Magnetic latch

Claim 2

A magnetic latch structure comprising, in combination: a magnetic structure having a pair of spaced magnetic members, first, second and third parallel magnetic paths extending between said pair of spaced magnetic members; said first magnetic path containing therein a source of baising flux; said second magnetic path containing therein a magnetic core having an energizing winding thereon; said third magnetic path containing therein a pair of spaced pole faces and an armature movable with respect to said pole faces and between sealing and released positions relative to said pole faces; said second magnetic path being disposed between said first and third magnetic paths; and a saturable magnetic region in at least one of said pair of spaced magnetic members; said saturable magnetic region being disposed between the regions at which said first and second magnetic paths intercept said at least one of said pair of spaced magnetic members; the magnetic flux generated by said source of biasing flux circulating in a first direction in the closed magnetic path containing said pair of spaced magnetic members and said first and third magnetic paths; the magnetic flux generated by said energizing winding upon the energization thereof circulating in said third magnetic path in a direction opposite to said first direction and circulating in said first magnetic path in said first direction; said saturable region having a higher reluctance than the remainder of said magnetic members when said energizing winding is energized and the flux thereof adds to the flux of said source of biasing flux in said saturable region; the flux through said saturable region due solely to said source of biasing flux being insufficient to saturate said saturable region.

Claim 3

The structure of claim 1 wherein said saturable magnetic region has at least one opening therethrough, thereby to define a reduced magnetic cross section for at least one of said pair of magnetic members.

Claim 4

The structure of claim 1 wherein said second magnetic path includes a relatively high-reluctance gap therein.

Claim 5

The structure of claim 1 wherein said source of biasing flux includes a permanent magnet.

Claim 6

The structure of claim 1 which further includes biasing means for biasing said armature away from said pole faces.

Claim 7

The structure of claim 2 wherein said second magnetic path includes a relatively high-reluctance gap therein.

Claim 8

The structure of claim 6 wherein said source of biasing flux includes a permanent magnet.

Claim 9

The structure of claim 1 which includes an adjustable airgap in series with said second magnetic path for adjusting the sensitivity of said latch.

Claim 10

The structure of claim 1 which includes a second winding on said second magnetic path; said second winding being insulated from said first winding.

Claim 11

A magnetic latch for the trip mechanism of a circuit breaker; said latch being directly operable from the energy of a circuit being protected by said circuit breaker; said magnetic latch comprising a magnetic structure having a pair of spaced magnetic paths extending between said pair of spaced magnetic members; said first magnetic path containing therein a source of biasing flux; said second magnetic path containing therein a magnetic core having an energizing winding thereon; said third magnetic path containing therein a pair of spaced pole faces and an armature movable with respect to said pole faces and between sealing and released positions relative to said pole faces; said second magnetic path being disposed between said first and third magnetic paths; and a saturable magnetic region in at least one of said pair of spaced magnetic members; said saturable magnetic region being disposed between the regions at which said first and second magnetic paths intercept said at least one of said pair of spaced magnetic members; the magnetic flux generated by said source of biasing flux circulating in a first direction in the closed magnetic path containing said pair of spaced magnetic members and said first and third magnetic paths; the magnetic flux generated by said energizing winding upon the energization thereof circulating in said third magnetic path in a direction opposite to said first direction and circulating in said first magnetic path in said first direction; said saturable region having a higher reluctance than the remainder of said magnetic members when said energizing winding is energized and the flux thereof adds to the flux of said source of biasing flux thereof adds to the flux of said source of biasing flux in said saturable region, the flux through said saturable region due solely to said source of biasing flux being insufficient to saturate said saturable region; said armature connected to said trip mechanism; and coupling means for coupling said circuit being protected to said energizing winding.

Claim 12

A magnetic latch for the trip mechanism of a circuit breaker; said latch being directly operable from the energy of a circuit being protected by said circuit breaker; said magnetic latch comprising a magnetic structure having a pair of spaced magnetic paths extending between said pair of spaced magnetic members; said first magnetic path containing therein a source of biasing flux; said second magnetic path containing therein a magnetic core having an energizing winding thereon; said third magnetic path containing therein a pair of spaced pole faces and an armature movable with respect to said pole faces and between sealing and released positions relative to said pole faces; said second magnetic path being disposed between said first and third magnetic paths; and a saturable magnetic region in at least one of said pair of spaced magnetic members; said saturable magnetic region being disposed between the regions at which said first and second magnetic paths intercept said at least one of said pair of spaced magnetic members; the magnetic flux generated by said source of biasing flux circulating in a first direction in the closed magnetic path containing said pair of spaced magnetic members and said first and third magnetic paths; the magnetic flux generated by said energizing winding upon the energization thereof circulating in said third magnetic path in a direction opposite to said first direction and circulating in said first magnetic path in said first direction; said saturable region having a higher reluctance than the remainder of said magnetic members when said energizing winding is energized and the flux thereof adds to the flux of said source of biasing flux thereof adds to the flux of said source of biasing flux in said saturable region, the flux through said saturable region due solely to said source of biasing flux being insufficient to saturate said saturable region; said armature connected to said trip mechanism; and coupling means for coupling said circuit being protected to said energizing winding.