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Worksheets

AC Machines

Total questions: 15

Worksheet time: 8mins

Name
Class
Date
1.

3-Phase Induction motor will have ____ power factor during no load condition:

a)

High

b)

Negative

c)

Low

d)

Moderate

2.

Which of the following method cannot be used for starting of 3-Phase Squirrel Induction Motor:

a)

DOL Starter

b)

Rotor Resistance Starter

c)

Line Resistance Starter

d)

Auto Transformer Starter

e)

Star Delta Starter

3.

The rotor slots of 3-Phase Induction Motor are kept inclined inorder to reduce noise, vibrations and synchronous cusps. This phenomenon in known as:

a)

Plugging

b)

Cogging

c)

Crawling

d)

Skewing

4.

3-Phase Induction Motor will have ____ Starting Torque and _____ Starting Current

a)

Low, Low

b)

High, High

c)

Low, High

d)

High, Low

5.

What happens when Induction motor runs at synchronous speed, motor will:

a)

Delivers real Power

b)

Stops

c)

Burn

d)

Delivers Reactive Power

6.

3-Phase Induction Motor has the advantage of Low Cost, Less Maintenance and Rugged Construction:

a)

True

b)

False

7.

Crawling occurs in Induction Motor due to which of the following:

a)

Harmonics

b)

Low Voltage

c)

High Voltage

d)

Over Load

8.

A single Phase Induction motor is self starting

a)

True

b)

False

9.

In large synchronous machine, field winding is placed on ______ and ac supply on ______

a)

Rotor, Stator

b)

Armature, Slots

c)

Stator, Rotor

d)

pole shoes, stator

10.

Which is called optimistic Method?

a)

EMF Method

b)

ZPF Method

c)

ASA Method

d)

MMF method

11.

Which alternator is used for high speed applications?

a)

Saleint pole

b)

Slip Ring

c)

Squirrel Cage

d)

Cylindrical pole

12.

Which factor is not considered for synchronization?

a)

Voltage

b)

Current

c)

Frequency

d)

Phase Sequence

13.

Which of the following supply is given to the rotor winding of 3-Phase Induction Motor:

a)

DC

b)

No Supply but by induction

c)

pulsating supply

d)

AC

14.

In Case of Synchronous Generator, when the load is thrown-off what happens to terminal voltage:

a)

Decreases

b)

Increases

c)

Remains same

15.

A Synchronous Machine having 4 poles and supplied with 60 Hz supply will rotate at ___:

a)

1500

b)

3000

c)

3600

d)

1800