Abstract: An electrical machine (20) has a stator (22) comprising: a core (50) having a first end (52) and a second end (54); one or more windings carried by the core and having: one or more first portions (62) protruding from the first end; and one or more second portions (64) protruding from the second end. A rotor (24) is mounted for rotation relative to the stator about an axis (500, 502). One or more chambers (70, 72) surround the one or more first portions and the one or more second portions. Ferromagnetic particles are in a fluid in the one or more chambers. The machine has means (80, 82, 104, 106) for varying a concentration of the ferromagnetic particles in the one or more chambers.

Abstract: A modular system of motorized conveyor rollers comprises a conveyor roller tube, a first axle unit, a second axle unit, a first bearing unit on a first tube end and a second bearing unit on a second tube end about which the conveyor roller tube is mounted rotatably about the first and second axle units, respectively, and an electric motor for generating a torque between the conveyor roller tube and the second axle unit. The modular system comprises, as the electric motor, a motor of a first design, which may be coupled to the conveyor roller tube via a first interface and to the second axle unit via a second interface, and a motor of a second design different from the first design, which may be coupled to the conveyor roller tube via the first interface and to the second axle unit via the second interface.

Abstract: An end plate for a rotor of a switched reluctance motor is disclosed. The end plate includes an annular body and a plurality of ribs. The annular body has a first axial end, a second axial end, and a thickness. Further, the annular body defines an outer surface and a bore configured to receive a shaft of the rotor. The plurality of ribs extends radially outwardly from the outer surface. The plurality of ribs is adapted to respectively abut with a plurality of poles of the rotor.

Abstract: The method for repairing a stator having a damaged part includes providing the stator with a seat, removing the damaged part of the stator, connecting the inserts replacing the damaged part of the stator to the seat, and fixing the inserts.

Abstract: A motor-driven compressor that includes a metal housing accommodating a compression unit and an electric motor, a cover coupled to the housing, wherein the cover includes a resin portion and a metal shield, and the shield blocks electromagnetic noise, and a bolt that couples the cover to the housing. The housing and the cover define an accommodating chamber that accommodates a motor driving circuit that drives the electric motor. The cover includes an insertion hole into which the bolt is insertable. The shield includes a seat that surrounds the insertion hole and is held between the bolt and the housing. The cover is configured to allow for an axial force of the bolt to be applied to the seat and not to the resin portion.

Abstract: A rotor for a motor comprising a frame having a hub for connecting the rotor to a shaft and a perimeter portion for interacting with a stator of the motor to cause the rotor to rotate about an axis of rotation. The frame comprises legs extending from an outer portion of the frame towards the hub, each leg having an inner end at the hub and an outer end at the outer portion of the frame, the inner ends of a first plurality of legs being spaced from the inner ends of a second plurality of legs in a direction along the axis of rotation.

Abstract: A damping device for use with a rotatably-mounted steering shaft. The damping device comprises a magnetorheological material that can be embedded in an open-network carrier and is directly or indirectly in contact with the steering shaft, a coil arranged in effective proximity to the magnetorheological material, and a body indirectly in contact with the steering shaft through the magnetorheological material, which does not rotate with the steering shaft. A voltage can be applied the coil to activate the magnetorheological material, increasing a viscosity of the magnetorheological material to inhibit relative rotation of the steering shaft and the body.

Abstract: A rotor for an electric rotating machine includes a core body member formed, first and second end plates provided at respective side faces of the core body member, and a fixing member inserted into through holes provided at the core body member and the end plates. The end plates include positioning portions at an outer or inner circumferential surface, wherein when the fixing member is engaged with the end plates, the positioning portion is engageable with positioning receive portions corresponding to the positioning portions and positioning at radially outer or inner portion of the end plate. When one of the end plates is placed facing the side face of the core body member in a reversed state, the end plate and the core body member are not assembled each other by positional relationship between the positioning portions, the positioning receive portions and the through holes.

