The permanent magnet synchronous motor has a configuration almost identical to the conventional synchronous machine with the absence of _______________.

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Question

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SSC JE Electrical 11 Oct 2023 Shift 3 Official Paper-I

Answer 1

The correct answer is option 2.

Permanent magnet synchronous motor

This type of motor operates at synchronous speed, which is constant and it is synchronous with the supply frequency and the period of rotation is equal to the integral no. of AC cycles. That means the speed of the motor is equal to the rotating magnetic field.
A permanent magnet synchronous motor is also called as brushless permanent magnet sine wave motor.
Permanent magnet synchronous machines generally have the same operating and performance characteristics as synchronous machines.
A permanent magnet machine can have the configuration almost identical to that of the conventional synchronous machine with the absence of slip rings and a field winding, but a permanent magnet is used as a rotor to create a magnetic field. Hence there is no need to wound field winding on the rotor.
Instead of using winding for the rotor, permanent magnets are mounted to create a rotating magnetic field. As there is no supply of DC source, these types of motors are very simple and less costly. It contains a stator with 3 windings installed on it and a rotor with a permanent magnet mounted to create field poles. The 3-phase input AC supply is given to the stator to start working.
This type of motor is mainly used in power systems to improve the power factor.