Abstract: A motor with small ripple and capable of high-speed rotation includes six stator poles having widths of about 60 degrees, which is less than 60 degrees when converted to rotor rotational angle. Excitation windings (HA3, HA4, and so forth) wound around the stator poles are connected in series with adjacent excitation winding connected in reverse series. Torque windings (HA1, HA2, and so forth) wound around the stator poles have three phases, where each phase winding comprises a pair on opposite sides with respect to the center of rotor rotation, separated from each other by 180 degrees, and connected in reverse series. In addition, two rotor poles (3) having widths from 60 degrees to 120 degrees when converted to the rotor rotational angle are provided.

Abstract: A reluctance motor electric machine including a number of stator pole teeth and a number of rotor pole teeth selected so that with a minimal reluctance, due to the rotational alignment of the rotor in relation to the stator, three air gaps that can be flowed through are produced between three pairs of stator pole teeth and rotor pole teeth. This results in the fact that now three regions of the yoke body are elastically pulled in the direction of the rotor rotational axis and consequently, the elastically deformed zones of the yoke body only extend over essentially and therefore act in a more rigid fashion. This results in the advantage that with the same excitation frequency, the deformations take place with small amplitudes and therefore with less generation of noise.

Abstract: An inductance rotating electric machine comprises a primary armature having a core that includes a core winding portion, a coil wound within a slot and a facing core portion. The facing core portion faces a secondary armature at a projection end of the core winding portion. The facing core portion has a core height which is higher than that of the core winding portion.

Abstract: A low inductance electrical machine that may be used as an alternator or motor with low armature inductance is disclosed. Arrangements of complementary armature windings are presented in which the fluxes induced by currents in the armature windings effectively cancel leading to low magnetic energy storage within the machine. This leads to low net flux levels, low core losses, low inductance and reduced tendency toward magnetic saturation. The inclusion of additional gaps in the magnetic circuit allows for independent adjustment of air gap geometry and armature inductance. Separately excited field arrangements are disclosed that allow rotor motion to effect brush-less alternator or brush-less motor operation. An exemplary geometry includes a stator including two annular rings and a concentric field coil together with a rotor structure separated from the stator by four air gaps.

Abstract: A low inductance electrical machine which may be used as an alternator or motor with low armature inductance is disclosed. Arrangements of complementary armature windings are presented in which the fluxes induced by currents in the armature windings effectively cancel leading to low magnetic energy storage within the machine. This leads to low net flux levels, low core losses, low inductance and reduced tendency toward magnetic saturation. Separately excited field arrangements are disclosed that allow rotor motion to effect brushless alternator or brushless motor operation. An exemplary geometry includes a stator including two toroidal rings and a concentric field coil together with a rotor structure separated from the stator by four air gaps. An alternate embodiment allows for counter-rotation of two rotor elements for use as a flywheel energy storage system in which the external gyroscopic effects cancel.

Abstract: A rotary electric apparatus functions as either a generator or a motor and has a rotary shaft defining an axial direction and a stator disposed around an external periphery of the rotary shaft. The stator has coil assemblies including coils wound around core members extending parallel to the axial direction and equidistantly disposed about the rotary shaft. The core members have opposing first and second stator pole surfaces normal to the axial direction and disposed respectively in opposing first and second sides of the stator. A first monopole rotor is fixed on the rotary shaft adjacent the first side of the stator and has all N-polar magnetic pole surfaces normal to the axial direction, disposed diametrically opposed about the rotary shaft, and alignable opposite the first stator pole surfaces during rotation of the first monopole rotor.

