Electrical Engineering Mcqs Practice Test

Question 1

Slip of an induction motor is negative when_____________?

Accepted Answer

C. rotor speed is more than the synchronous speed of the field and are in the same direction

Question 2

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____________?

Accepted Answer

C. crawling

Question 3

The ‘cogging’ of an induction motor can be avoided by____________?

Accepted Answer

D. having number of rotor slots more or less than the number of stator slots (not equal)

Question 4

The power factor of an induction motor under no-load conditions will be closer to_____________?

Accepted Answer

A. 0.2 lagging

Question 5

The ‘crawling” in an induction motor is caused by___________?

Accepted Answer

D. harmonics developed in the motor

Question 6

The speed of a squirrel-cage induction motor can be controlled by all of the following except_____________?

Accepted Answer

C. changing winding resistance

Question 7

DOL starting of induction motors is usually restricted to_____________?

Accepted Answer

A. low horsepower motors

Question 8

In a three-phase induction motor, the number of poles in the rotor winding is always__________?

Accepted Answer

D. equal to number of poles in stator

Question 9

In three-phase squirrel-cage induction motors____________?

Accepted Answer

B. rotor conductors are short-circuited through end rings

Question 10

The maximum torque in an induction motor depends on___________?

Accepted Answer

D. all of the above

Question 11

An induction motor is__________?

Accepted Answer

C. self-starting with low torque

Question 12

If any two phases for an induction motor are interchanged_______?

Accepted Answer

A. the motor will run in reverse direction

Question 13

Rotor rheostat control method of speed control is used for____________?

Accepted Answer

B. slip ring induction motors only

Question 14

For which motor the speed can be controlled from rotor side ?

Accepted Answer

B. Slip-ring induction motor

Question 15

In the circle diagram for induction motor, the diameter of the circle represents____________?

Accepted Answer

B. rotor current

Question 16

Stepless speed control of induction motor is possible by which of the following methods ?

Accepted Answer

B. Changing the number of poles

Question 17

It is advisable to avoid line-starting of induction motor and use starter because__________?

Accepted Answer

A. motor takes five to seven times its full load current

Question 18

When the equivalent circuit diagram of doouble squirrel-cage induction motor is constructed the two cages can be considered__________?

Accepted Answer

B. in parallel

Question 19

The torque developed in the cage induction motor with autostarter is___________?

Accepted Answer

C. K2 x torque with direct switching

Question 20

The auto-starters (using three auto transformers) can be used to start cage induction motor of the following type__________?

Accepted Answer

C. A. and B. both