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46
PowlVac® ASD 27kV & 38kV Vacuum Circuit Breaker
IB-65100
Maintenance
2)
Timing
Perform CLOSE
and OPEN
timing tests at
the nominal control voltage. The voltage is
printed on the circuit breaker nameplate.
To measure CLOSE
timing, operate the test
source to the CLOSE
position. When the
circuit breaker closes, record the closing
time. The closing time from energizing the
closing coil to vacuum interrupter contact
touch should not exceed the values in
Table C, Timing
.
Table C Timing
Cycles
Closing Time
(ms)
Tripping Time
(ms)
3
< 80
< 35
5
< 80
< 55
To measure OPEN
timing, operate the test
source to the OPEN
position. When the
circuit breaker opens, record the closing
time. Operate the test source to the OPEN
position to open the circuit breaker and
record the opening time. The opening
time from energizing the shunt trip coil to
vacuum interrupter contact part should not
exceed the values listed in
Table C, Timing
.
3) Primary Resistance Check
The primary resistance check is not
required for routine maintenance but
it is recommended after any major
maintenance that requires disassembly of
any part of the primary current path.
To check the primary resistance, pass a
minimum of 100A DC through the circuit
breaker pole, with the circuit breaker
closed. Measure the voltage drop across
the primary contacts and calculate
the resistance. The resistance should
not exceed the values provided in this
instruction bulletin for the specific type
and rating of the circuit breaker being
measured.
Connect the current source leads to the
upper and lower primary disconnecting
devices of the circuit breaker.
The micro-ohm values of resistance must
not exceed the limits in
Table D, Primary
Resistance
.
Table D Primary Resistance
Breaker
Type
Rated
(kV)
Continuous
Current
(Amperes)
Resistance
(Micro-ohms)
38PV40ASD
38
1200
46
38PV40ASD
38
2000
36
27PV25ASD
27
1200
40
27PV25ASD
27
2000
36
