Single Phase Induction Motor MCQ: Electrical Engineering

Electrical Engineering Single Phase Induction Motor MCQ. Multiple Choice Questions and Answers.

 

Single Phase Induction Motor MCQ

 

If the capacitor of a single-phase motor is short-circuited ?

A. the motor will not start
B. the motor will run
C. the motor will run in reverse direction
D. the motor will run in the same direction at reduced r.p.m

View Answer

A. the motor will not start

 

A universal motor is one which ?

A. can be operated either on D.C. or A.C. supply at approximately the same speed and output
B. can be marketed internationally
C. runs at dangerously high speed on no-load
D. None of the above

View Answer

A. can be operated either on D.C. or A.C. supply at approximately the same speed and output

 

In repulsion motor, maximum torque is developed when ?

A. brush axis is at 45° electrical to the field axis
B. brush axis coincides with the field axis
C. brush axis is at 90° electrical to the field axis
D. none of the above

View Answer

A. brush axis is at 45° electrical to the field axis

 

The motor used for the compressors is ?

A. d.c. series motor
B. shaded pole motor
C. capacitor-start capacitor-run motor
D. reluctance motor

View Answer

C. capacitor-start capacitor-run motor

 

Torque developed by a single phase induction motor at starting is ?

A. pulsating
B. uniform
C. none of the above
D. nil

View Answer

D. nil

 

The shaded pole motor is used for ?

A. high starting torque
B. low starting torque
C. medium starting torque
D. very high starting torque

View Answer

B. low starting torque

 

A reluctance motor is a ?

A. self-starting
B. constant speed motor
C. needs no D.C. excitation
D. all of the above

View Answer

D. all of the above

 

Which type of load is offered by cranes and hoists ?

A. Gradually varying load
B. Non-reversing, no-load start
C. Reversing, light start
D. Reversing, heavy start

View Answer

D. Reversing, heavy start

 

Single Phase Induction Motor MCQ

 

The wattage rating for a ceiling fan motor will be in the range ?

A. 200 to 250 W
B. 250 to 500 W
C. 50 to 150 W
D. 10 to 20 W

View Answer

C. 50 to 150 W

 

The repulsion-start induction-run motor is used because of ?

A. good power factor
B. high efficiency
C. minimum cost
D. high starting torque

View Answer

D. high starting torque

 

Which of the following motors has highest starting torque ?

A. Repulsion motor
B. Shaped pole motor
C. Capacitor-start motor
D. Split-phase motor

View Answer

C. Capacitor-start motor

 

A hysteresis motor works on the principle of ?

A. hysteresis loss
B. magnetisation of rotor
C. eddy current loss
D. electromagnetic induction

View Answer

A. hysteresis loss

 

In a single phase motor the centrifugal switch ?

A. disconnects auxiliary winding of the motor
B. disconnects main winding of the motor
C. reconnects the main winding the motor
D. reconnects the auxiliary winding of the motor

View Answer

A. disconnects auxiliary winding of the motor

 

A shaded pole motor can be used for ?

A. toys
B. hair dryers
C. circulators
D. any of the above

View Answer

D. any of the above

 

In repulsion motor direction of rotation of motor ?

A. is opposite to that of brush shift
B. is the same as that of brush shift
C. is independent of brush shift
D. None of the above

View Answer

B. is the same as that of brush shift

 

Which of the following motor will have relatively higher power factor ?

A. Capacitor run motor
B. Shaded pole motor
C. Capacitor start motor
D. Split phase motor

View Answer

A. Capacitor run motor

 

Single Phase Induction Motor MCQ

 

In a split phase motor ?

A. the starting winding is connected through a centrifugal switch
B. the running winding is connected through a centrifugal switch
C. both starting and running windings are connected through a centrifugal switch
D. centrifugal switch is used to control supply voltage

View Answer

A. the starting winding is connected through a centrifugal switch

 

In a capacitor start and run motors the function of the running capacitor in series with the auxiliary winding is to ?

A. improve power factor
B. increase overload capacity
C. reduce fluctuations in torque
D. to improve torque

View Answer

A. improve power factor

 

In a split phase motor, the running winding should have ?

A. high resistance and low inductance
B. low resistance and high inductance
C. high resistance as well as high inductance
D. low resistance as well as low inductance

View Answer

B. low resistance and high inductance

 

In capacitor start single-phase motors ?

A. current in the starting winding leads the voltage
B. current in the starting winding lags the voltage
C. current in the starting winding is in phase with voltage in running winding
D. none of the above

View Answer

A. current in the starting winding leads the voltage

 

In a capacitor start motor, the phase displacement between starting and running winding can be nearly ?

A. 10°
B. 30°
C. 60°
D. 90°

View Answer

D. 90°

 

Which of the following motor will give relatively high starting torque ?

A. Capacitor start motor
B. Capacitor run motor
C. Split phase motor
D. Shaded pole motor

View Answer

A. Capacitor start motor

 

The capacitors used in single-phase capacitor motors have no ?

