The good power factor of an induction motor can be achieved if the average flux density in the air gap is

A synchronous motor installed at the receiving end substation operates with such an excitation that it takes power at lagging power factor. Now if the applied voltage of the synchronous motor goes down, the power factor of the synchronous motor will

A

remain same

B

go down

C

improve

D

none of the above

A wound rotor induction motor is preferred, as compared to squirrel cage induction motor, when major consideration is

A

Slop speed operation

B

High starting torque

C

Low windage losses

D

All of the above

A synchronous motor has better power factor as compared to that of an equivalent induction motor. This is mainly because

A

synchronous motor has no slip

B

stator supply is not required to produce magnetic field

C

mechanical load on the rotor remains constant

D

synchronous motor has large airgap

The power factor of a synchronous motor is better than that of induction motor because

A

stator supply is relieved of responsibility of producing magnetic field

B

mechanical load on the motor can be adjusted

C

synchronous motor runs at synchronous speed

D

synchronous motor has large air gap

In an induction motor if air-gap is increased

A

The power factor will be low

B

Windage losses will be more

C

Bearing friction will reduce

D

Copper loss will reduce in an induction motor

In case the air gap in an induction motor is increased

A

The magnetizing current of the rotor will decrease

B

The power factor will decrease

C

Speed of motor will increase

D

The windage losses will increase

What will happen if the relative speed between the rotating flux of stator and rotor of the induction motor is zero?

A

The slip of the motor will be 5%

B

The rotor will not run

C

The rotor will run at very high speed

D

The torque produced will be very large

The power factor of an induction motor under no-load conditions will be closer to

A

0.2 lagging

B

0.2 leading

C

0.5 leading

D

unity

The low power factor of induction motor is due to

A

Rotor leakage reactance

B

Stator reactance

C

The reactive lagging magnetizing current necessary to generate the magnetic flux

D

All of the above

The power factor of a single-phase induction motor is usually

A

lagging

B

always leading

C

unity

D

unity to 0.8 leading

The good power factor of an induction motor can be achieved if the average flux density in the air gap is

Related Questions