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51
Maintenance
01.4IB.77020
4) Slow Closing of Mechanism
The slow closing of mechanism described
is not required for routine maintenance;
however, it may be a useful procedure
for troubleshooting circuit breaker
misoperation.
For slow closing of mechanism, perform the
following steps:
1. With the main closing spring assembly
removed, rotate the camshaft so that
the crank arms are pointing upward.
The fundamental linkage will now move
into the reset position.
2. Push the manual close operator inward
and hold it in while operating the
manual charging handle to rotate the
camshaft.
3. When the close release latch arm is past
the close shaft latch plate, the manual
close operator may be released. As the
main closing cam engages the main
cam roller, the jackshaft will commence
to rotate.
4. Continue to operate the charging
handle until the crank arms point
downward. The circuit breaker will
now be closed and there will be a gap
between the operating pushrod lock
nuts and the contact spring yokes.
5. Return the circuit breaker to the open
position by depressing the manual trip
operator.
6. To install the main closing spring
assembly reverse the steps in
Ch 5 Maintenance, B. Mechanism Area,
.
Note:
Even though the mechanism was
“slow closed”, when it is opened, it will
operate at full speed, keep all fingers
and toes out of the way, etc.
5) Mechanism Adjustments
Several factory adjustments in the
stored energy mechanism are described
below.
NO ADJUSTMENT OF THESE
SETTINGS IS REQUIRED FOR ROUTINE
MAINTENANCE
, but they may need to be
adjusted after a major overhaul or removal
of the mechanism.
Do NOT adjust these settings unnecessarily as
damage to the circuit breaker may occur.
CAUTION
a. Adjustment of Ratchet Wheel Holding
Pawl
The holding pawl support arm is
adjusted by the holding pawl adjusting
eccentric
If the pawl is not properly adjusted,
there will be a “knocking” noise when
the ratchet mechanism is operating or
the stored energy mechanism will not
ratchet at all.
To adjust the pawl perform the
following steps:
1. Remove the escutcheon to gain
access to the head of the bolt
holding the adjusting eccentric.
2. Loosen the bolt slightly.
3. Grip the eccentric with a pair of
slip-joint pliers or a similar tool and
rotate the stop slightly.
4. Tighten the holding bolt with the
eccentric in the new position.
5. While charging the main closing
springs, using the charging motor
to drive the mechanism, observe
the ratcheting operation for
improvement.