Voltage-dividing dc circuit breaker and method

Claim 1

A voltage dividing DC circuit breaker for breaking a circuit against line voltage and having circuit breaking components of insufficient capability for withstanding open circuit line voltage comprising: first and second buses in said circuit breaker; first and second serially connected switches connected between said buses and connected to an intermediate bus therebetween; an electronic switch capable of offswitching all the current through said circuit breaker against voltage build up less than the open circuit voltage connected in parallel to said second switch between said intermediate and second buses; and first and second serially connected capacitors connected to said first and second buses and at their intermediate point connected to said intermediate bus, so thatin normal conduction current flows through said circuit breaker through said first and second switches in the closed condition, and when said first and second switches are opened, said first switch arcs and said second switch forces the circuit current through said electronic switch, and when said electronic switch is offswitched, current through said first switch decreases so that its arc extinguishes and current builds up with the standoff voltage divided between said first bus, and said intermediate bus and said second bus in accordance with the capacities of first and second capacitors.

Claim 11

The method of offswitching DC current flowing from a first bus to a second bus and where first and second serially connected switches are connected between the first and second buses and to an intermediate bus therebetween, with an electronic switch connected between the intermediate bus and the second bus, and with serially connected capacitors connected between the first and second buses and to the intermediate bus, comprising the steps of: permitting conduction through closed first and second switches for current flow from the first to the second bus; opening the second switch to force current flow through the electronic switch so that the second switch ceases conduction; opening the first switch so that it continues conduction of the circuit current through arcing; turning off the electronic switch so that the current through the first switch is reduced sufficiently low so that arcing of the first switch deionizes; and dividing the voltage rise across said first switch and said electronic switch resulting from cessation of conduction through said first switch and said electronic switch in accordance with the series capacitors connected in parallel thereto.

Claim 12

The method of offswitching DC current flowing from a first bus to a second bus and where first and second serially connected switches are connected between the first and second buses and to an intermediate bus therebetween, with an electronic switch connected between the intermediate bus and the second bus, and with serially connected capacitors connected between the first and second buses and to the intermediate bus, comprising the steps of: permitting conduction through closed first and second switches for current flow from the first to the second bus; opening the second switch to force current flow through the electronic switch so that the second switch ceases conduction; opening the first switch so that it continues conduction of the circuit current through arcing; turning off the electronic switch so that the current through the first switch is reduced sufficiently low so that arcing of the first switch deionizes; and dividing the voltage rise across said first switch and said electronic switch resulting from cessation of conduction through said first switch and said electronic switch in accordance with the series capacitors connected in parallel thereto.