Explore topic-wise MCQs in Electric Drives.

This section includes 14 Mcqs, each offering curated multiple-choice questions to sharpen your Electric Drives knowledge and support exam preparation. Choose a topic below to get started.

1.

Calculate the three-phase power using the following data: Vp=23 V, Ip=23 A, =60.

A. 793.5 W
B. 790 W
C. 792 W
D. 791 W
Answer» B. 790 W
Discussion
2.

A 3 phase, 4 pole IM is supplied from a 40 Hz source. Calculate rotor frequency when the rotor runs 100 rpm.

A. 35 Hz
B. 36.6 Hz
C. 9 Hz
D. 8 Hz
Answer» C. 9 Hz
Discussion
3.

What is the speed of the 11th order harmonics in the induction motor?

A. N<sub>s</sub>
B. N<sub>s</sub>/11
C. 2 N<sub>s</sub>
D. N<sub>r</sub>
Answer» C. 2 N<sub>s</sub>
Discussion
4.

What is the speed of the 6th order time harmonics in the induction motor?

A. N<sub>s</sub>
B. N<sub>s</sub>/6
C. 6 N<sub>s</sub>
D. 0
Answer» D. 0
Discussion
5.

Single phase induction motor is self-starting.

A. True
B. False
Answer» C.
Discussion
6.

Magnetizing current in the induction motor is ______

A. more than the transformer
B. equal as a transformer
C. less than the transformer
D. 0
Answer» B. equal as a transformer
Discussion
7.

The ratio of the rotor copper loss and air gap power is _______

A. s
B. 1-s
C. 1+s
D. 0
Answer» B. 1-s
Discussion
8.

What will happen if we increase the air gap in the induction motor?

A. Power factor will reduce
B. Power factor will increase
C. Reduction in harmonics
D. Speed will increase
Answer» B. Power factor will increase
Discussion
9.

The relative speed between the rotor and stator in the induction motor is ______

A. N<sub>r</sub>
B. N<sub>s</sub>-N<sub>r</sub>
C. N<sub>s</sub>+N<sub>r</sub>
D. 0
Answer» B. N<sub>s</sub>-N<sub>r</sub>
Discussion
10.

The relative speed between the stator magnetic field and stator in the induction motor is ______

A. N<sub>s</sub>
B. N<sub>s</sub>-N<sub>r</sub>
C. N<sub>s</sub>+N<sub>r</sub>
D. 0
Answer» B. N<sub>s</sub>-N<sub>r</sub>
Discussion
11.

The relative speed between the stator magnetic field and rotor in the synchronous generator is ______

A. N<sub>s</sub>
B. N<sub>s</sub>-N<sub>r</sub>
C. N<sub>s</sub>+N<sub>r</sub>
D. 0
Answer» E.
Discussion
12.

The relative speed between the stator magnetic field and rotor in the induction motor is ______

A. N<sub>s</sub>
B. N<sub>s</sub>-N<sub>r</sub>
C. N<sub>s</sub>+N<sub>r</sub>
D. 0
Answer» C. N<sub>s</sub>+N<sub>r</sub>
Discussion
13.

For motoring mode, the phase angle between the stator phase voltage and stator phase current should be _______

A. &lt; 90
B. &gt; 90
C. &lt; 40
D. 180
Answer» B. &gt; 90
Discussion
14.

Power input to an induction motor is given by _________

A. 3V<sub>p</sub>I<sub>p</sub>cos
B. 2V<sub>p</sub>I<sub>p</sub>cos
C. V<sub>p</sub>I<sub>p</sub>cos
D. 5V<sub>p</sub>I<sub>p</sub>cos
Answer» B. 2V<sub>p</sub>I<sub>p</sub>cos
Discussion