Why does the motor trip after soft starter start?

- Jul 17, 2019-

If it is a trip at start-up, first look at what the soft start reported fault, if the circuit breaker jumps, the estimated start-up current is large. If the trip is in operation, the estimate is the protective action, first confirm the motor load, is not overloaded or cut off phase.


1: Reason for circuit breaker tripping when soft starting motor This tripping situation, which occurs mostly at start-up and stop, should carefully recall whether it jumps just as soon as you start or stop, or whether you jump after starting or stopping for a few seconds.

1: a start or stop jump, should check the motor side of the short circuit, mechanism stuck or blocking.

2: start or stop in the process of tripping, the current is too large or too long, has reached the circuit breaker tripping set curve.


2: Solution of circuit breaker tripping when soft start-up motor

1: readjust the set value of the circuit breaker, so that the tripping curve is greater than the start-up current curve.

2: adjust the limit ingress of soft start multiple, so that the current in the specified range.

3: Reduce the start or stop time.


Summarize: The above is the soft start motor when the circuit breaker tripping reason and solution, under the general situation, will not appear, only the load is particularly heavy when the tripping phenomenon may occur, ABB soft start for example, the default start time is 10S, this time can be applied in almost 90% of the occasion. And the pump can be said to be 99% no problem.