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PowerVac
5kV Vertical Lift
®
Chapter 11. Mechanical Adjustments
6. Elevating mechanism limit switch consis-
tency.
7. Breaker elevating mechanism positive stops.
8. Seismic events.
Some of these elements also affect the other
important interfaces required for reliable opera-
tion of the equipment, such as:
1. Primary disconnect penetration.
2. Secondary coupler penetration.
3. The positive interlock mechanism.
A major goal in the design of switchgear has
always been the interchangeability of breakers.
GE Switchgear has been very successful in
achieving that goal for many years. Analysis of
instruction book adjustments, shop tolerances,
and service advice letters issued in recent years,
however, has demonstrated that tolerances in
switchgear equipment installed and presently
operating can result in situations where it is
impossible to meet all adjustments or that an
adjustment is brought into specification and it
causes a problem with another interface.
With specific reference to the plunger/station-
ary auxiliary switch interface, the following ad-
justments should be verified.
Courtesy of NationalSwitchgear.com
Nominal breaker plunger travel is 1-1/16". Nomi-
nal auxiliary switch rod travel is 1-1/16". It is
imperative that a gap is present between the
top of the plunger and the bottom of the rod,
when the breaker is in the fully connected posi-
tion and the breaker is open.
To assure the most reliable switch operation, it
is recommended that the plunger travel be mea-
sured for each breaker and recorded in mainte-
nance records. It is further recommended that
the auxiliary switch mechanism be adjusted, if
necessary, to result in a gap that is in accor-
dance with the table given in Figure 40.
This action may mean future adjusting when
and if different breakers are interchanged. Reli-
able switch operation is critical and it may re-
quire limiting your interchangeability of break-
ers. At a minimum, the criticality requires ad-
justment verification when swapping breakers.
11-8 Positive Interlock
THIS INTERLOCK IS FACTORY-SET AND
SHOULD NOT BE ROUTINELY ADJUSTED IN
THE FIELD.
Figure 39. Positive Interlock
40
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