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

If the field winding of an unloaded salient pole synchronous motor is open circuited, the motor will

A

stop

B

run as induction motor

C

function as static condenser

D

burn with dense smoke

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

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

When the excitation of an unloaded salient pole synchronous motor suddenly gets disconnected

A

the motor stops

B

it runs as a reluctance motor at the same speed

C

it runs as a reluctance motor at a lower speed

D

none of the above

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

A

zero

B

one

C

two

D

infinity

What are the salient features of the new scheme? Choose the meaning of salient.

A

silent

B

main

C

minor

D

stable

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 torque produced in induction type relay (shaded pole structure) is

A

inversely proportional to the current

B

inversely proportional to the square of the current

C

proportional to the current

D

proportional to square of the current

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

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

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