Ferromagnetic core with variable shunt air gap and method of making it

Claim 1

The method of making a magnetic core structure which includes a shunt having an effective air gap which is variable in assembly to produce different selected values, which comprises starting with flat shunt laminations of a length to provide a predetermined maximum air gap length, and with each lamination having an alignment hole adjacent the mid-point thereof but offset from such mid-point in the direction of flux flow therein by an amount not exceeding one-half said maximum air gap length, assembling a shunt leg by stacking said flat shunt laminations on an aligning guide with such guide extending through the alignment holes of the successive laminations to align said holes, and orienting the laminations in the stack in a staggered pattern in which successive groups of one or more laminations are oriented with their long ends in opposite directions, and selecting the proportion of laminations oriented in each direction in the stack so that the number of laminations oriented in one direction is substantially not more than half the number oriented in the other direction, so as to provide an effective air gap intermediate that provided by orienting all the laminations in one direction and that provided by orienting generally equivalent numbers of laminations in opposite directions.

Claim 2

The method of making a magnetic core structure which includes a shunt having an effective air gap which is variable in assembly to produce different selected values, which comprises starting with flat shunt laminations of a length to provide a predetermined maximum air gap length, and with each lamination having an alignment hole adjacent the mid-point thereof but offset from such mid-point in the direction of flux flow therein by an amount not exceeding one-half said maximum air gap length, assembling a shunt leg by stacking said flat shunt laminations on an aligning guide with such guide extending through the alignment holes of the successive laminations to align said holes, and orienting the laminations in the stack in a staggered pattern in which successive groups of one or more laminations are oriented with their long ends in opposite directions, and selecting the proportion of laminations oriented in each direction in the stack so that the number of laminations oriented in one direction is substantially not more than half the number oriented in the other direction, so as to provide an effective air gap intermediate that provided by orienting all the laminations in one direction and that provided by orienting generally equivalent numbers of laminations in opposite directions.

Claim 5

The method of making a shunt for a magnetic core structure having a pair of core legs spaced a predetermined distance apart and between which the shunt is to be mounted, which comprises making a plurality of identical flat shunt laminations each having a length less by a predetermined maximum air gap length than said predetermined distance between said core legs, and each having an alignment hole therein offset longitudinally from the longitudinal mid-point of the lamination by a distance not exceeding one-half said predetermined air gap length, and thereby defining a long end on the lamination, stacking said flat laminations on an aligning guide with such guide extending through the holes of the lamination to align such holes, and in a stacking pattern in which successive groups of one or more laminations are alternately oriented with their long ends in opposite directions from the aligning rivet, and securing the laminations in such stacked relationship, and thereby forming a shunt stack which when mounted between said core legs will provide an effective air gap intermediate that produced by a physical gap of said predetermined maximum air gap length and that produced by orienting generally equivalent numbers of laminations in opposite directions, the value of such effective air gap being dependent on the ratio of laminations oriented in one direction to the total laminations, such ratio being defined by the formula: Stacking Ratio = N.sub.1 /(N.sub.1 + N.sub.2) in which N 1 is the smaller number of laminations oriented with their long ends in one direction and N 2 is the number of laminations oriented with their long ends in the opposite direction, and such ratio being greater than zero and not substantially greater than 0.33.

Claim 6

The method of making a shunt for a magnetic core structure having a pair of core legs spaced a predetermined distance apart and between which the shunt is to be mounted, which comprises making a plurality of identical flat shunt laminations each having a length less by a predetermined maximum air gap length than said predetermined distance between said core legs, and each having an alignment hole therein offset longitudinally from the longitudinal mid-point of the lamination by a distance not exceeding one-half said predetermined air gap length, and thereby defining a long end on the lamination, stacking said flat laminations on an aligning guide with such guide extending through the holes of the lamination to align such holes, and in a stacking pattern in which successive groups of one or more laminations are alternately oriented with their long ends in opposite directions from the aligning rivet, and securing the laminations in such stacked relationship, and thereby forming a shunt stack which when mounted between said core legs will provide an effective air gap intermediate that produced by a physical gap of said predetermined maximum air gap length and that produced by orienting generally equivalent numbers of laminations in opposite directions, the value of such effective air gap being dependent on the ratio of laminations oriented in one direction to the total laminations, such ratio being defined by the formula: Stacking Ratio = N.sub.1 /(N.sub.1 + N.sub.2) in which N 1 is the smaller number of laminations oriented with their long ends in one direction and N 2 is the number of laminations oriented with their long ends in the opposite direction, and such ratio being greater than zero and not substantially greater than 0.33.

