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BASIC

ELECTRICAL ENGINEERING

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BASIC

ELECTRICAL

ENGINEERING

FOURTH EDITION

C. L. Wadhwa

Formerly Professor

Department of Electrical Engineering

Delhi College of Engineering, Delhi

Formerly Dean

Faculty of Technology

University of Delhi, Delhi

NEW AGE INTERNATIONALPUBLISHING FOR ONE(P)WORLDLIMITED, PUBLISHERS

New Delhi Bangalore Chennai Cochin Guwahati Hydcrnbad

Jalandhar Kolkata Lucknow Mumbai Ranchi

Visi[ us ac www.newagepublishers.com

Copyright© 2007, 2006, 2004NewAge International (P) Ltd., Publishers Published by NewAge International (P) Ltd., Publishers

All rights reserved.

No part ofthisebookmay be reproduced in anyform, by photostat, microfilm,xerography, or any other means, or incorporated into any information retrieval syslem, eleclronic or mechanical, without the written permission of the publisher. All inquiries should be emailed to rights@newagepublishers.com

ISBN (13) : 978-81-224-2947-3

PUBLISHINGFORONEWORLD

NEW AGE INTERNATIONAL(P) LIMITED,PUBLISHERS

4835/24,Ansari Road, Daryaganj, NewDelhi - 110002 Visitusat www.newagepublishers.com

To

My mother, who taught me how to hold pen in my little fingers. My father, who taught me modesty and tolerance.

My wife, a symbol of mutual trust and mutual respect. My daughter and son, who exhibited a high degree of patience.

My students, who made me learn the subject. The Almighty, who has created such a beautiful world.

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PREFACE TO THE FOURTH EDITION

In the fourth edition of Basic Electrical Engineering, two more chapters have been

added.

Chapter i on DC circuits explains the International System of Units and gives clear concepts ofelectrical circuits, current, voltage or potential, resistance, power and energy. Also, Ohm's law and Kirchoffs laws havebeen explainedwith asolutionofseries and parallel circuits using these laws.

Chapter ii on electromagnetic induction explains Faraday's laws of electromagnetic induction and Lenz's law. Laws of electromagnetic forces, dynamically and statically induced e.m.f.'s have also been explained. Further, concepts of mutual and self-inductances, and hysteresis losses and eddy current losses have been discussed.

UnderACcircuits, inchapter 1, theconcepts ofleakageflux, fringing flux, magnetostatic potential, m.m.f. and reluctance have been included.

With these additions, the utility of this book has been greatly enhanced.

Any constructive suggestion for further improvement of this book will be gratefully acknowledged.

C.L. Wadhwa

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PREFACE TO THE FIRST EDITION

Electrical Engineering has been written as a core course for all engineering students viz. Electronics and Communication, Computer Engineering, Civil, Mechanical Engineering etc. With advancement in technologies in almost all spheres of engineering, it is becoming difficult to provide more than one slot for interdisciplinary courses. However, the author feels that no engineering can work without electric energy. The basic input to all engineering is the electric energy. A basic course on Electrical Engineering is almost essential for all engineering students. Keeping this compulsion in mind and also that this course will normally he offered at the first year level of engineering, the author has made modest effort to give in a concise form various features of Electrical Engineering starting from simple ac circuits to Networktheorems, measuring instruments, transformers, various de and ac machines including stepper motor. Various physical phenomenon have been explained using simple language avoidingthe rigorus of mathematics.

Chapter I deals with the steady state analysis of a.c. series and parallel circuits and series and parallel resonance.

Chapter II describes various network theorems, star-delta transformation and methods of mesh and nodal analysis for de networks.

Balanced and unbalanced, three phase circuits have been analysed and methods of 3- phase power measurements have been discussed in Chapter III.

Measuring instruments like, ammeter, voltmeter, wattmeter and energy meter have been described in chapter IV.

Transformer is a very important electrical equipment. The construction, principle of operation, parametercalculations, efficiency and regulation of transformer have been discussed in chapter V.

Chapter VI deals in types of de machines, their operation and characteristics, efficiency and speed control and application of these machines.

Chapter VII deals into the construction, principle ofoperation and applications ofthree phase synchronous motors and stepper motor.

Three phase induction motors form atmost 60 to 70% of the total load on power system. These motors have been discussed in chapter VIII including types, construction, principle of operation, methods of starting, torque-slip characteristic, application and single phasing operation. Singlephaseinductionmotors findwideapplication in Office and domestic appliances. Construction, principle of operation and application of these motors have been described in chapter IX.

Power systems is the most capital intensive and the most complex system ever devel­ oped by man. Chapter X gives in brief, various supply and distribution systems and suggests methods for improvement of power factor.

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