Abstract: An electrical machine comprises a four-pole stator 2 provided with a field winding 10 and an armature winding 11, each of the windings 10, 11 being split into two coils 22, 23 or 24, 25 closely coupled and wound so that diametrically opposite portions of both coils are disposed within diametrically opposite stator slots. A two-pole rotor (not shown) without windings is rotatable within the stator 2, and a circuit is provided for energising the armature coils 24 and 25 when direct current is supplied to terminals 26 and 27 of the circuit. Switches 28 and 29 in series with the coils 24 and 25 are switched alternately to effect alternate energisation of the coils 24 and 25 so as to generate, as a result of the opposite winding of the coils, magnetomotive forces in opposite directions.

Abstract: In a VR-type resolver which is used in combination with a motor to detect the rotation position of the motor, the teeth number of a rotor of the resolver is reduced over the teeth number of a rotor of the motor. Also, the shape of the teeth of the resolver rotor is simplified into a curved shape such as a sine wave shape. Further, in another type of VR-type resolver, the number of the magnetic poles of the stator with respect to the number of the teeth of the rotor is set as a number being capable of satisfying not only the condition that it is a multiple of the phase number N and an even number but also the condition that it is a number which can be calculated according to one of the following expressions (1) and (2), that is,stator pole number=rotor teeth number/(M+1/N) (1)stator pole number=rotor teeth number/{M+(N-1)/N} (2),where M is an integral number of one of 1, 2, and 3.

Abstract: A reluctance motor is provided that reduces leaking magnetic flux. To generate magnetic flux between adjacent magnetic poles in a rotor 2, permanent magnets 4 are disposed in approximate centers of split magnetic paths near a borderline area between two magnetic poles in an internal portion of the rotor. Further, each of slots 8 in a stator 1 is wound with a coil of a corresponding phase such that the vector phase and amplitude expressed by the products of the number of coil turns and the amount of passing current, namely, ampere-turns, become almost identical for each of the slots. By reducing leaking magnetic flux according to this arrangement, generated torque can be increased. As the rotor mechanical strength is enhanced, the rotor can be safely driven at a higher speed. A practical motor is obtained that simultaneously achieves improved motor characteristics and reduced torque ripples.

Abstract: An inductor-alternator provides highly efficient conversion between mechanical and electrical energy. The inductor-alternator produces increased output by providing armature coils in a single air gap formed between two halves of a toothed rotor. In preferred embodiments, field coils of a magnetic circuit are energized with DC drive current that creates homopolar flux within the rotating rotor. Airgap armature coils are mounted with the field coils to form a stationary assembly that is placed within the single air gap in the rotor so that the changing flux density (due to the rotating teeth) induces an output voltage in the armature coils. The rotor and stationary assembly are mounted in a housing by bolts that may also be used as terminals for the armature coils to reduce assembly complexity and production cost. The combined assembly provides high energy and power density because tip speed of the rotor is maximized and the use of air gaps is minimized.

Abstract: A switched reluctance motor comprised of a stator having a plurality of evenly spaced, radially oriented, like stator poles that define a gap between adjacent stator poles. Windings for three phases are wound about the stator poles wherein a stator pole of a first phase is disposed circumferentially between a winding and an associated stator pole of a second phase and a winding and an associated stator pole of a third phase. A rotor is mounted for rotation relative to the stator. The rotor has an even number of rotor poles, the rotor poles being dimensioned such that when one of the phases is energized, the rotor poles operatively interact with the energized stator poles such that the motor moves from a first state wherein half of the rotor poles are magnetically coupled to a like number of the stator poles to a second state wherein all of said rotor poles are magnetically coupled to a like number of stator poles.

Abstract: A three-phase reluctance motor includes, a stator having a plurality of magnetic poles around which coils corresponding to three phases are wound, a rotatable rotor having a plurality of convex poles opposed to the magnetic poles of the stator, a magnet provided on the rotor for magnetizing alternately the convex poles to N- and S-polarities in a circumferential direction, and a control circuit for magnetically exciting selectively only two of the three phases to the N- and S-polarities, respectively, and for sequentially switching two phases which are to be excited, to thereby rotate drive the rotor.

