Synchronous Motor | MCQ

1. In a synchronous motor, damper winding is provided in order to

2. In a synchronous motor, the magnitude of stator back e.m.f. Eb depends on

3. An electric motor in which both the rotor and stator fields rotates with the same speed is called a/an ........motor.

4. While running, a synchronous motor is compelled to run at synchronous speed because of

5. The direction of rotation of a synchronous motor can be reversed by reversing

6. When running under no-load condition and with normal excitation, armature current Ia drawn by a synchronous motor

7. The angle between the synchronously-rotating stator flux and rotor poles of a synchronous motor is called........ angle.

8. If load angle of a 4-pole synchronous motor is 8º (elect), its value in mechanical degrees is

9. The maximum value of torque angle a in a synchronous motor is ........degrees electrical.

10. A synchronous motor running with normal excitation adjusts to load increases essentially by increase in its

11. When load on a synchronous motor running with normal excitation is increased, armature current drawn by it increases because

12. When load on a normally-excited synchronous motor is increased, its power factor tends to

13. The effect of increasing load on a synchronous motor running with normal excitation is to

14. Synchronous capacitor is

15. If the field of a synchronous motor is underexcited, the power factor will be

16. Ignoring the effects of armature reaction, if excitation of a synchronous motor running with constant load is decreased from its normal value, it leads to

17. A synchronous motor connected to infinite busbars has at constant full-load, 100% excitation and unity p.f. On changing the excitation only, the armature current will have

18. The V-curves of a synchronous motor show relationship between

19. When load on a synchronous motor is increased, its armature currents is increased provided it is

20. If main field current of a salient-pole synchronous motor fed from an infinite bus and running at no-load is reduced to zero, it would

21. In a synchronous machine when the rotor speed becomes more than the synchronous speed during hunting, the damping bars develop

22. In a synchronous motor, the rotor Cu losses are met by

23. A synchronous machine is called a doubly-excited machine because

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