Eaton 75VCPW-VSR Instruction Book

Contents

13Instruction Book IB02707112EAugust 201550/75VCPW-VSRBreaker To Vacuum Starter Replacement UnitEATON CORPORATION www.eaton.comFigurt 4.3. SL CNnoacoNrs Asstmbly4.2 ELECTRO-MOCInstallation / Operation / RatingsOverviewMV-VSR vacuum starter replacements are designed for thousands ofmechanical operations. The mechanisms utilize solenoids for closingand have limited excess kinetic energy and travel to operate auxiliarydevices. Mechanism Operated Contact (MOC) switch operationrequires more kinetic energy than the MV-VSR can deliver, so analternative must be utilized when MOC operation is required. Eatonoffers an electrical state-changing relay for this function. It does notrequire an electrical latch. Eaton calls this an “Electro-MOC”. TheElectro-MOC can be installed in place of or used in conjunction withthe exiting MOC and has sufficient “a” and “b” contacts for mostapplications. (Figure 4.4)Figurt 4.4. EltcorN-MOCContactor Closed1 Armature Shaft 4 Operating Plate2 Moving Armature 5 Overtravel3 StopContactor Open1 Armature Shaft 4 Operating Plate2 Moving Armature 5 Return Spring3 Stop1234512345InstallationInstallation is simple. The Electro-MOC may be mounted to eithera horizontal or vertical surface, but horizontal is preferred. Themounting location should also have sufficient room and access forcontrol power and a/b contact wiring. (Figure 4.6)An “order-specific” wiring diagram and schematic is furnished witheach MV-VSR for field connections. The information also providesdetails for interfacing to an existing MOC switch. The original “a”contacts must be wired in parallel with the “a” contacts on theElectro-MOC. The original “b” contacts must be wired in series withthe “b” contacts on the Electro-MOC. It is suggested that polarizedvoltages should not be used on adjacent contacts. This is becauseof the remote possibility of flashover during transition betweenadjacent contacts, especially at higher DC ratings or in highlyinductive circuits.Further clarification is provided in the “order-specific” information.(Figure 4.8)OperationThe operation of the Electro-MOC requires an available (free)“a” and “b” contact in the existing breaker and/or MV-VSR. Aninterposing relay may also be used when “a” and “b” contacts areunavailable. These contacts are used to operate the Electro-MOC.The diagrams provided with the order include this information.When the VSR, air circuit breaker, or vacuum replacement (describedas a switching device) is opened or closed, the Electro-MOC coil isenergized through the external breaker/interposing relay contacts,changes state and is mechanically latched in the new configurationuntil the coil is reenergized. The contacts selected to control theElectro-MOC coil require ratings for “making only”. The Electro-MOChas internal contacts to break the circuit.RatingsThe Electro-MOC relay has been tested to many different circuitconditions. The interrupting ratings are based on 10,000 life-operations, using suddenly applied and removed rated voltage, withno extensive burning of contacts. The interrupting rating columnheaded “double contacts” means two contacts in series. Short-timeand continuous ratings are based on temperature rise in contactmembers and supporting parts not exceeding 50°C above ambient. WARNINGTHIS VACUUM STARTER REPLACEMENT IS NOT DESIGNED TO OPERATE ASEPARATE EXTERNAL AUXILIARY SWITCH (MOC SWITCH).