Abstract: Losses in efficiency of operation of a dynamoelectric machine as a result of eddy current losses and poor coolant efficiency and/or disruption of the magnetic circuit in a rotor by coolant passages is avoided in a dynamoelectric machine including a stator (18) in which a rotor (16) is journaled. The rotor includes a stack (16) of thin laminations (17) made of a ferromagnetic material to define a rotor body. The rotor body includes a plurality of equally angularly spaced poles (58) separated by recesses (64). Coolant passages (76) located in the rotor at or just radially inward of the base (72) of each pole (58) and substantially radially outward of the rotational axis (56) of the rotor (14) to maximize cooling efficiency of the poles (58) without disrupting the magnetic circuit in the rotor. Slots (80) are placed in the tips (70) of the poles (58) of selected laminations (17) and extend generally radially inward to reduce eddy current losses.

Abstract: A reluctance type rotating machine includes a stator having armature windings arranged on an inner periphery of the stator, a rotor having projection portion forming magnetic poles, and a plurality of permanent magnets arranged on both side faces of the projection portions. Owing to the provision of the permanent magnets, it is possible to restrain magnetic fluxes of the armature windings of the stator from leaking toward interpole portions between the magnetic poles. The power output of the machine can be improved by increased effective fluxes.

Abstract: A motor having permanent magnets received therein includes a rotor having a plurality of circular sheet irons deposited in turn, a plurality pairs of magnet receiving slots formed through the deposited sheet irons at a predetermined angle toward the outer surface of the rotor, and permanent magnets of different polarities received into the magnet receiving slots, wherein a magnetic flux leakage preventive groove having a predetermined width and depth is formed at the outer surface of the rotor at the center between the pair of magnet receiving slots.

Abstract: A reluctance machine including a plurality of phase windings where each phase winding comprises a plurality of fractional-pitched coils. The reluctance machine may be coupled to a drive that can energize one, two or more of the phase windings to provide output torque that is derived from: (i) the self-inductances of the phase windings; (ii) a combination of the self-inductances of the phase windings and the mutual inductances between the phase windings; or (iii) the mutual inductances between the phase windings.

Abstract: A multiple phase heteropolar inductor electrical machine utilizing relatively movable stators and rotors wherein the rotors include electrical winding for producing electricity. The stators and rotors are spaced as to produce an electrical balancing among the machine phases. Preferably, a balance is achieved in the energy conversion process as measured over any given one-half electrical cycle within that phase. The machine substantially achieves equal and balanced peak torque per amp performance within a half cycle of operation of any given phase through the spacing between the stator and elements.

Abstract: A switched reluctance motor having a stator with a plurality of radially oriented stator poles. Windings for three phases are wound about the stator poles wherein a stator pole of a first phase is disposed circumferentially between a winding and an associated stator pole of a second phase and a winding and an associated stator pole of a third phase. A rotor is mounted for rotation relative to the stator. The rotor has a wide rotor pole and a narrow rotor pole. The rotor poles are distributed on the rotor wherein a narrow rotor pole is disposed to each side of a wide rotor pole in a direction of rotation.

Abstract: A variable reluctance electric motor includes a hollow cylindrical stator having a plurality of radially inwardly extending poles. Each of the stator poles is generally rectangular in cross sectional shape and is bifurcated into two stator teeth at its radially innermost end by a central, longitudinally extending slot. The outer circumferential edges of the stator pole teeth are beveled at their respective junctions with the sides of the stator pole. A stator pole gap width is defined between adjacent stator poles. A slot width is defined within each of the stator poles between the adjacent longitudinally extending edges of the slot. The ratio of the stator pole gap width to the stator pole slot width is in the range of from about 1.8 to about 2.3. A cylindrical rotor is co-axially supported within the stator for relative rotational movement. The rotor has a plurality of radially outwardly extending poles formed thereon. Each of the rotor poles is generally rectangular in cross sectional shape.

