Determining the causes of circuit breaker refusal and handling methods

Refusal to close occurs basically during the closing operation and reclosing process. This kind of fault is more hazardous.

For example, in the case of an accident requiring emergency input of backup power, if the backup power circuit breaker refuses to close, it will expand the accident. Determine the cause of the circuit breaker refuses to close and processing methods can generally be divided into three steps.

(1) check whether the previous refusal to close caused by improper operation (such as the control switch to let go too fast, etc.), with the control switch and close again.

(2) If the closure is still unsuccessful, check the electrical circuit parts to determine whether there is a fault in the electrical circuit. Check items are: whether the closing control power supply is normal. Close the control circuit fuse and close the circuit fuse is good. The contact of the closing contactor is normal. Control switch to the closing position, see whether the closing iron core action is normal.

(3) If the electrical circuit is normal, the circuit breaker still can not close, it means that the mechanical aspects of the failure, the circuit breaker should be disabled, report to the dispatch arrangements for maintenance treatment.