Series Gaps in Air Break Switches

This paper discusses the electrical characteristics of series gaps used in power switching equipment. The dielectric strength of the series gap for 60-cycle, impulse, and switching surge voltages is discussed and curves are included of the results for gaps of dimensions from 44 to 139 inches. The ability to isolate two circuits and maintain a minimum of disturbance on one circuit when voltage transients occur on the other is discussed. Further discussion includes the potential of the floating blade and the effect of a grounded plane near the floating blade on the series gap strength and the insulator dielectric strength.