARY CONTACTSTATIONARY CONTACTMOUNTING BOLT -- .ý /APPLY PRESSURENOTE: WHEN ASSEMBLING MAIN DIAL STATIONARY CONTACTS MAINTAIN PRESSURE AGAINST THECONTACT MOUNTING BOLTS TO ESTABLISH PROPERCONTACT ALIGNMENT.

13 TROUBLESHOOTING GUIDEIf any difficulty is experienced with theoperation 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 ofincident.

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 movingat time of incident.

3. Was switch on automatic or manualcontrol?4. Check the motor supply voltage.

Thevoltage should be 115 volts, measuredat terminals 55 and 57 or 56 and 57 atthe terminal block mounted on the sideof the drive box. (See Figure 17).5. The transformer serial number fromthe transformer nameplate.

& WARNINGBefore performing any work on the LTCarcing tap selector switch, drive, or con-trols, observe the warnings and cautionsappearing in Service Information S210-40-14 and S210-40-18.

0TROUBLESHOOTING GUIDEProblem Concition SolutionImproper manual operation Tap changer does not respond toof LTQ. Raise-Lower switch.Refer to the Troubleshooting Guide inTap changer operates in one direc- Service Information S210-40-14 Load-tion only or operates erratically.

Tap-Changing Controls.

Tap changer makes more than onestep 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-TTap changer runs to full buck position, vice Information S210-40-18 Load-Tap-but operates properly manually.

Changing ControlsTap changer overruns positionand/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-inswitch. Refer to LTC tap sequencing chartFigure 10 for 16-step unit and Figure 11 for32-step unit.3. Check for incorrect or defective motorbreaker.

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

(continued next page) (continued next page)0014 S210-40-3 TROUBLESHOOTING GUIDE (Continued)

Problem Condition SolutionSwitch 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 andreinstall 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 inexcess of ten minutes without forcedcooling.2. Check for switch bindingCheck the main drive shaft at thepoint it exits the drive control com-partment to be certain there is noInterference between the main driveshaft rain shield and the compart-ment. If there is interference movethe drive box assembly.

3. Check motor. windings, capacitor andbreaker.

Refer to chart Figure 17.4. If binding or jamming is suspected inthe tap selector switch, deenergize the transformer, drain and open theswitch compartment to inspect theswitch.5. Check the movable contacts for jam-ming.a. Check that the movable contactspring pins, both main dial and re-versing switches are not rubbing onthe stationary contacts or slip rings.It is suggested that an inspection mirror be used.NOTE: The switch must be operated toposition 3 raise and 2 lower to properlyCheck the reversing switch.b. Check that all stationary contacts.

both main dial and reversing switchare properly positioned relative tothe center of the contact circle.(Refer to Figure 16).NOTE: This condition can occur at thetime the tap leads are connected to thecontact studs on the transformer side.twisting the entire contact assembly it thecontact assembly is not properly sup-ported on the switch side,A similar condition can alsooccur at thelime replacement stationary contacts areinstalled if they are not held against thecontact mounting bolts toward the out-side of the stationary contact bolt circleto establish proper alignment.

Refer toFigure 16.(continued next page)15 TROUBLESHOOTING GUIDE (Continued)

Problem I Condition SolutionSwitch 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 inalignment with the stationary con-tacts. Hand crank the switch whileobserving the contact alignment withan 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 bearingssupporting the reversing pivot shaft. Inparticular, these units should be checkedto ensure there Is no galling of metal be-tween the reversing segment and scrollcam mounting bracket casting.

Alsocheck for galling between the reversing arm assembly and scroll cam mountingbracket casting.

If it is necessary to re-move the reversing segment to verify agalling condilion or to correct the condi-tion by polishing, be sure to mark thereversing segment and pivot shaft so theycan be reassembled exactly as removed.e.Check the main dial contacts, bothstationary and movable for any un-usual or blunt erosion pattern thatcould make it difficult for the mov-able contact to slide onto the station-ary contact.

Replace the contacts.

NOTE: This type of blunt erosion patternresults when the movable contact stopeoff the stationary contact but closeenough to arc.f. Check the clearance between therear insulating arm and rear slip ring.With zero pressure maintained in thetransformer tank and only the headof 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 throughthe stuffing box for binding by slidingthe drive shaft up and down slightly.

If there is binding of the shaft oroil leakage in the stuffing box usefollowing 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 thesnapring groove on shaft (25), andslide 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 SolutionSwitch failure to complete a tap change.(continued)

(continued next page)Motor breaker did trip.(continued)

2. Match-mark the components of theupper universal coupling end of drive-shaft subassembly (36) and the shaftso that components can be reassem-bled in exactly the same place if theycome apart3. Match-mark components of followerassembly (33) and stuffing box (27)so that components can be reassem-bled in exactly the same place.4. Loosen bolts (35) securing followerassembly (33) to stuffing box (27),S. Remove external shaft assembly (251and washer (14).6. Remove bolts (35) and lockwashers (34) that secure follower assembly(33) to stuffing box (27).7. Using a blunt instrument, carefully (toavoid damaging the packing) removethe 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 toremove any found.10. Be certain that the bearing in thestuffing box is not extending into thestuffing box. Ream the bearing withwith a 0.877 dia straight reamer.11. Lightly lubricate external shaft as-sembly (25), mate packing (30), Vpacking (31), and female packing (32)with petrolatum (vaseline).

12. Place washer (14) on external shaftassembly (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.CAUTIONWhen placing packing on the externalshaft assembly, handle the packingwith extreme care to avoid damagingthe packing.I(continued next page)17 III I IIIII[I I ,, , , ,I ,I ITROUBLESHOOTING GUIDE (Continued)

Problem Condition SolutionSwitch 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) andstuffing box (27), matching the marksmade when disassembling.

17. Tighten bolts (35) securing followerassembly (33) to stuffing box (27).A CAUTIONWhile tightening the bolts, rotate andmove external shaft assembly (24) upand down to prevent binding when thebolts are secured.18. Slide external shaft assembly (25)into driveshaft subassembly (36) untilinput shaft assembly (5) can be rein-stalled.19. Reinstall input shaft assembly (5).20. Align the holes in external shaftassembly (25) and drive shaft sub-assembly(36) and reinstall rollpin (26).21. Reengage snapring (1) in the samegroove on external shaft assembly(25) from which it was removed.22. Make sure all fasteners, lockstrips.

and electrical connections are tightand secure.Operation counter.

Operation counter not functioning Check the counter terminations andproperly.

associated circuitry Drive runs into mechanical stop. Motor operates beyond maximum Make sure the maximum position limitposition.

switch is open just prior to the LTC reach-ing the maximum position.

a. Check for a faulty limit switchb. Using an Allen wrench, adjust theswitch internally for proper operation.

Handcrank switch. Motor operates when the handcrank Make sure the handcrank switch opensis removed from its holder. when the crank is removed from theholder.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 andrealign the seal-in switch.NOTE- For setting seal-in switch refer to LTClap sequencing chart-Figure 10 for 16-stepswitch and Figure 11 for 32-step switch.0i18

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

..........

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

however, it is recommended that a few select parts be kept on handfor prompt replacement if needed. Theparts recommended for spares are indi-cated in the replacement parts list.Each replacement parts list is keyedto the related exploded view drawing andthe item numbers correspond to the ex-ploded view callout numbers.To ensure prompt receipt of the correctpart the following informaton must be sup-plied to McGraw-Edison when ordering.

1. The transformer serial number and thetype of LTC switch. This information isspecified on the transformer nameplate.

NOTE: Specification of type of LTC switchon the transformer nameplate began in1972.2. Specify the bulletin number and date,figure, item number, description, andquantity required.

Example:To order item 54 on the Driveunit.Transformer Serial#C- Type 550CS LTCS210-40-3, September 1982Figure 17Item 54-Limit Switch-2each.Limited Parts WarrantyMcGraw-Edison warrants to the originalpurchaser that type 550CS load tapchangers shipped after August 1, 1982are free of defective workmanship andmaterials, This warranty commences onthe date of arrival at destination andcovers any defects and malfunctions ofthe load tap changer except those causedby improper installation, improper main-tenance, improper operation, customer-furnished materials, alterations executedby customer or vandalism.

Type 550CS LTC Parts are warranted asfollows:Silver Contacts-five years or 75.000 op-erations, point of re-placement as described in figure 14 S210-40-3; cost prorated per % oftime 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-. MotorMotorSuppller Capacitor BMoteer Braking Winding MotorYear and Model Number Size Size Fuse Resistance Drawing(mfd) (amps) (amps) (ohms -10%) NumberOhio Motor1967 Model 915-23X-4909 100 6 2.5 B219444SeeCustom Motor Design Schematic 1982(2) Model 615-01-0602 100 6 Drawing 2.8 SLB00012A Custom Motor Design For1983(2) Model 700-01-0606 100 7 Particular

2.6 SL800028A

Century Elec Unit1988(2) 8-168935-01 175 7 0.9 SLB0281 A0(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 theService Department.

McGraw-Edison Power Products, Canonsburg, PA 16317. F N- 12811y~48,,61P37,.tý 6453116 s 104117 q119- OWARNING120 m McGra-Edson OCa3 not recom-mend hand c*Afk,,ng wnile theIleansfor'er ISenergizecs Seeinstruction bookTO c hange 0O31-NiOn during main.tenancC nPiano-crank until Ihe on0o0ition Dointe, iscenlered o0der theLO on-Dos'lion plateFigure 17.Exploded view of LTC drive unit.28-e29~141)30-03 13- 4o111120 S210-40-3

'4Parts List--LTC Drive Unit (Figure 17)Item DItem ItemNo. Description INo Description NO. Description 123456789101112131415161718192021222324252627282930313233343536Snap RingWasherDrive ShaftCouplingInsulating Drive Shaft Assy.CouplingDrive ShaftGearBearing Assy. (X)Lockwasher Gear SupportCam Mounting Brkt.Cam SpacerWashersCamDrive ShaftBearing Assy. (X)BoltInsulating Drive Shaft Assy.GearInner Race & Needle BearingWasherInput ShaftInput ShaftRoll PinStuffing BoxBearingWave WasherMale AdapterPackingFemale AdapterFollower Assy.Lockwasher BoltDrive Shaft Assy373839404142434445464748495051525354555657585960616263646566676869707172737475767778Roll PinDrive ShaftBoltLockwasher Snap RingWasherDrive Shaft SupportScrew"On Position" PlateSpline TubeDrive GearRoll PinGearWorm ShaftBoltMounting BracketSpacerLimit Switch (2 req'd)ScrewWorm Gear ShaftRoll PinLimit Switch CamIndicator Mounting BracketSpringRoll PinDial PlateSpacerPointerPointerSpacerPointerRoll PinWormRoll PinBrass TubeGear ShaftShaft SupportBoltMotorGasketMiter GearSeal-In Cam Assy.798081828384858687888990919293949596979B99100101102103104105106107108109110ill112113114115116117118119120ScrewSeal-In Switch(1 req'd)Spur Gear ShaftDrive BoxTerminal BlockScrewGeneva Pinion6 SpacerSpur GearSpline Tube Assy.WasherSpur GearDrive GearSpur GearWasherLock StripSnap RingRoller Assy.PinRoll PinMotor PinionSpur Gear ShaftSpur GearWasherSpur GearSpur Gear ShaftGeneva SegmentSpacerSpur GearSpline TubeSpur GearSpur GearDrive Box CoverBoltScrewCaution PlateCaution PlateBoltRubber WasherRubber WasherWasherLocknuti 2gD ___pCaution.8efw>e dsnm.9nh1nJ d~,vebo LTC n hgmso n'.,be 4. NEUTRAL POSMTONe. ,nst,uctobn book.IlneofreCl llmvng wIhmf drtvebo- 01 belween Wt~e JndSeleelor Sf lttCS ran CaueeK) 0Nx) lap selectors shipped atter August 1 1982 are provided with bearing assemblies items 9 and 18.2t-j21

/Typical assembly.

