Applications of Polyphase Induction Motors

When the poles of a 3-phase wound rotor induction motor increased, it

When a 3-phase 350V, 50Hz squirrel-cage induction motor is run at 35 Hz supply,then
A. Starting torque will increase
B. Maximum torque will increase
C. Maximum torque will remain same
D. Starting torque will decrease
E. Operating speed will rise

The torque in an induction motor varies as ______ and in synchronous motor as ____

A 3-phase induction motor is running for a constant load torque at rated voltage and frequency. If both the frequency and voltage are halved
following will be the related statements ignoring the stator losses.
A. The difference between actual speed and synchronous speed remains same.
B. Per unit slip remains same
C. Stator current remains same
D. Air gap flux remains same

Relatively a squirrel-cage induction motor is advantageous over wound rotor type induction motor of identical rating due to

Reducing the poles of a 3-phase induction motor, it

A 3-phase induction motor is running for a constant load torque at rated voltage and frequency. If both the frequency and voltage are halved
following will be the related statements ignoring the stator losses.
A. The difference between actual speed and synchronous speed remains same.
B. Per unit slip remains same
C. Stator current increases
D. Air gap flux remains same

Relatively a squirrel-cage induction motor is advantageous over wound rotor type induction motor of identical rating due to

Speed control is possible for _______ and not possible for __________

If a 3-phase 350V, 50Hz squirrel-cage induction motor is run at 55 Hz supply,then
A. Starting torque will increase
B. Maximum torque will increase
C. Maximum torque will remain same
D. Starting torque will decrease
E. Operating speed will rise

No load test has been conducted on an induction motor for different supply voltages and input power vs voltage plot has been drawn.
The curve is extrapolated to intersect the y-axis. This point is

Which of the following can be done using a synchronous motor but not by induction motor?

A 3-phase induction motor taking a line current of 200 A, is started by direct switching. If an auto transformer of with 50% tapping is made to be used, the motor line current and supply line current will be respectively

Wound rotor induction motor is most appropriate for the applications requiring

We can not operate a cage induction motor on a variable frequency load due to

A 3-phase induction motor is running for a constant load torque at rated voltage and frequency. If both the frequency and voltage are halved
following will be the related statements ignoring the stator losses.
A. The difference between actual speed and synchronous speed remains same.
B. Per unit slip remains varies
C. Stator current remains same
D. Air gap flux remains same