Eaton Cooper Power Series Installation, Operation And Maintenance Manual

Also see for COOPER POWER SERIES: Installation and operation instructions Installation instructions Installation instructions Installation and operation instructions Operation instructions

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Eaton Cooper Power Series Installation, Operation And Maintenance Manual Manual pdf 31 page image

Section 4: Control operationAutomatic operationIn the automatic mode of operation, the POWER switch willbe set on INTERNAL and the CONTROL FUNCTION switchwill be placed on AUTO/REMOTE. The regulator is assumedenergized from the primary circuit. If the sequential mode ofoperation (the standard mode set at FC 42) is selected, thecontrol response on Eaton's Cooper Power series voltageregulator is as follows:1. As the primary voltage moves to a level whichrepresents an out-of-band condition, the sensingvoltage will correspondingly reflect the same resultson the 120 V (or 240 V) base. Assuming the voltagedropped low, a lower than normal signal will appear atthe printed circuit board input terminals.2. The signal is transformed and converted into a digitalformat for use by the microprocessor.3. The microprocessor, recognizing the voltage conditionas low and out-of-band, issues an output whichactivates the Out-of-Band Low indicator and starts aninternal timer, which is equivalent to the time-delaysetting.4. During the time-out period, the voltage is continuallysensed and sampled. Should the voltage momentarilymove into band, the Out-of-Band Low indicator isdeactivated and the timer is reset.5. At the end of the time-delay period, the microprocessorissues an output which causes the raise triac to beactivated.6. The tap-changer motor begins to turn as a result oftriac closure, and a cam on the tap-changer closes theraise holding switch. The holding switch now providesan alternate source for the motor current, which passesthrough the input terminals on the circuit board.7. The microprocessor now recognizes that current isflowing in the holding switch circuit. The raise triac isdeactivated.8. As a result of the triac being deactivated, the motorcurrent is now carried solely by the holding switchcircuit. When the motor rotation is complete, theholding switch opens as a result of the cam action andthe motor stops.9. The microprocessor recognizes that the tap change isnow complete by detecting that motor current is nolonger flowing. The operations counter and tap positionindication are incremented. A 2-second pause thenoccurs, allowing the sensing voltage to stabilize aftermotor operation.10. At the end of this pause, if the voltage is still out-of-band, another output is issued to reactivate the raisetriac, thus starting another tap change sequence. If thevoltage is in-band, the OUT-OF-BAND LOW indicator isturned off and the time-delay timer is reset.This sequence is altered slightly if the voltage-averaging ortime-integrating mode of operation are selected. Thesecharacteristics are described in Control operatingmodes in this section of the manual.Manual operationIn the manual mode of operation, the POWER switch canbe set on either INTERNAL or EXTERNAL and the controlswitch will be placed on LOCAL MANUAL. If the externalposition is chosen, an external source must be applied tothe terminals on the control. This should be a nominal 120Vac source (or other ac voltage as indicated by a decal) andshould not be a direct current to alternating current (dc-to-ac) inverter.Operation of the momentary toggle RAISE/LOWER switchapplies power through the position indicator limit switchcontacts directly to the tap-changer motor. As the tap-changer motor cam rotates, the holding switch is closed,as described above in the Automatic operation section.This holding-switch current is sensed by the circuit board,and the operations counter and tap position indicator areappropriately updated.Tap change operation will continue as long as the RAISE/LOWER switch is held in either the raise or lower positionand the ADD-AMP™ limit switch is not activated to openthe circuit.Self-testThere are three events which trigger the self-test routine:the initial control power-up, operator entry of self-test modeusing FC 91, or detection of a firmware problem. Refer toSection 8: Troubleshooting for more information on controlself-test.25INSTALLATION, OPERATION, AND MAINTENANCE INSTRUCTIONS MN225003EN April 2018CL-7 Voltage Regulator Control