THE ULTIMATE Tesla Coil Design AND CONSTRUCTION GUIDE This page intentionally left blank THE ULTIMATE Tesla Coil Design AND CONSTRUCTION GUIDE Mitch Tilbury New York Chicago San Francisco Lisbon London Madrid Mexico City Milan New Delhi San Juan Seoul Singapore Sydney Toronto Copyright © 2008 by The McGraw-Hill Companies, Inc. All rights reserved. Manufactured 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 database or retrieval system, without the prior written permission of the publisher. 0-07-159589-9 The material in this eBook also appears in the print version of this title: 0-07-149737-4. All trademarks are trademarks of their respective owners. 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If you’d like more information about this book, its author, or related books and websites, please click here. These works are dedicated to my brother Romney. His contributions to the human endeavor are best stated: All that was great in the past was ridiculed, condemned, combated, suppressed—only to emerge all the more powerfully, all the more triumphantly from the struggle. Let the future tell the truth and evaluate each one according to his work and accomplishments. The present is theirs, the future, for which I really worked, is mine. —Nikola Tesla This page intentionally left blank Disclaimer he author has made every effort to warn the reader of any known dangers involved when working with high voltage. The intent of the material in this text is to assist a hob- T byist in designing and operating a Tesla coil while developing insight to safe working practices. Some degree of existing experience is inferred. Electrical design work is by nature interpretive, following the procedures in a design guide are not always reproducible or pre- dictable. Chapters have been included in this guide on electrical safety and designing control circuits that should prevent operator injury if followed. Beware when using surplus parts, whose operating history and material condition is always unknown and should always be treated with caution. The author accepts no legal responsibility for any personal injury or equipment damage encountered by users as a result of following the methods and information contained in this text. If you are careless, senseless, or otherwise irresponsible you should not engage in this work! This may not be readily apparent as a person would tend to avoid such criticism or awareness. Evaluate your current hobbies or what you do as a profession and how well you do it. Does it involve a degree of creativity? Does it include manual skills and hands-on work? Are you familiar with basic electrical theory and have you applied it to any electrical work? Are you experienced in such matters? If you cannot answer yes to these questions you should engage in another line of interest for your own safety. vii Copyright © 2008 by The McGraw-Hill Companies, Inc. Click here for terms of use. This page intentionally left blank For more information about this title, click here Contents Disclaimer .................................................................. vii List of Illustrations .......................................................... xiii List of Tables ................................................................ xxi Foreword ................................................................... xxiii Preface ...................................................................... xxv 1 Introduction to Coiling ...................................................... 1 1.1 Surplus Parts ........................................................... 2 1.2 Using Microsoft Excel .................................................. 2 1.3 Using a Computerized Analog Circuit Simulation Program (Spice) ..... 3 1.4 Derivation of Formulae Found in This Guide ........................... 3 1.5 Electrical Safety, the Human Body Model and Electrocution ............ 3 1.6 Derating ............................................................... 9 2 Designing a Spark Gap Tesla Coil .......................................... 11 2.1 Designing the Tesla Coil Using a Spark Gap Topology .................. 11 2.2 Calculating the Secondary Characteristics of a Spark Gap Coil .......... 15 2.3 Calculating the Primary Characteristics of a Spark Gap Coil ............ 23 2.4 Calculating the Resonant Characteristics of a Spark Gap Coil ........... 33 2.5 Simulating the Waveforms in a Spark Gap Coil Design ................. 44 2.6 Optimizing the Spark Gap Coil Design ................................. 47 2.7 Calculation Accuracy .................................................. 56 3 Resonance ................................................................... 59 3.1 Resonant Effects in Series RLC Circuits ................................. 59 3.2 Resonant Effects in Parallel LC Circuits ................................. 64 3.3 Determining the Resonant Frequency of Two Tuned Circuits in a Spark Gap Coil ......................................................... 68 3.4 Other Resonant Calculations ........................................... 71 4 Inductors and Air Core Transformers ....................................... 75 4.1 Calculating Inductor Parameters ....................................... 75 4.2 Helical Inductors ....................................................... 76 4.3 Helical Solenoids ....................................................... 81 4.4 Archimedes Spiral Inductors ........................................... 83 4.5 Toroidal Inductors ..................................................... 85 4.6 Effect of Coil Form Geometry .......................................... 87 4.7 Calculating Magnet Wire Parameters ................................... 90 4.8 Skin Effect in Inductors ................................................ 92 ix x Contents 4.9 Mutual Inductance ..................................................... 98 4.10 Leakage Inductance .................................................... 108 4.11 Relationships of Primary and Secondary Windings in Iron Core Transformers ..................................................... 112 4.12 Determining Transformer Relationships in an Unmarked Iron Core Transformer ...................................................... 117 4.13 Relationships of Primary and Secondary Windings in Air Core Transformers ..................................................... 117 4.14 Hysteresis Curve in Air Core Resonant Transformers ................... 118 4.15 Measuring the Resonance of a Coil ..................................... 118 5 Capacitors ................................................................... 123 5.1 Capacitor Applications in Tesla Coils ................................... 124 5.2 Increasing Capacitance