Abstract: An apparatus in an electric vehicle including a propulsion electric motor powered by energy from an energy storage system, including a field oriented motor controller generating motor control signals for the electric motor, the motor control signals responsive to a flux command signal and a torque command signal; a torque command calculator, coupled to the motor controller, generating the torque command signal to command a desired torque; an optimal efficiency controller, coupled to the torque command calculator, generating an operating efficiency flux to operate the electric motor at a first determinable efficiency using a first power from the energy storage system while providing the desired torque; an excess dissipation controller generating an inefficient flux to operate the electric motor at a second determinable efficiency using a second power from the energy storage system independent of the desired torque wherein the second power is greater than the first power; and a mode controller setting the flux

Abstract: A multi-phase, permanent magnet brushless DC electric motor includes 24 phase windings operating at a reduced voltage so that the motor can be powered by batteries or other sources of DC voltage to enable the motor to be used safely for propelling watercraft or other vehicles where the higher voltages required for conventional high horsepower motors would not be acceptable. The motor is wound by solid conductors spaced apart by 7.5 degrees. The conductors are interconnected and electrically driven by a sequence of drive currents to provide a six-pole stator. The connections to and interconnections between the stator windings are mirrored at each end of the stator to distribute the connections and interconnections between the two ends of the motor. A corresponding six-pole rotor using permanent magnets secured to a hollow rotor core is caused to rotate by the fields generated by the stator.

Abstract: The invention relates to an electrical drive having a motor with a rotor and a stationary stator, which has a coil arrangement, and having a motor controller for controlling the motor, with the motor controller being configured to pass current through the coil arrangement in order to produce an excitation field, with the coil arrangement having a plurality of coil winding sections, and with each coil winding section having a plurality of coil sections, wherein the polarity of at least one coil section of the plurality of coil sections of each coil winding section can be selectively reversed with respect to the other coil sections of the coil winding section. The drive is particularly suitable for use for an electrical tool.

Abstract: The invention provides for flux-shields wrapped around the flux-sources at the core-end of large power generators. They prevent overheating of all core-end parts under all abnormal conditions of operation. A first flux-shield is an electrically conductive cylindrical shell concentric with rotating end-windings, held outside the retaining ring. The rotating flux source induces eddy currents in the first flux-shield whose flux repels the source flux. Only a small part of the rotating source flux is hence received by all the core-end parts, thereby greatly reducing their temperatures. A second flux-shield comprises an electrically conductive tape wrapped over the ground-insulation of stator bars protruding from the core. Alternating flux generated by the stator bars induces eddy currents in the second flux-shield whose flux repels the source flux. Only a small fraction of the source flux is hence received by all core-end parts, thereby greatly reducing their temperatures.

Abstract: A flux screen is provided for shielding a generator stator core from the magnetic field generated by end windings of the stator, wherein the flux screen comprises a frontside to be at least indirectly facing the end windings of the generator and a backside to be at least indirectly facing the stator core of the generator, and wherein the backside is provided with channels and/or grooves and/or pits.

Abstract: Provided is a starter that can ensure stable insulation and exhibits excellent leakage resistance. The starter includes: a starting motor realized with a dc motor that has a commutator, positive brushes which are disposed around the commutator to abut on the commutator and connected to an external power supply, negative brushes, which are opposed to the positive brushes, stored in a bracket bearing one end of a rotation shaft; and a starting switch that is mounted on the starting motor and electrically connects or disconnects the external power supply to or from the positive brushes. When an engine is started, the starting motor is driven with the external power supply via the starting switch, and the starting motor is mechanically coupled to the engine. Herein, the starting motor has an insulating member disposed only on the internal surface of the bracket neighboring the positive brushes.

