ElEctric Motors Control SyStemS Electric Motors and Control Systems, First Edition PDF

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Electric Motors and Control Systems, First Edition PETRUZELLA Frank D. Petruzella Browse www.mhhe.com/EMCS1e A TEXT WRITTEN FOR STUDENTS, ELECTRICAL APPRENTICES, JOURNEYMEN, MOTOR MAINTENANCE, AND REPAIRMEN this book has been written for a course of study that will introduce the reader to a broad ra...

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Frank D. Petruzella Browse www.mhhe.com/EMCS1e A TEXT WRITTEN FOR STUDENTS, ELECTRICAL APPRENTICES, JOURNEYMEN, MOTOR MAINTENANCE, AND REPAIRMEN this book has been written for a course of study that will introduce the reader to a broad range of motor types and control systems. It provides an overview of electric motor operation, selection, installation, control, and maintenance. the broad-based approach taken makes this text viable for a variety of motors and control systems courses. Content is suitable for colleges, technical institutions, and vocational/technical schools, as well as apprenticeship and journeymen training.

ELECTRICAL CODES REFERENCED IN THE BOOK electrical apprentices and journeymen will find this book to be invaluable due to national electrical Code references, as well as information on maintenance and troubleshooting techniques. OFFERING CONTENT ON OLDER AND LATEST MOTOR TECHNOLOGIES the text is comprehensive! It includes coverage of how motors operate in conjunction with their associated control circuitry. Both older and newer motor technologies are examined. topics covered range from motor types and controls to installing and maintaining conventional controllers, electronic motor drives, and programmable logic controllers. > > Features you will find unique to this Motors and Controls text include:

Discussion Topics and Critical Thinking Questions these open-ended questions are designed to give students an opportunity to reflect upon the material covered in the chapter. In most cases, they allow for a wide range of responses and provide an opportunity for the student to share more than just facts. ANCILLARIES Activities Manual with Constructor CD for Electric Motors and Control Systems, First Edition ISBN 978-0-07-352182-4 MHID 0-07-352182-5 ISBn: 0-07-734257-7 / 978-0-07-734257-9 EAN www.mhhe.com

Control SyStemS FRANK D. PETRUZELLA

MD DALIM #1017590 03/26/09 CYAN MAG YELO BLK

Troubleshooting Scenarios troubleshooting is an important element of any motors and Controls course. the chapter troubleshooting scenarios are designed to help students, with the aid of the instructor, develop a systematic approach to troubleshooting.

ElEctric Motors

AND

Integration of Diagrams and Photos When the operation of a piece of equipment is illustrated by means of a diagram, a photo of the device is included. this feature is designed to increase the level of recognition of devices associated with motors and control systems.

Control SyStemS

How Circuits Operate When the operation of a circuit is called for, a bulleted list is used to summarize its operation. they are used in place of paragraphs and are especially helpful when explaining the sequenced steps of a motor control operation.

AND

Self-Contained Chapters each chapter constitutes a complete and independent unit of study. All chapters are divided into several parts, each designed to serve as individual lessons. Instructors can easily pick and choose chapters or parts of chapters that meet their particular curriculum needs.

ElEctric Motors

MEETING INDUSTRY NEEDS WITH UP-TO-DATE INFORMATION this first edition text presents the most up-to-date information that reflects the current needs of the industry.

PETRUZELLA

Electric Motors and Control Systems, First Edition

Electric Motors and Control Systems

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Electric Motors and Control Systems

