THREE PHASE INDUCTION MOTORS QUIZ

If the air gap between the rotor and stator of a 3-phase induction motor is increased, then_______

Leakage reactances are decreased

None of the listed here

Leakage reactances are increased

No load current is decreased

TRUE ANSWER : ?
YOUR ANSWER : ?

The rotor of induction motor

Insufficient data

Always revolves in the direction opposite to stator flux

Always revolves in the direction of stator flux

None of the listed here

TRUE ANSWER : ?
YOUR ANSWER : ?

The condition of induction motor at no load resemble those of a transformer whose secondady is _______

Open circuited

None of the listed here

Supplying a variable resistive load

Short-circuited

TRUE ANSWER : ?
YOUR ANSWER : ?

In a squirrel cage induction motor, the number of rotor bars is generally ________

None of the listed here

Equal to stator poles

Even number

Prime number

TRUE ANSWER : ?
YOUR ANSWER : ?

The injected e.m.f. in the rotor of induction motor must have

High value for the satisfactory speed control

Zero frequency

The same phase as the rotor e.m.f.

The same frequency as the slip frequency

TRUE ANSWER : ?
YOUR ANSWER : ?

The maximum torque of a 3-phase induction motor under running conditions is

Directly proportional to rotor resistance

Inveresly proportional to supply voltage

None of the listed here

inversely proportional to rotor reactance at standstill

TRUE ANSWER : ?
YOUR ANSWER : ?

An induction motor is preferred to a dc motor because it _______

Has simple and rugged construction

Provides high starting torque

None of the listed here

Provides fine speed control

TRUE ANSWER : ?
YOUR ANSWER : ?

The air gap between stator and rotor of 3-phase induction motor ranges from ______

0.4 mm to 4 mm

1 cm to 2 cm

4 cm to 6 cm

2 cm to 4 cm

TRUE ANSWER : ?
YOUR ANSWER : ?

For the same kVA rating, the leakage flux in induction motor is _______ that of transformer.

Less than

More than

About the same

None of the listed here

TRUE ANSWER : ?
YOUR ANSWER : ?

A four speed squirrel cage induction motor uses______ stator windings.

Four

Two

Three

One

TRUE ANSWER : ?
YOUR ANSWER : ?

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