electrical

Synchronous Motor MCQ Questions and Answers Page - 1

1.

Synchronous motors generally have

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2.

Number of slip rings in a 3-kphase synchronous motor will be

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3.

An ideal synchronous motor has no starting torque because the

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4.

In a synchronous motor

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5.

A synchronous machine is revolving armature and stationary field type Under steady running conditios the air gap field

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6.

In a synchronous machine, if the armature field axisis ahead of the field flux axis in the direction of rotation the machine operating is

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7.

In a synchronous machine if the axis of the filed flux coincides with that of armature flux, the machine

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8.

In  a 3-phase synchronous motor

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9.

In a 3-phase synchronous motor

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10.

What is the angle between the induced voltage and supply voltage of a  synchronous motor under running condition

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11.

The  relative speed between  the magnetic fields of stator  and rotor under steady state operation is zero for

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12.

A 3- phase synchronous motor has

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13.

A 10 pole , 25Hz alternator is directly coupled to and is driven by 60 Hz synchronous motor. What is the number of poles for the synchronous motor ?

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14.

A 3- phase synchronous motor needs dc supply for excitation

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15.

The  coupling magnetic field reaction with ___system(s) is essential for extracting energy from an electrical system

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16.

The armature current of a synchronous motor on no load

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17.

As the load is increased on a synchronous motor, its  speed

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18.

The synchronous motor meets increase in load by taking more armature current as

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19.

A synchronous motor is operating with normal excitation . With the increase in load the armature current drawn from the supply main increases due to

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20.

The resultant voltage acting across the armature circuit of a synchronous motor (Er) is the _____of induced emf in the armature circuit (Eb) and supply voltage V

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21.

The magnitude of emf induced in the armature of a synchronous motor (Eb) depends upon

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22.

Synchronous motors are generally not self-starting because

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Answer : B

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23.

In case one phase of a three-phase synchronous motor is short-circuited the motor will

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Answer : A

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24.

A pony motor is basically a

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Answer : A

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25.

A synchronous motor can develop synchronous torque

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Answer : C

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26.

A synchronous motor can be started by

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Answer : D

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27.

A three-phase synchronous motor will have

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Answer : C

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28.

Under which of the following conditions hunting of synchronous motor is likely to occur?

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Answer : A

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29.

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

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Answer : A

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30.

The power developed by a synchronous motor will be maximized when load angle is

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Answer : C

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31.

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

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Answer : D

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32.

A synchronous motor is running on a load with normal excitation. Now if the load on the motor is increased

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Answer : D

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33.

Mostly, synchronous motors are of

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Answer : C

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34.

The synchronous motor is not inherently self-starting because

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Answer : A

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35.

As the load is applied to a synchronous motor, the motor takes more armature current because

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Answer : B

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36.

Synchronous motor always runs at

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Answer : A

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37.

An over-excited synchronous motor takes

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Answer : A

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38.

The working of a synchronous motor is similar to

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Answer : B

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39.

The minimum armature current of the synchronous motor corresponds to operation at

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Answer : B

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40.

In a synchronous motor, the magnitude of stator back e.m.f Eb depends upon

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Answer : A

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41.

If load (or torque) angle of a 4-pole synchronous motor is 6°electrical, its value in mechanical degree is

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Answer : B

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42.

The back e.m.f of a synchronous motor depends upon

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Answer : C

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43.

In a synchronous motor which loss varies with load?

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Answer : C

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44.

A synchronous motor can be made self-starting by providing

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Answer : D

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45.

The oscillations in a synchronous motor can be damped out by

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Answer : C

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46.

The shaft of synchronous motor is made of

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Answer : A

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47.

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

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Answer : B

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48.

The speed regulation of a synchronous motor is always

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Answer : D

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49.

The percentage slip in case of a synchronous motor is

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Answer : D

Explanation :

Synchronous Motor MCQ Questions and Answers Page - 1
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