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40
Maintenance
PowlVac® DHP 15kV Replacement Circuit Breaker
01.4IB.50032C
g. With a slight rocking motion of
the main closing spring assembly,
connecting rods (Figure 12, e) can now
be unhooked from the spring yoke pins
and the main closing spring assembly
can be removed.
Note:
Care should be taken on reassembly
to ensure correct location of the flat
washer, lock washer, and spacer
(Figure 13).
!
WARNING
When any maintenance procedure requires
the opening or closing of the circuit breaker
or the charging of any of the stored energy
mechanism springs, exercise extreme caution
to make sure that all personnel, tools, and
other miscellaneous objects are kept well
clear of the moving parts or the charged
springs. Failure to do this may cause serious
damage or injury to the circuit breaker or
personnel.
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.
a. With the main closing spring assembly
removed, rotate the camshaft so that
the crank arms are pointing downward.
The fundamental linkage will now move
into the reset position.
b. Push the manual close operator inward
and hold it in while operating the
charging handle to rotate the camshaft.
c. When the close release latch arm has
passed 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.
d. Continue to operate the charging
handle until the crank arms point
upward. The circuit breaker will now be
closed and there will be a gap between
the operating pushrod lock nuts and
the contact spring yokes.
e. Return the circuit breaker to the open
position by depressing the manual trip
operator.
f. To install the main closing spring
assembly reverse the preceding removal
procedure.
5) Mechanism Adjustments
Several factory adjustments in the stored
energy mechanism are described in this
section.
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.
Note:
Do NOT adjust these settings
unnecessarily, as damage to the
circuit breaker may occur.
a. Adjustment of Ratchet Wheel Holding
Pawl
The holding pawl support arm
(Figure 3, l) is adjusted by the holding
pawl adjusting eccentric (Figure 3, n).
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.