# Induction Motor MCQ [Questions with Answers]

Induction motor is one of the most popular motors in the electric industry. In an induction motor, the rotor voltage is induced rather than physically connecting the wires. Given below are the most important Induction Motor MCQ you should know.

## Starters are used in induction motor

Starters are used in induction motor:

1. To reduce torque
2. When light loads are connected
3. To reduce staring current
4. To obtain high starting torque

Correct answer: 3. To reduce staring current

## The slip of induction motor at no load is

The slip of induction motor at no load is:

1. 0.2
2. 0.05
3. 0.03
4. Less than 1%

Correct answer: 4. Less than 1%

## If induction motor turns at synchronous speed, the induced voltage is

If induction motor turns at synchronous speed, the induced voltage is:

1. Maximum
2. Zero
3. Halved
4. Doubled

## The synchronous speed of a 220 V, 4 pole, 1 hp, 50 Hz induction motor is

The synchronous speed of a 220 V, 4 pole, 1 hp, 50 Hz induction motor is:

1. 750
2. 1500
3. 3000
4. 6000

## Induction motor is a

Induction motor is a:

1. Singly excited machine
2. Doubly excited machine
3. Triple excited machine

Correct answer: 1. Singly excited machine

## The rotor windings are skewed to

The rotor windings are skewed to:

1. Increase torque
2. Reduce torque
3. Eliminate harmonics
4. None of these

## The rotor speed of induction motor is always ________ synchronous speed

The rotor speed of induction motor is always ___________ synchronous speed:

1. Smaller than
2. Greater than
3. Equal to
4. None of these

## The relationship between rotor slip, synchronous speed and rotor speed is

The relationship between rotor slip, synchronous speed and rotor speed is:

1. (1-slip) * Rotor speed = Sync speed
2. (1-slip) * Sync speed = Rotor Speed
3. (1-slip) * (1-slip) = Sync speed * Rotor Speed
4. Rotor Speed + Sync speed = 1-slip

Correct answer: 2. (1-slip) * Sync speed = Rotor Speed

## The induced torque in the absence of rotors magnetic field is

The induced torque in the absence of rotors magnetic field is:

1. Maximum
2. Zero
3. Halved
4. Doubled

## If rotor of the induction motor is driven faster than synchronous speed

If rotor of the induction motor is driven faster than synchronous speed:

1. Induced torque reverses direction
2. Motor becomes a generator
3. Both of these
4. None of these

Correct answer: 3. Both of these

## Which one of following is the correct relationship between rotor current in three phase induction motor and slip

Which one of following is the correct relationship between rotor current in three phase induction motor and slip

1. Rotor current is directly proportional to slip
2. Rotor current is inversely proportional to slip
3. Rotor current is independent of slip

Correct answer: 1. Rotor current is directly proportional to slip