Abstract: A flux barrier includes a radially outer proximate part and a radially inner proximate part that are a rotor radially outer side surface and a rotor radially inner side surface extending from a communicating part, at least one of the radially outer proximate part and the radially inner proximate part is connected to an end part of a magnet fixing part of a magnet hole in an inward direction of the magnet hole, and a projecting part projecting in an inward direction of the flux barrier is provided on at least one of the radially outer proximate part and the radially inner proximate part connected to the magnet fixing part. A constricted part in which a width of the flux barrier is narrower than on a side closer to the communicating part than the projecting part is formed by the projecting part.

Abstract: A rotor for an electromagnetic apparatus including: ferromagnetic laminates stacked along a longitudinal axis of the rotor; non-magnetic laminates stacked along the longitudinal axis, wherein the non-magnetic laminates are between the ferromagnetic annular laminates; cavities in the rotor formed by aligned slots in the ferromagnetic and non-magnetic laminates, wherein the cavities are parallel to the axis of the rotor, and a permanent magnet(s) in each of the aligned cavities. The laminates may each be an annular disc or may be segments arranged in an annular array around a shaft of the rotor.

Abstract: For applications standard d-c machines require gear-boxes, there is designed a d-c motor provided with a first basic element (1) made of magnetic conductive material and carrying a system of unipolar oriented magnets (3) and further provided with a second basic element (2) made of magnetic non-conductive material and carrying at least one coil (4) with leads for connection to a source of d-c current. The coil (4) is located on a core (5) made of a magnetic conductive material and arranged mutually spaced apart along the system of the magnets. The first and the second parts are mutually relatively movable. In a preferred application the magnets are made of permanent magnets (3).

Abstract: An electric motor comprises a stator assembly having at least two armature coils, and a rotor assembly arranged radially inward of the stator assembly. The rotor assembly has a rotor core, a magnetic ring, and a plurality of permanent magnets. The rotor core is substantially cylindrical in shape and constructed of a diamagnetic material. The magnetic ring is positioned about the rotor core, and the permanent magnets are positioned in the magnetic ring in such a way that magnetic fields created by the armature coils provide an attractive force which selectively attracts the permanent magnets toward the armature coils so as to impart rotational mechanical energy to the rotor assembly.

Abstract: A 2-pole machine arrangement (10) has a stator (100) with windings (101) in conventional form, wound either in a single phase or three phase configuration. The rotor is formed of stacked laminations. The laminations include rotor pole pieces (107) located between the two magnetic poles. Each pole is formed by a pair of (embedded) permanent magnets (103), angularly spaced-apart by inter-magnet segments (106). The rotor pole pieces (107) include a series of evenly-spaced slots (109) and a central void (108). The slots (109) are of various lengths to direct the flux from the magnets (103) into the air gap (121) at a desired angle normal to the rotor surface. The slots 109 may be varied in width and angle to achieve the desired lowest waveform distortion under load and the highest air gap flux. The slots (109) also contribute to changing the saliency of the rotor.

Abstract: In order to provide a motor rotor in which a permanent magnet is prevented from corroding, wherein a motor rotor for use in a motor for driving a pump rotor rotating shaft of a vacuum pump is provided which comprises a rotor core made up of a plurality of steel plates which are laminated in an axial direction and having a through hole, a permanent magnet which is disposed in the through hole, and end plates which are attached individually to axial end portions of the rotor core, wherein an adhesive is applied to a whole surface of each of the plurality of steel plates, and the plurality of steel plates are surface joined to each other and to the end plates via the adhesive.

Abstract: A single stator electric machine includes a plurality of magnets for generating a first magnetic field. Each respective magnet represents a respective rotor pole. A magnet holder retains the plurality of magnets. A stator is disposed radially outward from the plurality of magnets for generating a second magnetic field. The stator includes a plurality of stator poles separated by slots with each of the stator poles having a concentrated winding with a respective number of turns formed around each respective stator pole. Each respective concentrated winding within the stator comprises non-overlapping phases which increase an active length of the windings of the stator and reduce an overhang of each respective winding with respect to each stator pole for improving torque efficiency. A number of rotor poles is at least eight and the number of rotor poles and a number of stator slots have a least common multiple of at least 36.