TERMINAL 19Figure 18.Exploded view ol tap selector.

22 S210-40-3 Parts List--Tap Selector (Figure 18)Recoin-Iter mendedRoNo Description lStockRecom-SNutJam NutBelleville WasherSpanner NutCollarCollarLocknutWasherGasketPanelInsulating TubePinsGasket (A)CollarStationary ContactSupportReversing Stationary ContactLock StripShoulder StudBoltSnap RingInsulating TubePinCollarStationary ContactSupportRingPinGasket (B)CollarRear Slip RingNutWasherMain MovableContact Assy.Rear Shaft Assy.Less Contact Assy.BoltFront Shaft Assy.Less Contact Assy.BoltLock StripFront Slip RingBoltSpacerReversing MovableContact AssyReversing Assy.Less Contact Assy.Insulating TubeCollarended Itemtock No. Description 54 49 Support Stud50 Front Insulating Panel5152 Scroll CamMounting Bracket53 Roll Pin54 Reversing Segment55 Bolt56 Thrust Bearing Assy.(X)57 Rear Roller PlateAssy.58 Snap Ring59 Collar60 Roll Pin61 Shaft Support62 Front Roller PlateAssy.63 Snap Ringr64 Lock Strip65 Bolt.66 Lock Strip67 Stud Assy.68 Connection Bar69 Bolt70 Nut71 Shoulder Bolt72 Spacer73 Washer74 Belleville Washer75 Thrust Bearing Assy.(X)76 Bearing Assy. (X)0-20Buna-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 76.7061,6323

/S70/5J--02 10a4-Service Information COOPER P~WER SYSTEMSPower Transformers W Load-Tap-Changing Automatic ControlsS210-40-14 CONTENTSGENERAL ............................

1Automatic Control Panel ...............

2Manual Operation

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

2Autiomatic Operation

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

2Components

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

3Setting .................

...........

4Une-Drop Compensator

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

5Voltage Sensor ......................

6Troublehooting GuideFor New Equipment

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

8Urmited Parts Warranty

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

11GENERALThe LTC control is divided into two basiccomponents-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 shownin Figure 1. Service Information S210-40-14 and S210-40-18 describes the standardfeatures for automatic control of McgrawEdison load tap changing transformers.

To operate the load tap changer, thewiring schematics that accompany eachtransformer must be consulted beforemaking the power supply connections, CAUTIONIncorrect supply voltage could dam-age drive, motor or controls.

Referto wiring schematics which accom-pany each transformer.

T_BREAKERNORMA# CONTROL SWITCH4ES TESTI REACTANCE~

REMOTE MANUAL RAISE TERMINALS LuV9SE ALAUTO OwERFigure 1.Automatic control panel.To operate the load tap changer in theautomatic mode, it is necessary to connecta potential transformer between the regu-lated lineaand the automatic voltage sens-ing circuit.

The potential transformer (nor-mally supplied by the user) must have asecondary 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 drawingsthat accompany the transformer beforeconnecting the potential source to theinput connections.

To energize the voltagesensing 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 aproblem not covered sufficiently for the user's purpose, please contact your Cooper Power Systems sales engineer.

May 1989

• Supercedes 6/86I CHASSIS-FRONT VIEW CONTROL PANEL-REAR VIEWFigure 2.Typical automatic control panel wiring.AUTOMATIC CONTROL PANELThe automatic control panel includessolid-state voltage sensing and timingdevices 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 andbandwidth adjustments are obtainable byusing calibrated control knobs which canbe 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 motorbreaker, all of the controls for both manualand automatic operations are mounted onthe front of the automatic control panel.The motor breaker is located on the motoroperating panel.Manual Operation The bottom section of the automatic controlpanel contains four toggle switches, threeof which are used to select and direct man-ual or automatic control of the load tapchanger (Figures 1 and 2). With the RE-MOTE-LOCAL switch in the LOCAL posi-tion and the MANUAL-AUTO switch in theMANUAL position, the load tap changercan be operated in the manual mode byactuating the momentary RAISE-LOWER switch in the desired direction.

When more than one lap change is neces-sary. holding the RAISE-LOWER switch inthe appropriate position until just beforethe tap changer reaches the desired tapposition causes the tap changer to operatein a sequential mode. Releasing the RAISE-LOWER switch and allowing it to return tothe OFF (center) position permits a shorttime delay and enforces motor brakeoperation.

NOTE: The manual operation of the load tapchanger isnot affected by or related toany ofthe other components on the automatic con-trol panel.Automatic Operation Before attempting to place the load tapchanger 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 wiringschematic for each specific transformer).

To place the load-tap-changing equip-ment in the automatic mode, all relatedcontrol settings must be predetermined and selected.

Individual circuits and controls relatingto the automatic operation are covered inthe COMPONENTS for automatic controlpanel section.

To clarify the automatic operating procedure, a control settingchecklist follows:1. Place the CONTROL CIRCUITBREAKER (8-90) Figure 2 in the OFFposition.

2. Loosen the four locking screws on the,,dknobs 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 atzero (0).5. Set the VOLTAGE LEVEL control tothe desired voltage.6. Set the BANDWIDTH control to thepreselected value-7. Set the LINE-DROP COMPENSATOR (LDC on control panel). REACTANCE and RESISTANCE controls at zero (0).(Alter the calibration check, thesecontrols should be set at the calculated levels.)8. Place the MOTOR BREAKER on themotor operating panel in the ON posi-tion. See S210-40-18.

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

Waitapproximately 15 minutes before pro-ceeding, to allow warm-up.I t the vollage level and bandwidth arenot going to be checked with a volt-meter, operate Ihe load tap changerin the manual mode until the LOWER4test light in energized-then proceed Woto checking the bandwidth as out-lined in 11 E.2 S210-40-14

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

the TEST RHIEOSTAt control can beused to advantage:

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

C. Set the TEST RHEOSTAT controlto a value which equals the voltageincrement above the desired bandcenter obtained in Step 11 A.Example:To obtain a desired band center of 120volts:(1) Operate the load tap changer in themanual mode until the voItmeler reads as close as possible to thedesired band center +3 volts.a, Nearest voltage obtainable is123.5 volts.b. Therefore.

123.5 -120 -- 3.5 volts,(2) Place the MOTOR BREAKER in theOFF position and putl the dual fuseholder out o1 its retaining block.(3) Set TEST RHEOSTAT control for3.5 volts.D. It necessary, adjusl the VOLTAGE.EVEL qgntrQl VnI!j neither theRAISE nor the LOWER test light islit. For the most accurate setting.center the control between the twopoints where the RAISE and LOWERlest lights are lit.NOTE, Al the lime the band level andthe bandwidth are being adjusted.

themake and break points of both theraise and the lower Circuits dilter byapproximately 0.5 volt. This ditleren-hal is a seat-in feature furnished toassure the positive making of the con-tacts at the extremities of the band-width.E. Check the bandwidth by rotatingthe TEST RHEOSTAT control inboth directions and observing thedial voltage differential between thepoints where the RAISE and LOWERtest lights come on.Example (continued from 11 C):*Assume BANDWIDTH controlhas been preset to 3 volts." Voltnteter (if used) reads 123.5volts." TEST RHEOSTAT control set at3.5 volts." BAND LEVEL control set at 120volts." Rotate TEST RHEOSTATcontrot in both directions:

LOWER testlight comes on at two volts:RAISE lest light comes on at fivevolts.* Therefore.

5 -2 = 3 volts band-width.F Secure BAND LEVEL and BAND-WIDTH controls by tightening theirlocking screws.G. Check operation of time-delay re-lays by rotating the TEST RHEO-STAT control and noting the timedifferential between the test lightignition and dimming, (Output relayclosure 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 forautomatic control panel beforechanging 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 StepSand instructions under Line-Drop Compensator.)

Secure the LOCRESISTANCE knob locking screw,J. Replace the dual fuse holder andmove the MOTOR BREAKER to theON position.

K. After completing the preceeding steps, move the AUTO-MANUAL switch to the AUTO position andthe load tap changer will respond tothe automatic control mode.Components

1. CONTROL CIRCUIT BREAKER.

Asingle-pole.

tip-ffee breaker providesON-OFF. short-circuit and overloadprotection for the control panel.2. TEST TERMINALS.

Two test terminals facilitate connecting a voltmeter duringcalibration tests.3. VOLTAGE-REGULATING RELAY. Asolid-state, adjustable voltage sensorpermits the selection of a band levelbetween 105 and 135 volts. The BAND-WIDTH control permits the selection ofa 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 withreverse-reactance switch, variable-reactance and variable-resistance con-trols, facilitates the regulation of theleeder 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 avariable external power source may notbe available.

7. CONTROL SWITCHES.

Three controlswitches mounted in the lower sectionof the automatic control panel provide aselection 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 changerfrom within the cabinet in either theautomatic or manual mode. theREMOTE-LOCAL switch must be inthe LOCAL position.

To operate theload tap changer from a remotepoint, the REMOTE-LOCAL switchmust be in the REMOTE position.

Auxiliary auto-manual and raise-lower switches must be supplied bythe user when operating from aremote point.8. To operate the load tap changerfrom within the cabinet in the manualmode or to deactivate local auto-matic operation, place the AUTO-MANUAL switch in the MANUALposition.