Abstract: A brushless DC motor includes a base, a stator, a rotor, and a leak flux absorber. The base couples with the rotor. The stator has a coil module and is mounted on the base. The rotor has a shaft and a permanent magnet, with the rotor coupling with the base through the shaft. A gap is axially formed between the permanent magnet and the coil module. Also, the leak flux absorber is disposed around the coil module and is adjacent to, partially in, or totally in the gap. Consequently, a leak flux generated by the permanent magnet, which does not pass through the coil module, is absorbed by the leak flux absorber and forms close magnetic flux paths, so that high-frequency noise in operation is thus lowered.

Abstract: A stator component whose composition and processing enable the component to axially compress magnetic sheets of a stator and also inhibit joule heating of the component to the extent that the need for a separate flux shield can be eliminated. The component is formed of a ductile iron alloy containing, by weight, about 3.25 to about 3.40% carbon, about 3.70 to about 3.80% silicon, about 4.50 to about 4.70% nickel, up to about 0.20% manganese, up to about 0.06% magnesium, less than 0.02% phosphorus, less than 0.02% sulfur, with the balance being iron and incidental impurities. Following heat treatment, the component exhibits properties that inhibit joule heating of the component by eddy currents induced by alternating magnetic fields of the stator.

Abstract: A brushless motor including a rotor which has ten permanent magnets each containing rare earth neodymium and provided around a rotor yoke and an outside diameter of 45 mm to 55 mm, and a stator which has a stator core having twelve slots and an outside diameter of 75 mm to 85 mm and whose magnetomotive force at maximum current is 700 AT or more. The stator core is configured such that a teeth width b is 0.14 times or more of the outside diameter of the rotor.

Abstract: A brushless DC motor includes a base, a stator, a rotor, and a leak flux absorber. The base is for the rotor to couple. The stator has a coil module and is mounted on the base. The rotor has a shaft and a permanent magnet, with the rotor coupling with the base through the shaft and a gap is axially formed between the permanent magnet and the coil module. And the leak flux absorber is disposed around the coil module and is adjacent to, partially in, or totally in the gap. Consequently, a leak flux generated by the permanent magnet, which does not pass through the coil module, is absorbed by the leak flux absorber and forms close magnetic flux paths, so that the high-frequency noise in operation is thus lowered.

Abstract: A permanent magnet rotary motor is provided in which cogging torque can be reduced and an increase in copper loss can also be prevented. A first divided core unit 13 is combined with a second divided core unit 15, thereby constituting a stator core 9. The first divided core unit 13 constitutes a yoke portion 17. The second divided core unit 15 includes pole pieces 25, magnetic pole surface constituent portions 27, and first and second type connecting portions 29A and 29B each mutually couple two adjacent magnetic pole surface constituent portions 27, all of which are formed integral with one another. The thickness of the first type connecting portions 29A in a radial direction of the stator core 9 is set to be smaller than the thickness of the second type connecting portions 29B in the radial direction of the stator core 9.

Abstract: In an electric motor drive, a asynchronous motor, such as drum motor, has a stator (2) mounted on a non-rotatory shaft (1) and has rotatory, like by means of bearings (3), connected rotor (4), is arranged to drive the machine construction (actuator). The rotor (4) of the asynchronous motor conveyor's is arranged to be directly a functional part of the machine construction (actuator), like conveyor's (5) driving roll (5a). Also the rotor can be formed as a shell of pulley (4) which is part of a vacuum belt conveyor comprising a stationary vacuum box (11), the rotor drive further including a non-rotatory shaft (1) supported by at least one supporting bracket (8) which is connected to the vacuum box.

Abstract: The invention relates to an electrical apparatus having an actuator including at least two permanent magnets (1, 1a) and at least one electrical coil (2) which is movably supported by means of a swing arm (3), which coil is arranged to be traversed by magnetic fields of the permanent magnets (1, 1a), the actuator having a cage (4), which encloses the coil (2) and the permanent magnets (1, 1a), as a closed magnetic return path.

