An induction motor is a popular machine that is widely employed in industries. Given below is Induction Motor MCQs Part 1.
Also, check List of other Induction Motor MCQs
Contents
- 1 Crawling in an induction motor is caused by
- 2 The crawling in motors is solved by
- 3 Schrage motor is
- 4 Starting torque of slip ring induction motor is
- 5 DC excitation in induction motors
- 6 At the start, the frequency of induced e.m.f in the rotor is
- 7 The resistance of squirrel cage rotor is
- 8 The speed of rotating magnetic field in 4 pole induction motor operating at 50 Hz is
- 9 The power factor of squirrel cage induction motor is
- 10 Higher the number of poles
Crawling in an induction motor is caused by
1. Crawling in an induction motor is caused by:
- Harmonics
- Low voltage
- High voltage
- Design fault
Correct answer: 1. Harmonics
The crawling in motors is solved by
2. The crawling in motors is solved by:
- Skewing
- Changing stator
- Decreasing FLA
- Increasing FLA
Correct answer: 1. Skewing
Schrage motor is
3. Schrage motor is:
- An induction motor
- A frequency changer
- Useful for shunt speed-torque drives
- All of above
Correct answer: 4. All of above
Starting torque of slip ring induction motor is
4. Starting torque of slip ring induction motor is:
- Very high
- Medium
- Low
- Zero
Correct answer: 1. Very high
DC excitation in induction motors
5. DC excitation in induction motors:
- Should be very high
- Should increase exponentially
- Is not required
- None of these
Correct answer: 1. Is not required
At the start, the frequency of induced e.m.f in the rotor is
6. At the start, the frequency of induced e.m.f in the rotor is:
- Same as the applied voltage to the stator
- 2 Times higher than the applied voltage to the stator
- Half the applied voltage
- Zero
Correct answer: 1. Same as the applied voltage to the stator
The resistance of squirrel cage rotor is
7. The resistance of squirrel cage rotor is:
- Infinite
- Very high
- Very small
- Zero
Correct answer: 3. Very small
The speed of rotating magnetic field in 4 pole induction motor operating at 50 Hz is
8. The speed of rotating magnetic field in 4 pole induction motor operating at 50 Hz is:
- 1500 RPM
- 3000 RPM
- 4500 RPM
- 6000 RPM
Correct answer: 1. 1500 RPM
Explanation: Speed = 120 * f / P = 120 * 50 / 4 = 1500 RPM
The power factor of squirrel cage induction motor is
9. The power factor of squirrel cage induction motor is:
- Low at no load
- Low at high loads
- Both of these
- None of these
Correct answer: 1. Low at no load
Higher the number of poles
10. Higher the number of poles:
- Higher the speed
- Lower the speed
- Speed has no impact
Correct answer: 2. Low the speed