Eaton MVS Instructional Booklet

Contents

27Instructional Booklet IB02102006EEffective May 2011Type MVS (previously WLImetal-enclosed switchgear4.76 kV, 15.0 kV, 27.0 kV, and 38.0 kVeaton corporation www.eaton.comMain shaft position with door interlock(shaft blocking cam) WARNINGDEFEATING THE SHAFT BLOCKING CAM-DOOR INTERLOCK WHEN THESWITCH IS ENERGIzED MAy RESULT IN SEVERE INJURy OR DEATH.DE-ENERGIzE THE SWITCH AND GROUND ALL LIVE PARTS BEFOREDEFEATING THIS INTERLOCK TO PERFORM MAINTENANCE, ADJUSTMENT,AND INSPECTION PROCEDURES.When the enclosure door is opened, a spring biased cam assembly,located at the opposite end of the operating shaft from main spring,moves into position to block inadvertent switch closingThe shaft rotation is prevented by the blocking action between theblocking cam on the shaft and the ramping cam of the spring biasedassembly If the door is open and a “trip-to-close” action is initiated,a jamming action takes place between the blocking cam and theramping cam to stop shaft rotation; thus, the switch cannot close(see Figure 39)Figure 39. Operating Mechanism Showing Door Interlock, ShaftBlocking Cam, and Ramping CamThe blocking action must be released by inserting the operatinghandle into the maintenance hub and slightly rotating to resetthe charged main spring again over toggleInspection and maintenance WARNINGFAILURE TO DISCONNECT AND TO GROUND ALL POWER SOURCES BEFOREPERFORMING ANy INSPECTION AND/OR MAINTENANCE PROCEDURESMAy RESULT IN SEVERE INJURy OR DEATH.DISCONNECT AND GROUND ALL POWER SOURCES BEFORE COMMENCINGPROCEDURES. WARNINGFAILURE TO REPLACE THE SHAFT BLOCKING ASSEMBLy BEFORE RETURN-ING SWITCH TO SERVICE MAy RESULT IN SEVERE INJURy OR DEATH.REPLACE THE SHAFT BLOCKING ASSEMBLy BEFORE ENERGIzING.Blade and arc chute alignmentThe blade and arc chute alignment procedures are the same forthe standard MVS switch described in the “Maintenance” sectionHowever, before the maintenance hub may be used, the followingsteps must be takenStep 1e: Remove the door interlock-shaft blocking camassembly by removing its two 0 375 in (9 53 mm) boltsStep 2e: “Close” the switch and leave spring in its dischargedposition The maintenance hub may now be used for alignmentprocedures, provided the trigger latch is raised during initial rotationof the operating shaft Failure to release the trigger latch willdamage components in the linkage assemblyOver toggle adjustmentThis adjustment is identical to that in “Maintenance” sectionOpen gap adjustmentThis adjustment is to be made identical to that in the“Maintenance” sectionSpring release mechanism adjustmentThe spring release mechanism is bolted to the side sheet withfour bolts It is adjusted by loosening these bolts, then slidingthe mechanism up or down slightly as appropriate, tighteningthe bolts, then operating the switch to both the “Open” and“Closed” positionsThe mechanism should:• Be latched prior to charging the operating spring• Stay latched when the main spring is charged• Release the linkage and the charged operating spring to “Close”or “Open” the switch (depending on the original position ofthe switch)• Latch after the switch has “Closed” or “Opened”If the spring release mechanism is not latching and releasingcorrectly, make sure that the spring is either discharged or the springrod restrained (see “Spring replacement” section), then loosen thefour mounting bolts and again sliding the mechanism up or down asnecessary to obtain the proper action Be sure to operate the switch“Open” and “Closed” to ensure that the mechanism is latching andreleasing correctly

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