# Rotor Voltage Injection MCQ Questions & Answers

Rotor Voltage Injection MCQs : This section focuses on the "Rotor Voltage Injection". These Multiple Choice Questions (MCQs) should be practiced to improve the Rotor Voltage Injection skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.

Question 1

A 20-pole, 3-phase, 90 Hz induction motor is operating at a speed of _______ rpm. The frequency of the rotor current of the motor in Hz is 20.

A. 418.56
B. 420.12
C. 421.23
D. 422.45

Question 2

A 32-pole, 3-phase, 70 Hz induction motor is operating at a speed of 112 rpm. The frequency of the rotor current of the motor in Hz is __________

A. 40.2
B. 46.1
C. 40.1
D. 40.6

Question 3

Calculate mark to space ratio if the system is on for 4.3 sec and off for 78.2 sec.

A. 0.054
B. 0.047
C. 0.039
D. 0.018

Question 4

Calculate the active power in a .89 H inductor.

A. 1.535 W
B. 0 W
C. 2.484 W
D. 1.598 W

Question 5

Calculate the amplitude of the sinusoidal waveform z(t)=.27sin(.369?t+.142?÷4.25).

A. 0.287
B. 0.27
C. 0.216
D. 0.287

Question 6

Calculate the line voltage in star connection when phase voltage=45 V.

A. 77.9 V
B. 77.6 V
C. 77.2 V
D. 77.8 V

Question 7

Calculate the time period of the waveform i(t)=sin(?t+6?÷4)+sin(?t+5?÷6).

A. 2 sec
B. 4 sec
C. 5 sec
D. 3 sec

Question 8

Calculate the total heat dissipated in a rotor resistor of 14.23 ? when .65 A current flows through it.

A. 6.45 W
B. 6.01 W
C. 6.78 W
D. 6.98 W

Question 9

If induction motor air gap power is 67 KW and mechanically developed power is 26 KW, then rotor ohmic loss will be _________ KW.

A. 41
B. 42
C. 43
D. 44

Question 10

If induction motor rotor power is 157.5 KW and gross developed power is 79.9 KW, then rotor ohmic loss will be _________ KW.

A. 77.5
B. 77.6
C. 76.9
D. 77.1

Question 11

The no-load circuit test on a 3-? induction motor is conducted at a rotor speed of _______

A. Zero
B. < Ns
C. > Ns
D. Ns

Question 12

The power factor of a squirrel cage induction motor generally is ___________

A. .6-.8
B. .1-.2
C. .2-.4
D. .5-.7

Question 13

The slope of the V-I curve is 1.1°. Calculate the value of resistance. Assume the relationship between voltage and current is a straight line.

A. .019 ?
B. .036 ?
C. .075 ?
D. .084 ?

Question 14

Calculate the amplitude of the sinusoidal waveform z(t)=.27sin(.369πt+.142π÷4.25).

A. 0.287
B. 0.27
C. 0.216
D. 0.287

Question 15

Calculate the time period of the waveform i(t)=sin(πt+6π÷4)+sin(πt+5π÷6).

A. 2 sec
B. 4 sec
C. 5 sec
D. 3 sec

Question 16

Calculate the total heat dissipated in a rotor resistor of 14.23 Ω when .65 A current flows through it.

A. 6.45 W
B. 6.01 W
C. 6.78 W
D. 6.98 W

Question 17

The no-load circuit test on a 3-Φ induction motor is conducted at a rotor speed of _______

A. Zero
B. < Ns
C. > Ns
D. Ns