Troubleshooting - GE AKR-4-30 Maintenance Manual Supplement

BREAKER­
MOUNTED
Fig. 20. Neutral sensor secondary disconnect
blocks
EQUIPMENT·
MOUNTED
Power Circuit Breakers, GEI-86134

TROUBLESHOOTING

When malfunctioning is suspected, the first step
in troubleshooting is to examine the circuit breaker
and its power system for abnormal conditions such
as:
)
a Breaker tripping in proper response to over­
currents or incipient ground faults.
)
b Breaker remaining in a trip-free state due to
mechanical interference along its trip shaft.
)
c Inadvertent shunt trip activations.
WARNING:
DO NOT CHANGE TAPS ON
THE CURREN T SENSORS OR
THE PROGRAMMER UNIT SET KNOBS
WHILE THE BREAKER IS CARRYING
CURRENT.
Once it has been established that the circuit
breaker can be opened and closed normally from the
test position, attention can be directed
device proper. Testing is performed by either of
two methods:
1. Conduct high-current, single-phase tests on
the breaker using a high current-low voltage test
set.
NOTE :
For these single- phase tests, spe­
cial connections must be em ployed/or SST
breakers equipped with Ground Fault. Any
single- phase input to the ground differential
transformer will generate an unwanted
''ground fault" output signal which will trip
the breaker. This can be nullified either
by
or
(a) testing two poles of the breaker in
series,
(b) Using the Ground Fault Defeat Cable
as shown in Fig. 28.
test cable energizes all the primary
windings of
former in a self-cancelling, series­
parallel connection so that its second­
ary output is always zero.
2. Test the components of the SST system using
portable Test Set Type TAK-TSI
applicable test procedures are detailed in Instruc­
tion Book GEK-64454 and are summarized on the
next page.
ADJUST
the trip
to
This special
the differential trans­
(
Fig. 21). The
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