To operate the load tapchanger in the local automatic mode,place the AUTO-MANUAL switch inthe AUTO position, C. The RAISE-LOWER switch is usedto operate the load tap changer inthe local manual mode. The switch isequipped with a center OFF and twomomentary ON positions.

Makingmomentary contact in the up direc-tion for RAISE or down for LOWERwill cause the load tap changer tomove one step at a time. If more thanone tap change is required.

holdingthe momentary contact in the desireddirection will permit sequential operation.

8. TIME-DELAY RELAYS, Two adjustable time-delay relays (one for RAISE. onefor LOWER) are in the circuit betweenthe voltage-regulating relay and the tapchanger motor control.

These relaysprovide a selection of time delays fromto to 90 seconds.

Unless otherwise specified, the relays are factory-set for30 seconds,To change the setting, insert a smallscrewdriver (preferably a '.-in.-diameter handle) in the potentiometer screwdriver slot and rotate clockwise to increase orcounterclockwise to decrease the limedelay. Changing of potentiometer settingswill show resistance to movement becauseof a mechanical drag which has beenplaced on the shaft to prevent accidental movement.

Total rotation is about 300degrees and can be observed by relatingthe slot position relative to the graduations surrounding the shaft (Figure 3).&t CAUTIONTo prevent potentiometer damage, donot use a large screwdriver or force thesettings at the extreme ends of therange.3 NOTE: Potentiometer must be securelymounted Hold potentiometer while tighten-ing mounting nut. Bottom section ol shaftlock must be locked against potentiometer mounting nut, Top section of shaft lock is tobe pulled snug enough to make it necessary to use a small screwdriver to adjuSt thepotentiometer.

(Screwdriver--Stanley 1010 orequivalent).

CIRtC UITSHAFTLOCKINGDEVICETOP SEC TION-SHAFT LOCK'POT SHAFTVIEW A-ATIME DELAYLEDMOUNTEDON SAMESIDE ASFOILLegendLED Light emitting diode (TEST LIGHT)R1 5600. 1/2WR2 1.5KO. 1/2 WR3 100KO. 1/2 WR4 Pol. 2.5M"C1 100 MFD. 25V0 400V. 1ACIRCUIT BOARDFigure 3.Physical representation of time-delay relay circuit board.Time-delay settings can be measuredwithout operating the tapchanger.

Put theauto-manual switCh in the MANUAL posi-tion and observe the time interval betweenthe light ignition and the point when thelight goes dim due to the closing of theoutput relay.SettingWhen setting from an independent source,the automatic control panel should beenergized by a variable source connected toTerminals 10 and G, Figures 2 and 4.POT TRANSFBY OTHERS1R02 = 03T1I02 TDC 03ZE-- j-vM>408.88/5 0-0.2AMP RCTSA CAUTIONMake sure that the normal potential source is not connected to I0-G beforeconnecting an external source. If theexternal power source is grounded, thesource and ground terminals on thepanel must be phased out or the inter-nal ground on the control panel mustbe removed.

(Refer to wiring diagramfor ground connections.)

Before ener-gizing the independent power source.pull the dual fuse holder on the motoroperating panel and make sure thatboth the CONTROL and MOTORBREAKERS are in the OFF position.

90 Solid-state voltage sensorTR Time-delay RAISETL TIme-delay LOWER8-90 Control breakerRCTB 8.66/5-0,2-amp CTRCTA 0.2-O.O1-amp CTAPT Aux pwr transformer ARA ArresterFigure 4.Automatic voltage regulation scheme.4 S21 0-40-141. Connect an ac voltmeter to TESTTERMINALS G and A.2. Loosen the four locking screws on theknobs above the control switches.

3. Place the AUTO-MANUAL switch inthe MANUAL position and the REMOTE-LOCAL switch in the LOCAL position.

4. Set the TEST RHEOSTAT control atzero (0).5. Set the VOLTAGE LEVEL control forthe desired level.6. Set the BANDWIDTH control for thetotal desired bandwidth.

7. Set all three LINE-DROP COMPEN-SATOR controls at zero (0).8. Place the CONTROL CIRCUITBREAKER in the ON position.

9. Adjust the source voltage until neithertest light is energized.

Wait approxi-mately 15 minutes before proceeding.

10. To check band level and bandwidth.

adjust the source voltage and recordthe voltmeter readings at the levelswhere the raise-lower test lights areenergized.

If required, the VOLTAGELEVEL and BANDWIDTH controls canbe adjusted slightly to obtain the exactbandwidth and level desired.NOTE. At the time Ihe band level and thebandwidth are being adjusted.

the makeand break points o0 both the RAISE andthe LOWER circuits differ by approxi-mately 0.5 volt. This ditferential prod ucesa seal-in leature to assure the positivemaking of the contacts at the extremities o0 the bandwvidth.

11. After having obtained the exact bandlevel and bandwidth

required, securethe TEST RHEOSTAT.

BAND LEVEL.and BANDWIDTH control knobs bytightening the locking screws.12. Check TIME-DELAY relay settings byadjusting the source voltage and re-cording the time differential betweentest light ignition and dimming.

(Out-put relay closure causes test light toattenuate.)

Each time-delay relay isfactory set for 30-second time-delay.

See instructions for time-delay relaysunder 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 controlknob locking screw.Line-Drop Compensator The line-drop compensator is suppliedwith one resistance control and two react-ance controls, furnishing resistance andreactance compensation up to 24 volts ineither, or both, elements.

The resistance compensation is continuously variablefrom 0 to 24 volts; the reactance compen-sation is variable in both 1- and 5-volt stepsto a total of 24 volts.It reverse reactance compensation isrequired, move the NORMAL REACT-ANCE-REVERSE REACTANCE swilchon the front panel to the REVERSE REACT-ANCE position.

To determine proper settings requiredfor the line-drop compensator, it is neces-sary to understand the principle of line-drop compensation.

The principle involvedconsists of connecting a resistance-react-ance network in series with the voltage-regulating relay input. Current from aninternal current transformer is passedthrough the compensator, producing avoltage drop which is opposed to the ap-plied potential.

Since the current is proportional to thefeeder current and, if the resistance andthe reactance of the compensator are pro-portional to those of the feeder from thetransformer to the desired point, the volt-age at the voltage-regulating relay inputwill drop by an amount proportional to thefeeder voltage drop to that point. This willcause 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 loadcenter. should be selected with great care.It may be an actual point on the feederwhere the main trunk branches out in astar-shaped pattern in the center of thefeeder's territory.

it may also be a fictitious point recurrent about the middle of eachfeeder branch so that it represents anaverage condition existing over a widearea,The line-drop compensator circuitemployed by McGraw-Edison is designedto operate at 10 ma and has been equippedwith an intermediate current step of 0.2amp to accommodate provisions for thecirculating current method of paralleling with existing load tapchanging equipment.

To determine the settings for the line-drop compensator:

1. Determine the feeder line current thatwill 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 windingswith one current transformer for line-drop compensation, this value will bethe primary current rating of thecurrent 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 currenttransformer for line-drop compen-sation,C, For wye-connected output windingswith two current transformers forline-drop compensation (each hav-ing a secondary rating of 5.0 amps).the feeder line current will be equalto the primary current rating of eithercurrent transformer.

The second-aries are so interconnected that. withrated 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 useof a line-to-line potential transformer which is connected as shown on theload tap changing schematic dia-gram.2. Calculate line resistance and reactance.

3. Calculate line-drop in resistance voltsand reactance volts as the products ofStep 1 times Step 2.4. Divide the values obtained in Step 3 bythe potential transformer ratio.5. Set the dials of the line-drop compen-sator equal to the values obtained inStep 4. The dials, calibrated in volts, arelabeled RESISTANCE and REACT-ANCE VOLTS,Example:

Consider a delta-connected transformer supplying one mile offeeder 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 0.60ohm per mile.If the current transformer for the line-drop compensator has a primary ratingo1300 amps. the feeder line current willbe -,/3times 300 or 520 amps.The line drop will be 520 times 0. 41 or213 volts resistance and 520 times 0.60or 312 volts reactance.

If a 20:1 potential transformer is usedto step the Output voltage down for usewith the voltage-regulating relay. theline-drop compensator settings wouldbe 213 divided by 20 or 10.7 volts re-sistance and 312 divided by 20 or 15.6volts 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.& WARNINGIf any work is to be done on the line-drop compensator portion of thecontrol circuit while the transformer is energized, care must be exer-cised so that the secondary circuitsof the current transformers are notaccidentally opened. The currenttransformers must be short-circuited at the short-circuiting device in thedrive-and-control compartment be-fore any work begins.Accidental opening of the currenttransformer circuits will cause adangerously high voltage to appearacross the opened circuit.S Voltage SensorThe 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 theinput voltage (E across RB) to furnish theintelligence required to select one of threepossible relay output modes.Conduction through silicon-controlled Rectifier

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

1. 2 (SCR2) indicates that inputvoltage T1-T2 exceeds the magnitude required to produce a voltage across RBwhich equals the Z3 reference voltage.

Alack of conduction through either SCR1 orSCR2indicates that the input voltage Tl-T2 is at the proper level to produce a matchbetween the voltages across R8 and Z3.Operational amplifier OP1 compares thevoltages across R8 and Z3. If the Z3 volt-age exceeds the R8 voltage.

OP1 outputswings positive causing the OP2 output togo positive and furnish the turn on gatevoltage for SCRi. It the R8 voltage ex-ceeds the Z3 voltage.

OPt output swingsnegative causing the OP3 output to gopositive and furnish the gate voltage forSCR2. A rheostat (bandwidth control)connected between T5 and T6 desensi-tizes OP1 input, thereby providing a vari-able band between the voltage level inputswhich cause OP1 output to change. Re-sistor R11 fixes the minimum bandwidth obtainable.

ResistorsR t 7and R22 furnisha small feedback voltage to OP2 and OP3after 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 theuse of a standard rheostat for the voltagelevel 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 hasbeen calibrated.