Abstract: An electric motor (1), comprising a primary part (2a, 2b) having an iron-free winding device (3) that comprises at least two phases (6) , wherein one phase (6) comprises at least two phase windings (4) and at least one electrical connecting element (5) , a secondary part (7a, 7b) having an even number of magnetic poles (8), which are arranged alternatively on the secondary part (7a, 7b), wherein the winding device (3) is arranged in an air gap (9) between the primary part (2a, 2b) and the secondary part (7a, 7b) relative to an axis (10a, 10b), in such a manner that each phase winding (4) of a phase (6) is arranged opposite a respective magnetic pole (8) and all magnetic poles (8) are usable simultaneously for force formation.

Abstract: Provided is a coercive-force specifying apparatus capable of creating a demagnetization curve for each divisional area of a coercive-force distributed magnet without breaking the coercive-force distributed magnet and of specifying an average coercive force for each divisional area precisely. A coercive force specifying apparatus of the present invention includes: a yoke including an insertion space into which a coercive-force distributed magnet is to be inserted; a magnetizing coil; a search coil that detects a magnetization change when the magnetic field is applied to the coercive-force distributed magnet; and a tracer that creates a demagnetization curve on a basis of a voltage value generated due to the magnetization change. The end face is provided with two or more loop-shaped thread grooves bored therein, the search coil being provided in each thread groove.

Abstract: A device having a directly driven rotating body (1), its circumference (11) being radially seated on radial bearings (4, 4?) in relation to the stationary body (2), and its at least one first face side (10) being axially seated in relation to the stationary body (2), wherein aerostatic bearings (5, 5?, 5?) are provided for the axial support mounting, characterized in that the first face side (10) has an annular magnet arrangement (32), which is configured coaxially to the axis of rotation (X) of the rotating body (1), and that the stationary body (2) has at least one electric coil arrangement (30), which is located opposite the annular magnet arrangement (32) in the axial direction and which forms together with the annular magnet arrangement (32) the components of an electrical direct drive (3) for the rotating body (1).

Abstract: A permanent magnet embedded type rotating electrical machine includes a rotor includes a rotor core formed by a plurality of laminated magnetic steel plates and a plurality of permanent magnets and a stator. Each magnetic steel plate has a plurality of pairs of magnet holes, pairs of joining portions and peninsula portions. The magnet holes of each pair are disposed at positions adjacent to an outer periphery of the magnetic steel plate so as to form a V-shape that is divergent toward the outer periphery. The joining portion is configured to connect the magnet hole with a circumference of the peninsula portion. A distance between a center of the rotor core and at least one of a pair of ends of the circumference of the peninsula portion is smaller than a distance between the center and an intersection of a d-axis of the rotor and the circumference.

Abstract: Apparatus and methods for manufacturing magnets, and magnets, having magnetically oriented grains, and apparatus including such magnets. The field of a permanent magnet may be shaped by applying an external field to the material from which the magnet is made in such a way as to magnetize different regions of the material in different directions. The apparatus may include, and the methods may involve, a metal-powder press that may press metal powder in the presence of a magnetic field. The press may compress the powder in an axial direction. The field may have flux lines that are transverse to the axial direction. The field may have flux lines that are along the axial direction.

Abstract: An easy-to-start motor includes a base, a stator and a rotor. The base has a plastic member and a metallic induction member wrapped with the plastic member. The metallic induction member includes at least one magnetic attraction portion. Each magnetic attraction portion is in the form of a protrusion. The stator is coupled with the base. The rotor has a shaft and a permanent magnet. The shaft is capable of being coupled with the base. The at least one magnetic attraction portion is magnetically attracted by the permanent magnet, so as to prevent the rotor from stopping at a dead location where it is difficult to start the motor. A base of the easy-to-start motor is also disclosed and adapted to be coupled with a rotor, including a plastic member and a metallic induction member wrapped with the plastic member.

