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51
Maintenance
01.4IB.65131
D. o
ptIonAl
M
AIntenAnce
p
roceDureS
1) High Potential Tests
High potential tests are not required for
routine maintenance but are recommended
after a heavy fault interruption, any major
circuit breaker repair that involves the
primary current path or when the circuit
breaker has been in storage for an extended
time, especially in a damp location or other
adverse environment. In these cases, both
the High Voltage Insulation Integrity and
Control Voltage Insulation Integrity tests
should be performed. Refer to
Ch 4 Installation, D. Placing the Circuit
, for details of these
procedures.
2) Timing
At normal control voltage, operate the
test source to the “close” position to close
the circuit breaker and record the closing
time. The closing time from energizing the
closing coil to vacuum interrupter contact
touch should not exceed the values in
. Again, at normal control
voltage, 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 in the timing table.
Table C Timing
Cycles
Closing Time
(ms)
Tripping Time
(ms)
3
<80
<35
3) Primary Resistance Check
This 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 resistance, pass a minimum
of 100A DC through the circuit breaker
pole, with the circuit breaker closed. The
100 ampere reading should not exceed the
values given in
when connected to the primary studs on
the breaker side of the disconnect fingers.
Do not connect directly to the disconnect
fingers as errors may occur due to finger
spring pressure. The resistance should
not exceed the values provided in this
instruction bulletin for the specific type
and rating of the circuit breaker being
measured.
The micro-ohm values of resistance must
not exceed the following limits:
Table D Primary Resistance
Breaker Type
Rated
(kV)
Rated
Continuous
Current A
Resistance
Micro-ohms
38PV40ARMM-4
38
3000
90
38PV40ARMX-4
38
3000
90
38PV40ARMS-4
38
3000
90