Compensating resistorR9 is a factory-set potentiometer used tocompensate forsmall value changes in Z3.R5. R6. R7. and R8 and still permit settingthe sensor null input voltage within thepermissible range, A 24-volt input to Ter-minals T3 and T4 furnishes the powersupply for the OP amps and the regulated reference voltage.The schematic

diagram, parts layout,and component identification are shownin Figures 5 and 6.E1,TopXl) VIEW7<13-C4OPt, OP2. OP3 CONNECTION DETAILFigure 5.Schematic of voltage sensor.6 S210-40-14 Hem i Value8 '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). 'bW2.5W2KM. 1,5W3300), 1.5W470. '/?W13KG, 3W4,7KG. 3WPot, 10KO500O, '/AW1200. Y*W82KO. 'kW10K. %W4.7K". 1W39KG. "*W33K-50K (selected)

Pot. 5KG20 MFD. 75V2OMFD, 250V5 MFD. NP, 25V0. 1 MFO, 200V400V. IA12V. 1W8 4V (temperature compensaled)

OP ampsSilicon controlled reclifier Figure 6.Physical representation of voltage sensor circuit board.7 TROUBLESHOOTING GUIDEFor Equipment Built After 111182AUTOMATIC OPERATION OF LOAD TAP CHANGERTrouble SolutionTap 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. Shouldbeapproximately 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, LDCresistance

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 sectionhunts. 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 currentbalance parallel operation.

4. If using current balance type paralleling check connections for crossedwires 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 (0-900terminals) for wide bandwidth setting.Tap changer operates properly manually

1. Check positions and integrity of automatic control panel CONTROLbut 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 checkingvoltage between terminals Ta and T4 on voltage sensor card. Should beapproximately 24 Vac. If "0" volts check 11 to G and 12 to G. Shouldbe approximately 120 Vac (SeeFigure2).

4. Check for open circuit in time delay relay source by checking voltagebetween terminal D4 on the delay relay cards and T7 on the voltagesensor card. Should be approximately 12 Vac. I1 no voltage appearscheck 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 SENSORTROUBLESHOOTING GUIDE).LINE DROP COMPENSATOR Trouble SolutionBoth 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 onLTC control box backwall.)

(Polarity must be as shown on wiring diagramsfurnished with the transformer.)

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

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

84D S210-40-14 TROUBLESHOOTING GUIDE (Continued)

For Equipment Built After 111182W VOLTAGE SENSORMake certain that the theory of voltage sensor and automatic operation is understood.

Read voltage sensor operation, page 6, andautomatic operation, page 2.TroubleISolutionRAISE 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 thecircuit 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 formultiple failures of SCRi and SCR2. OP2 and OP3, or a combination ofthe two failures.

VOLTAGE SENSOR VOLTAGE READINGSThe following readings are given as a A The Voltage Chart readings shouldguide to use when troubleshooting a volt- CAUTION appear on the voltage sensor circuit boardage 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, theital) with the voltage sensor mounted in tain that the source ground lead is BANDWIDTH, TEST RHEOSTAT, andthe 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 whereerences 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 theNOTE: With the translormer energized and VOLTAGE LEVEL control setting isthe normal potential transformer connected more than 5 volts different than theto Terminals l0 and Gin the LTC control box. voltmeter

reading, set the VOLTAGE1. Place the AUTO-MANUAL control LEVEL control at the voltmeter reading,switch in the MANUAL position.

2. Place the LOCAL-REMOTE control VOLTAGE CHARTswitch in the LOCAL position.

Terminal 1 to Terminal 2 ......................................

80 Vac +/-13. Set the TEST RHEOSTAT and BAND- Terminal 3 to Terminal 4 ......................................

24 Vac i1WITH 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 +/-.2NALS G and A. Top (.) R13 to Bottom (-) R8 ..................................

11 volts +/-16. Place the CONTROLCIRCUIT BREAKER Bottom (t) R23 to Bottom (-) R21 ..............................

1 volt +/-1.5in the ON position.

Top (+) R26 to Bottom (-) R21 .................................

t volt 11.57. 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 areading as close to 120 Vac as system Top (4) R13 to Bottom (-) R8 ..................................

1 volt +/-1.5conditions permit. Bottom (*) R23 to Bottom (-) R2t ..............................

22 volts +/-2NOTE: If it is necessary to use an Outside Top (+) R26 to Bottom (-) R21 .................................

1 volt t1.5source, 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 inesource level at 120 Vac. Top 1+) R13 to Bottom ('-I R8 22 volts +/-Bottom f') R23 to Bottom (-) R21 ..............................

1 volt +/-1.5Top ( -) R26 to Bottom (-) R21 .. ............................

22 volts +/-129 TROUBLESHOOTING GUIDE (Continued)

For Equipment Built After 111182VOLTAGE READINGSCondition Neither test light can be energizeVoltmeter 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 B8and C1 for a short.C. If the voltage from Terminal 3 to Terminal 4 is 24 Vac +/- 5%, checkthe 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 foran 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 bottomtime-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 B2and 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.

SeeBIAS 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 (+) oftime-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 (+) ofR13 to bottom (-) of R8.Voltage should be 11 to 12 volts.If voltage stays high regardless of change in differential betweenR8 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 BIASandlor 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/orBANDWIDTH controls.

410 S210-40-14 TROUBLESHOOTING GUIDE (Continued)

For Equipment Built After 111182BIAS POTENTIOMETER SETTINGBias potentiometer R9 has been factoryset and sealed. It should not be necessary to change its setting unless it becomesdefective 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 120volts.3. Turn calibration potentiometer P30(on the lefthand edge of the voltagesensor circuit board) to its fully coun-terclockwise position.

4. Place bias potentiometer R9 in its $ullyclockwise position.

5. Connect a high-impedance voltmeter (preferably digital) to voltage sensorTerminals 1 and 2.6. Connect a 114-volt

+/-1 Vac, 60-Hz, sinu-soidal waveform voltage source toLTC control box Terminals 10 and G.NOT E: This can be done from the normalpower source with the transformer ener-gized or from an external source.CALIBRATION RESISTOR SETTINGIf necessary to reset calibration resistorR30:1. Set all controls except the BAND LEVELcontrol 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 LTCcontrol box Terminals 10 and G.NOTE: This can be done from the normalsource with the transformer energized orfrom an external source.& CAUTIONIf 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 WARRANTYMcGraw-Edison warrants to the originalpurchaser that load tap changing equip-ment controls shipped after August 1, 1982are free of defective workmanship andmaterials for a period of five years. Thislimited parts warranty commences on thedate of arrival at destination and covers anydefects and malfunctions of the load tapchanger controls except those caused byimproper installation, improper mainte-nance, improper operation, customer fur-nished materials, alterations executed bycustomer or vandalism.

&x CAUTIONIf 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, ifnecessary, adjust the VOLTAGELEVEL control until the voltmeter reads 75 Vac +/-0.2 volts.5, Slowly turn R9 counterclockwise untilthe RAISE test light is just energized.

9. Seal the bias potentiometer settingwith a hot iron or cement.10. Reset calibration resistor R30 inaccordance with the instructions In theCALIBRATION RESISTOR SETTINGsection.4. Energize the power source and set theVOLTAGE LEVEL control to the settingthat corresponds to the voltmeter read-ing -0.6 volts.Example:

Voltmeter reading is 119.5volts + 0.6 = 120.1 Vac; therefore, theVOLTAGE LEVEL control should be setat 120.1 volts.5. If the LOWER test light is energized.

slowly turn calibration resistor R30clockwise until the LOWER test lightgoes out and the RAISE test light justcomes on.6. If the RAISE test light is energized.

slowly turn calibration resistor R30counterclockwise until the RAISE testlight goes out and then clockwise untilthe RAISE light just comes on.11

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

TAPCHANGER CONTROLM-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 0I, INPUTSPower. A two wire input, requiring less than 3 W at 90 to 140 V ac, provides all power requirements.

Theunit 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 Ato 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 Anominal 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 paralleloperation with other transformers.

OUTPUTSTwo outputs drive a raise and lower motor starter relay. The starters may be any voltage up to 240 V ac. Theoutput contacts are rated at 2.5 A inrush current and will handle a NEMA size I starter or smaller.CONTROLSVOLTAGE CENTER OF BAND: The center of the control band may be set to any voltage from 105 to 135 V ac. Thescale 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 accuracyis +/-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 fewmilliseconds 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 inphase with the input voltage.

The reactance compensation provides 24 V compensation for 0.2 amps inputat a phase angle of +/-90W as chosen by the DIRECT/REVERSE switch. The magnitude and angle of each circuit isindividually set by a pair of trimpots to any accuracy limited only by the instruments used in setting.

Thefactory setting of magnitude will be within +/-5% and the phase angles within +/-2%. The voltage and twocurrent 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 thevoltage may be raised and lowered by means of an uncalibrated voltage control.

An external voltmeter witha burden of 500 £t per V or higher can be connected to test the band limits by observing when the RAISE andLOWER 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

...... ....... IMODES OF OPERATION

.Either of the following modes are available as determined by presence or absence of a cam switch which isclosed 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 outputwill be obtained down to this threshold.

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

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.OPTIONSVoltage 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 willbe 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 willbe 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 ofANSI/IEEE C37.90.1-1989 defining oscillatory surge withstand capability.

All inputs and outputs willwithstand 1500 V ac to chassis or instrument ground for one minute. Voltage inputs are electrically isolatedfrom each other, from other circuits, and from ground.MOUNTING1. Standard vertical2. Horizontal

3. 19" rack mount0!Iii *.

ENVIRONMENTAL Temperature:

The voltage band limits will vary no more than 0.5 V from -500 to +800 C. The timer will varyno 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.PHYSICALSize and Mounting:

Overall dimensions are 6-3/8" x 16-1/2" (16.2 cmx 41.9 cm); requires a panel cutout of5-7/8" 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).PATENTSU.S. Patent 3,721,894; Canadian Patent 985,368; British Patent 1,432,607; Swedish Patent 7,301,667-7; andother foreign patents applied for.WARRANTYThe M--0067E Tapchanger Control is covered by a two year warranty from date of shipment.

IV.

NOTICEAny 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 ANEXPRESS WARRANTY OF AFFIRMATION,

PROMISE, DESCRIPTION OR SAMPLE AND ANY AND ALLSUCH EXPRESS WARRANTIES ARE SPECIFICALLY EXCLUDED NOR SHALL SUCH ILLUSTRATION OR DESCRIPTION IMPLY A WARRANTY THAT THE PRODUCT' IS MERCHANTABLE OR FIT FOR APARTICULAR PURPOSE.THERE SHALL BE NO WARRANTIES WHICH EXTEND BEYOND TIIOSE CONTAINED IN THEBECKWITH ELECTRIC CO., INC. TERMS OF SALE.All rights reserved by Beckwith Electric Co., Inc. No reproduction may be made without prior writtenapproval of the Company.0 051V.

