Current Evolution in a Pulsed Overstressed Radial Vacuum Gap

F. T. Warren, R. L. Boxman, J. E. Thompson, J. M. Butner

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


The evolution of current in a radial, two element, vacuum gap has been studied as a function of applied voltage. Gap spacings of 1 and 2 mm, between coaxial brass electrodes, at a pressure of 1×102 Pa, have been used. Voltage pulses between 20 kV and 176 kV, with 15 ns risetimes and 50 ns durations, have been applied to the vacuum gap using a water-filled Blumlein generator having a source impedance of 10 Ω. The data indicate that voltages on the order of 32 and 60 kV can be applied to 1 and 2 mm gaps, respectively, without drawing currents larger than 100 A during the excitation time. For applied voltages greater than 60 kV, current approximately equal to the short circuit value was observed in a 1 mm gap. For higher voltage excitations, breakdown delays on the order of 5 ns, with an initial current rate of rise of up to 8×1011 A/s, have been obtained.

Original languageEnglish
Pages (from-to)226-229
Number of pages4
JournalIEEE Transactions on Electrical Insulation
Issue number3
StatePublished - Jun 1983
Externally publishedYes


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