The Synchronous Motor is an AC motor in which, at steady state, the rotation of the shaft is synchronized with the frequency of the supply current; the rotation period is exactly equal to an integral number of AC cycles. The motor is that which runs at a constant speed i.e., synchronous speed. The speed depends upon the supply frequency and number of poles. The rotor of this type of motor is a wound rotor, which receives the excitation (magnetizing) current from its excitation system (a separate direct current source with controller). The Synchronous Motor is made for use in the industrial applications.