Claim 7

The method of making a shunt for a magnetic core structure having a pair of core legs spaced a predetermined distance apart and between which the shunt is to be mounted, which comprises starting with a plurality of identical flat shunt laminations each having a length less by a predetermined maximum air gap length than said predetermined distance between said core legs, and each having an alignment hole therein offset longitudinally from the longitudinal mid-point of the lamination by a distance not exceeding one-half said predetermined air gap length, and thereby defining a long end on the lamination, stacking said flat laminations on an aligning rod-shaped fastener with such fastener extending through the holes of the lamination and acting to align such holes, and in a predetermined stacking pattern in which successive groups of one or more laminations are alternately oriented with their long ends in opposite directions from the aligning fastener, selecting the proportion of laminations oriented in each direction so that the number of laminations oriented in one direction is substantially not more than half the number oriented in the other direction, so as to form a shunt stack which when mounted between said core legs will provide an effective air gap of a desired value intermediate said maximum air gap length and that produced by orienting substantially the same number of laminations in opposite directions, and securing said fastener to fasten the laminations in such stacked relationship.

Claim 8

The method of making a shunt for a magnetic core structure having a pair of core legs spaced a predetermined distance apart and between which the shunt is to be mounted, which comprises starting with a plurality of identical flat shunt laminations each having a length less by a predetermined maximum air gap length than said predetermined distance between said core legs, and each having an alignment hole therein offset longitudinally from the longitudinal mid-point of the lamination by a distance not exceeding one-half said predetermined air gap length, and thereby defining a long end on the lamination, stacking said flat laminations on an aligning rod-shaped fastener with such fastener extending through the holes of the lamination and acting to align such holes, and in a predetermined stacking pattern in which successive groups of one or more laminations are alternately oriented with their long ends in opposite directions from the aligning fastener, selecting the proportion of laminations oriented in each direction so that the number of laminations oriented in one direction is substantially not more than half the number oriented in the other direction, so as to form a shunt stack which when mounted between said core legs will provide an effective air gap of a desired value intermediate said maximum air gap length and that produced by orienting substantially the same number of laminations in opposite directions, and securing said fastener to fasten the laminations in such stacked relationship.

Claim 9

The method of making a shunt for a magnetic core structure having a pair of spaced core legs, which comprises starting with a plurality of identical flat shunt laminations each having a length less by a predetermined air gap length than the distance between said core legs, stacking said flat laminations in a predetermined stacking pattern of a plurality of successive sets with each set containing a plurality of groups of one or more laminations offset in opposite directions so as to substantially abut the side faces of the spaced core legs, thereby to form interfaces between oppositely offset laminations at a multiplicity of positions in the stack, the proportion of laminations offset in one direction being not more than half those offset in the opposite direction so that the ratio of laminations offset in one direction in relation to the total number of laminations is not substantially greater than 0.33, so as to provide an effective air gap intermediate that produced by positioning all the laminations to abut the same core leg and that produced by offsetting substantially equal numbers of laminations in each direction.

Claim 10

The method of making a shunt for a magnetic core structure having a pair of spaced core legs, which comprises starting with a plurality of identical flat shunt laminations each having a length less by a predetermined air gap length than the distance between said core legs, stacking said flat laminations in a predetermined stacking pattern of a plurality of successive sets with each set containing a plurality of groups of one or more laminations offset in opposite directions so as to substantially abut the side faces of the spaced core legs, thereby to form interfaces between oppositely offset laminations at a multiplicity of positions in the stack, the proportion of laminations offset in one direction being not more than half those offset in the opposite direction so that the ratio of laminations offset in one direction in relation to the total number of laminations is not substantially greater than 0.33, so as to provide an effective air gap intermediate that produced by positioning all the laminations to abut the same core leg and that produced by offsetting substantially equal numbers of laminations in each direction.

