Friday, February 6, 2009

Frequency of inspection of breaker

Contact assemblies need to be changed according their condition but at least after

10,000 operation for SIZE 1 & SIZE 2

5000 operation for SIZE 3

1000 operation for SIZE 2 & SIZE3 when used in1000V appliances

(Note: To calculate number of operation of circuit breaker you can use mechanical counter available as a option with circuit breaker)

Switchgear operator has to determine the inspection intervals depending on the breaker application condition but at least

• One time per annum

• After interruption of heavy loads

• After trips by over current release(Electronic trip unit)

Down stream connected non automatic circuit breaker have to be inspected also after 1000 switching operation, an inspection has to be comprise

• Arc chutes & contact system

• Mechanical functionality

• Main & auxiliary circuit, function & connecting quality

• Plausibility control of trip unit setting& correction, if necessary

Draw out guide frame with arc chute covers installed; have to be replaced after no more than three short circuit interruption of circuit breaker

Arc chutes& contact system must be replaced depending upon their condition, but latest after 10000 switching operation

Depending upon the circuit breaker stress it may also be necessary to replace the operating system after 10000switching operation

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