The common squirrel cage asynchronous motor has many advantages, but its direct larger starting current, the starting torque is not large. Using the method of step-down start to reduce the starting current, but also significantly reduce the starting torque. In order to improve the performance of the starting motor, can begin from the rotor slot, using the "skin effect", the rotor resistance increases when starting, in order to increase the starting torque and reduce the starting current, during normal operation of the rotor resistance and can automatically reduce, rotor copper loss is not big, does not affect the efficiency of the runtime. Starting performance of the rotor with deep groove type and double squirrel cage asynchronous motor to improve.