Induction Motor MCQ – 1

1. In a squirrel cage induction motor, torque with autostarter is ....... times the torque with direct-switching. Where K is the transformation ratio of the autotransformer.

2. If stator voltage of a squirrel cage induction motor is reduced to 50 per cent of its rated value, torque developed is reduced by ....... per cent of its full-load value.

3. For the purpose of starting an induction motor, a Y-Δ switch is equivalent to an auto-starter of ratio.......per cent.

4. A double squirrel-cage motor (DSCM) scores over SCIM in the matter of

5. In a DSCM, outer cage is made of high resistance metal bars primarily for the purpose of increasing its

6. Which of the following motor is an interesting example of beneficially utilizing a phenomenon that is often considered undesirable ?

7. A 6-pole 3-φ induction motor taking 25 kW from a 50-Hz supply is cumulatively-cascaded to a 4-pole motor. Neglecting all losses, speed of the 4-pole motor would be ....... r.p.m.

8. In the shaded pole squirrel cage induction motor the flux in the shaded part always

9. When a stationary 3-phase induction motor is switched on with one phase disconnected

10. If single-phasing of a 3-phase induction motor occurs under running conditions, it

11. One of the characteristics of a single- phase motor is that it

12. After the starting winding of a single- phase induction motor is disconnected from supply, it continues to run only on ............winding.

13. The direction of rotation of a single-phase motor can be reversed by

14. If a single-phase induction motor runs slower than normal, the more likely defect is

15. The capacitor in a capacitor-start induction- run ac motor is connected in series with ...... winding.

16. The starting torque of a capacitor-start induction-run motor is directly related to the angle α between its two winding currents by the relation

17. In a two-value capacitor motor, the capacitor used for running purposes is a/an

18. If the centrifugal switch of a two-value capacitor motor using two capacitors fails to open, then

19. Each of the following statements regarding a shaded-pole motor is true except

20. Compensating winding is employed in an ac series motor in order to

21. A universal motor is one which

22. In a single-phase series motor the main purpose of inductively-wound compensating winding is to reduce the

23. A repulsion motor is equipped with

24. A repulsion-start induction-run single- phase motor runs as an induction motor only when

25. If a dc series motor is operated on ac supply, it will

26. An outstanding feature of a universal motor is its

27. The direction of rotation of a hysteresis motor is determined by the

28. Speed of the universal motor is

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