Abstract: “IMPROVEMENT IN ELECTRICAL EQUIPMENT GENERATOR OF ELECTRICAL POWER”, the invention herein refers to improvements in electrical power generating equipment which, due to the construction adopted, allows simplified maintenance at reduced frequency; in addition to useful application in several types of hydro electrical power plants, namely: micro, mini and small sized hydroelectric power plants.

Abstract: A drive unit for a revolving door with an electronically commutated multipole motor having a quantity of coil elements and a quantity of magnet elements. The multipole motor has a flat base structure and a disk-shaped or cup-shaped stator part arranged at a stationary structural component part. A disk-shaped or cup-shaped rotor part is arranged in a plane-parallel manner with respect to the stator part and can be drivingly connected to a turnstile of the revolving door. The coil elements and the magnet elements are received in an area between the stator part and the rotor part.

Abstract: A drive unit for a revolving door having a turnstile includes: an electronically commutated multipole motor having: (i) a disk-shaped or cup-shaped stator part configured to be arrangable at a stationary structural component part of the revolving door, (ii) a disk-shaped or cup-shaped rotor part configured to be gearlessly connectable to the turnstile of the revolving door, and (iii) an engagement device arranged between the stator part and the rotor part, the engagement device being configured to intervene in rotational movement of the rotor part. The stator part and the rotor part are in a plane-parallel arrangement with respect to one another.

Abstract: The present invention is a high efficiency permanent magnet machine capable of maintaining high power density. The machine is operable over a wide range of power output. The improved efficiency is due in part to copper wires with a current density lower than traditional designs and larger permanent magnets coupled with a large air gap. In a certain embodiment wide stator teeth are used to provide additional improved efficiency through significantly reducing magnetic saturation resulting in lower current. The machine also has a much smaller torque angle than that in traditional design at rated load and thus has a higher overload handling capability and improved efficiency. In addition, when the machine is used as a motor, an adaptive phase lag compensation scheme helps the sensorless field oriented control (FOC) scheme to perform more accurately.

Abstract: Electric motor systems and methods may provide highly efficient operation. The electric motor systems and methods discussed herein provide an oil filled motor that is low speed and utilizes permanent magnets. The electric motor may utilize a large number of poles and fractional slot design. Further, in some embodiments, the electric motor systems and methods may be suitable for use downhole.

Abstract: Method for mounting a bush round a part (2) of a shaft with a force fit, which method comprises the following steps: providing a guide element (7, 23) with an outer surface (8) which is at least partly conical; providing the guide element (7, 23) in the extension of the aforesaid part (2) of the shaft (1); pushing the bush (5) over the guide element (7, 23) on the part (2) of the shaft (1).

Abstract: The device comprises a single circular row of permanent magnetic poles and a circular row of electromagnets, magnetic-force-conducting elements of which have central polar part and two lateral polar parts connected to the central polar part and spaced from opposing (in the direction which is essentially perpendicular to the rotation axis) sides of the central polar part. Winding is situated upon central polar part. The part of winding positioned between the polar parts of the magnetic-force-conducting element is more than half the length of the whole winding. Central polar part may have at least one groove. The distance between the centers of adjacent polar surfaces of the magnetic-force-conducting element is set depending on the angle between the magnetic poles in the circular row. The angular dimension of the polar surface of the lateral polar part depends on the angular dimension of the polar surface of the central polar part.

Abstract: A rotor is provided that includes a rotor core formed in a cylindrical shape so as to be disposed and rotatable in a hollow portion of a hollow cylinder of a stator and a rotating shaft that penetrates a rotational center of the rotor core and rotates together with the rotor core accordingly. Furthermore, permanent magnets are disposed along a circumference of the rotor core and are each divided into a plurality of individual units along an axial direction of the rotor core. In particular, the plurality of individual units includes an intermediate permanent magnet positioned at a center portion in the axial direction. This intermediate permanent magnet is made of a material having coercive force higher than that of the other individual units.