S WARNINGDANGEROUS

VOLTAGES, CAPABLE OFCAUSINGDEATH OR SERIOUS INJURY, ARE PRESENT ONTHE EXTERNAL TERMINALS AND INSIDE THIS EQUIPMENT.

USE EXTREME CAUTION ANDFOLLOW ALL SAFETY RULES WHEN HANDLING, TESTING OR ADJUSTING THE EQUIPMENT.

HOWEVER, THESE INTERNAL VOLTAGE LEVELS ARE NO GREATER THAN THE VOLTAGESAPPLIED 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 repairof 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 noliability 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 orexplosion.

KEEP AWAY FROM LIVE CIRCUITSOperating personnel must not remove the cover or expose the printed circuit board while power is applied.

In no case mayScomponentsbe 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 ispreferred.

If authorized modifications are to be attempted, be sure to follow replacement procedures carefully to assure that safetyfeatures are maintained.

A PRODUCT CAUTIONSBefore 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, alwaysfollow replacement procedurescarefully to assure safety features are maintained.

Always replace components with those of equalor better quality as shown in the Parts List of the Instruction Book.AVOID STATIC CHARGEIf this unit contains MOS circuitry, it can be damaged by improper test or rework procedures.

Care should be taken to avoid staticcharge 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. 051vi TABLE OF CONTENTSM-0067E TAPCHANGER CONTROLinstruction BookIntroduction

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

1Block Diagram ........................................................................

Figure 1 .........................

2Principles of Operation

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

3Line Drop Com pensation

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

3Voltage Sensing .....................................................................................................................

4Timer and Output ...................................................................................................................

4Stability

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

5Application

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

6General ................................................................................................................................

6Parallel Operation

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

6External Connections

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

Figure 2 ..........................

7Options ..................................................................................................................................

8Voltage Reduction

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

Figure 3 ..........................

9Use of the M-0329 LTC Backup Control with theM --0067E Tapchanger Control ...........................................................................................

9Schem atic ...........................................................................................

Figure 4 .............................

10Installation

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

12Lightning Protection

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

12M ounting and Outline Dimensions

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

Figure 5 .........................

13Horizontal M ounting Configuration

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

Figure 6a .........................

1419" Rack M ount Configuration

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

Figure 6b ........................

14M-0329 Interconnection with Beckwith M-0067Tapchanger Control .................................................................

Figure 7 .........................

15Adjustm ent .....................................................................................................................................

16Checkout Procedure

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

17Settings

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

17Power ..................................................................................................................................

17Test Circuit ...........................................

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

17Component Location

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

Figure 8 .........................

18M aintenance

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

19How to Avoid Damaging Your Control Through Testing ................................................

20Test Procedure

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

21Equipment Required

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

21Hints in M easurements

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

21Removing the Printed Circuit Board ......................................

21W aveshape

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

Figure 9 .........................

22Power Supply ......................................................................................................................

22Voltage and Bandwidth

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

23Tim er ...................................................................................................................................

23Resistance Compensation

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

23VI','

Reactance Compensation

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

23Paralleling Com pensation

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

23Typical Voltages

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

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

25Optional Components

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

29Single or M ulti-Step Voltage Reduction Option ..............................................................

29Instantaneous Voltage Reduction Option .........................................................................

2950 Hz Operating Frequency Option .................................................................................

29Patent, W arranty and Indemnification

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

30In our efforts to provide accurate and informative technical literature, suggestions to improve theclarity or to correct errors will receive immediate attention.

Please contact the Marketing Services.Department, specifying the publication and page number.Vil l} I IINTRODUCTION The M-0067 is a solid-state control that makes novel use of the latest electronic techniques to achieve a highlystable and reliable transformer or regulator control.

The Block Diagram is shown in Figure 1. The M-0067 controlis suitable for use on existing LTC transformers, single-phase regulators or induction voltage regulators, as wellas new transformers.

All components are mounted on a single printed circuit board which in turn is mounted on a metal panel. Thepanel can be easily removed, leaving a completely functional circuit board with both sides exposed for ease inservicing.

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 isindependent of all others.U0m v~w0cc~7I'I~~i II00FIGURE 1 Block Diagram PRINCIPLES OF OPERATION U NOTE. It will help in following the Schematic shown in Figure 4 to know that generally dcvoltages are positive at the top and negative at the bottom. Information generally flows fromleft 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 byadjustment 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 thecurrent.

Resistor R2 is the main burden, and trimmer R4 adjusts the half-scale point of the resistance control R5to 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.

SwitchS2 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 atlower cost than inductances.

A reversal of T2 polarity brings the phasing to the correct point, making thecapacitive burden look like an inductive burden.Transformer T3 with C3 and C4 produce a secondary

voltage, approximately 90' out of phase with the primarycurrent, for use in parallel operation of transformers.

This angle is actually 84' and is not compensated toprecisely 90 since this is not required for proper paralleling.

Again, reversal of polarity through TP3 makes itscapacitive 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 outputwill serve itself so that the sum of the four currents flows through R16. When the sum of the input voltages ispositive, Q1 output will be a negative voltage in precise proportion to the sum (at the juncture of D4, R18 andfeedback resistor R1 6). When the sum of the input is negative, the feedback is blocked by D4 so that the summinginput 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, R18and 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 thecurrent 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 Inarrow bandwidth.

When the bandwidth is so narrow that it can be matched by only one tap position, it isessential 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 SENSINGPower transformer T5 and full-wave rectifiers D5 and D6 provide an unregulated 24 V for noncritical circuitsand 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 D14and D15.Integrated operational amplifier circuits Q3 and Q4 are used as threshold detectors.

Their outputs switch as thedc 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 isindependent of voltage control R26. The zener diode D7, and the fact that R27 equals R30, assures that thebandwidth 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 bandedge operation, energizing the motor starter without chattering.

TIMER AND OUTPUTA precise and stable timer is formed by charging C12 through R43 to a point where operational-amplifier Q6switches.

The second input to Q6 is by timing control R40. Resistor R45 provides a snap action when thethreshold is reached.RAISE and LOWER LEDs I1 and 12 operate when either threshold detector Q3 or Q4 operate.

Until the timer timesout, the LED current is shunted to -6 V by diodes D11 and D12. When the timer does time out, the current fromeither 11 or 12 is passed to the base of Q9 or Q7, thereby turning it on. This transistor operates relay K1 or K2which causes a raise or lower operation.

Transistor Q5 shorts the timing capacitor, thereby cutting off either relay whenever the voltage goes back withinthe band. This occurs in 1/2 cycle or less, assuring that the tapchanger will stop in the band whenever minimumbandwidth 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 stepregardless of the voltage.

STABILITY Excellent stability is achieved from -50P to +800 C (-58* to 1760 F). This is accomplished by using circuits andcomponents each having inherent stability.

In units with serial numbers up to 5000, it was necessary to includea 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 thecontrols were to drift apart in voltage setting, first one transformer would operate to bring the voltage within itsband 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 theirrating 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 areused as voltage dividers in such a way that the essential divided voltage is independent of the small variation ofresistance with temperature.

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

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.

Thiseliminates all interaction between the several inputs to the compensator.

It also includes half-wave rectifier D4inside a high gain feed-back path to eliminate the effect of the voltage drop across D4 which varies withtemperature.

The ac voltage and current compensation voltages are scaled down 10:1 to values more appropriate for use withintegrated circuits.

This and other techniques reduce the power input within the band to about 1 W whichreduces 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 astable dc voltage using an operational amplifier to compare these voltages to within a few millivolts.

Throughuse 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 withusage and variations in ambient temperature.

0 APPLICATION GENERALExternal connections are shown in Figure 2. 3oth power (I to 3 W) and voltage sensing are obtained from apotential 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 mustbe 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 noadditional burden present.

The M-0169 Current Transformer (8.66 A or 5 A to 0.2 A) is for use in high burdencurrent 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 measurepotential.

If this is not done, hunting at the upper band edge may result. As soon as the motor starts and beforeit is sealed in, the motor current can drop the voltage within the band and reset the control.

Some motor seal-inschemes 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 oftransformers in parallel.

The net result is excessive operations as noted on the counter.

In order to prevent theseoperations, it is essential that the various causesbe carefully distinguished and eliminated to the extent providedby 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 resetbefore a second change is initiated.

If not, the tapchanger will move up two steps, reset, time out, move downtwo steps, time out and continue this indefinitely.

The M-0067 has been designed with a sufficiently fastresponse 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, assumingno 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 atcenter of band of units being paralleled.

If the Beckwith control is used with a control of poor stability, evenwider 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 isused. 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 nottrack the rather exact line drop compensator of the M-0067. This may cause hunting to occur at load levelsdifferent than those existing when the controls were initially adjusted.

.-a-Current Withstand; Eiher inputAMP MAX TIME5 2 sec4 3secS.3 4 sec2.9 5 sac0.4 2 hoJursTapchanger Control TermirPOLARITYPotential If DesiredTransformer LineCurrent POLARIn5An 25AItalsInstantaneous VoltageReduction Connections Cam Swilch Contact,Closed while LTC IsIn transition fornon-sequenlial operation.

K1'K2Circulating CurrentCurrent Inputs are 0.2 A*Full Scale*. Add 5/0.2 ACurrent Transformers If required120/240 VMotorStarter RelayCam Switch Contact, Closed "while LTC Is in transition fornon-sequential operation External Resistor A%Close one Contact at aK3 time for various steps ofVoltage Reduction, asT Indicated on ODlions Par*.l NOTE: For Instantaneous Voltage Reduction, use additional contact from the KI andK2 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 duringoperation.

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 orderto eliminate

hunting, it is now necessary to desensitize the circulating current circuit so that no tapchange resultsfrom this minimal circulating current.This can be accomplished by changingR12 (normally 270 K). The sensitivity is inversely proportional to the sizeof 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/0.2A. 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 theTEST 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 itcontains 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 anovercurrent relay in the circulating current circuit is so high as to reduce the current from the C.T. below thevalue which should flow. Here a lower than normal R12 value can be used to increase the sensitivity andcompensate for the high relay impedance.

This problem is best avoided by using a Beckwith Electric M-0127 10-100 mA ac Overcurrent Relay. The inputimpedance 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 periodsand with no readjustment if the above points are carefully considered.

OPTIONSVOLTAGE REDUCTION The voltage setpoint may be reduced by closing the external dry contacts one at a time from terminal 11 or 12 to13. 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 andwithin 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. Theresistors for two preselected steps of voltage reduction will be mounted on the printed circuit board. Pleaseindicate the desired percentage(s) of voltage reduction (based on 120 V) on the OPTIONS page when orderingthe unit. Resistors R74 and R75 will be factory selected and installed to provide the desired voltage reduction.

