Explore topic-wise MCQs in Electrical Engineering Questions.

This section includes 101 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering Questions knowledge and support exam preparation. Choose a topic below to get started.

51.

In case of a double cage induction motor, the inner cage has__________?
A. high inductance arid low resistance
B. low inductance and high resistance
C. low inductance and low resistance
D. high inductance and high resistance
Answer» B. low inductance and high resistance
Discussion
52.

In a three-phase induction motor_______________?
A. iron losses in stator will be negligible as compared to that in rotor
B. iron losses in motor will be neg¬ligible as compared to that in rotor
C. iron losses in stator will be less than that in rotor
D. iron losses in stator will be more than that in rotor
Answer» E.
Discussion
53.

As load on an induction motor goes on increasing______________?
A. its power factor goes on decreasing
B. its power factor remains constant
C. its power factor goes on increasing even after full load
D. its power factor goes on increasing up to full load and then it falls again
Answer» E.
Discussion
54.

In an induction motor if air-gap is increased__________?
A. the power factor will be low
B. windage losses will be more
C. bearing friction will reduce
D. copper loss will reduce In an induction motor
Answer» B. windage losses will be more
Discussion
55.

In a squirrel cage motor the induced e.m.f. is___________?
A. dependent on the shaft loading
B. dependent on the number of slots
C. slip times the stand still e.m.f. induced in the rotor
D. none of the above
Answer» D. none of the above
Discussion
56.

The purpose of using short-circuit gear is___________?
A. to short circuit the rotor at slip rings
B. to short circuit the starting resistances in the starter
C. to short circuit the stator phase of motor to form star
D. none of the above
Answer» B. to short circuit the starting resistances in the starter
Discussion
57.

Less maintenance troubles are experienced in case of___________?
A. slip ring induction motor
B. squirrel cage induction motor
C. both A. and (b)
D. none of the above
Answer» C. both A. and (b)
Discussion
58.

The auto-starters (using three auto transformers) can be used to start cage induction motor of the following type__________?
A. star connected only
B. delta connected only
C. A. and B. both
D. none of the above
Answer» D. none of the above
Discussion
59.

It is advisable to avoid line-starting of induction motor and use starter because__________?
A. motor takes five to seven times its full load current
B. it will pick-up very high speed and may go out of step
C. it will run in reverse direction
D. starting torque is very high
Answer» B. it will pick-up very high speed and may go out of step
Discussion
60.

The torque developed in the cage induction motor with autostarter is___________?
A. k/torque with direct switching
B. K x torque with direct switching
C. K2 x torque with direct switching
D. k2/torque with direct switching
Answer» D. k2/torque with direct switching
Discussion
61.

Which of the following methods is easily applicable to control the speed of the squirrel-cage induction motor _____________?
A. By changing the number of stator poles
B. Rotor rheostat control
C. By operating two motors in cascade
D. By injecting e.m.f. in the rotor circuit
Answer» B. Rotor rheostat control
Discussion
62.

In the circle diagram for induction motor, the diameter of the circle represents____________?
A. slip
B. rotor current
C. running torque
D. line voltage
Answer» C. running torque
Discussion
63.

In Ns is the synchronous speed and s the slip, then actual running speed of an induction motor will be___________?
A. Ns
B. s.N,
C. (l-s)Ns
D. (Ns-l)s
Answer» D. (Ns-l)s
Discussion
64.

In case of the induction motors the torque is___________?
A. inversely proportional to (Vslip)
B. directly proportional to (slip)2
C. inversely proportional to slip
D. directly proportional to slip
Answer» E.
Discussion
65.

The good power factor of an induction motor can be achieved if the average flux density in the air gap is___________?
A. absent
B. small
C. large
D. infinity
Answer» C. large
Discussion
66.

A double squirrel-cage induction motor has______________?
A. two rotors moving in oppsite direction
B. two parallel windings in stator
C. two parallel windings in rotor
D. two series windings in stator
Answer» D. two series windings in stator
Discussion
67.

