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D.C. Motors

Study 130 Electrical Engineering MCQs with correct answers and explanations.

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31Electrical EngineeringMedium

Kingdom Protoctista includes________?

AFungi

BProkaryotic organisms

CUnicellular organisms

DEu-cariotiquic organisms

Correct answer

C. Unicellular organisms

Explanation

The correct answer is Unicellular organisms.

32Electrical EngineeringMedium

In a D.C. generator, the iron losses mainly take place in________/

Aarmature rotor

Byoke

Carmature conductors

Dcommutator

Correct answer

A. armature rotor

Explanation

The correct answer is armature rotor.

33Electrical EngineeringMedium

Following motor is used where high starting torque and wide speed range control is required?

ANone of the above

BSynchronous motor

CInduction motor

DSingle phase capacitor start

ED.C. motor

Correct answer

E. D.C. motor

Explanation

The correct answer is D.C. motor.

34Electrical EngineeringMedium

The purpose of retardation test on D.C. shunt machines is to find out________?

Astray losses

Bwindage losses

Cfield copper losses

Deddy current losses

Correct answer

A. stray losses

Explanation

The correct answer is stray losses.

35Electrical EngineeringMedium

The losses occurring in a D.C. generator are given below. Which loss is likely to have highest proportion at rated load of the generator?

Aeddy current loss

Bhysteresis loss

Cfield copper loss

Darmature copper loss

Correct answer

D. armature copper loss

Explanation

The correct answer is armature copper loss.

36Electrical EngineeringMedium

If the speed of a D.C. shunt motor is increased, the back e.m.f. of the motor will________?

Adecrease

Bbecome zero

Cincrease

Dremain same

Correct answer

C. increase

Explanation

The correct answer is increase.

37Electrical EngineeringMedium

Three point starter can be used for________?

Ashunt motor only

Bboth shunt and compound motor

Cseries motor only

Dcompound motor only

Correct answer

B. both shunt and compound motor

Explanation

The correct answer is both shunt and compound motor.

38Electrical EngineeringMedium

In D.C. shunt motors as load is reduced________?

Athe speed will increase in proportion to reduction in load

Bthe speed will reduce

Cthe speed will increase abruptly

Dthe speed will remain almost/constant

Correct answer

D. the speed will remain almost/constant

Explanation

The correct answer is the speed will remain almost/constant.

39Electrical EngineeringMedium

Which D.C. motor will be preferred for machine tools?

ACumulative compound motor

BShunt motor

CSeries motor

DDifferential compound motor

Correct answer

B. Shunt motor

Explanation

The correct answer is Shunt motor.

40Electrical EngineeringMedium

Which D.C. motor has got maximum self relieving property?

AShunt motor

BCumulatively compounded motor

CDifferentially compounded motor

DSeries motor

Correct answer

D. Series motor

Explanation

The correct answer is Series motor.

31Electrical EngineeringMedium

Kingdom Protoctista includes________?

AFungi

BProkaryotic organisms

CUnicellular organisms

DEu-cariotiquic organisms

Correct answer

C. Unicellular organisms

Explanation

The correct answer is Unicellular organisms.

32Electrical EngineeringMedium

In a D.C. generator, the iron losses mainly take place in________/

Aarmature rotor

Byoke

Carmature conductors

Dcommutator

Correct answer

A. armature rotor

Explanation

The correct answer is armature rotor.

33Electrical EngineeringMedium

Following motor is used where high starting torque and wide speed range control is required?

ANone of the above

BSynchronous motor

CInduction motor

DSingle phase capacitor start

ED.C. motor

Correct answer

E. D.C. motor

Explanation

The correct answer is D.C. motor.

34Electrical EngineeringMedium

The purpose of retardation test on D.C. shunt machines is to find out________?

Astray losses

Bwindage losses

Cfield copper losses

Deddy current losses

Correct answer

A. stray losses

Explanation

The correct answer is stray losses.

35Electrical EngineeringMedium

The losses occurring in a D.C. generator are given below. Which loss is likely to have highest proportion at rated load of the generator?

Aeddy current loss

Bhysteresis loss

Cfield copper loss

Darmature copper loss

Correct answer

D. armature copper loss

Explanation

The correct answer is armature copper loss.

36Electrical EngineeringMedium

If the speed of a D.C. shunt motor is increased, the back e.m.f. of the motor will________?

Adecrease

Bbecome zero

Cincrease

Dremain same

Correct answer

C. increase

Explanation

The correct answer is increase.

37Electrical EngineeringMedium

Three point starter can be used for________?

Ashunt motor only

Bboth shunt and compound motor

Cseries motor only

Dcompound motor only

Correct answer

B. both shunt and compound motor

Explanation

The correct answer is both shunt and compound motor.

38Electrical EngineeringMedium

In D.C. shunt motors as load is reduced________?

Athe speed will increase in proportion to reduction in load

Bthe speed will reduce

Cthe speed will increase abruptly

Dthe speed will remain almost/constant

Correct answer

D. the speed will remain almost/constant

Explanation

The correct answer is the speed will remain almost/constant.

39Electrical EngineeringMedium

Which D.C. motor will be preferred for machine tools?

ACumulative compound motor

BShunt motor

CSeries motor

DDifferential compound motor

Correct answer

B. Shunt motor

Explanation

The correct answer is Shunt motor.

40Electrical EngineeringMedium

Which D.C. motor has got maximum self relieving property?

AShunt motor

BCumulatively compounded motor

CDifferentially compounded motor

DSeries motor

Correct answer

D. Series motor

Explanation

The correct answer is Series motor.