Abstract: In a motor having a permanent magnet built in a rotor, a hole for preventing a short-circuit of magnetic flux is disposed so that the hole is adjacent to the outer rim of rotor core, and adjoins to a slit for receiving a permanent magnet as well as the permanent magnet per se. This structure prevents a short-circuit of magnetic flux generated by both ends of the permanent magnet, and the magnetic flux at both ends of the magnet can flow to a stator, thereby contributing to generate torque effectively. As a result, the highly efficient motor with less cogging torque, less vibration and lower noise can be provided.

Abstract: This invention provides a novel switched reluctance machine and a method of its control. The machine rotor has rotor poles that are wider than the stator pole, which allows two phases to be energized simultaneously, reducing torque ripple and noise.

Abstract: A high inertia inductor-alternator energy storage device provides backup energy in a simple, compact device. The inductor-alternator stores an acceptable level of energy via an improved rotor that provides a high level of rotational inertia. The improved rotor can be manufactured at a reduced cost due to reduced milling requirements. Moreover, the inductor-alternators of the present invention have reduced complexity and increased reliability as a result of the geometry of the improved rotor.

Abstract: An axial flux reluctance machine including a rotor formed from a wound tape of paramagnetic material, a first stator formed from a wound tape of paramagnetic material and a similarly constructed second stator, where the first and the second stators define stator poles and wherein the stator poles of the first stator are not completely aligned with the stator poles of the second stator. Also a reluctance machine system for energizing the axial flux reluctance machine and methods for forming the wound tape rotor and stators.

Abstract: A reluctance machine system including a reluctance machine having a rotor and a stator including at least one phase winding and a full pitch auxiliary field winding where constant currents are established in the auxiliary field winding to assist in the establishment of a magnetic field in the machine so as to improve the machine's performance. A novel power converter uses residual energy remaining in the phase windings at the time the phase winding is de-energized (turned-off) to provide the constant energy for the auxiliary field winding.

Abstract: A switched reluctance motor includes a stator having a plurality of pairs of opposing stator pole portions which project inward in the diametrical direction and which extend in the axial direction, a rotor rotatably disposed in the stator and having a plurality of rotor pole portions which project outward in the diametrical direction and which extend in the axial direction and axis portion which is rotatably supported on a housing. A plurality of coils are wound on each of the pair of the stator pole portions and an absorbing mechanism is provided for absorbing radial vibrations of the rotor which are generated by a variation of the magnetic attracting force acting on the rotor pole portions.

Abstract: The invention relates to a single-phase induction motor comprising a main winding, an auxiliary winding which is arranged so that an electrical angle of the auxiliary winding is different from that of the main winding, a plurality of driving capacitors which are connected to the auxiliary winding, a relay for controlling on/off of the driving capacitor in response to the driving load, and a rotor having apertures on the gap side of the slots. The invention further relates to a rotor assembling apparatus comprising a bush to which a rotor core assembly is inserted for die-casting, wherein a clearance between said bush and said rotor core assembly is narrower to the extent that said rotor core assembly can be taken out after die casting; and a core band having a clearance between the core band and the bush in the circumferential direction of said bush, said core band is engaged into said bush so that movement in the axis direction is restricted.

Abstract: An induction generator having a pair of magnetic poles of the same polarity opposed to each other with respect to a rotation shaft is characterized by a high energy conversion efficiency.

Abstract: A multi-phase permanent-magnet type electric rotating machine comprising: a permanent magnet type rotor, the permanent magnet type rotor including pairs of magnetic bodies magnetized by an axially magnetized cylindrical permanent magnet and disposed so as to face each other in a manner so that different poles of the magnetic bodies are disposed alternately or including a cylindrical permanent magnet having a multi-polar-magnetized outer circumferential surface; and a stator disposed so as to face the rotor through an air gap therebetween, the stator having 6N or 10N (N being an integer not smaller than 1) main poles formed in a distributed fashion, the stator having coils wound on 3N or 5N in total of the 6N or 10N main poles selected every other one, wherein the coils wound on the 3N or 5N main poles are connected so as to form a star connection and at least one of the three or five terminals of the star connection of the coils is connected to a predetermined polarity of a power supply while all or part of t

