Troubleshooting - GE AKR-30 Series Maintenance Manual

1 0.4

TROUBLESHOOTING

W h e n malfu nction ing i s suspected t h e fi rst step i n
troubleshoot ing is to exam i ne t h e c i rc u it breaker a n d its
power system for abnormal cond itions such as:
a) Breaker tripping in proper response to overc u rrents
or inci pient ground fau l ts.
b) Breaker remai n i n g in a tri p-free state due to
mechanical interference along its trip shaft.
c) I n advertent shunt trip act ivat ions.
WARN ING:
DO N O T CHA N G E TA PS ON THE
CURRENT SENSORS OR A DJUST THE PRO­
GRAMMER UNIT SET KNOBS WHILE THE
BREA KER IS CA R R YING CURRENT.
Once it has been establi shed that the c i rcuit breaker
can be operated and closed normally from the test pos i­
tion, attention can be di rected to the trip device proper.
Testing is performed by either of two methods.
1 . Conduct h i g h-cu rrent, sing le-phase tests on the
breaker u s i ng a high cu rrent-low voltage test set.
NOTE:
For these single-phase tes ts; special con­
nections m us t be, employed for SST breakers
equipped with Ground Fault. Any single-phase in­
put to the ground differential transformer will
generate an unwanted
signal which will trip the breaker.
nullified either by
a) testing two poles of the breaker in series, or
FIG. 67 - SST/ECS TEST S ET, CAT. NO. TAK-TS1
"ground fault" output
This can be
b) using the Ground Fault Defeat Cable as shown
in Fig. 71. This special test cable energizes all the
primary windings of the differen tial 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 appl icable test proced u res are detai led in i n­
struction Book G EK-64454 and are summarized in Sec­
tion 1 0.4. 1 .
The TAK-TS1 and TAK-TS2 Test Sets are portable i n­
struments designed for field checking the ti me-cu rrent
characteristics and pickup cali brat ion of the SST's
various trip e lements.
Fl ux-Shift Tri p Device to trip the breaker and, i n add i­
tion, i n c l udes means for. continu ity checking the phase
sensors. A TA K-TS1 Test Set is shown i n Fig. 67.
The time-cu rrent characteristics for the SST Tri p
Device are g iven i n c u rves G ES-6033, G ES-6034 and
G ES-6035.
It can verify the abil ity of the
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