In a synchronous motor, damper windings are provided on____________? - PakMcqs

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. The back e.m.f. in the stator of a synchronous motor depends on____________?

   A. number of poles B. flux density C. rotor speed D. rotor excitation E. none of the above...

4. 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...

5. 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...

6. When the stator windings are connected in such a fashion that the number of poles are made half, the speed of the rotor of a synchronous motor___________?

   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...

7. 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...

8. A synchronous motor is running on a load with normal excitation. Now if the load on the motor is increased

   A. power factor as well as armature current will decrease B. power factor as well as armature current will increase C. power factor will increase but armature current will decrease D. power factor will decrease and armature current will increase...

9. 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...

10. In a 3-phase synchronous motor, the negative phase sequence exists when the motor is_______________?

    A. supplied with unbalanced voltage B. under-loaded C. over-loaded D. none of the above...