Frank D. Petruzella

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ELECTRIC MOTORS AND CONTROL SYSTEMS Published by McGraw-Hill, a business unit of The McGraw-Hill Companies, Inc., 1221 Avenue of the Americas, New York, NY, 10020. Copyright © 2010 by The McGraw-Hill Companies, Inc. All rights reserved. No part of this publication may be reproduced or distributed in any form or by any means, or stored in a database or retrieval system, without the prior written consent of The McGraw-Hill Companies, Inc., including, but not limited to, in any network or other electronic storage or transmission, or broadcast for distance learning. Some ancillaries, including electronic and print components, may not be available to customers outside the United States. This book is printed on acid-free paper. 1 2 3 4 5 6 7 8 9 0 DOW/DOW 0 9 ISBN 978-0-07-352182-4 MHID 0-07-352182-5 Vice president / Editor in chief: Elizabeth Haefele Vice president / Director of marketing: John E. Biernat Director of Development, Business Careers: Sarah Wood Freelance developmental editor: Kelly H. Lowery Marketing manager: Kelly Curran Lead media producer: Damian Moshak Director, Editing / Design / Production: Jess Ann Kosic Project manager: Jean R. Starr Senior production supervisor: Janean A. Utley Senior designer: Srdjan Savanovic Senior photo research coordinator: Jeremy Cheshareck Photo researcher: Robin Sand Media project manager: Cathy Tepper Cover and interior design: Kay Lieberherr Typeface: 11/13 Times Compositor: Macmillan Publishing Solutions Printer: R. R. Donnelley Cover credit: ©Baldor Electric Company. Photo Baldor, www.baldor.com Credit: All chapter opening photos © Baldor Electric Company. Reprinted with their permission. Photo Baldor, www.baldor.com. Library of Congress Cataloging-in-Publication Data Petruzella, Frank D. Electric motors and control systems / Frank Petruzella. p. cm. Includes index. ISBN-13: 978-0-07-352182-4 (alk. paper) ISBN-10: 0-07-352182-5 (alk. paper) 1. Electric motors. 2. Electric controllers. 3. Electric driving. I. Title. TK2514.P48 2010 621.46--dc22 2009004490 The Internet addresses listed in the text were accurate at the time of publication. The inclusion of a Web site does not indicate an endorsement by the authors or McGraw-Hill, and McGraw-Hill does not guarantee the accuracy of the information presented at these sites.

www.mhhe.com

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Contents Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x About the Author . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi Walkthrough . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xii Chapter 1

Safety in the Workplace

1

Part 1 Protecting against Electrical Shock . . . . . . . . . 1 Electrical Shock . . . . . . . . . . . . . . . . . . . . . . . . 1 Personal Protective Equipment . . . . . . . . . . . . . 4 Part 2 Grounding—Lockout—Codes . . . . . . . . . . . . . 6 Grounding and Bonding . . . . . . . . . . . . . . . . . . 6 Lockout and Tagout . . . . . . . . . . . . . . . . . . . . . 8 Electrical Codes and Standards. . . . . . . . . . . . 10 Chapter 2 Understanding Electrical Drawings

Switchboards and Panelboards . . . . . . . . . . . . Motor Control Centers (MCCs) . . . . . . . . . . . Part 2 Transformer Principles . . . . . . . . . . . . . . . . . . Transformer Operation . . . . . . . . . . . . . . . . . . Transformer Voltage, Current, and Turns Ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . Transformer Power Rating . . . . . . . . . . . . . . . Part 3 Transformer Connections and Systems . . . . . Transformer Polarity . . . . . . . . . . . . . . . . . . . . Single-Phase Transformers . . . . . . . . . . . . . . . Three-Phase Transformers . . . . . . . . . . . . . . . Instrument Transformers . . . . . . . . . . . . . . . . .

44 47 48 48

Chapter 4 Motor Control Devices

60

Part 1 Manually Operated Switches . . . . . . . . . . . . . Primary and Pilot Control Devices . . . . . . . . . . . . . . . . . . . . . . . Toggle Switches . . . . . . . . . . . . . . . . . . . . . . . Pushbutton Switches . . . . . . . . . . . . . . . . . . . . Pilot Lights . . . . . . . . . . . . . . . . . . . . . . . . . . . Selector Switch . . . . . . . . . . . . . . . . . . . . . . . . Drum Switch . . . . . . . . . . . . . . . . . . . . . . . . . . Part 2 Mechanically Operated Switches . . . . . . . . . . Limit Switches . . . . . . . . . . . . . . . . . . . . . . . . Temperature Control Devices . . . . . . . . . . . . . Pressure Switches . . . . . . . . . . . . . . . . . . . . . . Float and Flow Switches . . . . . . . . . . . . . . . . . Part 3 Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Proximity Sensors . . . . . . . . . . . . . . . . . . . . . . Photoelectric Sensors . . . . . . . . . . . . . . . . . . . Hall Effect Sensors . . . . . . . . . . . . . . . . . . . . . Ultrasonic Sensors . . . . . . . . . . . . . . . . . . . . . Temperature Sensors . . . . . . . . . . . . . . . . . . . . Velocity and Position Sensors . . . . . . . . . . . . . Flow Measurement . . . . . . . . . . . . . . . . . . . . . Magnetic Flowmeters . . . . . . . . . . . . . . . . . . . Part 4 Actuators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Relays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Solenoids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Solenoid Valves . . . . . . . . . . . . . . . . . . . . . . . . Stepper Motors . . . . . . . . . . . . . . . . . . . . . . . . Servo Motors. . . . . . . . . . . . . . . . . . . . . . . . . .

