29
5.3 Starting conditions
The erected circuit breaker is isolated from high voltage
system and earthed according to regulation. The control
current circuit is connected to the low-voltage system.
5.4 Function test
Check correspondence with the customer related
diagram and that the connections have been made
correctly. Then the trial switching can be carried out from
a protected position.
The trial switching may be performed if:
The circuit breaker is isolated from the high voltage
and earthed according to regulations.
The spring tension indicator of the spring operated
mechanism indicates the position “tensioned”.
5.5 Trial switching operations
Give few Close/Open command and see that the breaker
Close/Open Properly.
5.6 Anti-pumping device
Issue a "close" command by applying a control voltage
to terminal 101 & 102 leave the voltage applied. The
breaker will close.
Issue open command by applying a voltage to
terminal 103 & 104. The breaker will open.
After the interruption by OPEN command the
circuit breaker should not re-close in spite of
the CLOSE command still being present.
Note:
The ESH operating mechanism on VBF circuit
breaker is fitted with a mechanical anti-pumping
device, which prevents re-closing due to either
electrical or mechanical commands.
5.7 Check of heaters:
Measure the resistance or apply voltage and
measure the current, when the thermostat
controlled additional heater is installed, check
the adjustment of thermostat.
5.8 Concluding Work:
Remove all test and measuring equipment.
Connect circuit breaker to high voltage power
lines.
Make sure that safety regulations are followed.
Take the breaker in to service.
PART B Installation, Operation & Maintenance
