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39
Maintenance
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reading of the operations counter should
be recorded when the circuit breaker
is placed into service and when any
maintenance work is performed.
2) Inspection and Cleaning
When cleaning the circuit breaker insulating
supports and bus insulation, use only
denatured alcohol or isopropyl alcohol to
remove foreign material. Failure to do so may
damage the dielectric and/or the mechanical
properties of the insulation.
!
CAUTION
Visually check the circuit breaker for loose
or damaged parts. Tighten or replace
loose or missing hardware. Any damaged
parts that will interfere with the normal
operation of the circuit breaker should be
replaced. This inspection will be much
easier if the front cover and interphase
barrier assembly are removed.
Clean the circuit breaker by removing any
loose dust and dirt. Do not use compressed
air to clean the circuit breaker. This may
result in loose dirt or grit being blown
into bearings or other critical parts, thus
causing excessive wear. Use a vacuum
cleaner, or wipe with a dry lint-free cloth or
an industrial-type wiper to clean the circuit
breaker. Do not use solvents, de-greasers,
or any aerosol products to clean in the area
of any mechanisms.
Primary insulation, including the vacuum
interrupter supports and the operating
pushrods, should be cleaned. Wipe clean
with a dry lint-free cloth or an industrial
type wiper. If dirt adheres and cannot be
removed by wiping, remove it with distilled
water or a mild solvent such as denatured
alcohol. Be sure that the circuit breaker
is dry before returning it to service. Do
not use any type of detergent to wash the
surface of the insulators as detergent may
leave an electrically conducting residue on
the surface as it dries.
B. M
echAnISM
A
reA
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 damage
to the equipment or moderate/minor injury to
personnel.
!
WARNING
1) Mechanical Operation
Remove the circuit breaker front cover
to expose the stored energy mechanism.
Make a careful visual inspection of the
mechanism for loose, damaged, or
excessively worn parts.
Note:
For circuit breakers without a CBM.
If timing tests are performed as
in,
, do not
operate the circuit breaker until these
tests are completed. Operation of the
mechanism may alter the “As found”
operating condition of the circuit
breaker stored energy mechanism.
For further details, see
Ch 4 Installation, D. Placing the Circuit
.
