Sensitivity of ignitrons to stray capacitance

Conference · Fri May 10 04:00:00 EDT 1991

OSTI ID:5660937

Cummings, D B

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 capactitive energy input to the ignitor was 0.14 mJ, more than 3 orders of magnitude less than the ignitron firing chassis. 5 figs.

• Research Organization: Lawrence Livermore National Lab., CA (USA)
• Sponsoring Organization: DOE; USDOE, Washington, DC (USA)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 5660937
• Report Number(s): UCRL-JC-105599; CONF-910640--4; ON: DE91013825
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
426000* -- Engineering-- Components
Electron Devices & Circuits-- (1990-)
CAPACITANCE
ELECTRICAL EQUIPMENT
ELECTRICAL PROPERTIES
ELECTRON TUBES
ELECTRONIC CIRCUITS
EQUIPMENT
GAS DISCHARGE TUBES
IGNITRONS
PHYSICAL PROPERTIES
PULSES
RECTIFIER TUBES
SENSITIVITY
TESTING
TRANSFORMERS