Star-delta starting of motors is not possible in case of____________?
A. single phase motors
B. variable speed motors
C. low horse power motors
D. high speed motors
Answer» B. variable speed motors
Discussion
68.

The starting torque of a squirrel-cage induction motor is___________?
A. low
B. negligible
C. same as full-load torque
D. slightly more than full-load torque
Answer» B. negligible
Discussion
69.

When the equivalent circuit diagram of doouble squirrel-cage induction motor is constructed the two cages can be considered__________?
A. in series
B. in parallel
C. in series-parallel
D. in parallel with stator
Answer» C. in series-parallel
Discussion
70.

Stepless speed control of induction motor is possible by which of the following methods ?
A. e.m.f. injection in rotor eueuit
B. Changing the number of poles
C. Cascade operation
D. None of the above
Answer» C. Cascade operation
Discussion
71.

In squirrel cage induction motors, the rotor slots are usually given slight skew in order to__________?
A. reduce windage losses
B. reduce eddy currents
C. reduce accumulation of dirt and dust
D. reduce magnetic hum
Answer» E.
Discussion
72.

In case the air gap in an induction motor is increased____________?
A. the magnetising current of the rotor will decrease
B. the power factor will decrease
C. speed of motor will increase
D. the windage losses will increase
Answer» C. speed of motor will increase
Discussion
73.

In three-phase squirrel-cage induction motors____________?
A. rotor conductor ends are short-circuited through slip rings
B. rotor conductors are short-circuited through end rings
C. rotor conductors are kept open
D. rotor conductors are connected to insulation
Answer» C. rotor conductors are kept open
Discussion
74.

If any two phases for an induction motor are interchanged_______?
A. the motor will run in reverse direction
B. the motor will run at reduced speed
C. the motor will not run
D. the motor will burn
Answer» B. the motor will run at reduced speed
Discussion
75.

The speed of a squirrel-cage induction motor can be controlled by all of the following except_____________?
A. changing supply frequency
B. changing number of poles
C. changing winding resistance
D. reducing supply voltage
Answer» D. reducing supply voltage
Discussion
76.

The ‘crawling” in an induction motor is caused by___________?
A. high loads
B. low voltage supply
C. improper design of machine
D. harmonics developed in the motor
Answer» E.
Discussion
77.

For which motor the speed can be controlled from rotor side ?
A. Squirrel-cage induction motor
B. Slip-ring induction motor
C. Both A. and (b)
D. None of the above
Answer» C. Both A. and (b)
Discussion
78.

Slip ring motor is recommended where____________?
A. speed control is required
B. frequent starting, stopping and reversing is required
C. high starting torque is needed
D. all above features are required
Answer» E.
Discussion
79.

DOL starting of induction motors is usually restricted to_____________?
A. low horsepower motors
B. variable speed motors
C. high horsepower motors
D. high speed motors
Answer» B. variable speed motors
Discussion
80.

In a three-phase induction motor, the number of poles in the rotor winding is always__________?
A. zero
B. more than the number of poles in stator
C. less than number of poles in stator
D. equal to number of poles in stator
Answer» E.
Discussion
81.

The maximum torque in an induction motor depends on___________?
A. frequency
B. rotor inductive reactance
C. square of supply voltage
D. all of the above
Answer» E.
Discussion
82.

An induction motor is__________?
A. self-starting with zero torque
B. self-starting with high torque
C. self-starting with low torque
D. non-self starting
Answer» D. non-self starting
Discussion
83.

In an induction motor the relationship between stator slots and rotor slots is that_____________?
A. stator slots are equal to rotor slots
B. stator slots are exact multiple of rotor slots
C. stator slots are not exact multiple of rotor slots
D. none of the above
Answer» D. none of the above
Discussion
84.

