Accession Number:

ADA633396

Title:

Sensitivity of Ignitrons to Stray Capacitance

Descriptive Note:

Conference paper

Corporate Author:

LAWRENCE LIVERMORE NATIONAL LAB CA

Personal Author(s):

Report Date:

1991-06-01

Pagination or Media Count:

5.0

Abstract:

The surprising sensitivity of ignitors was encountered on RACE, a compact torus device. Its capacitor bank has both the common reverse-crowbar circuit and an unusual forward-crowbar circuit that made this investigation necessary. The ignitors were fired with high-capacitance coaxial-cable pulse transformers. When the bank fired, because of negative bank charge, forward-crowbar ignitrons saw both positive anode voltage and a positive pulse to their ignitors coupled through pulse transformer capacitance. One tube prefired as low as 3 kV. Prefires ceased when coaxial transformers were replaced with double-shielded transformers. Pulse duration and energy were much less than expected. The computed ignitor pulse RC time was only 5.6 ns, far less than a typical 250-ns anode firing delay. The positive capacitive energy input to the ignitor was 0.14 mJ, more than 3 orders of magnitude less than the ignitron firing chassis.

Subject Categories:

  • Electricity and Magnetism

Distribution Statement:

APPROVED FOR PUBLIC RELEASE