2nd Edition

The Vacuum Interrupter Theory, Design, and Application

By Paul G. Slade Copyright 2021
    666 Pages 575 B/W Illustrations
    by CRC Press

    666 Pages 575 B/W Illustrations
    by CRC Press

    Title: The Vacuum Interrupter: Theory, Design, and Application
    Shelving guide: Electrical Engineering

    Dr. Paul Slade draws from his nearly six decades of active experience to develop this second edition of The Vacuum Interrupter: Theory, Design, and Application. This book begins by discussing the design requirements for high voltage vacuum interrupters and then the contact requirements to interrupt the vacuum arc. It then continues by describing the various applications in which the vacuum interrupter is generally utilized.

    Part 1 of this book begins with a detailed review of the vacuum breakdown process. It continues by covering the steps necessary for the design and the manufacture of a successful vacuum interrupter. The vacuum arc is then discussed, including how it is affected as a function of current. An overview of the development and use of practical contact materials, along with their advantages and disadvantages, follows. Contact designs that are introduced to control the high current vacuum arc are also analyzed.

    Part 2, on application, begins with a discussion of the arc interruption process for low current and high current vacuum arcs. It examines the voltage escalation phenomenon that can occur when interrupting inductive circuits. The occurrence of contact welding for closed contacts subjected to the passage of high currents, and for contacts when closing on high currents, is explored. The general requirements for the successful manufacture and testing of vacuum circuit breakers is then presented. The general application of vacuum interrupters to switch load currents, especially when applied to capacitor circuits, is also given. The interruption of high short circuit currents is presented along with the expected performance of the two major contact designs.

    Owing to the ever-increasing need for environmentally friendly circuit protection devices, the development and application of the vacuum interrupter will only increase in the future. At present the vacuum circuit breaker is the technology of choice for distribution circuits (5kV to 40.5kV). It is increasingly being applied to transmission circuits (72.5kV to 242kV). In the future, its application for protecting high voltage DC networks is assured.


    • This is a practical source book for engineers and scientists interested in studying the development and application of the vacuum interrupter
    • Research scientists in industry and universities
    • Graduate students beginning their study of vacuum interrupter phenomena
    • Design engineers applying vacuum interrupters in vacuum switches, vacuum contactors, vacuum circuit breakers, and vacuum contactors
    • It provides a unique and comprehensive review of all aspects of vacuum interrupter technology for those new to the subject and for those who wish to obtain a deeper understanding of its science and application
    • Scientists and engineers, who are beginning their research into vacuum breakdown and aspects of the vacuum arc, will find the extensive bibliography and phenomenological descriptions to be a useful introduction

    1. High Voltage Vacuum Interrupter Design
    1.1. Introduction
    1.2. The External Design
    1.3. Electrical Breakdown in Vacuum
    1.4. Internal Vacuum Interrupter Design

    2. The Vacuum Arc
    2.1. The Closed Contact
    2.2. The Formation of the Vacuum Arc During Contact Opening
    2.3. The Diffuse Vacuum Arc
    2.4. The Columnar Vacuum Arc
    2.5. The Transition Vacuum Arc
    2.6. The Interaction of the Vacuum Arc and a Transverse Magnetic Field
    2.7. The Vacuum Arc and an Axial Magnetic Field
    2.8. Overview and Review of the Three Forms of Anode Spot

    3. The Materials, Design and Manufacture of the Vacuum Interrupter
    3.1. Introduction
    3.2. Vacuum Interrupter Contact Materials
    3.3. The Contact Structures for the Vacuum Interrupter
    3.4. Other Vacuum Interrupter Design Features
    3.5. Vacuum Interrupter Manufacture

    4. General Aspects of Vacuum Interrupter Application
    4.1. Introduction
    4.2. The Interruption of Ac Circuits
    4.3. Interruption of Ac Circuits When the Contacts Open Just Before Current Zero
    4.4. Contact Welding

    5. Application of The Vacuum Interrupter for Switching Load Currents
    5.1. Introduction
    5.2. Load Current Switching
    5.3. Switching Inductive Circuits
    5.4. Vacuum Contactors
    5.5. Switching Capacitor Circuits
    5.6. Vacuum Interrupters for Circuit Switching, Circuit Isolation And Circuit Grounding
    5.7. Summary

    6. Circuit Protection, Vacuum Circuit Breakers and Reclosers
    6.1 Introduction
    6.2. Load Currents
    6.3. Short-Circuit Currents
    6.4. Late Breakdowns and Non-Sustained Disruptive Discharges (Nsdd’s)
    6.5. Vacuum Circuit Breaker Design
    6.6. Vacuum Circuit Breaker Testing and Certification
    6.7. Vacuum Circuit Breakers for Capacitor Switching, Cable and Line Switching and Motor Switching
    6.8. Application of Vacuum Circuit Breakers for Distribution Circuits (4.76 Kv to 40.5 Kv)
    6.9. Vacuum Interrupters in Series
    6.10 Vacuum Interrupters for Sub-Transmission and Transmission Systems
    6.11. Swiching Dc Ciruits Using Vacuum Interrupters
    6.12. Development of Vacuum Interrupters for Low Voltage (< 1000v) Circuit Breakers
    6.13. Concluding Summary


    Paul G. Slade has been an independent consultant for vacuum interrupter technology, electrical contacts and circuit interruption, since his retirement. He is also the holder of 23 US patents. He is the major contributor and editor of the 2nd edition of the book “Electrical Contacts: Principles and Applications”. He is the recipient of the IEEE Ragnar Holm Scientific Achievement Award and of the German VDE Albert Keil Pries for his contributions to the science of electrical contacts. He is a fellow of the IEEE.