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49
Recommended Renewal Parts and Replacement Procedures
01.4IB.50032C
Figure 19 Bell Crank Removal
t. Set the height of the operating yoke
by using gauge 100B774. With the
long arm of the gauge against the
lower surface of the upper primary
disconnecting devices, the lower
surface of the pin should touch the step
of the gauge. Alternate the gauge from
side to side while adjusting the height
of the operating yoke in increments of
1/2 turn to achieve best fit (Figure 20).
u. Remove the pin and reassemble the bell
cranks.
Figure 20 Operating Yoke Setting
v. Lubricate the pin with a liberal coat of
A-grease. Insert the pin through both
the bell cranks and the operating yoke,
and place a new X-washer in the groove
of the pin. Tighten the X-washer by
squeezing the two open ends together
with pliers. It may be necessary to
align the operating yoke and bell crank
holes to allow pin insertion. This can be
accomplished by applying a downward
force to the lower contact block just
sufficient to overcome the force of the
vacuum.
!
CAUTION
Do not force the lower contact block down
farther than required to align the pin, bell
cranks, and operating yoke as damage to
the vacuum interrupter bellows and loss of
vacuum may result.
w. Apply a light coat of B-grease to the
left and right sides of the lower contact
block and reassemble the sliding
contact finger assembly. Tighten with a
torque wrench to 8-12 lb-ft. If present,
tighten the set screw in the bottom of
the operating yoke.
x. Tighten the six previously loosened
bolts in the upper contact structure to
45 lb-ft.
y. Fully open the circuit breaker by
reversing
. Rest the opening
springs to the dimension recorded
in
breaker about 50 times to properly seat
the vacuum interrupter contact surface.
