Test: DC Machine Applications


15 Questions MCQ Test Electrical Machines | Test: DC Machine Applications


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This mock test of Test: DC Machine Applications for Electrical Engineering (EE) helps you for every Electrical Engineering (EE) entrance exam. This contains 15 Multiple Choice Questions for Electrical Engineering (EE) Test: DC Machine Applications (mcq) to study with solutions a complete question bank. The solved questions answers in this Test: DC Machine Applications quiz give you a good mix of easy questions and tough questions. Electrical Engineering (EE) students definitely take this Test: DC Machine Applications exercise for a better result in the exam. You can find other Test: DC Machine Applications extra questions, long questions & short questions for Electrical Engineering (EE) on EduRev as well by searching above.
QUESTION: 1

Inspite of heavy initial investments, dc motors are used due to

Solution:

The control of dc machines is very much simplified when compared to other machines. So this makes it very useful when compared.

QUESTION: 2

Separately excited dc generators are used in

Solution:

Separately excited dc generators are used in Ward leonard system of speed control.

QUESTION: 3

 Maximum torque in dc series motor is limited by

Solution:

Commutation is the process which reduces the induced emf and so the torque.

QUESTION: 4

 Hoists, cranes and battery powered vehicles use _________ motors in the locomotive.

Solution:

Hoists, cranes require large starting torque which can be provided by dc series motor.

QUESTION: 5

There is an application which required pulsating loads, punch presses. The most preferred machines would be

Solution:

 It is compound machine whose flux can varied higher as well as lower in order to have variable torques.

QUESTION: 6

The manufacturer has mentioned a medium starting torque and 15% speed regulation. The most appropriate motor for his requirement is

Solution:

The dc shunt motor provides a medium values of the torque.

QUESTION: 7

Centrifugal pumps, fans-blowers use

Solution:

 Centrifugal pumps, fans-blowers use shunt as well as induction motor.

QUESTION: 8

Most commercial compound dc generator are normally supplied by manufacturers as over compound machines because

Solution:

 It is usually over compounded so that degree of compounding can be adjusted by diverters across series field.

QUESTION: 9

 Which of the following are applied with differential compound motor?

Solution:

Practically it is never used as the speed can rise very high.

QUESTION: 10

Most commercial compound dc generator are normally supplied by manufacturers as ______ compounded machines.

Solution:

Most commercial compound dc generator are normally supplied by manufacturers as over compounded.

QUESTION: 11

Long back ago, magnetic casette were in use, having permanent magnet dc motors which had

Solution:

PMDC motors have field fixed on the stator and rotor has coils.

QUESTION: 12

. If a dc shunt motor is stopped by forcing starter handle back to OFF position, then

Solution:

The sparking will occur at the last stud not all the studs of the starter.

QUESTION: 13

 Interpoles are used to start the dc motor above the base speed.

Solution:

 Interpoles do not reduce the flux across the windings, hence the speed does not rise above base speed.

QUESTION: 14

A 200 V dc motor has external resistances of Ra and Rf in armature and field circuits respectively. The starting current is reduced when

Solution:

When Ra is maximum and Rf minimum then the current to the armature is reduced. And hence the sparkings are reduced while starting.

QUESTION: 15

A d.c. generator has been provided tappings on the armature winding at intervals of 120 degrees from the side of commutator. The connection will be

Solution:

Dc generator if has displaced by 120 degrees physically then it will be act as ac machine.

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