Electric circuit breaker with electro-magnetic means for opposing magnetic contact-repulsion forces

Claim 1

In an electric circuit breaker, a. a first contact and a second contact movable into and out of engagement with said first contact, b. a movable contact rod mechanically and electrically connected to said second contact for carrying current to and from said second contact, c. closing-assist means for exerting on said contact rod when the contacts are engaged a magnetic hold-closed force varying in magnitude directly with current through said contact rod, d. opening means effective during the initial portion of an opening operation for applying an impact force to said contact rod that acts to separate said contacts and to reduce the effectiveness of said closing-assist means, e. opening-assist means effective after said contacts are separated during an opening operation for developing magnetic force acting on said contact rod in an opening direction comprising: e 1 . an armature comprising spaced segments of high permeability material fixed to opposite sides of said contact rod and projecting laterally therefrom in side-by-side relationship, e 2 . a pair of bridging members of high permeability material located at opposite sides of said contact rod and each disposed to extend between said side-by-side segments when said segments are located in proximity to said bridging members, f. said bridging members and said segments being magnetically attracted toward each other with a force that varies in magnitude inversely with the spacing therebetween when current flows through said contact rod, g. means mounting said bridging members for movement with said segments during the final portion of a circuit-breaker opening operation and during the initial portion of a circuit-breaker closing operation, h. blocking means for blocking said bridging members from moving toward said segments when said contacts are engaged and for maintaining a relatively large spacing between said segments and said bridging members when said contacts are engaged, i. said bridging members when blocked by said blocking means being positioned in the path of movement of said segments during a circuit-breaker opening operation and in such a location that the spacing between said segments and said bridging members decreases during the initial portion of a circuit-breaker opening operation.