Induction Motors MCQs Multiple Choice Questions and Answers, Objective Questions and Answers

Induction Motors MCQs

1. An Induction motor is turning at 1200 rpm, the frequency is 60 Hz. The number of poles are:

1. 2 poles
2. 4 poles
3. 6 poles
4. 8 poles

Ans: 3

2. The correct statement about the induction motor (IM):

1. It requires no dc field current
2. It requires only one dc field current
3. It requires multiple dc field currents
4. None of them is correct

Ans: 1

3. Crawling is a phenomenon associated with squirrel cage design in which IM runs at a very slow speed, this phenomenon occurs due to:

1. Low voltage
2. Heavy loads connected to rotor
3. Bad mechanical design of the machine
4. Harmonics

Ans: 4

4. Fractional slip can be expressed by the equation:

1. Rotor’s copper loss / Rotor’s input
2. Rotor’s copper loss / Rotor’s output
3. Stator’s copper loss / Stators input
4. Stator’s copper loss / Stators input

Ans: 1

5. A single phase motor is running slower than its original speed, the most obvious case which happened can be:

1. Winding is open
2. Winding is short
3. Bearings are warm
4. All are possible

Ans: 3

6. The motor which has high starting torque:

1. Squirrel cage induction motor
2. Slip ring induction motor

Ans: 2

7. The synchronous speed of a 4 pole machine operated at 50 Hz is:

1. 200 r/min
2. 1500 r/min
3. 10,000 r/min
4. 50 r/min

Ans: 2

8. Commonly, the power factor of a single phase induction motor is:

1. Leading
2. Lagging
3. Unity

Ans: 2

9. Which of the following method Starting methods has the lowest starting torque associated with it:

1. ATL
2. Auto-transformer
3. Wye-delta
4. All have equal

Ans: 3

10. The statement VFDs never use electronic components is:

1. True
2. False

Ans: 2