ARC SUPPRESSION CIRCUIT USING A SEMI-CONDUCTOR SWITCH

摘要

An arc suppression circuit in a protection relay having trip contacts is use d to turn off a battery-powered solenoid and trip an AC power circuit breaker. The arc suppression circuit uses a switch-control circuit to control the turning off of a semi--conductor switch so that the semi-conductor switch provides a current path around the trip contacts, and is carrying all, or substantially all, of the load curren t, before the trip contacts are opened. When the trip contacts begin to open, the switch-contro l circuit holds the semi-conductor switch on for a sufficient time to prevent an arc from becoming established before turning the semi-conductor switch off. In a seco nd embodiment, the arc suppression circuit provides a second switch-control circuit. This second switch-control circuit is configured to accept control signals from a microprocessor within a protection relay. The microprocessor turns the semi- conductor switch on before the contacts begin to open, thereby providing a current path around the contacts before the contacts begin to open. The microprocess or turns the semi-conductor switch off after a time sufficient to prevent an arc from becoming established.