60

49 51 53 53 53 55 56

14

Part 1 Symbols—Abbreviations—Ladder Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Motor Symbols . . . . . . . . . . . . . . . . . . . . . . . . 14 Abbreviations for Motor Terms . . . . . . . . . . . 15 Motor Ladder Diagrams . . . . . . . . . . . . . . . . . 15 Part 2 Wiring—Single Line—Block Diagrams. . . . . 21 Wiring Diagrams . . . . . . . . . . . . . . . . . . . . . . . 21 Single-Line Diagrams . . . . . . . . . . . . . . . . . . . 23 Block Diagrams . . . . . . . . . . . . . . . . . . . . . . . 24 Part 3 Motor Terminal Connections . . . . . . . . . . . . . 24 Motor Classification . . . . . . . . . . . . . . . . . . . . 24 DC Motor Connections . . . . . . . . . . . . . . . . . . 25 AC Motor Connections . . . . . . . . . . . . . . . . . . 27 Part 4 Motor Nameplate and Terminology . . . . . . . . 32 NEC Required Nameplate Information . . . . . 32 Optional Nameplate Information . . . . . . . . . . 34 Guide to Motor Terminology . . . . . . . . . . . . . 35 Part 5 Manual and Magnetic Motor Starters . . . . . . . 37 Manual Starter. . . . . . . . . . . . . . . . . . . . . . . . . 37 Magnetic Starter . . . . . . . . . . . . . . . . . . . . . . . 37 Chapter 3 Motor Transformers and Distribution Systems

40

Part 1 Power Distribution Systems . . . . . . . . . . . . . . Transmission Systems . . . . . . . . . . . . . . . . . . . Unit Substations . . . . . . . . . . . . . . . . . . . . . . . Distribution Systems . . . . . . . . . . . . . . . . . . . .

