While starting a salient pole synchronous motor by induction motor action and connecting field discharge resistance across field, starting and accelerting torque is produced by
A. induction motor torque in field winding
B. induction motor torque in damper winding
C. eddy current and hysteresis torque in pole faces
D. reHetance motor torque due to saliency of the rotor
E. all of the above methods
Answer: Option E
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
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