Rotor rheostat control method of speed control is used for____________?
A. squirrel-cage induction motors only
B. slip ring induction motors only
C. both A. and (b)
D. none of the above
Answer» C. both A. and (b)
Discussion
85.

A 3-phase induction motor stator delta connected, is carrying full load and one of its fuses blows out. Then the motor_______________?
A. will continue running burning its one phase
B. will continue running burning its two phases
C. will stop and carry heavy current causing permanent damage to its winding
D. will continue running without any harm to the winding
Answer» B. will continue running burning its two phases
Discussion
86.

Low voltage at motor terminals is due to____________?
A. inadequate motor wiring
B. poorely regulated power supply
C. any one of the above
D. none of the above
Answer» D. none of the above
Discussion
87.

A 3-phase induction motor delta connected is carrying too heavy load and one of its fuses blows out. Then the motor______________?
A. will continue running burning its one phase
B. will continue running burning its two phase
C. will stop and carry heavy current causing permanent damage to its winding
D. will continue running without any harm to the winding
Answer» D. will continue running without any harm to the winding
Discussion
88.

If an induction motor with certain ratio of rotor to stator slots, runs at 1/7 of the normal speed, the phenomenon will be termed as____________?
A. humming
B. hunting
C. crawling
D. cogging
Answer» D. cogging
Discussion
89.

The shaft of an induction motor is made of_____________?
A. high speed steel
B. stainless steel
C. carbon steel
D. cast iron
Answer» D. cast iron
Discussion
90.

The frame of an induction motor is usually made of____________?
A. silicon steel
B. cast iron
C. aluminium
D. bronze
Answer» C. aluminium
Discussion
91.

Size of a high speed motor as compared to low speed motor for the same H.P. will be__________?
A. bigger
B. smaller
C. same
D. any of the above
Answer» C. same
Discussion
92.

Slip of an induction motor is negative when_____________?
A. magnetic field and rotor rotate in opposite direction
B. rotor speed is less than the synchronous speed of the field and are in the same direction
C. rotor speed is more than the synchronous speed of the field and are in the same direction
D. none of the above
Answer» D. none of the above
Discussion
93.

The power factor of an induction motor under no-load conditions will be closer to_____________?
A. 0.2 lagging
B. 0.2 leading
C. 0.5 leading
D. unity
Answer» B. 0.2 leading
Discussion
94.

The ‘cogging’ of an induction motor can be avoided by____________?
A. proper ventilation
B. using DOL starter
C. auto-transformer starter
D. having number of rotor slots more or less than the number of stator slots (not equal)
Answer» E.
Discussion
95.

In an induction motor, no-load the slip is generally____________?
A. less than 1%
B. 1.5%
C. 2%
D. 4%
Answer» B. 1.5%
Discussion
96.

The torque of an induction motor is___________?
A. directly proportional to slip
B. inversely proportional to slip
C. proportional to the square of the slip
D. none of the above
Answer» B. inversely proportional to slip
Discussion
97.

In case the air gap in an induction motor is increased?
A. the magnetising current of the rotor will decrease
B. the power factor will decrease
C. speed of motor will increase
D. the windage losses will increase
Answer» C. speed of motor will increase
Discussion
98.

A 3-phase 440 V, 50 Hz induction motor has 4% slip. The frequency of rotor e.m.f. will be____________?
A. 200 Hz
B. 50 Hz
C. 2 Hz
D. 0.2 Hz
Answer» D. 0.2 Hz
Discussion
99.

The injected e.m.f. in the rotor of induction motor must have__________?
A. zero frequency
B. the same frequency as the slip frequency
C. the same phase as the rotor e.m.f.
D. high value for the satisfactory speed control
Answer» C. the same phase as the rotor e.m.f.
Discussion
100.

An induction motor is identical to_________?
A. D.C. compound motor
B. D.C. series motor
C. synchronous motor
D. asynchronous motor
Answer» E.
Discussion