Abstract: An electric motor for an x-ray tube of a medical imaging system is described herein. The electric motor includes a stator and a substantially cylindrical rotor. The stator includes stator winding slots and stator windings injected into the stator winding slots. The stator also has a stator bore. The rotor is rotatably mounted within a stator bore so that the rotor is coaxial with the stator bore. The rotor includes a rotor core, a plurality of rotor bars, and end rings. The rotor bars are at located in rotor bar openings at a periphery of the rotor. At least one of the rotor bars has a different cross-sectional area than one of the other rotor bars.

Abstract: A reluctance machine system including a reluctance machine having a rotor and a stator including at least one phase winding and a full pitch auxiliary filed winding where constant currents are established in the auxiliary field winding to assist in the establishment of a magnetic field in the machine so as to improve the machine's performance. Alternate embodiments are disclosed wherein the auxiliary field winding is positioned in a conventionally-shaped stator with phase windings of different types (e.g., short-pitched and fractional-pitched).

Abstract: A switched reluctance motor is provided with a rotor position detecting apparatus for detecting a rotor position wherein the apparatus comprises a rotor position-sensing mechanism removably mounted in a ventilator hole formed in a side wall of a motor housing for enabling an easy replacement of printed circuit boards and photo-interrupters when they need to be repaired and maintained. The sensing mechanism includes a fixing member having spaced slots for receiving respective circuit boards.

Abstract: The invention relates to a single-phase induction motor comprising a main winding, an auxiliary winding which is arranged so that an electrical angle of the auxiliary winding is different from that of the main winding, a plurality of driving capacitors which are connected to the auxiliary winding, a relay for controlling on/off of the driving capacitor in response to the driving load, and a rotor having apertures on the gap side of the slots. The invention further relates to a rotor assembling apparatus comprising a bush to which a rotor core assembly is inserted for die-casting, wherein a clearance between said bush and said rotor core assembly is narrower to the extent that said rotor core assembly can be taken out after die casting; and a core band having a clearance between the core band and the bush in the circumferential direction of said bush, said core band is engaged into said bush so that movement in the axis direction is restricted.

Abstract: A switched reluctance motor includes a stator defining a plurality of radially-inwardly-extending poles and a rotor defining a plurality of radially-outwardly-extending poles. The poles of the stator define a shape in radial cross-section characterized by a generally rectangular body portion, and a tip portion which tapers at an angle no greater than 40.degree. relative to the sides of the rectangular body portion. The nominal width of the rectangular body portion of each stator pole is at least 1.3 times the nominal (chordal) dimension across the arcuate, radially-innermost surface on the tip portion thereof.

Abstract: A reluctance machine including a stator defining a plurality of stator poles and a plurality of stator slots, a rotor positioned to rotate with respect to the stator, and a plurality of phase windings, where each phase winding comprises a plurality of coils, where each coil is wound about more than one stator pole, where each coil comprises two coils sides, and where only one coil side is positioned in each stator slot, wherein the self-inductance of each phase winding varies as a function of the angular position of the rotor with respect to the stator. Also a reluctance machine similar to that described above where each of the phase windings is magnetic uni-polar.

Abstract: A permanent magnet machine combines both principles of variable reluctance machines and permanent magnets, and comprises a rotor with salient rotor poles and a stator with salient stator poles. A pair of ferrite arched permanent magnets are embedded in the stator yoke beneath respective stator poles and are arranged symmetrically around the central axis of the machine. A field winding for boosting or weakening the primary flux generated by the permanent magnets is wound in a special arrangement.

Abstract: A linear motor having a plurality of stator pieces rather than a ring-shaped stator. Accordingly, production costs are reduced and controllability can be improved. By coupling directly two sets of rotors and stators with a pulsator and spinning tub, an extra power transfer device can is unnecessary.

