What are the Types of a Synchronous Motor?

Synchronous motors are considered the most efficient AC motors. At a steady-state, the rotation of the shaft of Synchronous AC motors is synchronized with the rate of the supplied current. The rotation period here is exactly the same as an integral number of AC cycles. The following are the two main types of Synchronous motors.

Direct Current (DC) Excited Synchronous Motors

The Direct Current (DC) Excited Synchronous Motor needs DC supply to the rotor to produce a magnetic field. This type has both rotor winding and stator winding. This current could even be supplied from a distinct DC source or from a DC generator associated with the motor shaft.

Non-Excited Synchronous Motors

In Non-Excited Synchronous Motors, the rotor is made of steel. It is made of high-retentivity steel. It revolves with the revolving magnetic field of the stator at synchronous speed, which means it has a constant magnetic field. This type of Synchronous Motor is accessible in three different designs which are the following.

1. Hysteresis motors are sole phase motors in which the rotor is fabricated of ferromagnetic material. The hysteresis motors are self-starting and do not require any extra winding.

2. Reluctance is always the least when a piece of iron revolves to finish a magnetic flux path. The reluctance boosts with the angle between them when the poles are ranged with the magnetic field of the stator. This will produce a torque that pulls the rotor into alignment with the pole near the stator field.

3. A permanent Magnet Motor or the pmsm motor control system (as the name indicates) uses permanent magnets in the steel rotor to produce a constant magnetic flux. As soon as the speed reaches near synchronous speed, the rotor locks.