A vacuum circuit breaker needs less maintenance and no inflammable substance that support fire compared with that of oil in the OCB. Table below is the types of maintenance needed for a VCB.
No
Classification
Check point
Interval
Method of inspection
1
General
Cleaning for every component
3
Clean the circuit breaker to remove dust and dirt. The envelope of the vacuum interrupter and insulating materials should be wiped with a clean cloth
2
Vacuum
Contact wear
5
every 5000 switching of load current
Check the contact for wear. Replace if the contact piece has worn out
Judgement of vacuum
5
Withstand test at 22kV a.c for one minute
3
Operating mechanism
Lubrication of each component
5
Apply a small amount of oil to rotary sections, sliding surfaces, pins, coupling section, etc. use grease for the operating shaft and bearings, and machine oil for other parts
Coupling section
5
Check for rust and wear
Springs
5
Visual check for rust and deformation
Clamping section
5
Check for loosened bolts and nuts, broken spring washers and snap pins, their coming off, etc
Control circuit
3
Check for loosened connections, rust, damaged lead wires
Control switches
3
Check whether the contacts are damaged by arcing
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