40 40 41 42

60 61 61 64 65 65 66 66 68 69 70 71 71 73 75 76 76 78 79 80 81 81 81 82 84 84

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Chapter 5 Electric Motors

87

Part 1 Motor Principle . . . . . . . . . . . . . . . . . . . . . . . . 87 Magnetism . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 Electromagnetism . . . . . . . . . . . . . . . . . . . . . . 88 Motor Rotation . . . . . . . . . . . . . . . . . . . . . . . . 88 Part 2 Direct Current Motors . . . . . . . . . . . . . . . . . . . 91 Permanent-Magnet DC Motor . . . . . . . . . . . . 91 Series DC Motor . . . . . . . . . . . . . . . . . . . . . . . 93 Shunt DC Motor . . . . . . . . . . . . . . . . . . . . . . . 93 Compound DC Motor . . . . . . . . . . . . . . . . . . . 94 Direction of Rotation . . . . . . . . . . . . . . . . . . . 95 Motor Counter Electromotive Force (CEMF) . . 96 Armature Reaction . . . . . . . . . . . . . . . . . . . . . 97 Speed Regulation . . . . . . . . . . . . . . . . . . . . . . 98 Varying DC Motor Speed . . . . . . . . . . . . . . . . 98 DC Motor Drives . . . . . . . . . . . . . . . . . . . . . . 99 Part 3 Three-Phase Alternating Current Motors . . . 101 Rotating Magnetic Field . . . . . . . . . . . . . . . . 101 Induction Motor . . . . . . . . . . . . . . . . . . . . . . 103 Squirrel Cage Induction Motor . . . . . . . . . . . 103 Wound-Rotor Induction Motor . . . . . . . . . . . 107 Three-Phase Synchronous Motor . . . . . . . . . 107 Part 4 Single-Phase Alternating Current Motors . . . 109 Split-Phase Motor . . . . . . . . . . . . . . . . . . . . . 109 Split-Phase Capacitor Motor . . . . . . . . . . . . . 111 Shaded-Pole Motor . . . . . . . . . . . . . . . . . . . . 113 Universal Motor . . . . . . . . . . . . . . . . . . . . . . 113 Part 5 Alternating Current Motor Drives. . . . . . . . . 114 Variable-Frequency Drive . . . . . . . . . . . . . . . 114 Inverter Duty Motor . . . . . . . . . . . . . . . . . . . 116 Part 6 Motor Selection. . . . . . . . . . . . . . . . . . . . . . . 117 Mechanical Power Rating . . . . . . . . . . . . . . . 117 Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117 Code Letter . . . . . . . . . . . . . . . . . . . . . . . . . . 117 Design Letter. . . . . . . . . . . . . . . . . . . . . . . . . 118 Efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . 118 Energy-Efficient Motors . . . . . . . . . . . . . . . . 118 Frame Size . . . . . . . . . . . . . . . . . . . . . . . . . . 118 Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . 119 Full-Load Speed . . . . . . . . . . . . . . . . . . . . . . 119 Load Requirements . . . . . . . . . . . . . . . . . . . . 119 Motor Temperature Ratings . . . . . . . . . . . . . 120 Duty Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . 120 Torque . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120 Motor Enclosures . . . . . . . . . . . . . . . . . . . . . 121 Metric Motors . . . . . . . . . . . . . . . . . . . . . . . . 121 Part 7 Motor Installation . . . . . . . . . . . . . . . . . . . . . 123 Foundation . . . . . . . . . . . . . . . . . . . . . . . . . . 123 Mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123 Motor and Load Alignment. . . . . . . . . . . . . . 123 Motor Bearings . . . . . . . . . . . . . . . . . . . . . . . 124

vi

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Electrical Connections . . . . . . . . . . . . . . . . . Grounding . . . . . . . . . . . . . . . . . . . . . . . . . . . Conductor Size . . . . . . . . . . . . . . . . . . . . . . . Voltage Levels and Balance . . . . . . . . . . . . . Built-in Thermal Protection . . . . . . . . . . . . . Part 8 Motor Maintenance and Troubleshooting . . . Motor Maintenance . . . . . . . . . . . . . . . . . . . . Troubleshooting Motors . . . . . . . . . . . . . . . . Chapter 6 Contactors and Motor Starters

Part 1 Magnetic Contactor. . . . . . . . . . . . . . . . . . . . Switching Loads . . . . . . . . . . . . . . . . . . . . . . Contactor Assemblies . . . . . . . . . . . . . . . . . . Arc Suppression . . . . . . . . . . . . . . . . . . . . . . Part 2 Contactor Ratings, Enclosures, and Solid-State Types . . . . . . . . . . . . . . . . . . . . . NEMA Ratings . . . . . . . . . . . . . . . . . . . . . . . IEC Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . Contactor Enclosures . . . . . . . . . . . . . . . . . . Solid-State Contactor . . . . . . . . . . . . . . . . . . Part 3 Motor Starters . . . . . . . . . . . . . . . . . . . . . . . . Magnetic Motor Starters . . . . . . . . . . . . . . . . Motor Overcurrent Protection . . . . . . . . . . . . Motor Overload Relays . . . . . . . . . . . . . . . . . Chapter 7 Relays

Part 1 Electromechanical Control Relays . . . . . . . . Relay Operation . . . . . . . . . . . . . . . . . . . . . . Relay Applications . . . . . . . . . . . . . . . . . . . . Relay Styles and Specifications . . . . . . . . . . Part 2 Solid-State Relays . . . . . . . . . . . . . . . . . . . . . Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . Specifications . . . . . . . . . . . . . . . . . . . . . . . . Switching Methods . . . . . . . . . . . . . . . . . . . . Part 3 Timing Relays . . . . . . . . . . . . . . . . . . . . . . . . Motor-Driven Timers . . . . . . . . . . . . . . . . . . Dashpot Timers . . . . . . . . . . . . . . . . . . . . . . . Solid-State Timing Relays . . . . . . . . . . . . . . Timing Functions . . . . . . . . . . . . . . . . . . . . . Multifunction and PLC Timers . . . . . . . . . . . Part 4 Latching Relays . . . . . . . . . . . . . . . . . . . . . . Mechanical Latching Relays . . . . . . . . . . . . . Magnetic Latching Relays . . . . . . . . . . . . . . Latching Relay Applications . . . . . . . . . . . . . Alternating Relays . . . . . . . . . . . . . . . . . . . . Part 5 Relay Control Logic . . . . . . . . . . . . . . . . . . . Control Circuit Inputs and Outputs . . . . . . . . AND Logic Function . . . . . . . . . . . . . . . . . . OR Logic Function . . . . . . . . . . . . . . . . . . . . Combination Logic Functions . . . . . . . . . . .