Ifno voltage reduction is specified on the option sheet, R74 and R75 will not be installed at the factory.

If more thantwo steps of voltage reduction are required, additional voltage reduction resistors may be added externally tothe 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. Whenordering the M-0067, please indicate if this option is desired by checking the appropriate entry on the OPTIONSpage.

21O)LLC/)01.'040NL101 2 3 4 9 6 7 8 9 10 11 12 t.3 14 153VEVOLTS REDUCTION ON 120 V BASEFIGURE 3 Voltage Reduction The external circuitry required is shown in Figure 2. When voltage reduction is required, the contacts fromterminal 10 to terminal 13 dose, forcing the timer to instantaneously time out. Subsequent tap changes will occurwith no time delay. Meanwhile, the normally closed contacts will open to keep the cam switch from resetting thetimer 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 andwithin the control cabinet in order to avoid circuit damage or misoperation.

USE OF THE M-0329 LTC BACKUP CONTROLWITH THE M-0067 TAPCHANGER CONTROLThe 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 areavailable for the fixed bandwidth.

The M-0329 Instruction Book is available on request and gives added details.

Since the M-0329 voltage and thefixed bandwidth value must be specified at the time of purchase, please refer to the M-0329 Instruction Book forcomplete ordering information.

0

• C27 & C28 installed for 50 Hz SystemRESISTANCE VALUE FACTORY SELECTEDFIGURE 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 samemounting 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 thetypical 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 normallytied to tenninal 3 and that these excessive voltages were causing occasional failure.

In the '"S version of theM-0067 units, these voltages are suppressed by a string of varistors which still permit the unit to pass a 1500 V achi-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 theM-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 couldadd 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). Anyexternal device, e.g. a voltmeter, connected to TB1-2 must not draw more than 0.25 A toensure F2 will not be blown. Refer to the TEST CIRCUIT section for instructions on usingT71-2 for external voltage monitoring.

This fuse can be replaced by unsoldering the oldfuse 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 newM-0067E units, and additional fuses can be obtained from the manufacturers or fromBeckwith Electric Co.Units returned with only a blown fuse are not covered by warranty, and a nominal repaircharge 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) cC0)0A~ III( CAP__ ____I___0 _ _ _ __.__o_ __ _ _ _ _ _oLL C000 ~C4::NbE(j)PLa, I0RGURE 5 Mounting and Outilne Dfrmensions hAICHANGER CONTROL RiErS! (gffiECTM-0067E RI Mxwn 00 IN~u*~ CLM.ELECTRIC:[>

LINE DROPCOMPENSATOR 0 QTOT00 LOWER0TTerminal BlocksFIGURE 6a Horizontal Mounting Configuration WfW4CANGER CONTROL "WUC OO LaaRN-M067ETerminal Blocks4 Rack Units(7 inches)FIGURE 6b 19" Rack Mount Configuration MOTORSUPPLYTAPCHANGER CONTROL M-032990 M-0067E8 BLKRAISE9 8LK00 _L F-ý 1 LOWER 90 B.U.ISLimit switcher, auxiliary contacts asrequired in motor control circuits.

4 84R -Raise Motor Auxiliary Relay84L -Lower Motor Auxiliary RelayFIGURE 7 M-0329 interconnection with Beckwlth M-0067 TapchangerControl IADJUSTMENT The BANDCENTER and BANDWIDTH controls of the LTC Backup Control should be set so that the Block Lowerlimit is a small amount, (approximately 2 V), below the lower band limit of the Tapchanger

Control, and theBlock 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 thetransformer.

If line drop compensation is used, the Backup Control Block Raise limit should be set higher than the highestvoltage expected from the transformer under full load.The M-0329 LTC Backup Control also includes a First Customer Protection function that regulates the maximumvoltage from the transformer.

This "LOWER" function operates slightly above the Block Raise limit and isconnected 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 Bookon 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 theM-0067Tapchanger Control.

Connections for this combination are shown in Figure 7. With this combination, theLDC is set at a value surely greater than the impedance to the load center. The M-0329 lower output contact willoperate 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'IrNGSBefore power is applied to the transformer, adjust the VOLTAGECENTER OF BAND, TOTAL BANDWIDTH, TIME and Rand X LINE DROP COMPENSATOR knobs to the desired setting.

Remove wires from terminals 7,8 and 9 and placelead from terminal 4 temporarily on terminal 3.POWERMake certain by measurement, if possible, that the potential to be applied to terminals I through 3 is nominal 120V 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 thevoltage 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 themotor 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 bygetting 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 Amultiplied by the fraction of full load on the transformer.

If correct, reconnect the lead to terminal

4. If thetransformer is energized when making this connection, be sure to first short the C.T secondary.

TEST CIRCUITThis circuit permits checking the band limits as well as the operation of the tapchanger.

Voltmeter terminals areordinarily provided external to this control and tied to terminals 2 and 3 of the control.

Connect a voltmeter ofnot less than 500 fQ per V to these terminals.

With the TESTIOPERATE switch on TEST, vary the TEST knob and readthe 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 tothe setting of the VOLTAGE knob asit would be in practice (but might not be in a laboratory test setup). The circuitdepends on the voltmeter burden to lower the voltage.

If the voltmeter burden is more than 500 0 per V, connecta 50 K resistor across the voltmeter terminals or from 2 to 3 of the M-0067 control.

If the voltmeter burden isappreciably 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.

Withsuch motors, never set the timer less than the lime it takes the motor to stop. In such a casea 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 standardC37.90.1-1989.

Since serial number 5500, all units have been tested per this standard before shipment a il LLII, I I--a *le t mFIGURE 8 Component LocationEg...lowi

• MAINTENANCE Due to the extremely sophisticated nature of the circuitry in the M-0067, field repair is not recommended.

Allunits are fully calibrated at the factory prior to shipment; there is not need to re-calibrate a unit prior to initialinstallation.

Calibration is only required after a component is replaced.

In the event that a unit does not operateproperly, it should be established that the problem is caused by malfunction of a Beckwith unit and not causedby 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 toprotect the contents.

0 NOTE: Any equipment returned for repair must be sent with transportation chargesprepaid.

The equipment must remain the property of the user. The warranty is void if the valueof the unit is invoiced to Beckwith Electric at the time of return or If the unit is returned withtransportation charges collect.If under warranty, units will be repaired rapidly and returned at no cost and with return transportation paid ifthe fault is found to be due to workmanship or failure of material.

If a unit is under warranty and expressshipment for return of the repaired unit is requested, shipping charges will be billed at the current rate. If thefault is due to abuse or misuse, or if the unit is out of warranty, a modest charge will be made. Repair cannormally be expected to take two weeks, plus shipping time. If faster service is required, it should be requested at the time of return.0E NOTE: Units returned with only a blown fuse are not covered by warranty and a nominalrepair 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 failureshould 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 thebeginning of this manual.If Fl blows, it is surely due to the failure of another component, which should be identified and replaced togetherwith the fuse.It is suggested that first a visual inspection be made for any component that does not appear normal or appearsto have overheated.

Analysis of the circuit will then often lead to the cause of the failure and components thatneed to be replaced.

If no obvious problems exist, it is suggested that the TEST PROCEDURES be followed until a portion of acircuit is detected which does not perform as expected or until a calibration point is found which will not meetrequirements.

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 toassure trouble-free operation.

HOW TO AVOID DAMAGING YOUR CONTROL THROUGH TESTINGThis 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 damagesemiconductors.

2. Don't make measurements from "hot" 120 V ac to terminals TB1-10, TB1-11, TB1-12, TB1-13 or to anypoints within the circuit.

In particular, a low impedance ac voltmeter will introduce sufficient current intothese 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 somay cause damage to Q3 and Q4.A CAUTION:

In testing the unit, make certain that the motor starterand motor operate offa supply other than the test supply for the unit. If this is not done, the current drawn by themotor and starter may drop the voltage back within the band when checking the Loweroperation.

This will cause an oscillation which must be correctly attributed to the test circuitand Is not an Indication of improper operation of the control.Any attempt to measure resistance between points on the printed circuit board may causedamage to the unit.

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

EQUIPMENT REQUIRED1. 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 orequivalent 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 inseries is suggested.

The potentiometer should be at least 2 W and preferably carbon-ceramic construction.

Thiswill 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-C8filter network to catch up.In checking the line drop compensator, polarity must be observed, otherwise a 180' error will occur. See Figure4 Schematic for standard polarity marking.REMOVING THE PRINTED CIRBCUIT BOARDThe circuit board and panel can be easily separated leaving a completely functional circuit.

To do this, removethe knobs using a small screwdriver.

Remove the nuts securing the switches and knobs. Remove all screwsshowing 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 wickor 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 holeas 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 withthe pointer at the minimum calibration point. Before tightening the setscrew, back out the locking knoband 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 LineFigure 9 Waveslape If the waveshape is found to differ, then QI or a closely associated component may be defective.

POWER SUPPLYConnect 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 VdcR21-R33 junction to 0 V 12 V dc(Trimmer R23 should vary this voltage)D14 (Anode) toO0 V -12 VdcD14 (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. Varythe uncalibrated TEST knob and see that the RAISE and LOWER LEDs light at correct voltages with some deadband where both are extinguished.

Set theTOTAL BANDWIDTH knob to 2.0 and adjust trimmer R28 to give 2 V bandwidth.

Set the VOLTAGE CENTER OFBAND dial to 125 and the TOTAL BANWIDTH knob to 1.0. Adjust R23 so that 25 V is in the center of the band asindicated by the RAISE and LOWER LEDs. Set the VOLTAGE CENTER OF BAND knob to 110 and adjust R31 so that110 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.TIMERConnect a reversing type motor starter from TB1-7 and TB1-9 to the low side of a 120 V ac supply. This sourceneed not be regulated, and may be the same source that is used for calibration procedures.

Connect the high sideof this supply to TB1-8. If a motor starter is not available, two 60 W light bulbs may be connected from TBI1-7 andTB1-9 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 afterthe 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 suddenlyout 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 onthe first try.RESISTANCE COMPENSATION Set the VOLTAGE CENTER OF BAND knob on 120. Connect a separate variable ac voltage from the output of a phaseshifter through a 600 0, 10 W non-inductive resistor and ac ammeter from TB1-4 to TB1-3. Set the UNE DROPCOMPENSATOR X knob on zero and the R knob on 12. Set the current to 0.2 A, angle to 00. Adjust R4 so that withcurrent present, the voltage at the center of band is increased precisely 12 V. Note that the voltage on TB11-2 is notaffected 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, withthe 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 (900 leading).

