**Induction Motors MCQs**

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

- 2 poles
- 4 poles
- 6 poles
- 8 poles

Ans: 3

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

- It requires no dc field current
- It requires only one dc field current
- It requires multiple dc field currents
- 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:

- Low voltage
- Heavy loads connected to rotor
- Bad mechanical design of the machine
- Harmonics

Ans: 4

4. Fractional slip can be expressed by the equation:

- Rotor’s copper loss / Rotor’s input
- Rotor’s copper loss / Rotor’s output
- Stator’s copper loss / Stators input
- 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:

- Winding is open
- Winding is short
- Bearings are warm
- All are possible

Ans: 3

6. The motor which has high starting torque:

- Squirrel cage induction motor
- Slip ring induction motor

Ans: 2

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

- 200 r/min
- 1500 r/min
- 10,000 r/min
- 50 r/min

Ans: 2

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

- Leading
- Lagging
- Unity

Ans: 2

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

- ATL
- Auto-transformer
- Wye-delta
- All have equal

Ans: 3

10. The statement VFDs never use electronic components is:

- True
- False

Ans: 2