Related Mcqs:

1. 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

2. When the rotor speed, in a synchronous machine, becomes more than the synchronous speed during hunting, the damper bars develop_________________?

   A. inductor motor torque
   B. induction generator torque
   C. synchronous motor torque
   D. d.c. motor toque
   E. none of the above

3. 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

4. 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

5. Armature of a synchronous machine is____________?

   A. of reducing number of slip rings on the rotor
   B. armature is associated with large power as compared to the field circuits
   C. of difficulty of providing high voltage insulation on rotor
   D. all of the above reasons

6. Synchronsizing power of a synchronous machine is_____________?

   A. direcly proportional to the synchronous reactance
   B. inversely proportional to the synchronous reactance
   A. equal to the synchronous reactance
   D. none of the above

7. A synchronous machine with large air gap has______________?

   A. a higher value of stability limit
   B. a small value of inherent regulation
   C. a higher synchronizing power which makes the machine less sensitive to load variations
   D. all of the above

8. Stability of a synchronous machine:

   A. decreases with increase in its excitation
   B. increases with increase in its excitation
   C. remains unaffected with increase in excitation
   D. any of the above

9. The duration of sudden snort-circuit test on a synchronous motor is usually about_____________?

   A. one hour
   B. one minute
   C. one second
   D. none of the above

10. If the field circuit of an unloaded salientpole synchronous motor gets suddenly open-circuited, then

    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