An accurate quantitative picture of electric field distribution is essential in many electrical and electronic applications. In composite dielectric configurations composed of multiple dielectrics, anomalous or unexpected behavior of electric fields may appear when a solid dielectric is in contact with a conductor or another solid dielectric. The electric field near the contact point may become higher than the original field not only in the surrounding medium but also in the solid dielectric. Theoretically it may become infinitely high, depending on the contact angle. Although these characteristics are very important in a variety of applications, they have been clarified only recently using analytical and numerical calculation methods, and this is the first book to cover these new findings.
<EM>Electric Fields in Composite Dielectrics and Their Applications describes the fundamental characteristics and practical applications of electric fields in composite dielectrics. The focus is on the field distribution (and the resultant force when appropriate) near points of contact. Applications include insulation design of high-voltage equipment with solid insulating supports, utilization of electrostatic force on dielectric particles in electrophotography and electrorheological fluids, and others. <EM>Electric Fields in Composite Dielectrics and Their Applications also explains the calculation methods used to analyze electric fields in composite dielectrics.
Power Systems For further volumes: http://www.springer.com/series/4622 . Tadasu Takuma l Boonchai Techaumnat Electric Fields in Composite Dielectrics and their Applications Dr. Tadasu Takuma Atlas Tower 710, Noborito 2130-2 Tama-ku, Kawasaki-City Kanagawa-Pre. 214-0014 Japan
[email protected] Dr. Boonchai Techaumnat Chulalongkorn University Fac. Engineering Dept. Electrical Engineering Phyathai Road 10330 Bangkok Thailand
[email protected] ISSN 1612-1287 e-ISSN 1860-4676 ISBN 978-90-481-9391-2 e-ISBN 978-90-481-9392-9 DOI 10.1007/978-90-481-9392-9 Springer Dordrecht Heidelberg London New York Library of Congress Control Number: 2010933730 # Springer Science+Business Media B.V. 2010 No part of this work may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, microfilming, recording or otherwise, without written permission from the Publisher, with the exception of any material supplied specifically for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work. Cover design: SPI Publisher Services Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com) Preface When a solid dielectric is placed in an electric field, how does the field change? Does it increase or decrease from the original value? The commonsense answer is as follows: the field becomes higher in the surrounding medium (gas, liquid, or vacuum), but lower in the solid dielectric. This is mainly because the normal component of the electric flux density, which is the electric field strength multiplied by the permittivity, is continuous at the dielectric interface (solid surface) when no true charge exists. Thus the field will increase in the surrounding medium with a lower dielectric constant (relative permittivity) and decrease in the solid dielectric with a higher dielectric constant. The situation is quite different if a solid dielectric is in contact with a conductor o