Stator core end magnetic shield for large A.C. machines
AssigneeGeneral Electric Company
InventorMichael J. Jefferies
Life of this patent
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Abstract
A magnetic shield to reduce stator core end heating in an A.C. machine, which may also serve as a support structure for the end-turns of the stator windings, is formed of small-diameter iron wire circumferentially wound in a matrix of fiberglass impregnated with epoxy. The iron wire provides a low magnetic reluctance path in the circumferential direction at the core end. The higher reluctance path provided by the shield in the axial direction reduces the axial magnetic flux penetrating the core end. The wire and epoxy-impregnated fiberglass matrix may also constitute a high strength support for the end-turns.
Claims8
A stator core-end magnetic shield for a large A.C. machine having stator windings that extend, in the form of end-turns, beyond the axial end of the stator core in a longitudinal and radially-outward direction, said shield comprising:
- a plurality of circumferentially-wound turns formed of a single, continuous length of low magnetic reluctance material surrounding said end-turns and situated adjacent said stator core at the axial end of said core, the material of each turn being spaced apart from the material of each other turn, said material being of sufficiently limited extent in the radial and axial directions to restrict eddy current paths therein in the radial and axial directions;
- and
- a matrix of epoxy-impregnated fiberglass filling the volume separating each of said circumferentially-wound low reluctance turns from each other, said matrix being adapted to support a radially-outward component of force on said end-turns as said end-turn tends to spread radially outward about said rotor under the influence of magnetic forces acting on said end-turns.
Dependencies are inferred from the claim text.