Objective DC Motors Questions – Electrical Engineering

#1📜 EE Pre-Board August 2012📘 PowerhouseEasy

The greatest percentage of power loss in dc motor is due to

AWindage loss

BCore Loss

CCopper Loss

DFriction Loss

#2📜 EE Pre-Board August 2012📘 PowerhouseEasy

Which motor is used to start heavy loads?

ASeries

BShunt

CCumulative Compound

DDifferential Compound

#3📜 EE Pre-Board March 2014📘 PowerhouseEasy

As the load is increased the speed of a dc shunt motor will

Aremain constant

Bincrease slightly

Cincrease proportionally

Dreduce slightly

#4📜 EE Pre-Board March 2014📘 PowerhouseEasy

The armature current drawn by any dc motor is proportional to

Athe voltage applied to the motor

Bthe torque required

Cthe flux required in the motor

Dthe speed of the motor

#5📜 EE Pre-Board March 2015📘 PowerhouseEasy

The armature current drawn by any dc motor is proportional to

AThe voltage applied to the motor

Bthe torque required

CThe flux required in the motor

DThe speed of the motor

#6📜 EE Pre-Board March 2015📘 PowerhouseEasy

An external resistance is added in series with the field of a dc shunt motor. When the motor runs, the effect of resistance is

ATo reduce the speed of the motor

BTo increase the speed of the motor

CTo reduce the armature current drawn by the motor

DTo reduce the losses

#7📜 EE Pre-Board August 2015📘 PowerhouseEasy

The primary reason for using carbon brushes over copper brushes in DC motors is

AThey have low loss

BThey are stronger

CThey produce less arcing

Dall of these

#8📜 EE Pre-Board August 2015📘 PowerhouseEasy

Power developed by a dc motor is maximum when the ratio of back emf to applied voltage is

ADouble

BZero

CUnity

DHalf

#9📜 EE Pre-Board March 2016📘 PowerhouseEasy

When a dc motor has no load, what will happen to the back emf?

AReduces

BIncreases

CBecomes Maximum

DBecomes Zero

#10📜 EE Pre-Board March 2016📘 PowerhouseEasy

The current flowing in the armature conductors of a dc motor is

Aac

Bdc

Cac as well as dc

DTransients

#11📜 EE Pre-Board August 2017📘 PowerhouseEasy

If the load current and flux of a dc motor are held constant and the voltage applied across its armature is increased by 10%, its speed will ___________.

Adecrease by about 10%

Bremain the same

Cincrease by about 10%

Ddouble

#12📜 EE Pre-Board March 2018📘 PowerhouseEasy

In a shunt motor, what is the relative connection of the armature winding with respect to the field winding?

Aseries

Bparallel-series

Cseries-parallel

Dparallel

#13📜 EE Pre-Board March 2018📘 PowerhouseEasy

In a series motor, what is the connection of the field winding with respect to the armature?

Aseries

Bparallel

Cseries-parallel

Ddelta

#14📜 EE Pre-Board March 2018📘 PowerhouseEasy

When the motor runs on no load, then

ABack emf is almost equal to applied voltage

BBack emf will be greater than applied voltage

CBack emf will be less than applied voltage

DNone of these

#15📜 EE Pre-Board March 2018📘 PowerhouseEasy

A device that repeatedly reverses the polarity of a magnetic field in order to keep a dc motor rotating is known as

Aa solenoid

Ban armature coil

Ca commutator

Da field coil

#16📜 EE Pre-Board August 2018📘 PowerhouseEasy

If the field of a dc shunt motor is opened

Ait will continue to run at its rated speed

Bthe speed of the motor will become very high

CThe motor will stop

Dthe speed of the motor will decrease

#17📘 EE Pocket Reviewer RojasEasy

Which motor is used in electric shavers?

AShaded-pole motor

BHysteresis motor

CReluctance motor

DUniversal motor

#18📘 EE Pocket Reviewer RojasEasy

What is the purpose of the compensating windings in a series ac motor?

ATo compensate for decrease in field flux

BTo increase the torque capacity

CTo reduce the sparking at the brushes

DTo reduce effects of armature reaction

#19📘 EE Pocket Reviewer RojasEasy

Ward Leonard controlled DC drives are generally used in which of the following types of excavators?

ALight duty

BMedium duty

CHeavy duty

DAll of these

#20📘 EE Pocket Reviewer RojasEasy

Which of the following is true about a capacitor- start, capacitor-run induction motor?

AIt has no centrifugal switch

BIt has a noisy operation

CIt has a low power factor

DIt has a low efficiency

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