Abstract: a high-voltage generator, notches (3) leading radially inward are provided in each segmental lamination (1) on the radial outside of the laminated stator body and end in a relief opening. The notches (3) cause the amplitude and the frequency of, for example, a 4-node vibration occuring during operation to be limited to noncritical values, although the laminated body is undersized mechanically with regard to its yoke height (JH).

Abstract: A DC brushless motor structure comprises a cylinder-like base having a through-hole or a chamber. The through-hole acts as an axle hole for rotatably receiving a shaft of a rotor. Alternatively, the shaft of the rotor is rotatably received in the chamber. An axle hole is defined in an end of the base. Another axle hole is defined in a lid attached to an end of the base. The shaft of the rotor is rotatably received in the axle holes. At least two sets of windings are mounted to the base. Also mounted to the base is an IC control member electrically connected to the windings. A magnetic force is generated by a magnetic field that is created as a result of energizing the windings to thereby repulse the permanent magnet of the rotor having a north pole and a south pole, thereby driving the rotor to turn.

Abstract: An electric motor 10 has an armature 12 including windings 14. The armature is constructed and arranged to rotate a shaft 16. The motor includes a commutator 18 and a brush card assembly 20 having brushes to engage the commutator and conduct electrical current to the windings. A permanent magnet structure 21 is disposed about the armature. A frame assembly 22 carries the permanent magnet structure. A coil spring structure 36, containing iron, is disposed about and contacts the permanent magnet structure to define a flux path of the motor.

Abstract: A series-wound motor is disclosed which is particularly suitable as a universal motor for an electric power tool. The motor comprises a stator with at least two field poles, each having two pole horns. At least one of the pole horns of each pole comprises first and second protrusions extending circumferentially from an axial edge of the pole horn. Sparking is reduced thereby. Also a retarded motor is disclosed, wherein each pole comprises a pole horn having a run-on edge, and further comprises a pole horn having a run-off edge. The pole horns having run-off edges are shortened in circumferential direction compared to the pole horns having run-on edges or comprise at least one cutout section extending in circumferential direction. The motor can be switched between a motor operation and a brake operation, without the need for providing commutating windings or additional coils to avoid excessive sparking.

Abstract: A brushless generator is composed of a front bracket, a rear bracket, a stator, a rotary shaft, a core, poles, a ring, a field core, a field winding bobbin, and a field winding. Air gaps are defined by facing surfaces between the field core and the core, between the poles and the stator, between one side of a pole and the field core, and between the core and another side pole. Magnetic coating made of magnetic particles and a binding material is applied to the surfaces which face the air gaps. A tensile strength of the magnetic coating is set smaller than a bonding strength of the same. Thus, in case that the surfaces to which the magnetic coating is applied is damaged by an external force, the magnetic coating does not peel but rather the breaking of the base material occurs.

Abstract: A winding body has a winding area (31) for a winding (13), which winding area (31) is formed by a winding carrier (32) and two legs (34, 35) which define the winding area (31) in axial direction (L) and are connected with the winding carrier (32). The winding carrier (32) has a locking device (40) for locking the winding body (30) at a winding tooth (24). Further, a temperature sensor (50) for measuring the temperature in a coil (25) can be provided in the winding body (30). The winding body (30) has a receiving area (36) for a connection device (70) for the windings (13), wherein the receiving area (36) is formed by one of the legs (35), an elongation area (33) of the winding carrier (32) extending beyond this leg (35), and a fixing leg (60) at a distance from the leg (35).

Abstract: A process to perform a flaring operation on a rotating electrical device (stator) designed with a number of these spaced axially oriented splines around its perimeter. The design of the stator requires that these perimeter splines possess a flared outer end, creating a rounded cavity contour between adjacent splines to effectively retaining the stator winding in place. The method of this invention reduces damage to the stator windings and allows more wire fill during the manufacturing process.

