High-voltage crowbar circuit with cascade-triggered series ignitrons
AssigneeThe United States of America as represented by the United States Department of Energy
InventorWilliam R. Baker
Life of this patent
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Abstract
A series string of ignitrons for switching a large current at high voltage to ground. Switching is initiated by means of a negative trigger pulse applied to the cathode of the lowest voltage level ignitron next to ground to draw ground current through diodes in the ignitor circuit. The trigger pulse is applied thereby to the next higher ignitron cathode and sequentially to the remainder of the ignitrons in the string through diodes in respective ignitor circuits. Full line voltage is held off of nonconducting diodes and ignitrons by means of varistors.
Claims16
A crowbar circuit for shunting current from a high voltage level to a low voltage level, comprising:
- a first triggerable high voltage current conducting device for connection to the high-voltage level;
- a second triggerable high voltage current conducting device for connection between the low-voltage level and said first device;
- a trigger pulse source for generating a trigger pulse;
- and
- passive means responsive to the trigger pulse from said source for triggering said second device to conduct, said responsive means being operable upon conduction of said second device to apply substantially the full trigger pulse to said first device for triggering said first device to conduct.
A method for shunting current from a high voltage level to a low voltage level through a plurality of ignitrons each including an anode, a cathode and an ignitor, connected anode-to-cathode in a series string from the high voltage level to the low voltage level, comprising the steps of:
- applying a trigger pulse across the ignitron string to ignite the ignitron having its cathode connected to the low voltage level;
- and
- conducting the trigger pulse successively to each ignitron towards the high voltage level, each successive ignitron being ignited thereby to conduction so that upon conduction of the ignitron having its anode connected to the high voltage level, the current at the high voltage level is shunted through the ignitrons to the low voltage level.
Dependencies are inferred from the claim text.