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55
Recommended Renewal Parts and Replacement Procedures
IB-60201
i. Loosen, but do not remove the four
bolts connecting the vertical connector
bars above the vacuum interrupter
to the upper primary disconnecting
devices.
j. While supporting the vacuum
interrupter, remove the two bolts
connecting the upper contact block to
the vertical connector bars.
Note:
Depending upon the rating of the
vacuum interrupter to be replaced,
it may be necessary to remove the
vertical connector bars from one side
of the assembly to gain adequate
clearance for removal of the vacuum
interrupter assembly.
k. Remove the vacuum interrupter
assembly.
l. Measure and record the position of the
upper contact block on the interrupter
stem and unscrew the upper contact
block from the vacuum interrupter.
m. Check the contents of the replacement
vacuum interrupter kit. It should
contain the following:
i. Vacuum interrupter of the proper
rating, with the lower contact block
attached.
ii. Two X-washers.
iii. Two lubricants, Rheolube 368A
grease and Mobilgrease 28.
iv. Set-up gauges 100B774 and
100B775.
n. Screw the upper contact block that
was removed in
step l
onto the fixed
terminal end of the vacuum interrupter.
Position the block at the approximate
location measured in
step l
. The exact
location of the block is not critical as
it will be adjusted in a following step.
The block should be rotated until
the longest dimensions of the upper
and lower blocks are approximately
parallel. The recommended method of
installing the upper contact block is to
restrain the block in a vise or a similar
clamping method while assembling the
upper block to the vacuum interrupter.
Exercise care when clamping the upper
block to prevent damage to the silver
plated contact surfaces.
CAUTION
CAUTION
!
Do not use the lower block to turn the vacuum
interrupter assembly into the upper block as
damage to the interrupter bellows assembly
and loss of vacuum may result.
o. Install the new vacuum interrupter in
the circuit breaker by reversing
steps k
through g
in this section.
p. Set the height of the lower contact
block by rotating the vacuum
interrupter assembly. Use gauge
100B775. With the gauge sitting on the
upper surfaces of the lower primary
disconnecting devices, the lower
surface of the lower contact block
should touch the step of the gauge.
Alternate the gauge from side to side
while rotating the interrupter assembly
in increments of ½ turn to achieve best
fit. The block should be approximately
1.125” above the edge of the lower
primary disconnecting devices
(Figure 30).
