When a synchronous motor is running at synchronous ___

Electrical Engineering MCQ Electrical Machines MCQ
1

When a synchronous motor is running at synchronous speed, the damper winding produces

A. no torque.
B. damping torque.
C. eddy current torque.
D. torque aiding the developed torque.

Show Answer

Answer: D

Share your understanding of this question with the correct explanation.

2

The answer is D. torque aiding the developed torque.

The damper winding in a synchronous motor is a short-circuited winding that is placed on the rotor. When the motor is running at synchronous speed, the damper winding produces a torque that aids the developed torque. This helps to keep the motor running smoothly and prevents it from stalling.

The damper winding is not used when the motor is starting up. When the motor is starting up, the rotor is not rotating at synchronous speed. In this case, the stator field creates a rotating magnetic field that induces a current in the damper winding. This current creates a torque that causes the rotor to start rotating.

Once the rotor reaches synchronous speed, the stator field and the damper winding are aligned. In this case, the damper winding does not create any torque. However, it is still there to help prevent the motor from stalling.

Here are some additional details about damper windings:

  • They are short-circuited windings that are placed on the rotor of a synchronous motor.
  • They produce a torque that aids the developed torque when the motor is running at synchronous speed.
  • They are not used when the motor is starting up.
  • They help to prevent the motor from stalling.

Damper windings are an important part of synchronous motors. They help to keep the motor running smoothly and prevent it from stalling.