Electric circuit breaker assembly

An electrical circuit breaker assembly comprising, in combination, a pair of contact elements movable relative to each other to effect making and breaking of a circuit having said circuit breaker assembly connected therein, said contact elements having defined therebetween an arc site through which a circuit breaking arc is struck between said contact elements upon breaking of said circuit, means defining an arc quenching chamber surrounding said arc site, an arc quenching gas contained within said arc quenching chamber, means for passing said arc quenching gas out of said arc quenching chamber and across said arc site to quench an arc struck between said contact elements upon breaking of said circuit, means defining an auxiliary chamber having a gas contained therein, electrode means comprising at least one pair of electrodes movable relative to each other located within said auxiliary chamber with each of said electrodes having an annular configuration and being arranged concentrically about one of said contact elements, means for imparting to at least one of said contact elements a force derived from pressure within said auxiliary chamber tending to move said contact elements relative to each other in a circuit breaking direction, means for connecting said electrode means within said circuit in series with said contact elements, and means for moving said at least one pair of electrodes relative to each other in association with said contact elements, said electrodes being in abutting relationship when said contact elements are in abutting relationship to close said circuit, with separation of said electrodes to effect striking of a secondary arc thereacross occurring simultaneously with separation of said contact elements, said electrodes being shaped to cause said secondary arc to move while being struck therebetween along a generally annular path coincident with said annular configuration of said electrodes around said one of said contact elements, said secondary arc when of sufficient magnitude being operative to increase pressure in said auxiliary chamber to impart to said contact elements a force derived from said increased auxiliary chamber pressure assisting movement of said contact elements in a circuit breaking direction thereby to provide power for quenching of current intensities through said circuit breaker substantially to the level of rated current therethrough in order to ensure quenching of an arc at said arc site sufficient to effect cutoff of rated current through said breaker.