Abstract: A magnetic device having a stator assembly having a magnetic flux return path comprising at least a pair of pole plates located a fixed distance apart from each other and at least one flux return strip pressed between each pair of spaced apart pole plates, and a rotor assembly having permanent magnetic material and being disposed for rotation relative to the stator assembly. Use of the flux return strip eliminates the need for a housing of ferrous material to complete the flux return path and facilitates flexible design of light-weight non-metallic housings and mounting systems or integral mounting to mating components.

Abstract: Core laminations for laminated cores of rotors and stators are partially made of partial ring segments that are at least partially stamped out of a central part produced as a remainder in a piece of sheet metal when manufacturing annular core laminations.

Abstract: An uncluttered secondary induction machine (100) includes an uncluttered rotating transformer (66) which is mounted on the same shaft as the rotor (73) of the induction machine. Current in the rotor (73) is electrically connected to current in the rotor winding (67) of the transformer, which is not electrically connected to, but is magnetically coupled to, a stator secondary winding (40). The stator secondary winding (40) is alternately connected to an effective resistance (41), an AC source inverter (42) or a magnetic switch (43) to provide a cost effective slip-energy-controlled, adjustable speed, induction motor that operates over a wide speed range from below synchronous speed to above synchronous speed based on the AC line frequency fed to the stator.

Abstract: A flux collector for an electrical machine includes a continuous strand of ferromagnetic material; and an electrical insulator covering the strand. The strand forms a tight cylindrical coil including a plurality of turns that are stacked axially. The insulator provides turn-to-turn insulation. The insulated wire is covered with a binder and cured. The strand can be a high permeability wire made of soft iron, silicon steel or cobalt steel. In the alternative, the strand can be a strip of METGLAS® amorphous alloy.

Abstract: The electric motor, especially a permanently excited direct current motor, has a housing (16) carrying a magnetic pole (15) and a grounding ring (17) made from magnetically conductive material and mounted on the housing. In order to reduce the noise generation of the motor the grounding ring (17) is a knit article made from a thread-form or wire-form magnetically conductive material.

Abstract: On the stationary side of a radial bearing constructed of a plurality of magnetic poles, the magnetic poles are formed into a shape such that the magnetic flux density distribution formed between the inner surfaces of these magnetic poles and a rotor located on the rotating side of the radial bearing has a distribution inclined from the magnetic pole end portion to the magnetic pole center portion. With this arrangement, the rate of change in magnetic flux density during the shift of the rotor from a magnetic pole to the adjacent magnetic pole is reduced, thereby reducing the eddy current loss and heat generation.

Abstract: A dynamoelectric machine such as a motor or generator has an end winding ring of ferromagnetic material in an area of the end winding portions of the stator and/or rotor winding. The end winding ring improves the overall power density of the motor by reducing the stator and/or rotor flux leakage (the magnetic flux that is produced by the windings that is not utilized to produce torque in the rotor). By operatively coupling end winding portions of the stator winding with ferromagnetic material, the end winding portion is employed to produce torque in the rotor. The end winding ring may be a ring of ferromagnetic material attached to the stator core or the frame or the rotor, or may be a coating of ferromagnetic material applied indirectly to the end winding portions. The end winding ring also may support the end winding portions to reduce movement thereof.

Abstract: An electronically commutated external rotor motor has an external rotor having a cup-shaped housing and a radially magnetized permanent magnet connected in the cup-shaped housing. An interior stator is positioned in the cup-shaped housing. The interior stator has a laminated core having grooves. Windings are provided within the grooves. The windings have first end turns proximal to a bottom of the cup-shaped housing and second end turns positioned distal to the bottom. The first and second end turns electrically connect the windings to one another. The permanent magnet has an end face remote from the bottom of the cup-shaped housing. At least one galvano-magnetic rotor position sensor is arranged opposite the end face of the permanent magnet so as to be located within a magnetic leakage of the permanent magnet and within a magnetic leakage of the interior stator. The at least one rotor position sensor is designed to control current within at least a portion of the windings.

