GE AKR-30 Series Maintenance Manual page 229

1 0.4 TROUBLESHOOTI N G
When malfunctioning i s suspected t h e fi rst step i n
troubleshooti n g i s t o exam i ne the c i rc u i t breaker and its
power system for abnormal conditions such as:
a) Breaker tripping i n proper response to overcu rrents
or i nc i pient ground fau lts.
b) Breaker remai n i ng in a tri p-free state due to
mechanical i nterference along i ts trip shaft.
c) Inadvertent shunt trip activations.
WARN I NG:
DO N O T CHA NGE TA PS ON THE
CURRENT SENSORS OR A DJUST THE PRO­
GRAMMER UNIT SET KNOBS WHILE THE
BREAKER IS CA RR YING CURRENT.
Once it has been estab l i shed that the c i rc u i t breaker
can be operated and c losed normally from the test posi­
tion, attention can be d i rected to the trip device proper.
Testi n g is performed by either of two methods.
1 . Cond u ct h i g h-c u rrent, sing le-phase tests on the
breaker using a h i g h c u rrent-low voltage test set.
NOTE:
For these single-phase tests; special con­
nections m ust be .. employed for SST breakers
equipped with Ground Fault. Any s ingle-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
71.
in Fig. This special test cable energizes all the
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 com ponents to the SST system u s i ng por­
table Test Set Type TAK-TS1 (Fig. 67) or TA K-TS2.
The applicable test proced u res are detai led in i n­
struction Book G EK-64454 and are summarized i n Sec­
tion 1 0.4. 1 .
The TAK-TS1 and TAK-TS2 Test Sets are portable i n­
struments desig ned for field checking the t i me-cu rrent
characteristics and pickup cali brat ion of the SST's
various trip e lements.
Fl ux-Sh ift Trip Device to trip the breaker and, i n addi­
tion, incl udes means for. cont i n u ity checking the phase
sensors. A TAK-TS1 Test Set is shown in Fig. 67.
The t i m e-cu rrent characteristics for the SST Tri p
Device are g iven i n cu rves G ES-6033, G ES-6034 and
G ES-6035.
It can verify the abi l ity of the
5 1