tailieunhanh - HANDBOOK OF SMALL ELECTRIC MOTORS

Electric motors convert electrical energy into mechanical energy by utilizing the properties of electromagnetic energy conversion. The different types of motors operate in different ways and have different methods of calculating the performance, but all utilize some arrangement of magnetic fields. Understanding the concepts of electromagnetics and the systems of units that are employed is essential to understanding electric motor first part of this chapter covers the concepts and units and shows how forces are developed. Nonlinearity of magnetic materials and uses of magnetic materials are explained. Energy and coenergy concepts are used to explain forces, motion, and activation. Finally, this chapter explains how motor torque is developed. | HANDBOOK OF SMALL ELECTRIC MOTORS William H. Yeadon PE . Editor in Chief Alan W. Yeadon . Associate Editor Yeadon Energy Systems Inc Yeadon Engineering Services P. C. McGraw-Hill New York Chicago San Francisco Lisbon London Madrid Mexico City Milan New Delhi San Juan Seoul Singapore Sydney Toronto Library of Congress Cataloging-in-Publication Data Handbook of small electric motors William H. Yeadon editor in chief Alan W. Yeadon associate editor. p. cm. IsBn 0-07-072332-X 1. Electric motors Fractional horsepower. I. Yeadon William H. II. Yeadon Alan W. TK2537 .H34 2001 dc21 00-048974 McGraw-Hill A Division of The McGraw-Hill Companies Copyright 2001 by The McGraw-Hill Companies Inc. All rights reserved. Printed in the United States of America. Except as permitted under the United States Copyright Act of 1976 no part of this publication may be reproduced or distributed in any form or by any means or stored in a data base or retrieval system without the prior written permission of the publisher. 1234567890 DOC DOC 0 7 6 5 4 3 2 1 ISBN 0-07-072332-X The sponsoring editor for this book was Scott Grillo and the production supervisor was Sherri Souffrance. It was set in Times Roman by North Market Street Graphics. Printed and bound by R. R. Donnelley Sons Company. McGraw-Hill books are available at special quantity discounts to use as premiums and sales promotions or for use in corporate training programs. For more information please write to the Director of Special Sales Professional Publishing McGraw-Hill Two Penn Plaza New York NY 10121-2298. Or contact your local bookstore. This handbook is intended to be used as a reference for information regarding the design and manufacture of electric motors. It is not intended to encourage or discourage any motor type design or process. Some of the configurations or processes described herein may be patented. It is the responsibility of the user of this information to determine if any infringement may occur as a .