A synchronous motor can be made self starting by providing
A. Damper winding on rotor poles
B. Damper winding on stator
C. Damper winding on stator as well as rotor poles
D. None of the above
Answer: Option A
Solution(By Examveda Team)
To make a synchronous motor self-starting, a damper winding on the rotor poles is provided.The damper winding consists of bars embedded in the rotor poles and short-circuited at both ends. When the motor is started, the relative motion between the rotating magnetic field of the stator and the rotor induces currents in the damper winding. These currents produce a magnetic field that interacts with the stator's magnetic field, generating torque and assisting in the motor's starting process.
Hence, option A is the correct choice.
This Question Belongs to Electrical Engineering >> Synchronous Motors
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Comments ( 4 )
The maximum power developed in a synchronous motor occurs at a coupling angle of
A. 30°
B. 60°
C. 90°
D. 180°
A. remains same as the original value
B. decreases to half the original value
C. tends to becomes zero
D. increases to two times the original value
The speed of a synchronous motor
A. increases as the load increases
B. decreases as the load decreases
C. always remains constant
D. none of the above
In which of the following motors the stator and rotor magnetic field rotate at the same speed ?
A. Universal motor
B. Synchronous motor
C. Induction motor
D. Reluctance motor
The synchronous motor is made self-starting by providing a special winding on the rotor poles, known as damper winding or squirrel cage winding.
Correct: A
Detailed Solution
Option: A
The synchronous motor is made self-starting by providing a special winding on the rotor poles, known as damper winding or squirrel cage winding. AC supply given to the stator produces a rotating magnetic field which causes the rotor to rotate. Therefore, in the beginning synchronous motor provided with damper winding starts as a squirrel cage induction motor. The exciter moves along the rotor. When the motor attains about 95%of synchronous speed, the rotor winding is connected to exciter terminals and the rotor is magnetically locked by the rotating field of the stator and the motor runs as a synchronous motor.
Damper winding in rotor perifery just as sq induction motor for initial start
Ans- c