Light-weight high-power electrical machine
First Claim
1. A brushless electrical machine, comprising:
- a rotor for rotation about an axis, said rotor being constructed of a rim portion and a substantially hollow a center portion;
said rim portion being constructed from ferromagnetic material and having a partially hollow core at an inner end of a slot into said hollow core, said slot being defined by opposing surfaces, one of which has multiple, circumferentially spaced protrusions around said rotor;
a stationary field coil mounted coaxial with said rotor and located in said partially hollow core of said rim portion, said field coil having windings that can be electrically energized to produce homopolar magnetic flux in said protrusions, and said flux circulates in a poloidal flux path in said rim, said poloidal flux path having a single magnetic air gap across said slot;
a plurality of stationary armature windings located within said magnetic air gap such that said homopolar flux from said protrusions induces an alternating voltage in said armature windings when said rotor rotates.
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Accused Products
Abstract
A brushless electrical machine, usable as a motor, generator, or alternator, has a rotor that is comprised of a rim portion and a substantially open center portion. The rim portion has a partially hollow core in which a stationary field coil is supported. Current to the field coil generates magnetic flux that circulates in a poloidal flux path in the rim, crossing a single magnetic air gap formed by the rim. Protrusions in the rim located around the circumference form poles all having the same polarity. As the rotor rotates, the flux exiting the poles passes through multiple stationary armature windings around the circumference that are located in the single air gap. An AC voltage is induced in the armature windings from rotation.
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Citations
25 Claims
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1. A brushless electrical machine, comprising:
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a rotor for rotation about an axis, said rotor being constructed of a rim portion and a substantially hollow a center portion;
said rim portion being constructed from ferromagnetic material and having a partially hollow core at an inner end of a slot into said hollow core, said slot being defined by opposing surfaces, one of which has multiple, circumferentially spaced protrusions around said rotor;
a stationary field coil mounted coaxial with said rotor and located in said partially hollow core of said rim portion, said field coil having windings that can be electrically energized to produce homopolar magnetic flux in said protrusions, and said flux circulates in a poloidal flux path in said rim, said poloidal flux path having a single magnetic air gap across said slot;
a plurality of stationary armature windings located within said magnetic air gap such that said homopolar flux from said protrusions induces an alternating voltage in said armature windings when said rotor rotates. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A brushless electrical machine, comprising:
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a rotor for rotation about an axis, said rotor being comprised of a ferromagnetic rim with multiple, circumferentially spaced protrusions around said rotor, and having a slot therein that forms a single magnetic air gap, and an internal cavity in said rim communicating through said slot with an exterior of said rim;
said rim having an inner diameter and an outer diameter, said inner diameter of said rim being spaced from said axis by an open space;
a stationary field coil mounted in said cavity coaxial with said rotor, wherein said field coil has exterior surfaces that are surrounded on three sides by interior surfaces of said cavity such that said field coil produces homopolar flux in said protrusions, and said flux circulates in a poloidal flux path in said rim;
more than one stationary armature windings located within said magnetic air gap such that said homopolar flux from said protrusions crosses said air gap and links said armature windings, inducing an alternating voltage therein when said rotor rotates.
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11. A brushless electrical machine, comprising:
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a rotor mounted on bearings for rotation about an axis, said rotor having a central supporting structure and a rim formed from at least two ferromagnetic pieces having opposed facing surfaces that, when assembled, define therebetween a hollow core and a slot communicating from said core to an exterior surface of said rim, said opposed facing surfaces in said slot defining a single magnetic air gap between said two pieces;
said rim having an inner diameter and an outer diameter, said inner diameter being spaced apart from said axis by an open space spanned by a hub that connects said rim to said central supporting structure;
multiple circumferentially spaced protrusions around at least at one of said opposed surfaces of said rim in said single magnetic air gap;
a stationary field coil mounted coaxial with said rotor in said hollow core such that said field coil produces homopolar flux in said protrusions;
a plurality of stationary armature windings located within said single magnetic air gap such that said homopolar flux from said protrusions induces an alternating voltage in said armature windings when said rotor rotates. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A brushless electrical machine, comprising:
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an annular rim supported on a hub for rotation about a center shaft, said rim constituting an annular shell made of two connected ferromagnetic rings, each having an inside diameter spaced from said shaft by at least the radial thickness of said rim, at least one of said rings having a nonplanar cross section;
said rim having an exterior surface and a hollow core communicating with said exterior surface through an annular slot defining a magnetic air gap between opposed, spaced apart surfaces of said two ferromagnetic rings, said ferromagnetic rings and said air gap together providing a poloidal flux path in said rim;
multiple circumferentially spaced protrusions around at least at one of said opposed surfaces facing said magnetic air gap;
a stationary annular field coil in said hollow core and having electrical conductors for connection to a source of electrical power to electrically energize said field coil for generating homopolar flux to circulate in said rim in said poloidal flux path;
a stationary annular armature supported in said magnetic air gap in a position to intersect magnetic flux in said flux path as said rotor rotates about said shaft, and having electrical conductors for connection to a source of electrical power, or operatively to a load, for electrically energizing said armature to generate torque in said rim, or for generating electrical power to said load.
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25. A brushless electrical machine for converting between mechanical and electrical energy, comprising:
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a rotor supported for rotation about an axis, said rotor having an annular rim spaced apart from said axis and formed from at least two annular ferromagnetic pieces such that said rim, when assembled from said pieces, defines a partially hollow interior core and forms a single magnetic air gap between opposed facing surfaces of said two pieces;
said rotor including a central supporting structure and a hub for connecting said rim to said central supporting structure, wherein said rim has a moment of inertia that is greater than about 90% of the total moment of inertia of said rotor about said axis;
a field coil located in said partially hollow interior core of said rim for generating homopolar flux in a poloidal flux path in said rim around said core when energized by electric current;
circumferentially spaced protrusions projection from one of said facing surfaces around at least at one of said opposed surfaces of said single magnetic air gap for concentrating said flux in rays of flux across said air gap; and
multiple stationary armature windings supported in said single magnetic air gap for inducing AC power when said rotor rotates, or for producing torque on said rotor when to said multiple stationary armature windings are energized by synchronous AC power.
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Specification