Adjust R8 for 108 Vbandeenter with the UNE DROP COMPENSATOR switch on DIRECT and 132 V bandcenter with the UNE DROPCOMPENSATOR 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 phaseangle 900 lagging.

The center of band should now be close to 132 V.

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

FROM0V0V0V0V12V12 V0V0V0V0V0VTO20 V12V-6V-12 VTP-2R46-R48JunctionR46-R48JunctionR47-R49JunctionR36-R38JunctionR41-C26JunctionCONDITION VOLTAGEVoltage 120 V ac, S1 on OPERATE 243 V dcAc Ripple, above condition 1.0 V ppAc Ripple 0.01 V ppAc Ripple 0.06 V ppAc Ripple 0.2 V ppVoltage 105 V ac -7.0 V dcVoltage 120 V ac -8.2 V dcVoltage 135 V ac -9.1 V dcVoltage swing from +12 R (Regulated Voltage)(for waveshape, see TEST PROCEDURE section)Voltage 105 V ac +1.0 V dc to-13.0 V dcVoltage 120 V ac +1.0 V dc to-15.0 V dcVoltage 135 V ac +1.0 V dc to-17.0 V dcR26 cw, R29 ccw +3.2 V dcR26 ccw, R29 ccw +5.1 V dcR26 cw, R29 ccw +3.4 V dcVoltage in band -4.0 V dcRAISE LED on +8.7 V dcAbove condition after timing +8.9 V dcVoltage in band -4.1 V dcLOWER LED on +8.7 V dcAbove condition after timing +8.9 V dcVoltage in band 0 V dcVoltage out of band +0.6 V dcVoltage in band +0.6 V dcVoltage out of bandOV dc

..... .....PARTS LISTM-0067E Tapchanger ControlThis list includes all electrical and mechanical parts which could conceivably either require replacement orbe lost. The COMPONENT DESIGNATION is the same as that appearing on schematics or referred to inInstruction Books.The BECO NUMBER refers to an index maintained by the company.

This lists the currently available devicewhich 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 currentsubstitute will be carried in stock by Beckwith Electric.

Parts not marked with an asterisk are normally available from an electronics components house. Those partsor 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 ofspecifications 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 TESTPROCEDURES Section must be followed in replacing these components.

, All resistors are 1/2 W unless noted.COMPONENT BECO DECITODESIGNATION NUMBER DIESCRIPTION 450-00036*

C1C2,C3,C4C5C6C7C8C9c00Cll,C22,C23 C12000-00850 010-00529 000-W0501 000-00617 010-400527 000-40626 000-00903 000-O0902 000-00533 P.C. Board, P-0273Not UsedCapacitor, Polyester Film, 1 jiF+/-10%,

200 VCapacitor, Mylar, 0.47 p.F +/-10%, 200 VCapacitor,

Tantalum, 3.9 IjF +/-10%, 35 VCapacitor, Electrolytic,50 jiF +75%/-10%,

50 VCapacitor, Mylar, 0.068 I+/-F +/-10%, 100 VCapacitor, Electrolytic, 150 ;iF +75%/-10%,

75 VCapacitor, Ceramic Disc, 100 pF +/-10%, 1 kVCapacitor, Ceramic Disc, 680 pF +/-_10%, 1 kVCapacitor,

Tantalum, 150 pF+/-10%, 15 V0 COMPONENT BECO DESCRIPTION DESIGNATION NUMBER_C13,C14,C1 6C15C17,C18C19C20C21C24C25C26C27,C28D1,D2,D5,D6,D13,D18 D3,D19D4,D9-D12,D16 D7D8D14,D15D17D20,D2-ZD21Fl, F211J12K1,K2QI,Q3,Q4,Q6 Q2000-00418 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 UsedCapacitor, Electrolytic, 170 +/-F +75%/-10%,

50 VCapacitor, Mylar, 0.033 4xF +/-10%, 100VCapacitor, Mylar, 0.1 ptF +/-10%, 200 VNot UsedCapacitor, Ceramic Disc, 0.0047 gFF+/-20%,

1 kVCapacitor, Ceramic Disc, 0.001 ;+/-F, I kVCapacitor, Ceramic Disc, 0.1 iF +/-20%, 50 VCapacitor, Solid Tantalum, 2.7 gF +/-10%, 15 VRefer to OPTIONAL COMPONENTS Diode, Rectifier, 600 V, G.E. 1N5061Diode, Zener, 15 V +/-5%, 400 mW, 1N965BDiode, 1N662/B692X13-4 Diode, Reference, 6.2 V +/-5%, 400 mW, 1N823A,Not UsedDiode, Zener, 6.2 V +/-5%, 400 mW, 1N753A/IN5234B Diode, Zener, 33 V +10%, 5 W, 1N5364ADiode, Zener, 15 V +/-5%, 5 W, 1N5352Diode, Zener, 12 V +/-5%, 5 W, 1N5349Microfuse, Plug-in, 1/4 A, Littelfuse 273.250Diode, Light Emitting, HP HLMP-3316 Relay, AZ, 420-07-4H Integrated

Circuit, Op Amp, UA741, TO- 99Integrated

Circuit, Regulator, UA723, TO -100 eCOMPONENT r BECO DESCRIPTION DESIGNATION NUMBERi ii ...... .. ViQ5,Q7-29,Ql3 400-00300 Transistor, NPN Signal, 2N1711Q1O-Q12Q14-Q22Q23RIR2R3R4,R$R5,R9,R40 R6R7RIOR11R12R13R14RISR16R17R18R19R20, R67R21R22400-00728 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 UsedVaristor, 275 V, G.E. V275LA2Varistor, 460 V, G.E. V460LB20Not UsedResistor, Metal Film, 1.5 K +/-2%Potentiometer, 5 K, 2 W, U-0048-1Trimmer, Cermet, 10 K +/-20%, Bourns 3386P-1-103 Potentiometer, 50 KY, 2 W, U-0048-2Not UsedTrimmer, 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 WResistor, Metal Film, 274 K +/-1%, 1/4 W, RN60ENot UsedResistor, Carbon, 1 K +/-5%Resistor, Metal Film, 243 K +/-1%, 1/4 W, RN60EResistor, Metal Film, 4.75 K +/-1%, RN65DResistor, Metal Film, 681 Q +/-1%, RN65DResistor, 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 DR23,R28,R31 R24R25R26,R29R27,R30R32R33,R70,R73 R34R35R36R37R38,R48,R49 R39R41R42,R44,R65,R72 R43R45R46, R47R50-R54R55R56-R63R64R66R68R69360-00034 330-00469 330-00393 360-00047*

330-00460 200-00101 200-00684 200-"0155 200-00683 200-00682 360004200-00223 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, RN60EResistor, 909 ohms +/-1%, 1/4 W, RN60EPotentiometer, 500 ohms, 4 W, U-0031-1Resistor, 4.12 K +/-1%, 1/4 W, RN60ENot UsedResistor, 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 UsedResistor, Carbon, 330 ohms +/-5%Not UsedResistor, Carbon, 100 K +/-5%Resistor, Carbon, 27 K +/-5%Not UsedResistor, Metal Film, 2 K +/-2%-28--

0COMPONENT BECO DESCIPTION DESIGNATION NUMBER DR71 240-00151

Resistor, Carbon, 150 ohms +/-10%, 2 WS1, S2 430-00054 Switch, DPDT Toggle, U-0079T1-T3 410-00023*

Transformer,

Current, U-0025T4 410-00022*

Transformer,

Sensing, U-0027T5 410-00017 Transformer, Power, U-0029TBI 420-00012 Terminal Block, Cinch-Jones 12-140-YREV VOPTIONAL COMPONENTS Single or Multi-Step Voltage Reduction OptionR74 and/or R75 j Factory select (based on reduction specified)

REV AInstantaneous Voltage Reduction OptionR37 200-00222

Resistor, Carbon, 2.2K +/-5%REV A50 Hz Operating Frequency OptionVttC27C28REV 0000-00716 000-00859 Capacitor, Polyester,

.18 gF +/-10%, 50 VCapacitor, Polyester,

.39 jIF +/-10%, 50 V0 CPATENTThe units described in this manual are protected by U.S. Patent 3,721,894; and Canaidan Patent 985,368; British Patent1,432607, 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 costsand expense, damage or loss, resulting from any alleged infringement of United States Letters Patent or rights accruingtherefrom or trademarks whether federal, state, or common law, arising from the Seller's compliance with Buyer'sdesigns, specifications, or instructions.

WARRANTYSeller hereby warrants that the goods which are the subject matter of this contract will be manufactured In a goodworkmanlike manner and all materials used therein will be new and reasonably suitable for the equipment.

Sellerwarrants that if, during a period of two years from date of shipment of the equipment, the equipment rendered shall befound bythe Buyer to be faulty or shall failto perform in accordance withSeller's specifications of the product, Seller shallat his expense correct the same, provided however that Buyer shall ship the equipment prepaid to Seller's facility.

TheSeller'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 otherwarranties, whether written, oral, implied or statutory, except as to the title of the Seller to the equipment furnished.

Noimplied statutory warranty of merchantability or of fitness for a particular purpose shall apply. Seller does not warrantany product or services of others which Buyer has designated.

SELLER MAKES NO WARRANTIES EXPRESSED OR IMPLIED OTHER THAN THOSE SETOUT ABOVE. SELLER SPECIFICALLY EXCLUDES THE IMPLIED WARRANTIES OFMERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

THERE ARE NOWARRANTIES WHICH EXTEND BEYOND THE DESCRIPTION CONTAINED HEREIN. IN NOEVENT SHALL SELLER BE LIABLE FOR CONSEQUENTIAL, EXEMPLARY, OR PUNITIVEDAMACES OF WHATEVER NATURE.Any equipment returned for repair must be sent with transportation charges prepaid.

The equipment must remain theproperty of the Buyer. The aforementioned warranties arevoid if the value of the unit is invoiced to the Seller at the timeof 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 thiscontract.

In no event shallthe Sellerbe liableforspecial, incldental, exemplaryorconsequential damages including, but not limitedto 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 oremployees 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 orperformed in connection with any nuclear installation,

facility, or activity, Seller shall have no liability for any nucleardamage, personal injury, property damage, or nuclear contamination to any property located at or near the site of thenuclear 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 andincludes the site on which any of the foregoing is located, all operations conducted on such site and all premises used forsuch operations.

