pdfcrowd.comopen in browser PRO version Are you a developer? Try out the HTML to PDF API

Posts Tagged: "ElectricalEngineering Interviewquestions"

Electric Drives InterviewQuestions

Dileep - December 4, 2013 - Electric Drives

Q. What is an Electric Drive?

A. The entire unit consisting of an electric motor, the energy transmitting shaft and the control equipment is called

pdfcrowd.comopen in browser PRO version Are you a developer? Try out the HTML to PDF API

an electric drive.

Q. What are the advantages of electric drives?

A. 1. These drives are available in wide range torque, speed and power.

2. Flexible control characteristics.

3. They are adaptable to any type of working conditions

4. They can operate in all the four quadrants of speed torque plane, which is not applicable for other prime

movers.

5. The operation is pollution free.

6. Lower noise, less maintenance.

7. Their efficiency is high as no load losses are less

Continue Reading

Electrical Machines InterviewQuestions D.C Machines

pdfcrowd.comopen in browser PRO version Are you a developer? Try out the HTML to PDF API

Dileep - November 26, 2013 - Electrical Machines

Q. Principle of operation of a generator?

A. An electric generator is a machine that converts mechanical energy into electrical energy. An electric generator

is based on the principle that whenever flux is cut by a conductor, an e.m.f. is induced which will cause a current to

flow if the conductor circuit is closed. The direction of induced e.m.f. (and hence current) is given by Flemings

right hand rule.

Q. What is the role of a Commutator?

A. The function of commutator is to facilitate the collection of current from armature conductors. It converts the

alternating current induce in the armature conductors into unidirectional current in the external load circuit.

Q. What is the function of brushes?

A. The purpose of brushes is simply to lead current from the rotating loop or winding to the external stationary

load.

Q. What are the different types of generators?

A. Generators are generally classified based on their methods of field excitation

(i) Separately excited d.c. generators

(ii) Self-excited d.c. generators

pdfcrowd.comopen in browser PRO version Are you a developer? Try out the HTML to PDF API

Q. How do you define separately excited generators?

A. A d.c. generator whose field magnet winding is supplied from an independent external d.c. source (e.g., a

battery etc.) is called a separately excited generator.

Continue Reading

Power Electronics InterviewQuestions

Dileep - November 13, 2013 - Power Electronics

Q. Definition of power electronics?

A. Power electronics refers to control and conversion of electrical power by power semiconductor devices

wherein these devices operate as switches.

Q. What is the main purpose of power electronics?

pdfcrowd.comopen in browser PRO version Are you a developer? Try out the HTML to PDF API

A. The main task of power electronics is to control and convert electrical power from one form to another.

AC to DC conversion: Rectifier is used for converting an AC voltage to a DC voltage.

Rectifier applications: Variable speed dc drives, Battery chargers, DC power supplies and Power supply for a

specific application like electroplating.

DC to AC conversion: Inverter circuit is used to convert DC voltage to an alternating voltage.

Inverter applications: Emergency lighting systems, AC variable speed drives, Un-interrupted power supplies and

Frequency converters.

DC to DC conversion: A dc-to-dc converter circuit was called a chopper.

Chopper applications: DC drive, Battery charger and DC power supply.

AC to AC conversion: A cycloconverter converts an AC voltage to another AC voltage.

Cycloconverter applications: It is rarely used. Can be used for controlling the speed of an AC traction motor

Continue Reading

Transformers Interview QuestionsDileep - November 13, 2013 - Transformers

pdfcrowd.comopen in browser PRO version Are you a developer? Try out the HTML to PDF API

Q. What is a Transformer?

A. A transformer is a static electrical apparatus designed to convert alternating current from one voltage to

another .It transforms electrical energy from one circuit to another without any direct electrical connection, with the

help of mutual induction between to windings. It can be designed to step up or step down voltages.

Q. Explain the working principle of Transformer?

A. Working principle of Transformer is based on Faradays Laws of Electromagnetic Induction. If an alternating

current is applied to an electric coil, there will be an alternating flux surrounding that coil. Now if we bring another

coil near the first one, there will be an alternating flux linkage with that second coil. As the flux is alternating, there

will be obviously a rate of change of flux linkage with respect to time in the second coil. Therefore emf will be

induced in it as per Faradays laws electromagnetic induction.

Q. How do you classify transformers based on construction?

A. Based on construction transformers are of two types. They are distinguished from each other based on merely

the manner by which primary and secondary windings are placed around the core.

1. Core type: In these windings surround considerable part of the core.

2. Shell type: In these core surrounds considerable part of windings.

Another recent development is wound core type or spiral core.

pdfcrowd.comopen in browser PRO version Are you a developer? Try out the HTML to PDF API

Continue Reading

CONTACT US COPYRIGHT TERMS OF USE & PRIVACY POLICY

Copyright Electrical Prep 2013

Powered by Wordpress. Designed by