Singal phase induction motor mcq part-2

1. The direction of rotation of an hysteresis motor is determined by
(a) interchanging the supply leads
(b) position of shaded pole with respect to main pole
(c) retentivity of the rotor material
(d) none of these

Ans: b

2. Burning out of windings is due to
(a) short circuited capacitor
(b) capacitor value hiving changed
(c) open circuiting of capacitor
(d) none of the above

Ans: a

3. Direction of rotation of a split phase motor can be reversed by reversing the connection of
(a) running winding only
(b) starting winding only
(c) either (a) or (b)
(d) both (a) and (b)

Ans: c

4. Short-circuiter is used in
(a) repulsion induction motor
(b) repulsion motor
(c) repulsion start induction run motor
(d) none of the above

Ans: c

5. The range of efficiency for shaded pole motors is                                                           (a) 95% to 99%
(b) 80% to 90%
(c) 50% to 75%
(d) 5% to 35%

Ans: d

6. In a capacitor start single-phase motor, when capacitor is replaced by a resistance
(a) torque will increase
(b) the motor will consume less power
(c) motor will run in reverse direction
(d) motor will continue to run in same direction

Ans: d

7. The power factor of a single-phase induction motor is usually
(a) lagging
(b) always leading
(c) unity
(d) unity to 0.8 leading

Ans: a

8. A shaded pole motor can be used for
(a) toys
(b) hair dryers
(c) circulators
(d) any of the above

Ans: d

9. A hysteresis motor works on the principle of
(a) hysteresis loss
(b) magnetisation of rotor
(c) eddy current loss
(d) electromagnetic induction

Ans: a

10. Which of the following motor will give the highest starting torque ?
(a) D.C. shunt motor
(b) Schrage motor
(c) Repulsion start and induction run motor
(d) Universal motor

Ans: b

11. For which of the applications a reluctance motor is preferred ?
(a) Electric shavers
(b) Refrigerators
(c) Signalling and timing devices
(d) Lifts and hoists

Ans: c

12. The motor used on small lathes is usually
(a) universal motor
(b) D.C. shunt motor
(c) single-phase capacitor run motor
(d) 3-phase synchronous motor

Ans: c

13. Which of the following motors is preferred for tape-recorders ?
(a) Shaded pole motor
(b) Hysteresis motor
(c) Two value capacitor motor
(d) Universal motor

Ans: b

14. A single-phase induction motor is
(a) inherently self-starting with high torque
(b) inherently self-starting with low torque
(c) inherently non-self-starting with low torque
(d) inherently non-self-starting with high torque

Ans: c

15. A schrage motor can run on
(a) zero slip
(b) negative slip
(c) positive slip
(d) all of the above

Ans: d

16. A universal motor can run on
(a) A.C. only
(6) D.C. only
(c) either A.C. or D.C.
(d) none of the above

Ans: c

17. Which of the following single-phase motors is suitable for timing and control purposes ?
(a) Reluctance motor
(b) Series motor
(c) Repulsion motor
(d) Universal motor

Ans: a

18. Single phase induction motor usually operates on
(a) 0.6 power factor lagging
(b) 0.8 power factor lagging
(c) 0.8 power factor leading
(d) unity power factor

Ans: a

19. In split-phase motor iauxiliary winding is of
(a) thick wire placed at the bottom of the slots
(b) thick wire placed at the top of the slots
(c) thin wire placed at the top of the slots
(d) thin wire placed at the bottom of the slots

Ans: c

20. Which of the following motors will operate at high power factor ?
(a) Shaped pole motor
(b) Split phase motor
(c) Capacitor start motor
(d) Capacitor run motor

Ans: d