The maximum torque in an induction motor depends on

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

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

The torque of a rotor in an induction motor under running condition is maximum

A

At the unit value of slip

B

At the zero value of slip

C

At the value of the slip which makes rotor reactance per phase equal to the resistance per phase

D

At the value of the slip which makes the rotor reactance half of the rotor

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

The shape of the torque/slip curve of induction motor is

A

Parabola

B

Hyperbola

C

Rectangular parabola

D

Straight line

The torque of an induction motor is

A

Directly proportional to slip

B

Inversely proportional to slip

C

Proportional to the square of the slip

D

None of the above

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

Speed torque characteristic of a repulsion induction motor is similar to that of a D.C.

A

shunt motor

B

series motor

C

compound motor

D

separately excited motor

The maximum torque in an induction motor depends on

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