Multielement spark-gap switch system. Final report

Abstract

An engineering study was made to formulate a conceptual design for a multielement arc-type electrical switch system for switching 50,000-amp, 100-nsec or less pulses from a 50,000-v source at up to 1000 ppS. The switch is to have a lifetime of at least 5 x 10/sup 8/ pulse MTBF, litter time less than 10 nsec, closure time of less than 20 nsec, and 10 nh or less inductance. An offset midplane triggered spark gap (TSG) with ultraviolet (uv) preionization and forced air was selected as the most suitable switch for this application. Many but not all of the requirements of a full scale switch system were demonstrated in a 2-TSG subsystem. The requirements of current, pulse duration, frequency, lifetime, jitter, and inductance were equal to or better than needed; however, the TSG's were not operated above 36,000 v, mainly because of voltage limitations in the trigger switch. The TSG's were rated at only 35,000 v and were not holding off enough voltage in relation to their total gap spacing due to E-field distortions. Because the voltag-to-gap ratio was lower than optimum, the closure time was excessive to about 33 nsec, or 13 nsec in excess of the specification value.