Abstract: An electromechanical machine includes a stator fixed with respect to a housing structure and a rotor fixed with respect to a shaft. The shaft is rotatably supported by a pair of bearing assemblies maintained in the housing structure. A pair of coilheads extend from respective sides of the stator core axially external of the rotor. Shaft shields, preferably configured as tubular members, radially interpose the shaft and the respective coilhead. The shaft shields may be constructed of a magnetically permeable material to divert flux that would otherwise cut through the shaft. As a result, errant currents that could be induced in the shaft by such flux are desirably reduced.

Abstract: A synchronous generator which is driven by an engine whose rotation variation is large and which can easily incorporate an output voltage stabilization circuit. In this synchronous generator, magnetism shorting paths for a magnetic field produced by the armature coil is formed without changing the armature specifications. Magnetic fluxes produced by currents flowing in the armature coils can easily pass through the magnetism shorting paths, thereby increasing the equivalent inductance value and improving the frequency characteristic of the inductance. This in turn improves the voltage step-up chopper characteristic during generation to stabilize the generated voltage of the synchronous generator driven by, for example, an automobile engine that widely varies in revolution speed.

Abstract: This invention is to provide a low-cost structure that a cogging torque and a torque ripple are small and a stable rotation is provided in a radial gap type motor.A portion that stator pole teeth 37 to become interpoles are provided between stator poles 38 and a plurality of stator pole teeth 37 are not continuously provided between the partial stator poles 38 is provided. As a result, in this invention, a magnetic attraction force between the stator pole teeth 38 and the rotating pole 9 of a rotor 6 is stronger in the case that the pole teeth 37 are provided than in the case that the pole teeth 37 are not provided.Accordingly, the rotational shaft 12 of the rotor 6 is supported at three points of points P, Q and R of the bearing cylinder 4, and a rotary force is received at the point P as a center. As a consequence, the rotational shaft 12 is rotated with less contact friction with the bearing cylinder 4.

Abstract: The rotor cage of a motor is extended, a second stator is coupled to this extended rotor cage, and the windings have the same number of poles. The motor torque and speed can be controlled by either injecting energy into or extracting energy out from the rotor cage. The motor produces less harmonics than existing doubly-fed motors. Consequently, a new type of low cost, high efficiency drive is produced.

Abstract: A direct current motor for vehicle engine starters includes a plurality of primary and auxiliary magnetic poles made of permanent magnets arranged between a cylindrical yoke and a cylindrical sleeve inside which an armature is rotatably supported. In order to fixedly support each auxiliary magnetic pole in position between circumferentially adjacent two of the primary magnetic poles, the primary magnetic pole is formed with slanted faces on both circumferential sides thereof to provide a radially inwardly decreasing circumferential width and the auxiliary magnetic pole is formed with slanted faces on both circumferential sides thereof to provide a radially inwardly increasing circumferential width, so that the primary magnetic poles presses the auxiliary magnetic poles radially inwardly when the slanted faces abut each other.

Abstract: A shield band, made from grain-oriented silicon metal, is wrapped about a case of a motor to reduce electromagnetic emissions. The case is protected by a strip of tape adhered to an outer surface of the case. The shield band is made by pressing a strip of metal against a strip of tape with an adhesive agent between them. The resulting strip is cut to length and curled around a roller to form a band which conforms to the outer perimeter of the small D.C. motor. A plate bridges the facing ends of the shield band.

Abstract: A new class of higher phase-order (five or more) quasi square-wave back emf permanent magnet machines including radial, axial and linear embodiments which employ a greater number of active phase windings during continuous operation, thereby utilizing more of the machine copper and magnet material.

Abstract: A cylindrical shielding plate is provided on an inner circumference of the cylindrical recess formed on the bracket of an electric motor of a magnetic disk drive, and an open sector of the stator core is arranged to coincide with the moving direction of read/write head. Or a cylindrical boss is inserted between the stationary shaft and the stator core. Thereby, high frequency electromagnetic noise to the magnetic disk is drastically reduced.

