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US 4,631,621 AGranted
Gate turn-off control circuit for a solid state circuit interrupter
AssigneeGeneral Electric Company
InventorEdward K. Howell
Life of this patent
Estimating the term…
Abstract
A gate turn-off thyristor is connected across a pair of separable contacts for diverting the interrupted current first to the thyristor and then to a metal oxide varistor connected across the thyristor. A saturable core current transformer in combination with the capacitance provided by the metal oxide varistor turns on the thyristor when the contacts separate and turns off the thyristor after the contacts have further separated when the core becomes saturated.
Claims7
A circuit interrupter comprising:
- a pair of separable contacts serially connected within an electric circuit;
- a gated semiconductor device connected across said contacts for transferring circuit current away from said contacts upon separation;
- and
- control means in circuit with said gated semiconductor device for turning on said gated semiconductor device immediately upon separation of said contacts and for turning off said gated semiconductor device a predetermined time thereafter, said control means including a current transformer connected in series with said gated semiconductor device, a secondary winding of said current transformer being connected to the cathode and gate of said gated semiconductor device to provide regenerative gate current to said gate,
- said current transformer comprising a saturable core for interrupting said gate current to turn off said gated semiconductor after a predetermined time delay.
2 more elements
Dependencies are inferred from the claim text.