SYNCHRONOUS MOTORS QUIZ

A rotary converter can also be run as a

Dc series generator

Dc compound generator

Synchronous motor

Dc shunt generator

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When load on a synchronous motor is increased, its armature current is increased provided, it is ______

Normally excited

Under-excited

Over-excited

All of these

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When a synchronous motor is pulled out of synchronism, the stator current ________

Is decreased too much

Is increased too much

Become zero

Remains unchanged

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Leading power factor synchronous motors cost ______ the unity pf motors.

About the same as

Less than

None of the listed here

More than

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The operating speed of a synchronous motor can be changed to new fixed value by

changing the supply voltage

changing frequency

changing the load

using brakes

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Mostly, synchronous motors are of

Smooth cylindrical type machines

Induction type machines

Alternator type machines

Salient pole type machines

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When pull-out torque occurs in a synchronous motor, the poles of the rotor are _______

Mid way between N and S poles of stator

None of the listed here

Coincident with statorbpoles

45° (electrical) behind stator poles

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A synchronous motor can be used as a synchronous capacitor when it is

Under loaded

Over loaded

Over excited

Under excited

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When a unity pf synchronous motor is operated at a leading pf, it results in _______

More than rated rotor current

None of the listed here

More than rated horseppwer output

Less than rated horsepower output

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When the synchronous motor is pulled out of synchronism, the stator current _______

Remains unchanged

Is decreased too much

Is increased too much

Becomes zero

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