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39
Maintenance
IB-60201
Ch 5 Maintenance
A. G
enerAl
d
eScrIptIon
CAUTION
CAUTION
!
Prior to beginning any maintenance
procedures, make certain that the control
circuits are deenergized and the circuit
breaker is resting securely outside the circuit
breaker compartment. Do not work on a
closed circuit breaker or a circuit breaker with
the main closing spring charged.
IMPORTANT
IMPORTANT
!
Before attempting any maintenance work,
it is important to study and fully understand
the safety practices outlined in Chapter 2 of
this instruction bulletin. If there is any reason
to believe there are any discrepancies in the
descriptions contained in this instruction
bulletin, or if they are deemed to be confusing
and/or not fully understood, contact Powell
immediately.
1) Introduction
A regular maintenance schedule must
be established to obtain the best service
and reliability from the circuit breaker.
PowlVac® circuit breakers are designed to
comply with industry standards requiring
maintenance every 1000 or 2000 operations
depending upon the rating of the circuit
breaker, or once a year.
Actual inspection and maintenance will
depend upon individual application
conditions such as number of operations,
magnitude of currents switched, desired
overall system reliability, and operating
environment. Any time the circuit breaker
is known to have interrupted a fault current
at or near its rating, it is recommended
that the circuit breaker be inspected and
the necessary maintenance be performed
as soon as practical. Some atmospheric
conditions such as extremes of dust,
moisture, or corrosive gases might indicate
inspection and maintenance at more
frequent intervals. Very clean and dry
conditions combined with low switching
duty will justify longer times between
inspection and maintenance operations.
With experience, each user can set an
inspection and maintenance schedule that
is best suited for use.
If maintenance is performed at longer
time intervals than one year, the vacuum
integrity test should be performed each
time the circuit breaker is removed from
the metal-clad switchgear for reasons other
than scheduled circuit breaker maintenance
if it has been more than one year since the
last vacuum integrity test.
A permanent record of all maintenance
work should be kept, the degree of detail
depending upon the operating conditions.
The record will be a valuable reference for
subsequent maintenance work and for
station operation. It is also recommended
that the record include reports of tests
performed, the condition of circuit
breakers, and any repairs or adjustments
that were performed. This record should
begin with tests performed at the time of
installation and energization, and all data
should be graphed as a function of time to
ensure a proper maintenance cycle is being
scheduled.