Abstract: A doubly-fed switched reluctance machine in which at least two sets of phase winding are energized to produce desired output torque is disclosed. Also disclosed are dual and single power converters for energizing the doubly-fed machine as well as exemplary excitation schemes position. Sensorless techniques and systems for controlling the doubly-fed machine, and other machines having fully-pitched or fractional-pitched windings, are also disclosed.

Abstract: An open stator axial flux asynchronous induction electric motor has an open stator having two spaced insulating supports with a slot extending from a periphery of each of the supports to an inner location. A plurality of poles extend between and are secured to the supports. The stator has either distributed winding or salient phase pole windings associated with at least some of the poles with an opening between adjacent poles in the regions of the slots in the supports. The motor has a rotor with a shaft extending through the slots and at right angles to the supports. Two spaced rotor discs are present on the shaft and are located at either side of the stator. Each disc is made of a magnetically permeable material and has either an inner face of electrically conductive material or an inner face with conductive paths which function as rotor windings.

Abstract: An induction motor includes a stator defining stator inner and stator outer diameters extending about a longitudinal axis, the stator includes a plurality of windings extending longitudinally and circumferentially about the longitudinal axis between the stator inner diameter and the stator outer diameter, passing an electric current therethrough to create a magnetic field, a rotor extending along the longitudinal axis having a rotor length and a rotor outer diameter less than the stator inner diameter, the rotor being rotatable about the longitudinal axis relative to the stator in response to the magnetic field, the rotor including a hoop portion disposed adjacent the rotor outer diameter and extending radially inwardly toward the longitudinal axis, the hoop portion being a solid unitary structure.

Abstract: An induction motor includes a stator defining stator inner and stator outer diameters extending about a longitudinal axis, the stator includes a plurality of windings extending longitudinally and circumferentially about the longitudinal axis between the stator inner diameter and the stator outer diameter, passing an electric current therethrough to create a magnetic field, a rotor extending along the longitudinal axis having a rotor length and a rotor outer diameter less than the stator inner diameter, the rotor being rotatable about the longitudinal axis relative to the stator in response to the magnetic field, the rotor including a hoop portion disposed adjacent the rotor outer diameter and extending radially inwardly toward the longitudinal axis, the hoop portion being a solid unitary structure being fabricated of an Aermet alloy material.

Abstract: A reluctance machine system including a reluctance machine having a rotor and a stator including at least one phase winding and a full pitch auxiliary filed winding where constant currents are established in the auxiliary field winding to assist in the establishment of a magnetic field in the machine so as to improve the machine's performance.

Abstract: A bobbin-wound stator for small single-phase AC motors that surmounts magnetic compromises required by previous implementations is fabricated of stacked two-piece laminations and a split winding bobbin fitted about a first one of the lamination piece stacks that permits bobbin winding of a single coil about the pole neck of a magnetic yoke having pole shoes magnetically coupled to each other, but not in direct contact with each other, at a predetermined clearance distance chosen to balance rotor-to-armature flux linkage, armature inductance, and reluctance torque. The second lamination piece stack is pressed into the first lamination piece stack supporting the bobbin-wound coil to complete the stator. The stator is usable in several single-phase AC motors, including electronically commutated motors, chaotically-starting permanent magnet motors, and shaded-pole induction motors.

Abstract: An induction motor rotor particularly for x-ray tube applications comprises a series of hollow cylinders fitting concentrically on each other and on a motor shaft. The first cylinder is a highly heat resistant and electrically insulating material. The next cylinder is a highly magnetic material cylinder fitting on the first cylinder. The next and outermost cylinder is an electrically conductive material providing the armature conductor of the induction motor rotor.

