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Muliple Choice Interview Questions Of Singe Phase Motor Part 1

 Hello Engineers.


Welcome to Electrical Engineering Interview Questions Blog. Today i am going to share mcq based on single phase motor. Lets start...

Ques: 1 A repulsion motor is equipped with 

(a) a commutator  
(b) slip-rings
(c) a repeller 
(d) neither (a) nor (b).
 Answer : A
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Ques:2 If starting winding of a single-phase induction motor is left in the circuit, it will

(a) draw excessive current and overheat
(b) run slower
(c) run faster
(d) spark at light loads.
Answer : A
 

Ques:3 Each of the following statements regarding a shaded-pole motor is true except

(a) its direction of rotation is from un- shaded to shaded portion of the poles
(b) it has very poor efficiency
(c) it has very poor p.f.
(d) it has high starting torque.
Answer : D

Ques:4 The direction of rotation of a single-phase motor can be reversed by

(a) reversing connections of both windings
(b) reversing connections of starting winding
(c) using a reversing switch
(d) reversing supply connections.
Answer : B

Ques:5 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

(a) cos α
(b) sin α
(c) tan α
(d) sin α/2.
Answer : B

Ques:6 The capacitor in a capacitor-start induction- run ac motor is connected in series with ......winding.

(a) starting
(b) running
(c) squirrel-cage
(d) compensating
Answer : A

Ques:7 A permanent-split single-phase capacitor motor does not have

(a) centrifugal switch
(b) starting winding
(c) squirrel-cage rotor
(d) high power factor.
Answer : A

Ques:8 In a two-value capacitor motor, the capacitor used for running purposes is a/an

(a) dry-type ac electrolytic capacitor
(b) paper-spaced oil-filled type
(c) air-capacitor
(d) ceramic type.
Answer : B
 

Ques:9 If a single-phase induction motor runs slower than normal, the more likely defect is

(a) improper fuses
(b) shorted running winding
(c) open starting winding
(d) worn bearings.
Answer : D

Ques:10 If the centrifugal switch of a two-value capacitor motor using two capacitors fails to open, then

(a) electrolytic capacitor will, in all probability, suffer breakdown
(b) motor will not carry the load
(c) motor will draw excessively high current
(d) motor will not come upto the rated speed.
Answer : A

Ques:11 After the starting winding of a single- phase induction motor is disconnected from supply, it continues to run only on ............winding.

(a) rotor
(b) compensating
(c) field
(d) running
Answer : D

Ques:12 Compensating winding is employed in an ac series motor in order to

(a) compensate for decrease in field flux
(b) increase the total torque
(c) reduce the sparking at brushes
(d) reduce effects of armature reaction.
Answer : D

Ques:13 A universal motor is one which

(a) is available universally
(b) can be marketed internationally
(c) can be operated either on dc or ac supply
(d) runs at dangerously high speed on no-load.
Answer : C

Ques:14 In a single-phase series motor the main purpose of inductively-wound compensating winding is to reduce the

(a) reactance emf of commutation
(b) rotational emf of commutation
(c) transformer emf of commutation
(d) none of the above.
(Power App.-II, Delhi Univ. Jan. 1987)
Answer : D

Ques:15 A repulsion-start induction-run single- phase motor runs as an induction motor only when

(a) brushes are shifted to neutral plane
(b) short-circuiter is disconnected
(c) commutator segments are short- circuited
(d) stator winding is reversed
Answer : C

Ques:16 The starting winding of a single-phase motor is placed in the 

(a) rotor
(b) stator
(c) armature
(d) field.
Answer : B

Thanks.
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