SYNCHRONOUS MOTORS QUIZ

When the field of a synchronous motor is under-excited, the power factor will be

zero

leading

unity

lagging

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The mechanical power developed by a synchronous motor is ______ stator voltage.

Independent of

Invesely proportional to

Directly proportional to square of

Directly proportional to

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A synchronous motor can be started by

Pony motor

Dc compound motor

All of the listed here

Provinding damper winding

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Synchronous motor always run at

Less than synchronous speed

More than synchronous speed

None of the listed here

The synchronous speed

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The speed of a synchronous motor can be changed by varying _______

Mechanical load

Field excitation

None of the listed here

Supply frequency

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For the same active power consumed, the stator current of a synchronous motor is ______ that of a 3 phase induction motor.

More than

None of the listed here

The same as

Less than

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The shaft of synchronous motor is made of

Stainless steel

Chrome steel

Alcino

Mild steel

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The pull out torque of a synchronous motor is generally ______ times its full-load torque.

0.5

1.25 to 3.5

5 to 10

6 to 9

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In a 3-phase synchronous motor, the negative phase sequence exists when the motor is

over-loaded

supplied with unbalanced voltage

None of these

under-loaded

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If one phase of a 3 phase synchronous motor is short circuited, motor

Will not come upto speed

Will overheat in spots

Will fail to pull into step

Will refused ro start

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