Abstract: The invention relates to an axial-flow induction motor comprising a stator having a winding arranged in a slot and a rotably supported laminated rotor which is spaced from the stator by an air gap. The rotor has a magnetically highly conductive layer on the side which is remote from the stator and an electrically highly conductive layer on the side which faces the stator. In order to reduce losses caused by harmonics, the rotor also includes an additional magnetic conductive layer between the electrically highly conductive layer and the air gap. The magnetic conductivity of the additional magnetic conductive layer in the direction of rotation is low in comparison with the magnetic conductivity of the magnetically highly conductive layer. The electrically highly conductive layer is also thicker than the magnetically conductive layer.

Abstract: A three-phase reluctance type motor flat in shape and capable of generating a large output torque and rotating at high speeds, comprising a flat stationary armature (16) having a circumferential surface provided with three multiplied by integral number of magnetic poles wound by first, second and third phase armature coils, salient poles of a magnetic rotor (1) fixed to the inside of the outer periphery of a cup-shaped rotor (3), and a current supply control circuit for obtaining first, second and third phase position detecting signals responsive to the position of the salient poles and for quickly supplying current to the first, second and third phase armature coils based on these position detecting signals, so as to realize a high-speed rotation.

Abstract: A torque sensor including a coil bobbin around which a coil is wound, a coil yoke having a first end face and a second end face, the coil yoke accommodating the coil bobbin, a housing having a medium-diameter portion and a small-diameter portion, the housing being shaped to receive the coil yoke and having a receiving surface at one end of the small-diameter portion, the first end face of the coil yoke abutting against the receiving surface, and a seal member that contacts the second end face of the coil yoke and urges the coil yoke toward the receiving surface to fix a position of the coil yoke in the housing, an outer peripheral surface of the seal member being secured to an inner peripheral surface of the housing at the medium-diameter portion of the housing.

Abstract: An induction machine having ferromagnetic conducting material in the rotor is disclosed. The machine may be used as a motor, an alternator, a generator, or an alternator/starter. The machine includes a first stator and a second stator in a symmetrical mirrored relationship to the first stator such that a gap is defined intermediate the first and second stator. A disk-shaped rotor is disposed in the gap. The rotor is substantially comprised of ferromagnetic material electrically conducting in the radial direction and may include copper bars or rings embedded within the rotor.

Abstract: In a capstan motor, a gear portion and an FG detection portion are integrally formed of a plastic magnet at mutually different wall thicknesses and they are fixed to the outer circumference of a rotor yoke. The FG detection portion is provided with multipolar magnetization to generate a rotation detection signal with a magnetoresistance element. The gear portion is arranged to transmit the drive force to the outside. The outer diameter of the rotor yoke is different at the gear portion and at the FG detection portion, depending upon the wall thicknesses of the plastic magnet. The outer diameter is set to be greater in the portion corresponding to the FG magnet of the rotor yoke.

Abstract: A multi-rotor A.C. electric drive device comprises a stator capable of producing a rotating or an alternating magnetic field and at least two rotors capable of producing an electromagenetic torque at asynchronous speed. The rotors are respectively called the main rotor and the auxiliary rotors. In low speed operating mode of said device, the electromagnetic torque of the auxiliary rotor is amplified through a transmission portion and drives an output element together with the main rotor; after the auxiliary rotor is accelerated to the synchronous speed, an automatic unloading device releases the auxiliary rotor from the driving engagement with the output element. Examples illustrating several types of electromagnetic portion, transmission portion and the automatic unloading device are given.

Abstract: The invention provides a starter for a motor vehicle of the kind having an inductive winding composed of coils, each forming a magnetic pole of the inductor, in which each coil has a conductor of large cross section wound flat so as to form concentric contiguous turns, and in which the innermost turn of the coil is extended by a folding in the conductor which extends radially towards the outside of the coil, substantially in the plane of the turns and straddling them, wherein, in the area of straddling of the turns, the folding is of a reduced dimension along the axis of the turns so that the axial thickness of the coil in this area is reduced.