According to the situation of use, there are 3 types of circuit breakers used as motor protection:
1. AC contactor is used for starting and breaking of the motor, and thermal relay is used for overload protection (in addition to overload protection, thermal relay also has the return characteristic of avoiding the starting current of the motor, which also belongs to the overload range) , And the circuit breaker protection is used for short circuit protection, because the contactor is used to divide and close the circuit, so it can be operated more frequently
2. Use the contactor to start and stop the motor, and the faults such as overload, short circuit and undervoltage of the motor will be borne by the circuit breaker
3. The motor is operated and protected by a circuit breaker during starting, breaking, overload, short circuit, and under voltage, but it cannot be used frequently