Insertion of resistance in the rotcir of an induction motor to develop a given torque

Insertion of resistance in the rotor of an induction motor to develop a given torque

A

Decreases the rotor current

B

Increases the rotor current

C

Rotor current becomes zero

D

Rotor current remains same

While starting a salient pole synchronous motor by induction motor action and connecting field discharge resistance across field, starting and accelerting torque is produced by

A

induction motor torque in field winding

B

induction motor torque in damper winding

C

eddy current and hysteresis torque in pole faces

D

reHetance motor torque due to saliency of the rotor

E

all of the above methods

Insertion of resistance in the stator of an induction motor

A

Increases the load torque

B

Decreases the starting torque

C

Increases the starting torque

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

The maximum torque which a synchronous motor will develop at rest for any angular position of the rotor, at rated stator supply voltage and frequency, is known as

A

locked-rotor torque

B

synchronous torque

C

pull up torque

D

reluctance torque

The maximum value of torque that a synchronous motor can develop without losing its synchronism, is known as

A

slip torque

B

pull-out torque

C

breaking torque

D

synchronising torque

A synchronous motor can develop synchronous torque

A

when under loaded

B

while over-excited

C

only at synchronous speed

D

below or above synchronous speed

The starting torque of a three phase induction motor can be increased by

A

Increasing slip

B

Increasing current

C

Both (A) and (B)

D

None of the above

The stating torque of the slip ring induction motor can be increased by adding

A

External inductance to the rotor

B

External resistance to the rotor

C

External capacitance to the rotor

D

Both resistance and inductance to rotor

The starting torque of a squirrel-cage induction motor is

A

low

B

negligible

C

same as full-load torque

D

slightly more than full-load torque

Insertion of resistance in the rotcir of an induction motor to develop a given torque

Related Questions