Electrical Engineering (EE) Exam  >  Electrical Engineering (EE) Tests  >  Test: Effect of Brush Shift & Compensation Windings - Electrical Engineering (EE) MCQ

Test: Effect of Brush Shift & Compensation Windings - Electrical Engineering (EE) MCQ


Test Description

15 Questions MCQ Test - Test: Effect of Brush Shift & Compensation Windings

Test: Effect of Brush Shift & Compensation Windings for Electrical Engineering (EE) 2024 is part of Electrical Engineering (EE) preparation. The Test: Effect of Brush Shift & Compensation Windings questions and answers have been prepared according to the Electrical Engineering (EE) exam syllabus.The Test: Effect of Brush Shift & Compensation Windings MCQs are made for Electrical Engineering (EE) 2024 Exam. Find important definitions, questions, notes, meanings, examples, exercises, MCQs and online tests for Test: Effect of Brush Shift & Compensation Windings below.
Solutions of Test: Effect of Brush Shift & Compensation Windings questions in English are available as part of our course for Electrical Engineering (EE) & Test: Effect of Brush Shift & Compensation Windings solutions in Hindi for Electrical Engineering (EE) course. Download more important topics, notes, lectures and mock test series for Electrical Engineering (EE) Exam by signing up for free. Attempt Test: Effect of Brush Shift & Compensation Windings | 15 questions in 10 minutes | Mock test for Electrical Engineering (EE) preparation | Free important questions MCQ to study for Electrical Engineering (EE) Exam | Download free PDF with solutions
Test: Effect of Brush Shift & Compensation Windings - Question 1

 The brushes are placed

Detailed Solution for Test: Effect of Brush Shift & Compensation Windings - Question 1

The brushes are placed along magnetic neutral axi so that in ideal conditions commutations take place without sparking. 

Test: Effect of Brush Shift & Compensation Windings - Question 2

The brushes should be shifted in _______ direction in generator for the satisfactory operation of commutation.

Detailed Solution for Test: Effect of Brush Shift & Compensation Windings - Question 2

For the generator, the electromagnetic torque produced is in the opposite direction and so the induced current. So to eliminate the sparking the brushes should be shifted in the forward direction of rotation.

1 Crore+ students have signed up on EduRev. Have you? Download the App
Test: Effect of Brush Shift & Compensation Windings - Question 3

With no commutating poles used the brushes are given backward lead in the dc motor.

Detailed Solution for Test: Effect of Brush Shift & Compensation Windings - Question 3

The armature reaction flux at the trailing edge weakens the flux and at the leading edge is strengthens the flux in the dc motor.

Test: Effect of Brush Shift & Compensation Windings - Question 4

If the critical commutation time is 2 ms but it was observed that the practical commutation took 2.5 ms. This is the case of

Detailed Solution for Test: Effect of Brush Shift & Compensation Windings - Question 4

Since the time taken is more than the prescribed time limit for the commutation, it is under commutation.

Test: Effect of Brush Shift & Compensation Windings - Question 5

The coil under going commutation lies along _____ while the coil getting short circuited lies along ____ for a practical dc machine.

Detailed Solution for Test: Effect of Brush Shift & Compensation Windings - Question 5
  • GNA: Stands for geometrical neutral axis, and is the axis that bisects the angle between the center lines of adjacent poles.

  • MNA: Stands for magnetic neutral axis, and is the axis that is perpendicular to the mean direction of the flux passing through the center of the armature.

 In a practical dc machine, the coil undergoing commutation lies along GNA so as the brushes and the coils which actually get short circuited lies along mna. This lead to sparking as a voltage difference is created at the coils.

Test: Effect of Brush Shift & Compensation Windings - Question 6

The principle contributors to magneto motive force is/are

Detailed Solution for Test: Effect of Brush Shift & Compensation Windings - Question 6

 The interaction between the field excitation and armature supply create the mmf and the interconnected behaviour creates the emf.

Test: Effect of Brush Shift & Compensation Windings - Question 7

The absence of compensating winding lead to

Detailed Solution for Test: Effect of Brush Shift & Compensation Windings - Question 7

The static emf induced inside gets reduced due to the armature reaction in large machines when there is no compensating winding present.

Test: Effect of Brush Shift & Compensation Windings - Question 8

The number of compensating conductors/pole faces is _______ where Z is the number of active armature conductors/pole; A is number of parallel paths;(Ia is the armature current)

Detailed Solution for Test: Effect of Brush Shift & Compensation Windings - Question 8

Compensating conductors per pole face is Z/A*Ia.

Test: Effect of Brush Shift & Compensation Windings - Question 9

A 400-V, 1000-A, lap wound dc machine has 10 poles, 860 armature conductors. The number of conductors in the pole face to give full compensation if pole face covers 70% of pole span is

Detailed Solution for Test: Effect of Brush Shift & Compensation Windings - Question 9

AT/pole for the compensating winding = 0.7*(Z*I/2P)
= 0.7*(860*100/2*10)
= 3010 AT.

Test: Effect of Brush Shift & Compensation Windings - Question 10

Each of the following is valid for interpoles except

Detailed Solution for Test: Effect of Brush Shift & Compensation Windings - Question 10

All the options are valid for the interpoles except a because they are connected in series not in parallel.

Test: Effect of Brush Shift & Compensation Windings - Question 11

 Mark the most incorrect. In dc generator, commutation can be improved by

Detailed Solution for Test: Effect of Brush Shift & Compensation Windings - Question 11

All the given measures are used to eliminate the effect of armature reaction and hence improves commutation also.

Test: Effect of Brush Shift & Compensation Windings - Question 12

The commutation process involves basically reversal of current in armature coil as it crosses MNA.

Detailed Solution for Test: Effect of Brush Shift & Compensation Windings - Question 12

By reversing the current direction in the MNA the current can be limited in the coils to avoid sparking.

Test: Effect of Brush Shift & Compensation Windings - Question 13

The armature reaction is produced mainly by

Detailed Solution for Test: Effect of Brush Shift & Compensation Windings - Question 13

The armature reaction is initiated by the loaded conditions of the machine because an unloaded dc machine does not armature flux to get distorted.

Test: Effect of Brush Shift & Compensation Windings - Question 14

The compensating winding in dc generator is provided to

Detailed Solution for Test: Effect of Brush Shift & Compensation Windings - Question 14

The compensating winding functions such that to nullify the cross magnetization effects in the armature.

Test: Effect of Brush Shift & Compensation Windings - Question 15

 If the magnetic circuit of the dc machine is in the saturation region, the armature reaction

Detailed Solution for Test: Effect of Brush Shift & Compensation Windings - Question 15

In the saturation region the flux will be constant.

Information about Test: Effect of Brush Shift & Compensation Windings Page
In this test you can find the Exam questions for Test: Effect of Brush Shift & Compensation Windings solved & explained in the simplest way possible. Besides giving Questions and answers for Test: Effect of Brush Shift & Compensation Windings, EduRev gives you an ample number of Online tests for practice

Top Courses for Electrical Engineering (EE)

Download as PDF

Top Courses for Electrical Engineering (EE)