A. voltage rating
B. dielectric medium
C. polarity marking
D. definite value

View Answer

C. polarity marking

 

A repulsion motor is equipped with ?

A. slip rings
B. commutator
C. both A. and (b)
D. none of the above

View Answer

B. commutator

 

Single Phase Induction Motor MCQ

 

A shaded pole motor does not possess ?

A. centrifugal switch
B. capacitor
C. commutator
D. all of the above

View Answer

D. all of the above

 

The rotor of a hysteresis motor is made of ?

A. aluminium
B. cast iron
C. chrome steel
D. copper

View Answer

C. chrome steel

 

The purpose of stator winding in the compensated repulsion motor is to ?

A. provide mechanical balance
B. improve power factor and provide better speed regulation
C. prevent hunting in the motor
D. eliminate armature reaction

View Answer

B. improve power factor and provide better speed regulation

 

The speed control of universal motor used for sewing machines is by ?

A. friction
B. varying the resistance
C. tapping the field
D. centrifugal mechanism

View Answer

B. varying the resistance

 

The rotor slots in an induction motor are usually not quite parallel to the shaft because it ?

A. improves the efficiency
B. helps the rotor teeth to remain under the stator teeth
C. helps in reducing the tendency of the rotor teeth to remain under the stator teeth
D. improves the power factor

View Answer

C. helps in reducing the tendency of the rotor teeth to remain under the stator teeth

 

The electric motor used in portable drills is ?

A. capacitor run motor
B. hysteresis motor
C. universal motor
D. repulsion motor

View Answer

C. universal motor

 

Locked rotor current of a shaded pole motor is ?

A. equal to full load current
B. less than full load current
C. slightly more than full load current
D. several times the full load current

View Answer

C. slightly more than full load current

 

Which motor is normally free from mechanical and magnetic vibrations ?

A. Split phase motor
B. Universal motor
C. Hysteresis motor
D. Shaded pole motor

View Answer

C. Hysteresis motor

 

Single Phase Induction Motor MCQ

 

A.C. series motor as compared to D.C. series motor has ?

A. smaller brush width
B. less number of field turns
C. more number of armature turns
D. less air gap
E. all of the above

View Answer

E. all of the above

 

In which single-phase motor, the rotor has no teeth or winding ?

A. Split phase motor
B. Reluctance motor
C. Hysteresis motor
D. Universal motor

View Answer

C. Hysteresis motor

 

Speed control of a universal motor is achieved by ?

A. varying field flux with tapped field windings
B. connecting rheostat in series
C. applying variable voltage by means of silicon controlled rectifier
D. applying variable voltage by means of variable auto-transformer
E. all of the above methods

View Answer

E. all of the above methods

 

The starting winding of a single-phase motor is placed in ?

A. armature
B. field
C. rotor
D. stator

View Answer

D. stator

 

In split-phase motor auxiliary 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

View Answer

C. thin wire placed at the top of the slots

 

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

View Answer

A. 0.6 power factor lagging

 

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

View Answer

D. Capacitor run motor

 

A schrage motor can run on ?

A. zero slip
B. negative slip
C. positive slip
D. all of the above

View Answer

D. all of the above

 

Single Phase Induction Motor MCQ

 

A universal motor can run on ?

A. A.C. only
B. D.C. only
C. either A.C. or D.C.
D. none of the above

View Answer

C. either A.C. or D.C.

 

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

View Answer

C. inherently non-self-starting with low torque

 

Which of the following motors can be run on AC. as well as D.C. supply ?

A. Universal motor
B. Repulsion motor
C. Synchronous motor
D. Reluctance motor

View Answer

A. Universal motor

 

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

View Answer

C. single-phase capacitor run motor

 

In a two value capacitor motor, the capacitor used for running purposes is ?

A. air capacitor
B. paper spaced oil filled type
C. ceramic type
D. a.c. electrolytic type

View Answer

B. paper spaced oil filled type

 

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

A. start and then stop
B. start and run slowly
C. start and run at rated speed
D. not start at all

View Answer

D. not start at all

 

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

View Answer

B. Schrage motor

 

The power factor of a single-phase induction motor is usually ?

A. lagging
B. always leading
C. unity
D. unity to 0.8 leading

View Answer

A. lagging

 

Single Phase Induction Motor MCQ

 

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

View Answer

D. motor will continue to run in same direction

 

The value of starting capacitor of a fractional horse power motor will be ?

A. 100 uF
B. 200 uF
C. 300 uF
D. 400 uF

View Answer

C. 300 uF

 

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%

View Answer

D. 5% to 35%

 

A centrifugal switch is used to disconnect starting winding when motor has ?

A. run for about 1 minute
B. run for about 5 minutes
C. picked up about 50 to 70 per cent of rated speed
D. picked up about 10 to 25 per cent of rated speed

View Answer

C. picked up about 50 to 70 per cent of rated speed

 

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