LINEAR ELECTROMAGNETIC MACHINES
First Claim
1. A linear electromagnetic machine comprising first and second substantially cylindrical or elliptical parts arranged to move relative to each other along a common axis of motion, whereinthe first cylindrical or elliptical part produces a spatially periodic radial magnetic field across an air gap, the magnetic field having a regular alternating polarity along or parallel to the axis of motion, andthe second cylindrical or elliptical part comprises a plurality of laminar electrical conductors wrapped into cylindrical or elliptical form and placed in the air gap to intercept the magnetic field, each of the laminar electrical conductors comprising a regular pattern of electrically conductive paths, the electrically conductive paths of the plurality of laminar electrical conductors being interdigitated within the air gap;
- wherein the patterns of electrically conducting paths formed in each of the laminar conductors include conducting paths transverse the force vector and having a regular spatial dimension that is substantially equal to but less than one sixth of the length of the period of the spatially periodic magnetic field and which cause the current to flow alternately back and forth transverse the line of the force vector with a spatial period equal to one half of the magnetic period, the conducting paths of each laminar electrical conductor being arranged to lie closely adjacent those of the other laminar electrical conductors in the region of the spatially-periodic magnetic field and to overlap them elsewhere.
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Accused Products
Abstract
A linear electromagnetic machine is described which comprises first and second substantially cylindrical parts arranged to move relative to each other along a common axis of motion. The first cylindrical part produces a spatially periodic radial magnetic field across an air gap, the magnetic field having a regular alternating polarity along or parallel to the axis of motion. The second cylindrical part comprises a plurality of laminar electrical conductors wrapped into cylindrical form and placed in the air gap to intercept the magnetic field, each of the laminar electrical conductors compromising a regular pattern of electrically conductive paths, the electrically conductive paths of the plurality of laminar electrical conductors being interdigitated together within the air gap. The use of a plurality of laminar electrical conductors having respective electrically conductive paths which are interdigitated (nested) within the air gap provides for a very thin planar structure which enables the air gap to be made small, thereby improving the efficiency of the electromagnetic machine. In more general terms, improvements relating to the design of low-cost cylindrical or elliptical linear electromagnetic machines are described, in which a conventional assembly of wire coils is replaced by a small number of interdigitated metal laminations.
15 Citations
24 Claims
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1. A linear electromagnetic machine comprising first and second substantially cylindrical or elliptical parts arranged to move relative to each other along a common axis of motion, wherein
the first cylindrical or elliptical part produces a spatially periodic radial magnetic field across an air gap, the magnetic field having a regular alternating polarity along or parallel to the axis of motion, and the second cylindrical or elliptical part comprises a plurality of laminar electrical conductors wrapped into cylindrical or elliptical form and placed in the air gap to intercept the magnetic field, each of the laminar electrical conductors comprising a regular pattern of electrically conductive paths, the electrically conductive paths of the plurality of laminar electrical conductors being interdigitated within the air gap; wherein the patterns of electrically conducting paths formed in each of the laminar conductors include conducting paths transverse the force vector and having a regular spatial dimension that is substantially equal to but less than one sixth of the length of the period of the spatially periodic magnetic field and which cause the current to flow alternately back and forth transverse the line of the force vector with a spatial period equal to one half of the magnetic period, the conducting paths of each laminar electrical conductor being arranged to lie closely adjacent those of the other laminar electrical conductors in the region of the spatially-periodic magnetic field and to overlap them elsewhere. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
Specification