Current limiting circuit breaker with magnetic latch

Claim 2

A circuit breaker including first and second contact means operable into and out of engagement; first means urging said first contact away from a closed position wherein the latter is engageable by said second contact toward an inoperative position wherein said first contact is not engageable by said second contact; second means for maintaining said first contact in said closed position; third means for detecting current rate of rise in said circuit breaker and automatically releasing said second means to permit said first means to move said first contact to said inoperative position when said current rate of rise exceeds a predetermined magnitude; an operating mechanism for automatically disengaging said contacts by moving said second contact, as said first contact remains in its said closed position, in response to overload currents in said circuit breaker of a nature that will not cause said third means to automatically release said second means.

Claim 3

A circuit breaker as set forth in claim 1 in which said second means includes magnet means having a movable armature connected to said second contact means for movement in unison therewith; said first means biasing said armature to an open position wherein said second contact means is in its said inoperative position; said magnet means having a section generating a holding flux for maintaining said armature in a closed position wherein said second contact means is held in its said operative position; said third means including generating means operative, when said current rate of rise exceeds said predetermined magnitude, to generate a bucking flux which counteracts said holding flux thereby permitting said first means to move said second contact means to its said inoperative position.

Claim 4

A circuit breaker as set forth in claim 2 in which the section generating said holding flux includes a permanent magnet.

Claim 5

A circuit breaker as set forth in claim 3 in which the bucking flux is generated by current flowing through a coil means coupled to said magnet means.

Claim 6

A circuit breaker as set forth in claim 2 in which said generating means is also connected in series circuit to at least one additional circuit breaker having means for generating a bucking flux to counteract a contact holding flux.

Claim 7

A circuit breaker as set forth in claim 2 in which there is a further means active for a limited period of time after closing said circuit breaker to generate a flux aiding said holding flux.

Claim 8

A circuit breaker as set forth in claim 6 in which said generating means is also connected in series cirCuit to at least one additional circuit breaker having means for generating a bucking flux to counteract a contact holding flux.

Claim 9

A circuit breaker including first and second contact means operable into and out of engagement; first means urging said contacts out of engagement; second means for maintaining said contacts in engagement; third means for detecting current rate of rise in said circuit breaker and automatically releasing said second means to permit said first means to open said contacts when said current rate of rise exceeds a predetermined magnitude; an operating mechanism for moving said first contact means into and out of engagement with said second contact means when the latter is maintained in an operative position by said second means; said second means including magnet means having a movable armature connected to said second contact means for movement in unison therewith; said first means biasing said armature to an open position wherein said second contact means is in an inoperative position in which said first and second contact means are not engageable with each other; said magnet means having a section generating a holding flux for maintaining said armature in a closed position wherein said second contact means is held in its said operative position; said third means including generating means operative, when said current rate of rise exceeds said predetermined magnitude, to generate a bucking flux which counteracts said holding flux thereby permitting said first means to move said second contact means to its said inoperative position; a main arm and an auxiliary arm pivotally connected to said main arm near one end thereof for limited pivotal movement with respect thereto; said first contact means mounted to said auxiliary arm and extending beyond said one end of said main arm; means pivotally mounting said main arm near the other end thereof; said mechanism connected to said main arm for imparting pivoting movement thereto; and means for directing an electrodynamic force against said first contact means to pivot the latter and separate it from said second contact means.

