1 0.4
TROUBLESHOOTING
When malfunctioning i s suspected t h e fi rst step i n
troubleshooting i s t o exami ne the c i rcuit breaker and its
power system for abnormal conditions such as:
a) Breaker tripping i n proper response to overcurrents
or i nci pient ground fau lts.
b) Breaker remai n i ng in a tri p-free state due to
mechanical i nterference along its trip shaft.
c) Inadvertent shunt trip activations.
WARNING:
DO NOT 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 establ i shed that the c i rcuit breaker
can be operated and closed 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 . Conduct high-current, single-phase tests on the
breaker using a high current-low voltage test set.
NOTE:
For these single-phase tests; special con
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. This can be
nullified either by
a) testing two poles of the breaker in series, or
b) using the Ground Fault Defeat Cable as shown
in Fig.
71.
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 using por
table Test Set Type TAK-TS1 (Fig. 67) or TAK-TS2.
The applicable test proced ures 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 designed for field checking the t ime-cu rrent
characteristics and pickup calibration of the SST's
various trip elements. It can verify the abi l ity of the
Fl ux-Shift Trip Device to trip the breaker and, i n addi
tion, incl udes means for. conti n u ity checking the phase
sensors. A TAK-TS1 Test Set is shown in Fig. 67.
The time-current characteristics for the SST Tri p
Device are g iven i n cu rves G ES-6033, G ES-6034 and
G ES-6035.
FIG. 67 - SST/ECS TEST SET, CAT. NO. TAK-TS1
5 1
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