Synchronous Motor- Advantages, disadvantages and applications

Synchronous Motor- Advantages, disadvantages and applications

Advantages:

1.     Its power factor can be controlled by the control of field current.

2.     In certain applications, the fact that its speed is independent of load and applied voltage, may be important.

3.     It’s efficiency is slightly higher than that of induction motor.

4.     For low speeds and high rating, ( above 500 kW) a synchronous motor is cheaper than induction motor

Disadvantages:

1.     The need of dc source for excitation (usually a an exciter is mounted on the shaft to provide the excitation)

2.     Need of starting and synchronizing

3.     Instability

4.     Hunting

5.     Need of expensive control devices

In view of the above advantages, and  disadvantages, the synchronous motors are used only for low speed, high up speed, high hp requirements.

Applications:

1.     Large low head pumps

2.     Rubber mills and mixers

3.     Crushers

4.     Paper mill drives

5.     Compressors

6.     Rolling mills

7.     Ball mills etc

8.     Synchronous motor can also be used as a phase modifier for voltage regulation of transmission lines.