1VAL050503-MB Rev B Replaces (1VAL057485-MB Rev. C) Oct 2013
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Stored energy operating mechanism
Carry out the functional test of the operating mechanism after 5,000operations (2,000 operations for 3000 A circuit-
breakers) or during ordinary maintenance operations Before doing the test, open the circuit-breaker and carry out the
following operations
In the case of with-drawable circuit-breakers, take the circuit breaker to the isolated area for test
In the case of fixed circuit-breakers: cut off the power supply to the medium voltage circuit and follow proper lock-out tag
out procedures as specified by the facility.
Functional test
With the circuit-breaker not connected to the load, carry out a few opening and closing operations.
Remove the breaker from the cell or rack breaker out to the disconnected position to cut the power supply to the spring
charging motor.
Discharge the spring by closing and opening the circuit-breaker by means of the closing and opening pushbuttons
Visually inspect the lubrication conditions of the tulip isolating contacts, of the sliding surfaces, etc.
Check correct electrical and mechanical operation of the various devices, with particular attention to the interlocks.
The screws and nuts are tightened in the factory and correct tightening is marked with a collared sign. No further tighten-
ing operations are foreseen during the operating life of the circuit breaker.
However, following any maintenance interventions, should it be necessary to retighten the screws follow torque valus on
following page
Check the main actuator lever roller bearing lubrication detail
A
below, it is advisable to lubricate with a few drops of
SAE 80W/90 type oil, using a special oiler.
MAINTENANCE