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

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

Torque developed by a single phase induction motor at starting is

A

pulsating

B

uniform

C

none of the above

D

nil

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 ratio of starting torque to running torque in a synchronous motor is

A

zero

B

one

C

two

D

infinity

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

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

__________ method of starting a three phase induction motor needs six terminals.

A

Star-delta

B

Resistance starting

C

Autotransformer

D

None of the above

While starting a synchronous motor by induction motor action, field winding is usually

A

connected to D.C. supply

B

short-circuited by low resistance

C

kept open-circuited

D

none of the above

After the starting winding of a single phase induction motor is disconnected from supply, it continues to run only on

A

running winding

B

rotor winding

C

field winding

D

compensating winding

If starting winding of a single-phase induction motor is left in the circuit, it will

A

run faster

B

spark at light loads

C

draw excessive current and overheat

D

run slower

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

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