Abstract This invention relates to a compressed-gas circuit breaker having two hollow, nozzle-shaped contacts arranged on a common axis and between which an arc is formed upon the disconnection of the breaker. The compressed-gas circuit breaker has an essentially cylindrical arcing electrode centrally disposed in at least one of the hollow contacts and set back within the nozzle opening which surrounds the gap. When the breaker is disconnected the arc is confined between the two contacts within the gap by the flow of the quenching medium and possibly other additional forces. If a strong blast of quenching medium is employed on the arc, according to the invention, to prevent the arc from drifting off the inner arcing electrode during such strong blasts because of increased quenching medium flow and additional forces, the arcing electrode is provided with insulating material on its cylindrical surface and a contact surface is formed on its end face for the arc.
In a compressed-gas circuit breaker wherein a flow of quenching medium is directed toward the arc developed when the breaker is switched to the off position, a switching contact arrangement comprising: two hollow, nozzle-shaped contacts disposed on a common axis, said contacts being spaced from each other to conjointly define a gap therebetween across which the arc is drawn; and a substantially cylindrical arcing electrode centrally mounted in at least one of the hollow contact and set back from the nozzle opening of the hollow contacts, the arcing electrode defining an end-face contact surface for receiving the foot point of the arc driven thereon by the action of the quenching medium during the switch-off operation, said arcing electrode being covered with insulating material on the outer surface thereof up to said end-face contact surface thereby confining the action of the arc on said arcing electrode to said contact surface.
Claim 2
Dependent Claim
149 words
In a compressed-gas circuit breaker wherein a flow of quenching medium is directed toward the arc developed when the breaker is switched to the off position, a switching contact arrangement comprising: two hollow, nozzle-shaped contacts disposed on a common axis, said contacts being spaced from each other to conjointly define a gap therebetween across which the arc is drawn; and a substantially cylindrical arcing electrode centrally mounted in at least one of the hollow contact and set back from the nozzle opening of the hollow contacts, the arcing electrode defining an end-face contact surface for receiving the foot point of the arc driven thereon by the action of the quenching medium during the switch-off operation, said arcing electrode being covered with insulating material on the outer surface thereof up to said end-face contact surface thereby confining the action of the arc on said arcing electrode to said contact surface.
Claim 3
Dependent Claim
25 words
A compressed-gas circuit breaker as in claim 1 in which the contact surface is formed from graphite mounted at the end face of the electrode.
Claim 4
Dependent Claim
35 words
A compressed-gas circuit breaker as in claim 2 in which the graphite member is surrounded by a ring of insulating material having an upper lip extending partially over the contact surface of the graphite member.
Claim 5
Dependent Claim
20 words
A compressed-gas circuit breaker as in claim 3 in which both the arcing electrode and the graphite member are hollow.