The Vacuum Interrupter

Book excerpt: Drawn from the author's more than four decades of practical experience in the industry, The Vacuum Interrupter: Theory, Design, and Application first discusses the design and manufacture of the vacuum interrupter before delving into its general application. The book begins with a review of the vacuum breakdown process and what to consider when developing a design for a high-voltage application. It then discusses the vacuum arc and how its appearance changes as a function of current. This section concludes with an overview of existing contact materials, a summary of their advantages and disadvantages, an analysis of vacuum interrupter contact design, and considerations for the manufacture of vacuum interrupters. The next section on application describes the interruption process for low- and high-current vacuum arcs, examines the voltage escalation event that occurs if the contact gap is very small at the ac current zero, and explores the phenomenon of contact welding. It also studies the application of vacuum interrupters to switch load currents, circuit breakers, and reclosers. Owing to the increasing need for environmentally friendly interrupting systems, the development of vacuum interrupters will only intensify over time. With extensive references in each chapter for further exploration, this comprehensive guide provides essential, up-to-date knowledge to fully understand this vital technology.