Single Phase Motors Part 1 online mcq

Single Phase Motors Part 1

Single Phase Motors Part One

Instructions: Click the answer button to see the correct answer.

1.A capacitor start single phase induction motor will usually have a power factor of

1. 0.6 lagging.
2. 0.6 leading
3. unity
4. 0.8 leading

Answer: a

2. A capacitor start, capacitor run single phase induction motor is basically a

1. ac series motor
2. 2 phase induction motor
3. 3 phase induction motor.
4. 3 phase induction motor.

Answer: b

Single Phase Motors Part 1

3. The starting torque of a capacitor start motor is

1. zero
2. more than rated torque.
3. low
4. same as rated torque

Answer: c

4. The torque developed by a split phase motor is proportional to

1. Cosine of angle between lm and Is
2. Sine of angle between lm and ls
3. Auxiliary winding current,Is
4. Main winding current, Im

Answer: b

5. A capacitor start single phase induction motor is switched on the supply with its capacitor replaced by an inductor of equivalent reactance value. It will

1. start and then stall
2. start and run
3. none of the above.
4. not start

Answer: d

6. The starting capacitor of a single phase motor is

1. None of the above.
2. Electrolytic capacitor
3. Ceramic capacitor
4. Paper capacitor

Answer: b

Single Phase Motors Part 1

7. Which of the following is the most economical method of starting a single phase motor ?

1. Capacitance start method
2. Split-phase method.
3. Inductance start method
4. Resistance start method

Answer: a

8. The number of turns in the starting winding of a capacitor start motor as compared to that for split phase motor is

1. more
2. less
3. none of the above.
4. same

Answer: a

9. In a split phase motor, the ratio of number of turns for starting winding to that for running winding is

1. 2.0
2. more than 1
3. less than 1.
4. 1.0

Answer: c

10. A single phase motor generally used for small air compressor is

1. universal motor
2. shaded pole motor.
3. reluctance motor
4. capacitor start capacitor run motor

Answer: d

Single Phase Motors Part 1

11. Out of the following motors, which will give the highest starting torque ?

1. All have zero starting torque.
2. Universal motor
3. Capacitor start motor
4. Shaded pole motor

Answer: c

12. Which single phase ac motor will you select for record players and tape recorders ?

1. Reluctance motor
2. Shaded pole motor
3. Hysteresis motor
4. Two value capacitor motor.

Answer: c

13. A universal motor is one

1. which can operate on ac as well as dc voltage
2. which can work as single phase or three phase motor.
3. which can run on any value of supply voltage
4. which has infinitely varying speed

Answer: a

14. Under normal operating conditions which motor can run at 5000 rpm ?

1. Universal motor
2. Induction motor
3. Synchronous motor
4. No motor can give 5000 rpm.

Answer: a

Single Phase Motors Part 1

15. The motor used in household refrigerators is

1. single phase induction motor.
2. dc series motor
3. universal motor
4. dc shunt motor

Answer: a

16. Single phase motors are commercially manufactured up to

1. 5 H.P
2. 2 H.P
3. 1 H.P
4. 8 H.P

Answer: b

17. The direction of rotation of universal motor can be reversed by

1. reversing the supply terminals
2. interchanging the brush leads
3. switching over from ac to dc
4. any of the above.

Answer: b

18. A universal motor operates on

1. constant speed and varying load
2. synchronous speed with varying load
3. constant load and varying speed
4. approximately constant speed and load

Answer: d

19. Which of the following single phase motors will operate at high power factor ?

1. capacitor start motor.
2. shaded pole motor
3. split phase motor
4. capacitor run motor

Answer: d

20. A motor suitable for signaling device is

1. dc shunt motor
2. induction motor
3. dc series motor
4. reluctance motors.

Answer: d

Single Phase Motors Part 1