If one-phase of a 3-phase synchronous motor is short-circuited, motor
A. will refuse to start
B. will overheat in spots
C. will not come upto speed
D. will fail to pull into step
Answer: Option A
A. will refuse to start
B. will overheat in spots
C. will not come upto speed
D. will fail to pull into step
Answer: Option A
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
why...please explain...