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Instructional Booklet IB02102006E
Effective May 2011
Type MVS (previously WLI)
metal-enclosed switchgear—
4.76 kV, 15.0 kV, 27.0 kV, and 38.0 kV
EATON CORPORATION www.eaton.com
Main shaft position with door interlock
(shaft blocking cam)
WARNING
DEFEATING THE SHAFT BLOCKING CAM-DOOR INTERLOCK WHEN THE
SWITCH IS ENERGIzED MAy RESULT IN SEVERE INJURy OR DEATH.
DE-ENERGIzE THE SWITCH AND GROUND ALL LIVE PARTS BEFORE
DEFEATING 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 closing.
The shaft rotation is prevented by the blocking action between the
blocking cam on the shaft and the ramping cam of the spring biased
assembly. If the door is open and a “trip-to-close” action is initiated,
a jamming action takes place between the blocking cam and the
ramping cam to stop shaft rotation; thus, the switch cannot close
(see Figure 39).
Figure 39. Operating Mechanism Showing Door Interlock, Shaft
Blocking Cam, and Ramping Cam
The blocking action must be released by inserting the operating
handle into the maintenance hub and slightly rotating to reset
the charged main spring again over toggle.
Inspection and maintenance
WARNING
FAILURE TO DISCONNECT AND TO GROUND ALL POWER SOURCES BEFORE
PERFORMING ANy INSPECTION AND/OR MAINTENANCE PROCEDURES
MAy RESULT IN SEVERE INJURy OR DEATH.
DISCONNECT AND GROUND ALL POWER SOURCES BEFORE COMMENCING
PROCEDURES.
WARNING
FAILURE 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 alignment
The blade and arc chute alignment procedures are the same for
the standard MVS switch described in the “Maintenance” section.
However, before the maintenance hub may be used, the following
steps must be taken.
Step 1: Remove the door interlock-shaft blocking cam
assembly by removing its two 0.375 in. (9.53 mm) bolts.
Step 2: “Close” the switch and leave spring in its discharged
position. The maintenance hub may now be used for alignment
procedures, provided the trigger latch is raised during initial rotation
of the operating shaft. Failure to release the trigger latch will
damage components in the linkage assembly.
Over toggle adjustment
This adjustment is identical to that in “Maintenance” section.
Open gap adjustment
This adjustment is to be made identical to that in the
“Maintenance” section.
Spring release mechanism adjustment
The spring release mechanism is bolted to the side sheet with
four bolts. It is adjusted by loosening these bolts, then sliding
the mechanism up or down slightly as appropriate, tightening
the bolts, then operating the switch to both the “Open” and
“Closed” positions.
The 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 of
the switch)
•
Latch after the switch has “Closed” or “Opened”
If the spring release mechanism is not latching and releasing
correctly, make sure that the spring is either discharged or the spring
rod restrained (see “Spring replacement” section), then loosen the
four mounting bolts and again sliding the mechanism up or down as
necessary to obtain the proper action. Be sure to operate the switch
“Open” and “Closed” to ensure that the mechanism is latching and
releasing correctly.
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