Claim 11

The method of making shunts having different effective air gaps for magnetic core structures which each have a pair of core legs spaced a predetermined distance apart and between which a shunt is to be mounted, which comprises starting with a plurality of identical flat shunt laminations each having a length less by a predetermined maximum air gap length than said predetermined distance between said core legs, and each having an alignment hole therein offset longitudinally from the longitudinal mid-point of the lamination by a distance not exceeding one-half said predetermined air gap length, and thereby defining a long end on the lamination, assembling different shunts by stacking said flat laminations on an aligning guide with such guide extending through the holes of the lamination and acting to align such holes, and orienting the laminations in a predetermined stacking pattern in which successive groups of one or more laminations are alternately oriented with their long ends in opposite directions from the aligning guide and with the number of laminations oriented in one direction substantially not more than half the number oriented in the other direction, and varying the proportion of laminations oriented in opposite directions in different shunts to thereby produce shunts which when mounted between said core legs will provide effective air gaps of different values intermediate that produced by orienting all the laminations in one direction and that produced by orienting substantially the same number in opposite directions.

Claim 12

The method of making shunts having different effective air gaps for magnetic core structures which each have a pair of core legs spaced a predetermined distance apart and between which a shunt is to be mounted, which comprises starting with a plurality of identical flat shunt laminations each having a length less by a predetermined maximum air gap length than said predetermined distance between said core legs, and each having an alignment hole therein offset longitudinally from the longitudinal mid-point of the lamination by a distance not exceeding one-half said predetermined air gap length, and thereby defining a long end on the lamination, assembling different shunts by stacking said flat laminations on an aligning guide with such guide extending through the holes of the lamination and acting to align such holes, and orienting the laminations in a predetermined stacking pattern in which successive groups of one or more laminations are alternately oriented with their long ends in opposite directions from the aligning guide and with the number of laminations oriented in one direction substantially not more than half the number oriented in the other direction, and varying the proportion of laminations oriented in opposite directions in different shunts to thereby produce shunts which when mounted between said core legs will provide effective air gaps of different values intermediate that produced by orienting all the laminations in one direction and that produced by orienting substantially the same number in opposite directions.

Claim 14

The method of making a shunt for a magnetic core structure having a pair of core legs spaced a predetermined distance apart and between which the shunt is to be mounted, which comprises starting with a plurality of identical rectangular flat shunt laminations each having a length less by a predetermined maximum gap length than said predetermined distance between said core legs, and each having an alignment hole therein offset longitudinally from the longitudinal mid-point of the lamination by a distance not exceeding one-half said predetermined air gap length and thereby defining a long end on stacking said laminations in a stack of a series of sets with each set containing some laminations with their long ends oriented in one direction and at least one lamination with its long end oriented in the opposite direction, aligning the holes of the laminations in the stack with an aligning guide extending through all the laminations of the stack, and thereby locating the oppositely oriented laminations in the stack in correspondingly oppositely offset positions therein, and securing the laminations in said oppositely offset positions, thereby forming a shunt having an effective air gap determined by the pattern in which the laminations were oriented in the stack.

Claim 15

The method of making a shunt for a magnetic core structure having a pair of core legs spaced a predetermined distance apart and between which the shunt is to be mounted, which comprises starting with a plurality of identical rectangular flat shunt laminations each having a length less by a predetermined maximum gap length than said predetermined distance between said core legs, and each having an alignment hole therein offset longitudinally from the longitudinal mid-point of the lamination by a distance not exceeding one-half said predetermined air gap length and thereby defining a long end on stacking said laminations in a stack of a series of sets with each set containing some laminations with their long ends oriented in one direction and at least one lamination with its long end oriented in the opposite direction, aligning the holes of the laminations in the stack with an aligning guide extending through all the laminations of the stack, and thereby locating the oppositely oriented laminations in the stack in correspondingly oppositely offset positions therein, and securing the laminations in said oppositely offset positions, thereby forming a shunt having an effective air gap determined by the pattern in which the laminations were oriented in the stack.