Abstract: An electromagnetic shield for an AC motor comprises a stack including a plurality of ferro-magnetic shield layers. Each one of the plurality of shield layers is at least partially electrically insulated from and substantially aligned with the others of the plurality of shield layers. The plurality of shield layers are positioned over a portion of the AC motor near an area where an axle will be positioned.

Abstract: Magnetic circuit losses due to unnecessary magnetic fields are greatly curtailed or eliminated relative to the permanent magnet structures of electric machinery, without employing a conventional shunt or pole pieces. At least one coaxial cylinder of magnetic material is included in each permanent magnet structure of the invention and is magnetized to provide individual magnetic fields between sets of north and south poles on only one cylindrical surface thereof. Each of the cylinders is constructed from a plurality of segments in one preferred embodiment thereof and magnetically rigid materials are utilized to enhance the field magnitudes in another preferred thereof. Segments having a substantially triangular cross sectional configuration are utilized in other preferred embodiments, while flux contributions from at least three segments combine to sustain each set of north and south poles in still other preferred embodiments.

Abstract: A fluid-filled elastic mount including an elastic body elastically connecting a first and a second support, and partially defining a fluid chamber filled with a non-compressible fluid. The elastic mount includes an oscillating plate which partially defines the fluid chamber and which is displaceable to change a pressure of the fluid in the fluid chamber, and a permanent magnet disposed on one of opposite sides of the oscillating plate remote from the fluid chamber. A first and a second yoke member are connected to opposite magnetic pole faces of the magnet by a plastic material, and cooperate with the magnet to define a closed magnetic circuit. The yoke members define therebetween an annular gap in the magnetic circuit, in which a magnetic fluid and an annular moving coil are received. The magnetic fluid includes magnetic particles dispersed in a liquid medium. The coil is fixed to the oscillating plate, to oscillate the oscillating plate upon energization of the coil.

Abstract: A brushless electric motor with Hall-effect sensors is configured to provide its stator structure with a portion which projects axially away from a main armature. The projecting portion is radially congruent with a second, smaller armature coaxial with the main armature, with a portion of a sleeve in which the sensors are disposed in circumferentially spaced configuration, and with a laminated annular shield iron. The annular shield iron is radially interposed between the projecting portion of the stator structure and the sensors. In this configuration, the shield iron serves to close the magnetic field originating from the second armature and interacting with the sensors while simultaneously shielding the sensors from field effects attributable to current flow in the axially projecting portion of the stator structure.

Abstract: An electric motor used for example in a magnetic disk drive, includes a rotor having a hub on which the magnetic disk is mounted, and an annular driving permanent magnet, and rotating together with a rotary shaft, and a stator disposed outside the rotor, having a core and coils wound on the core. A signaling permanent magnet for detecting the rotary angle or the rotational speed of the rotor may be provided on the radially inner side of the driving permanent magnet. Part of the outer periphery of the stator core may be retracted radially inward or cut away to form a concavity or an open part. A magnetic shielding plate may further be provided to cover the coils, with part or the entirety of the magnetic shielding plate being positioned closer to the rotary shaft than the outermost periphery of the rotor to prevent the escape of the rotor in the direction of the rotary shaft.

Abstract: A reluctance torque coupler includes a first rotor assembly which provides a magnetic field and a second rotor assembly which rotates relative to the first rotor assembly. The second rotor assembly includes a pair of elongated, arcuate flux poles that are attached to a non-magnetic frame. The flux poles extend towards the first rotor such that they are magnetically coupled to the first rotor. Air gaps between ends define a position of minimum reluctance for the first rotor. When the conductors magnetic axis of the first rotor is aligned with the spaces, the leakage of flux across the spaces is at a minimum. If one rotor is rotated, there is a change in energy stored in the magnetic circuit. This change is resisted by a restoring torque toward the aligned position. In this manner, the torque coupler transmits torque from one rotor to another.