126 126 126 127 127 128 128 129 135

135 136 140 142 145 145 146 147 147 150 150 151 152 159

159 159 161 161 163 163 164 165 166 167 167 167 168 171 172 172 173 173 174 176 176 177 177 177

Contents

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NOT Logic Function . . . . . . . . . . . . . . . . . . . 177 NAND Logic Function . . . . . . . . . . . . . . . . . 178 NOR Logic Function . . . . . . . . . . . . . . . . . . 178 Chapter 8 Motor Control Circuits

Part 1 NEC Motor Installation Requirements . . . . . Sizing Motor Branch Circuit Conductors . . . . . . . . . . . . . . . . . . . . . . . . . . Branch Circuit Motor Protection . . . . . . . . . Selecting a Motor Controller . . . . . . . . . . . . Disconnecting Means for Motor and Controller . . . . . . . . . . . . . . . . . . Providing a Control Circuit. . . . . . . . . . . . . . Part 2 Motor Starting . . . . . . . . . . . . . . . . . . . . . . . . Full-Voltage Starting of AC Induction Motors. . . . . . . . . . . . . . . . . . . . . . Reduced-Voltage Starting of Induction Motors. . . . . . . . . . . . . . . . . . . . . . DC Motor Starting . . . . . . . . . . . . . . . . . . . . Part 3 Motor Reversing and Jogging . . . . . . . . . . . . Reversing of AC Induction Motors . . . . . . . . Reversing of DC Motors . . . . . . . . . . . . . . . . Jogging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Part 4 Motor Stopping . . . . . . . . . . . . . . . . . . . . . . . Plugging and Antiplugging . . . . . . . . . . . . . . Dynamic Braking . . . . . . . . . . . . . . . . . . . . . DC Injection Braking . . . . . . . . . . . . . . . . . . Electromechanical Friction Brakes . . . . . . . . Part 5 Motor Speed . . . . . . . . . . . . . . . . . . . . . . . . . Multispeed Motors . . . . . . . . . . . . . . . . . . . . Wound-Rotor Motors . . . . . . . . . . . . . . . . . . Chapter 9 Motor Control Electronics

180

Operational Amplifier ICs. . . . . . . . . . . . . . . 555 Timer IC . . . . . . . . . . . . . . . . . . . . . . . . . Microcontroller . . . . . . . . . . . . . . . . . . . . . . . Electrical Discharge (ESD) . . . . . . . . . . . . . . Digital Logic . . . . . . . . . . . . . . . . . . . . . . . . .

180 181 181 184 184 185 187 188 190 196 198 198 202 202 204 204 205 206 206 207 207 208 211

Part 1 Semiconductor Diodes . . . . . . . . . . . . . . . . . 211 Diode Operation . . . . . . . . . . . . . . . . . . . . . . 211 Rectifier Diode . . . . . . . . . . . . . . . . . . . . . . . 212 Zener Diode . . . . . . . . . . . . . . . . . . . . . . . . . 214 Light-Emitting Diode . . . . . . . . . . . . . . . . . . 215 Photodiodes . . . . . . . . . . . . . . . . . . . . . . . . . . 216 Part 2 Transistors . . . . . . . . . . . . . . . . . . . . . . . . . . . 217 Bipolar Junction Transistor (BJT). . . . . . . . . 217 Field-Effect Transistor . . . . . . . . . . . . . . . . . 219 Metal Oxide Semiconductor Field-Effect Transistor (MOSFET) . . . . . . . . . . . . . . ....