The biggest difference between synchronous motor and asynchronous motor is whether their rotor speed and stator rotating magnetic field are the same. If the rotor speed and stator rotating magnetic field are the same, it is called synchronous motor, otherwise, it is called asynchronous motor. Zusätzlich, the stator windings of synchronous motor and asynchronous motor are the same, the difference lies in the rotor structure of the motor. The rotor of asynchronous motor is a short circuit winding, which generates current by electromagnetic induction. The rotor structure of synchronous motor is relatively complex, with DC excitation winding, so it needs external excitation power supply to introduce current through slip ring; deshalb, the structure of synchronous motor is relatively complex, and the cost and maintenance cost are relatively high.