It is the intention of the parties that this is a complete indemnification and hold harmless agreement inregard to all claims arising from nuclear operations of Buyer.067

°%C-.S 0 iII BECKWITH ELECTRIC CO., INC.Mailing AddressP.O. Box 2999Largo, Florida 34649-2999 Shipping Address6190 -118th Avenue NorthLargo, Florida 34643(813) 535-3408© 1993 Beckwith ElectricPrinted in the U.S.A.6/93

-c,,,,/5~7/5~ c9~/a ~Service Information 15-7/ 01;ý -

Powe Trasfor ersCOOPER POWER SYSTEMSPower Transformers cooGFU ,McGraw-Edison@

Load Tap Changer Motor Control S210-40-1 8Maintenance Instructions CONTENTS o0Introduction

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

1Safety Advisory

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

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

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

2Components

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

21. Motor Reversing Contractors

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

22. Motor Braking Contractor

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

2 I3. Sequential Tim ing Relay .......................................

24. DC Power Source ...........................................

25. DC Braking Tim ing Relay .....................................

26. M otor B reaker .......................................................

27. Operation Counter .........................................

38. Fuses ....................................................................

3 8 4 L 84 R9. Heater Switch ..................................................

3 D j10. Convenience Outlet .........................................

3 [ j11. Motor Capacitor

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

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

3 <Maintenance

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

3 PULL-OUT FUSE BLOCK zTroubleshooting

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

4* 1. Load Tap Changer does not respond toRAISE-LOWER switch ..................

4 FBA F-2. Load Tap Changer operates inone direction only .................................................

4 84D3. Load Tap Changer over-runs

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

44. Load Tap Changer stops off position

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

4INTRODUCTION FUSESThe Load Tap Changer (LTC) Controls are divided into fourbasic components:

1 ) Drive Mechanism,

2) Motor Control,3) Automatic Regulation (when required),

4) Vacuum Inter-rupter Monitoring System (when applicable).

Service Infor- D84Amation 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. 084BWARNINGYOU MUST HAVE TRAINING IN THE OPERATION OFTHIS EQUIPMENT BEFORE USING IT. YOU MUST FBBALSO READ, UNDERSTAND AND OBEY ALL SAFETYADVISORIES.

l T84,o LLiFigure 1.s o Motor Control PanelThese 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 PowerSystems Representative.

March 1991

• Supercedes 9/90 * © 1991 Cooper Power Systems.

Inc. 1Printed in U.S.A.

-. 2SAFETY ADVISORYThis Safety Advisory is intended to identify the potential hazards and consequences to anyone who comes incontact with their contents.

The supportive wording isexpected to elicit a safe response from adults.& DANGERIMMEDIATE HAZARDS WHICH WILL RESULT INDEATH OR SEVERE PERSONAL INJURY OR SUB-STANTIAL PROPERTY DAMAGE, IF PROPER PRE-CAUTIONS ARE NOT TAKEN.OPERATION BY ELECTRICAL HAND CONTROLzI &WARNINGDO NOT OPERATE EQUIPMENT UNLESS IT IS COM-PLETELY AND PROPERLY ASSEMBLED.

LI\ WARNING Un vrlgfr! Cru"m~' I l ovv" Io.nr '.UULVRESULT IN DEATH OR SEVERE PERSONAL INJURYOR SUBSTANTIAL PROPERTY DAMAGE, IF PROPERPRECAUTIONS ARE NOT TAKEN.I & CAUTIONHAZARDS OR UNSAFE PRACTICES WHICH COULDRESULT IN MINOR PERSONAL INJURY OR PROD-UCT OR PROPERTY DAMAGE, IF PROPER PRE-CAUTIONS ARE NOT TAKEN.NOTICESITUATION WHICH COULD RESULT IN PRODUCTOR-PROPERTY DAMAGE WITH NO PROBABILITY OF PERSONAL INJURY, IF PROPER PRECAUTIONS ARE NOT TAKEN.MOTOR CONTROLMotor 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 andelectrically interlocked to insure positive operation of theLoad Tap Changer motor.McGraw-Edison utilizes two similar, but slightly differ-ent, motor control panels: 1) To control a 115 volt, singlephase, 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 controlsignal to initialize the motor control system. This electrical control signal or momentary contact must be closed from0.10 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 voltageis 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 supplycircuitand a fuse protects the DC braking circuit.

A breakeris provided for protection of the LTC drive mechanism motor.Hand-operated control switches are normally provided inthe control cabinet so that the Load Tap Changer mecha-nism may be operated during installation or periods ofpreventive maintenance.

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

The Load Tap Changerswitching mechanism may be energized and carryingload.COMPONENTS The actual components furnished on any specific unit,along with their ratings, may be determined by reading theparts description contained on the LTC Schematic draw-ings issued with that particular unit. The connections tothese components are also shown on these same draw-in9The motor control panel is usually equipped with thefollowing components:

1. Motor Reversing Contactors (84R and 84L)These contactors control the application of AC voltageto the LTC motor windings when a tap change isinitialized.

These contactors are mounted on a commonbase and are electrically and mechanically interlocked with each other. Each contactor is also equipped withadditional contacts to provide electrical interlocking between the LTC motor AC running and DC brakingcircuits.

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 ofthe automatic DC braking circuit.

The duration of thisapplication is controlled by the DC braking timing relay(62A). This contactor is equipped with additional con-tacts to provide electrical interlocking between themotor DC braking and AC running circuits.

3. Sequential Timing Relay (33A)This relay provides an immediate seal-in of a singleelectrical control signal to initialize a tap change op-eration.

It also provides a controlled time delay at thecompletion of the braking cycle to assure positiveoperation of the Load Tap Changer.4. DC Power SourceThis source is derived from a circuit consisting of afuse, an auxiliary step-down transformer (T84), and afull wave rectifier (two diodes, D84A & D84B, on a heatsink). The transformer connections are determined bythe motor used with the Load Tap Changer drivemechanism.

5. DC Braking Timing Relay (62A)This timing relay determines the duration of the DCbraking action. The relay is equipped with a normallyopen contact which closes immediately when the relayis energized by the operation of either the 84R or 84Lcontactor.

The 62A contact stays closed for approxi-mately two seconds after the 84R or 84L contactor hasbeen released, to energize the motor braking contactor (84D).6. Motor Breaker (8-84)The motor breaker is provided and wired for motorprotection only. The number of poles and current ratingof the breaker are determined by the Load Tap Changermechanism 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) tapchange operations of the LTC mechanism.

8. FusesCAUTIONDO NOT REMOVE ANY FUSE UNDER LOAD. FUSEBLOCKS ARE FOR DISCONNECT USE ONLY.WIRINGACAUTIONDO NOT TOUCH BARE WIRES,-UVE PARTS, ORTERMINALS, TO PREVENT ELECTRICAL SHOCKHAZARDSeparate fuses protect the control circuits, DC brakingcircuit, and auxiliary circuits.

A fuse has been providedin the motor control circuitto prevent electrical operation of the LTC mechanism in the event of DC braking circuitfailure.

All of the fuses are 250 volt cartridge type;however, the ampere rating and type depend on theapplication.

Many units are furnished with special equipment.

Consultthe wiring diagrams furnished with each specific unit forcustomer conforming variations.

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

I & -CAUTIONINCORRECTSUPPLY VOLTAGE MAY DAMAGETHE CONTROLS.

REFER TO LTC SCHEMATIC DRAW-INGS.INOTICETHE PULL-OUT FUSE BLOCK (FBA) USED IN THEMOTOR CONTROL AND SOURCE CIRCUITS HASBEEN FURNISHED AS A SAFETY FEATURE.

THISFUSE BLOCK SHOULD BE PULLED OPEN TOPROVIDE A VISUAL DISCONNECT WHEN SERVIC-ING THE CONTROL CIRCUITS, MOTOR CIRCUITS, LTC DRIVE MECHANISM OR LTC SWITCH.IA9. Heater Switch (43H)This ON-OFF switch controls the space heater(s) locatedin the cabinet.

It is recommended that the heater(s) beleft on at all times to prevent moisture condensation andattendant corrosion.

//i CAUTIONMAINTENANCE

& WARNINGDISCONNECT AND GROUND ALL ELECTRICAL POWER SOURCES, TO PREVENT ELECTRICAL I SHOCK HAZARD.& WARNINGGROUND AND SHORT CIRCUIT ALL CURRENTTRANSFORMERS, TO PREVENT HIGH VOLTAGESHOCK HAZARD.Maintenance and repairs must be done by authorized personnel only. Read, understand and obey all SafetyAdvisories, before doing any repairs, maintenance, orchanging the features and accessories of this equipment.

During the performance of established maintenance procedures,

annually, and every 100,000 tap changes theLTC Motor Control Panel, its components and wiring mustbe cleaned of all accumulated dust, dirt, and foreigndebris. Make certain all electrical connections are cleanand securely tightened.

Inspect for worn, cracked, frayedor otherwise damaged components and wires. Keep allfasteners tight. Keep all adjustments according to factoryspecifications Immediately notify Cooper Power Systems upon thedetection of probable defective parts. Failure to performthese 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 NOTAVAILABLE.

10. Convenience Outlet (DO)This NEMA 5-15R separately fused duplex outlet maybe used for portable lights and small power hand tools.11. Motor Capacitor (C84)This capacitor is used to both start and run the LTCmotor. Its voltage rating and capacitance value aredetermined by the LTC drive mechanism motor re-quirements.

& CAUTIONSHORT CIRCUIT CAPACITOR TERMINALS, TOPREVENT ELECTRICAL SHOCK HAZARD.a3 TROUBLESHOOTING (FOR EQUIPMENT BUILT AFTER 1/1/82)Electrical Operation of Load Tap Changer Motor Control1. 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 LTCschematic drawings for proper ratings.

If brakingfuse is open, check diodes (D84A and D84B) forshort circuit.

If a diode shorting problem persists, check timing of 62A relay. Check station servicesupply for transient problems.

c. Check position of handcrank.

(Must be in storageposition.)

d. Check 84R and 84L contacts and 840 contacts.

e. Check mechanical stop switch (if supplied).

It mustbe closed.f. If reversing contactor operates and motor breakerdoes not trip, check motor, capacitor, reversing contactor

contacts, and associated wiring for opencircuit condition.

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

Check formechanical 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 anderratic operation.

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

4. Load Tap Changer stops off position.

Refer to Ser-vice Information instructions covering specific LTCmechanisms.

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 84Lcontacts, the tap changer motor and the powersupply.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 TapChanger mechanism, Read LTC Maintenance andInstruction Manual.COOPER POWER SYSTEMSMcmaw.EdlsonO Power ProductsPost Office Box 440Canonsburg, PA 15317to4