In order to protect the motor, when selecting the circuit breaker, two characteristics of the circuit breaker-specific series motor should be taken into consideration: one has a certain overload capacity; the other is that the starting current is usually several times the rated current. It can even be up to ten times when reversible or reverse braking.
Under normal circumstances, in order to ensure the smooth start and operation of the circuit breaker-specific series of motors, the basic principles to be followed when selecting the circuit breaker are as follows: 1. Determine the long-delay action current setting value of the circuit breaker according to the rated current of the motor. 2, the circuit breaker's 6 times long delay action current setting value can be longer than the actual starting time of the motor; 3, should also ensure that the circuit breaker's instantaneous operating current setting value is within a reasonable range.
In addition, considering the requirements of long-distance control, if it is a circuit breaker-specific series motor that needs to be repeatedly started many times, and the probability of phase-breaking operation is not high or a phase-failure protection device is used, it can be combined with a magnetic starter through a fuse. The way to control and protect is also appropriate.