Low-voltage high-power AC motor soft start system

The utility model provides a soft start system for a low-voltage high-power alternating-current motor. The soft start system comprises a circuit breaker, a frequency converter, a main contactor and a programmable controller, an inlet wire of the circuit breaker is connected with a power supply of the motor; the frequency converter and the main contactor are arranged in parallel, an incoming line of the frequency converter and an incoming line of the main contactor are connected with an outgoing line of the circuit breaker, and an outgoing line of the frequency converter and an outgoing line of the main contactor are connected with an incoming line of the motor; wherein the wire inlet end and the wire outlet end of the frequency converter are provided with a first contactor and a second contactor respectively, the first contactor, the frequency converter and the second contactor are connected in series, and the power of the frequency converter is smaller than that of the motor; the programmable controller is e