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

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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

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