Explore topic-wise MCQs in Electrical Machines.

This section includes 7 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Machines knowledge and support exam preparation. Choose a topic below to get started.

1.

No load test has been conducted on an induction motor for different supply voltages and input power vs voltage plot has been drawn. The curve is extrapolated to intersect the y-axis. This point is?

A. friction and windage losses
B. core losses
C. stray losses
D. all of the mentioned
Answer» B. core losses
2.

A 3-phase induction motor taking a line current of 200 A, is started by direct switching. If an auto transformer of with 50% tapping is made to be used, the motor line current and supply line current will be respectively?

A. 100, 50
B. 50, 100
C. 50, 200
D. 50*1.73, 200
Answer» B. 50, 100
3.

When the poles of a 3-phase wound rotor induction motor increased, it _________

A. will decrease maximum power factor
B. will increase maximum power factor
C. will make no change in power factor
D. can not be depicted
Answer» C. will make no change in power factor
4.

Reducing the poles of a 3-phase induction motor, it _________

A. will decrease maximum power factor
B. will increase maximum power factor
C. will make no change in power factor
D. can not be depicted
Answer» B. will increase maximum power factor
5.

We can not operate a cage induction motor on a variable frequency load due to ___________

A. no availability of varying the speed
B. availability of variable speed
C. low starting torque
D. fixed slip
Answer» B. availability of variable speed
6.

Relatively a squirrel-cage induction motor is advantageous over wound rotor type induction motor of identical rating due to ___________

A. less conductor material used.
B. lower leakage flux
C. ruggedness
D. all of the mentioned
Answer» E.
7.

Wound rotor induction motor is most appropriate for the applications requiring ______________

A. high starting torque
B. variable starting torque
C. fixed starting torque
D. all of the mentioned
Answer» C. fixed starting torque