The inverter is used for operation, and the frequency and voltage are correspondingly increased with the acceleration of the motor, and the starting current is limited to below 150% of the rated current (125%~200% depending on the model). When starting directly with industrial frequency power supply, the starting current is 6 to 7 times, so there will be mechanical and electrical shocks. Using the inverter drive can start smoothly (starting time becomes longer). The starting current is 1.2~1.5 times of the rated current, and the starting torque is 70%~120% of the rated torque; for the inverter with automatic torque enhancement function, the starting torque is more than 100%, and it can start with full load .