Claim 10

A circuit breaker including first and second contact means operable into and out of engagement; first means urging said contacts out of engagement; second means for maintaining said contacts in engagement; third means for detecting current rate of rise in said circuit breaker and automatically releasing said second means to permit said first means to open said contacts when said current rate of rise exceeds a predetermined magnitude; an operating mechanism for moving said first contact means into and out of engagement with said second contact means when the latter is maintained in an operative position by said second means; said second means including magnet means having a movable armature connected to said second contact means for movement in unison therewith; said first means biasing said armature to an open position wherein said second contact means is in an inoperative position in which said first and second contact means are not engageable with each other; said magnet means having a section generating a holding flux for maintaining said armature in a closed position wherein said second contact means is held in its said operative position; said third means including generating means operative, when said current rate of rise exceeds said predetermined magnitude, to generate a bucking flux which counteracts said holding flux thereby permitting said first means to move said second contact means to its said inoperative position; a main arm and an auxiliary arm pivotally connected to said main arm near one end thereof for limited pivotal movement with respect thereto; said first contact means mounted to said auxiliary arm and extending beyond said one end of said main arm; means pivotally mounting said main arm near the other end thereof; said mechanism connected to said main arm for imparting pivoting movement thereto; and means for directing an electrodynamic force against said first contact means to pivot the latter and separate it from said second contact means.

Claim 11

A circuit breaker including first and second contact means operable into and out of engagement; first means urging said contacts out of engagement; second means for maintaining said contacts in engagement; third means for detecting current rate of rise in said circuit breaker and automatically releasing said second means to permit said first means to open said contacts when said current rate of rise exceeds a predetermined magnitude; an operating mechanism for moving said first contact means into and out of engagement with said second contact means when the latter is maintained in an operative position by said second means; said second means including magnet means having a movable armature connected to said second contact means for movement in unison therewith; said first means biasing said armature to an open position wherein said second contact means is in an inoperative position in which said first and second contact means are not engageable with each other; said magnet means having a section generating a holding flux for maintaining said armature in a closed position wherein said second contact means is held in its said operative position; said third means including generating means operative, when said current rate of rise exceeds said predetermined magnitude, to generate a bucking flux which counteracts said holding flux thereby permitting said first means to move said second contact means to its said inoperative position; said circuit breaker being connected in series circuit to a first load by a first branch circuit breaker having a fourth means for generating a bucking flux to counteract a contact holding flux, said circuit breaker also connected in series circuit with a second branch circuit breaker having a fifth means for generating a bucking flux to counteract a contact holding flux; said fourth and fifth means having means for detecting current rate of rise in the respEctive first and second loads; rate of rise detecting portions of said third, fourth and fifth means connected in a circuit arrangement fed by third, fourth and fifth outputs derived from the current rate of rise detecting portions in the respective third, fourth and fifth means; said fourth and fifth outputs arranged in opposition to said third output whereby either one of said branch circuit breakers may trip open without deenergizing the load connected to the other one of said branch circuit breakers.

Claim 12

A circuit breaker including first and second contact means operable into and out of engagement; first means urging said contacts out of engagement; second means for maintaining said contacts in engagement; third means for detecting current rate of rise in said circuit breaker and automatically releasing said second means to permit said first means to open said contacts when said current rate of rise exceeds a predetermined magnitude; an operating mechanism for moving said first contact means into and out of engagement with said second contact means when the latter is maintained in an operative position by said second means; said second means including magnet means having a movable armature connected to said second contact means for movement in unison therewith; said first means biasing said armature to an open position wherein said second contact means is in an inoperative position in which said first and second contact means are not engageable with each other; said magnet means having a section generating a holding flux for maintaining said armature in a closed position wherein said second contact means is held in its said operative position; said third means including generating means operative, when said current rate of rise exceeds said predetermined magnitude, to generate a bucking flux which counteracts said holding flux thereby permitting said first means to move said second contact means to its said inoperative position; said circuit breaker being connected in series circuit to a first load by a first branch circuit breaker having a fourth means for generating a bucking flux to counteract a contact holding flux, said circuit breaker also connected in series circuit with a second branch circuit breaker having a fifth means for generating a bucking flux to counteract a contact holding flux; said fourth and fifth means having means for detecting current rate of rise in the respEctive first and second loads; rate of rise detecting portions of said third, fourth and fifth means connected in a circuit arrangement fed by third, fourth and fifth outputs derived from the current rate of rise detecting portions in the respective third, fourth and fifth means; said fourth and fifth outputs arranged in opposition to said third output whereby either one of said branch circuit breakers may trip open without deenergizing the load connected to the other one of said branch circuit breakers.