Consequent pole permanent magnet rotor
First Claim
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1. A permanent magnet rotor for an electrical machine, comprising:
- a ferromagnetic yoke;
a plurality of permanent magnets installed about the periphery of said ferromagnetic yoke to form permanent magnet poles, said ferromagnetic yoke having a plurality of radially outwardly extending projections disposed between said permanent magnets, said ferromagnetic projections being consequent ferromagnetic poles;
a plurality of damper bars fitted between said permanent magnet poles and said ferromagnetic poles, said damper bars made of a non-ferromagnetic, conducting material; and
a retaining hoop placed in interference fit fashion over said permanent magnets, said ferromagnetic projections, and said damper bars.
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Accused Products
Abstract
A rotor for an electrical machine has large permanent magnets located at half the pole locations, with alternating pole locations containing ferromagnetic projections which become consequent poles in the rotor. The permanent magnet poles have a high reluctance, while the ferromagnetic poles have a very low reluctance, thereby affording variable flux linkage between the rotor and a stator. Magnetic homogeneity is improved, while susceptibility to thermal degradation in the rotor is reduced substantially.
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Citations
17 Claims
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1. A permanent magnet rotor for an electrical machine, comprising:
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a ferromagnetic yoke; a plurality of permanent magnets installed about the periphery of said ferromagnetic yoke to form permanent magnet poles, said ferromagnetic yoke having a plurality of radially outwardly extending projections disposed between said permanent magnets, said ferromagnetic projections being consequent ferromagnetic poles; a plurality of damper bars fitted between said permanent magnet poles and said ferromagnetic poles, said damper bars made of a non-ferromagnetic, conducting material; and a retaining hoop placed in interference fit fashion over said permanent magnets, said ferromagnetic projections, and said damper bars. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A permanent magnet rotor for an electrical machine, comprising:
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a yoke made of ferromagnetic material and essentially cylindrical in configuration, said yoke having an inner radius and an outer radius; a plurality of permanent magnets for installation on said yoke, said permanent magnets being crowned with a radius equal to said outer radius, portions of said ferromagnetic material being removed from said yoke to allow said plurality of permanent magnets to be received in said yoke with the crown of said permanent magnets coincidental with said outer radius of said yoke, said permanent magnets each being magnetically oriented in the same radial direction, said permanent magnets being equally spaced apart around the outer periphery of said yoke, with the ferromagnetic material remaining between said permanent magnets forming consequent ferromagnetic poles; a plurality of axially extending damper bars made of an electrically conductive, non-ferromagnetic material, said damper bars being located in said yoke between said permanent magnets and said ferromagnetic poles with portions of said ferromagnetic material removed to allow said damper bars to be received in said yoke, said damper bars being so arranged and configured as to be coincidental with said outer radius of said yoke; and a cylindrical retaining hoop made of non-magnetizable material and located in interference fit fashion over said outer radius of said yoke, retaining said permanent magnets and said damper bars in said yoke.
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11. A permanent magnet rotor for an electrical machine, comprising:
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a ferromagnetic yoke; a first plurality of poles located at one end of said ferromagnetic yoke, said first plurality of poles being alternating high reluctance permanent magnet poles mounted on said ferromagnetic yoke and low reluctance poles formed by projections from said ferromagnetic yoke; a second plurality of poles located at the other end of said ferromagnetic yoke, said second plurality of poles being alternating high reluctance permanent magnet poles mounted on said ferromagnetic yoke and low reluctance poles formed by projections from said ferromagnetic yoke; a first plurality of axially extending damper bars between adjacent ones of said first plurality of poles; a second plurality of axially extending damper bars between adjacent ones of said second plurality of poles; means for preventing said permanent magnets from moving axially on said ferromagnetic yoke; and a retaining hoop mounted around said ferromagnetic yoke, said permanent magnet poles, said ferromagnetic poles, said damper bars, and said preventing means. - View Dependent Claims (12, 13, 14, 15)
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16. A permanent magnet rotor for an electrical machine, comprising:
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a ferromagnetic yoke having a pair of oppositely disposed radially outwardly extending projections being consequent ferromagnetic poles; a pair of permanent magnets oppositely disposed about the periphery of said ferromagnetic yoke generally between the consequent ferromagnetic poles thereof; four non-ferromagnetic conducting material damper bars with an individual damper bar generally disposed between adjacent permanent magnets and ferromagnetic projections; and a retaining hoop disposed around said permanent magnets, said ferromagnetic projections, and said damper bars. - View Dependent Claims (17)
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Specification