A. it runs at a slower speed
B. the motor stops
C. it continues to run at the same speed
D. it runs at a very high speed
Related Mcqs:
- If the field winding of an unloaded salient pole synchronous motor is open circuited, the motor will__________?
A. stop
B. run as induction motor
C. function as static condenser
D. burn with dense smoke - When the excitation of an unloaded salient pole synchronous motor suddenly gets disconnected______________?
A. the motor stops
B. it runs as a reluctance motor at the same speed
C. it runs as a reluctance motor at a lower speed
D. none of the above - A synchronous motor installed at the receiving end substation operates with such an excitation that it takes power at lagging power factor. Now if the applied voltage of the synchronous motor goes down, the power factor of the synchronous motor will___________?
A. remain same
B. go down
C. improve
D. none of the above - In case one phase of a three-phase synchronous motor is short-circuited the motor will____________?
A. not start
B. run at 2/3 of synchronous speed
C. run with excessive vibrations
D. take less than the rated load - If one-phase of a 3-phase synchronous motor is short-circuited, motor will ______________?
A. will refuse to start
B. will overheat in spots
C. will not come upto speed
D. will fail to pull into step - While starting a salient pole synchronous motor by induction motor action and connecting field discharge resistance across field, starting and accelerating 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 - While starting a synchronous motor by induction motor action, field winding is usually_____________?
A. connected to D.C. supply
B. short-circuited by low resistance
C. kept open-circuited
D. none of the above - A synchronous motor can be used as a synchronous capacitor when it is____________?
A. under-loaded
B. over-loaded
C. under-excited
D. over-excited - A synchronous motor can develop synchronous torque:
A. when under loaded
B. while over-excited
C. only at synchronous speed
D. below or above synchronous speed - When a 3-phase synchronous generator is supplying a zero power factor lagging load, the armature field affects the main field in the following way
A. augments it directly
B. directly opposes it
C. cross-magnetises it
D. none of the above
