GE AKR-30 Series Maintenance Manual page 51

1 0.4 TROU BLESHOOTING
When malfunctioning is suspected the first step in
troubleshooti ng is to examine the circuit breaker and its
power system for abnormal conditions such as:
a) Breaker tripping in proper response to overcurrents
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.
DO NOT CHANGE TAPS ON THE
WARNING:
CURRENT SENSORS OR A DJUST THE PRO­
GRA MMER UNIT SET KNOBS WHILE THE
BREA KER IS CARRYING CURRENT.
Once it has been established that the circuit breaker
can be operated and closed normally from the test posi­
tion, attention can be directed to the trip 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.
For these single-phase tests, special con­
N OTE:
nections must be employed for SST breakers
equipped with Ground Fault. Any single-phase in­
put to the ground differential transformer will
generate an unwanted "ground fault" output
signal which will trip the breaker.
nullified either by
a) testing two poles of the breaker in series, or
FIG. 67 - SST/ECS TEST SET, CAT. NO. TAK-TS1
b) using the Ground Fault Defeat Cable as shown
in Fig.
primary windings of the differential transformer in
a self-cancelling, series-parallel connection so
tha t its secondary output is always zero.
2. Test the components to the SST system using por­
table Test Set Type TAK-TS1 (Fig. 67) or TAK-TS2.
The applicable test procedures are detailed i n i n­
struction Book GEK-644 54 and are summarized in Sec­
tion 1 0.4.1 .
The TAK-TS1 and TAK-TS2 Test Sets are portable in­
struments designed for field checking the time-current
characteristics and pickup cal ibration of the SST's
various trip elements.
Flux-Shift Trip Device to trip the breaker and, in addi­
tion, includes means for. continuity checking the phase
sensors. A TAK-TS1 Test Set Is shown in Fig. 67.
The time-current characteristics for the SST Trip
Device are given in curves G ES-6033, G ES-6034 and
GES-6035.
This can be
71.
This special test cable energizes a ll the
It can verify the ability of the
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