TAVRIDA ELECTRIC VCB Series, User Manual, Page: 103 / 142

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7.2 Secondary circuits
The CM is inherently maintenance free. However when maintenance is carried out on the switchgear then
commissioning tests should be repeated. It is also recommended to conduct regular visual checks of the
module housing and insulation of the wires connected to the CM. Test results should be treated as given in
the Table 19.
Table 19 - List of tests and check-ups of CM during maintenance
Operation description Required tool Approximate timing
Auxiliary circuits insulation check
Connect all points of the secondary circuits
with a shorting wire. ISM coil connection
wires must be disconnected from connector
X3 of the CM before the test.
Wires 5 minutes
Connect the shorting wire to the high
potential lead of the high voltage tester and
ground the circuit breaker housing. Start
with zero volts, gradually increase the test
voltage to 1500 V RMS, 50 or 60 Hz.
Maintain test voltage for one minute.
Power frequency withstand voltage test set 3 minutes
If no disruptive discharge occurs, the
secondary circuits insulation level is
satisfactory.
Power frequency withstand voltage test set -
Disconnect the shorting wire and reattach
the wires to connector X3 of the CM.
Visual check, no tool is required 5 minutes