SYNCHRONOUS MOTORS QUIZ

In a synchronous motor, the rotor copper loss are met by ______

Supply lines

Dc source

Motor input

Armature input

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The rotor copper losses, in a synchronous motor, are met by

armature input

c. source

supply lines

motor input

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Which of the following motors is non self starting?

Wound rotor induction motor

Dc series motor

Synchronous motor

Squirrel cage induction motor

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

Mechanical load

Supply frequency

None of the listed here

Field excitation

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

leading

zero

lagging

unity

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A 50 Hz synchronous motor runs at 200 rpm. The number of salient poles on the rotor are______

30

16

36

None of the listed here

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The construction of a synchronous motor resembles

a rotary converter

an induction motor

a series motor

an alternator

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A synchronous motor will always stop when

Excitation winding gets disconnected

Supply voltage frequency changes

Supply voltage fluctuates

Load in motor varies

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Synchronous motors are generally used in application requiring _______

Frequent stopping

Variable speed

Infrequent starting

Sudden application of heavy loads

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The efficiency of a properly designed synchronous motor will usually fall in range

99 to 99.5%

85 to 95%

60 to 70%

75 to 80%

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