Abstract: A permanent magnet motor is configured with selective variation of the radial distance between an interfacing pair of rotor permanent magnet and stator pole along the circumferential length of the pair. The effects of cogging torque on the overall torque signature can be controlled by setting an appropriate air gap variation profile. The stator pole and rotor magnet surfaces may be sloped with respect to each other, the angle therebetween being selected to obtain desired cogging torque compensation. Other air gap variation profiles may include provision of concave surfaces, the degree of concavity being selectable.

Abstract: A rotary electric motor has a stator with a plurality of separate and ferromagnetically isolated electromagnet core segments disposed coaxially about an axis of rotation. Core materials such as a soft magnetically permeable medium that is amenable to formation of a variety of particularized shapes. The core segments are supported by a non-ferromagnetic structure. The rotor comprises a plurality of permanent magnets with surfaces that face an air gap separation from the stator, the surfaces having a common geometric configuration. The stator pole surface geometric configuration and the rotor magnet surface geometric configuration are skewed with respect to each other. The effect of this skewing arrangement is to dampen the rate of change of the magnitude of the cogging torque that is produced by the interaction between a rotor magnet and a pole of a non-energized stator electromagnet as the permanent magnet traverses its rotational path.

Abstract: A rotary electric motor has a stator with a plurality of separate and ferromagnetically isolated electromagnet core segments disposed coaxially about an axis of rotation. The core segments are supported by a non-ferromagnetic structure. Each core segment has at least three poles aligned in a direction parallel to the axis. Windings are formed on portions linking the poles so that, when energized, the center pole forms a magnetic polarity opposite to the magnetic polarity of the other poles. The rotor comprises a plurality of axial rows of permanent magnets disposed circumferentially along the air gap. Each axial row of rotor magnets comprises a center permanent magnet of one magnetic polarity and, at each axial side thereof, a permanent magnet of a magnetic polarity opposite to the polarity of the center magnet.

Abstract: Rotary permanent magnet motors have salient stator poles with nonuniform pole thickness in the radial direction for compensating effects of cogging torque. Pole base portions terminate at pole shoes at the radial air gap. The pole shoes extend in the circumferential direction from the bulkier base portions. Variation of the thickness of the pole shoe changes the concentration of the effective flux at the point of coupling between the stator poles and the permanent magnet pole shoes. As there is no change in the active interfacing area of the pole shoes a uniform air gap is maintained. The torque signature for each stator pole/rotor permanent magnet interface can be selectively changed to smooth motor operation by configuring the stator pole shoe thickness to vary along its circumferential extent as appropriate. Pole shoes may have tapered leading or trailing edges with respect to a pole base to change the effective flux density in the air gap at a specific pitch of rotation.

Abstract: An electrically powered vehicle, for example a bicycle, has a motor, controller and power supply contained within a wheel compartment. A cylindrical stator frame is fixed on the wheel axle, with an inner surface of the stator frame defining a space for housing the power supply and controller circuitry. A plurality of electromagnet stator segments are mounted on an outer surface of the stator frame. A cylindrical rotor frame is coupled to the axle through bearings. An inner surface of the rotor frame supports a plurality of permanent magnets that surround the stator segments to form a radial air gap therebetween. Mounted to the outer surface of the rotor frame by appropriate supporting structure is a vehicle tire.

Abstract: A dynamoelectric generator comprises a rotor having a plurality of permanent magnet elements disposed in an annular ring configuration about an axis of rotation, the magnet elements successively alternating in magnetic polarity along an inner annular surface, and a stator spaced from the rotor by a radial air gap. The stator includes a plurality of magnetic core segments having respective coils wound thereon to form stator windings, the core segments separated from direct contact with each other and disposed along the radial air gap. Each stator segment comprises a plurality of poles aligned with each other in a direction parallel to the axis of rotation. Thus the stator comprises a plurality of sets of stator poles in radial alignment, the sets being axially displaced from each other.

Abstract: A rotary brushless electric motor is formed within a cylindrical rotor housing structure that surrounds an annular stator ring. The stator is formed of a plurality of individual power modules and corresponding core segments, each module comprising electrical control and drive elements supplied by a power source incorporated within the stator. Such parallel architecture provides relatively independently controlled functionality for each module. Each module and stator core segment can be individually installed and removed without disturbing the other units. Should a particular module or stator core segment fail, it can be easily removed for repair or replacement and reinstallation.

Abstract: A rotary electric motor has a stator with a plurality of separate and ferromagnetically isolated electromagnet core segments disposed coaxially about an axis of rotation. The core segments are supported by a non-ferromagnetic structure. Each core segment has at least three poles aligned in a direction parallel to the axis. Windings are formed on portions linking the poles so that, when energized, the center pole forms a magnetic polarity opposite to the magnetic polarity of the other poles. The rotor comprises a plurality of axial rows of permanent magnets disposed circumferentially along the air gap. Each axial row of rotor magnets comprises a center permanent magnet of one magnetic polarity and, at each axial side thereof, a permanent magnet of a magnetic polarity opposite to the polarity of the center magnet.

Abstract: A rotary electric motor is formed within a cylindrical rotor housing structure that surrounds an annular stator ring. The permanent magnet rotor is configured in an annular ring coaxial with, and outside of, the stator. The stator ring contains a plurality of wound core segments that are ferromagnetically isolated from each other. The core segments are secured to a rigid skeletal structure that is centrally fixed to a stationary shaft. The stator support structure is formed of spine members that extend radially away from the center. U-shaped plates at the outer ends of the spine members engage adjacent pair of stator segments. Within the inner periphery of the stator ring, space is provided within which motor control circuitry and battery power supply may be incorporated.

Abstract: A rotary electric motor comprises a rotor having a plurality of permanent magnet elements disposed in an annular ring configuration about an axis of rotation, the magnet elements successively alternating in magnetic polarity along an inner annular surface, and a stator spaced from the rotor by a radial air gap. The stator includes a plurality of magnetic core segments having respective coils wound thereon to form stator windings, the core segments separated from direct contact with each other and disposed along the radial air gap. Each stator segment comprises a pair of poles aligned with each other in a direction parallel to the axis of rotation. Thus the stator comprises a first set of stator poles in radial alignment and an axially displaced second set of stator poles in radial alignment.

Abstract: A rotary direct current electric motor in which rotor and stator members are each configured as annular rings, concentric with respect to each other, about an axis of rotation. Either of the rotor or stator members is formed of groups of electromagnet pole pairs, the groups substantially equidistantly distributed along the angular extent of the annular ring, each of the groups comprising magnetic material magnetically isolated and separated from the other groups. The other member includes a plurality of permanent magnet poles substantially equidistantly distributed with alternating magnetic polarity along the angular extent of the radial air gap formed between the members, the permanent magnet poles having a discontinuous magnetic return path, thereby dividing the member into magnetically isolated groups of permanent magnet poles.

Abstract: A rotary electric motor in which a stator comprises a first number of permanent magnet poles substantially similar to each other in configuration and spaced substantially equidistantly with alternating polarity along a radial air gap, and a rotor that comprises a second number of salient poles distributed along the radial air gap, the salient poles divided in groups that have magnetic circuits isolated from each other. The radial distance between rotor salient poles of each group and the radial difference between the stator permanent magnet poles are substantially the same.