Abstract: A BLDC motor for driving a cross flow fan in an air-conditioning application has an external rotor and an internal stator. The stator is a salient pole stator with insulated pole teeth and conductor coils. The inner diameter of the stator supports a single bearing. An electronic PCBA for control of the BLDC motor is optionally attached to the stator, all of which is encapsulated in a thermoset resin. The rotor comprises permanent magnet component(s) and a rotor frame. The rotor frame includes a stub axle that engages with the bearing element and features to provide torsional or rotational compliance between the rotor magnets and the fan. A level of compliance is provided between the bearing element and the stator to allow for angular misalignment between the rotational axis of the fan and the stator.

Abstract: A rotor assembly, including: a permanent magnet and a rotor core. The rotor core includes an annular ring and a plurality of magnetic induction blocks. The magnetic induction blocks protrude outward from the outer side of the annular ring. A radial recess is formed between every two adjacent magnetic induction blocks for mounting the permanent magnet. An end plate and a base plate are disposed on an end surface and a bottom surface of the rotor core by injection molding, respectively. A first connecting column passes through a through hole of the magnetic induction block and connects the end plate and the base plate. An end surface of the end plate protrudes upward to form the magnetic loop bracket. A magnetic loop is disposed on a magnetic loop bracket.

Abstract: An electric machine includes a stator core defining a number of stator slots (Z). A rotor assembly is positioned at least partially within the stator core. The rotor assembly includes at least one permanent magnet and defines a number of poles (M). A plurality of stator windings are positioned in the number of stator slots and define a number of phases (M). The machine defines a non-integer slots per pole per phase value (X), which is expressed as a mixed fraction in the form of A.(B/C), where A, B and C are integers. Optimal configurations for the electric machine are specified that maximize torque while minimizing torque ripple, noise and manufacturing complexity. In one embodiment, the slots per pole per phase value (X) is 2½. In another embodiment, the slots per pole per phase value (X) is 3½.

Abstract: A rotor of a motor includes a first rotor that includes a first rotor core and a plurality of first magnets that are coupled to an outer circumferential surface of the first rotor core, a second rotor that includes a second rotor core and a plurality of second magnets that are coupled to an outer circumferential surface of the second rotor core, and a third rotor that is stacked between the first rotor and the second rotor and includes a third rotor core and a plurality of third magnets that are coupled to an outer circumferential surface of the third rotor core, wherein magnetic fluxes of the plurality of third magnets are less than magnetic fluxes of the plurality of first magnets or second magnets.

Abstract: A rotor for a permanent magnet electric motor includes a rotor core having a generally cylindrical shape with an outer circumferential surface and a rotational axis and a plurality of magnet insertion hole arrangements formed in the rotor core and arranged circumferentially at a preset angular interval about the rotational axis. Each hole arrangement has a radially inward side, a radially outward side, and two ends that are respectively spaced apart from the circumferential surface by respective bridge regions formed by the rotor core. The material of the bridge regions is metallurgically transformed by having its grain structure changed, e.g., by heating the material to at least its Curie temperature, whereby the material possesses greater magnetic reluctance than the material of adjacent portions of the rotor core.

Abstract: Disclosed herein is a rotor permanent magnet apparatus for a drive motor based on temperature distribution.

Abstract: Various embodiments are described herein for a switched reluctance machine having a rotor excitation. In one example embodiment, the switched reluctance machine comprises a stator and a rotor. The rotor may be disposed inside or outside the stator. The rotor is spaced from the stator, and the rotor and the stator are concentrically disposed. The rotor has a plurality of rotor poles having an excitation source, where the excitation source comprises at least one adjustable parameter. The excitation source is provided by a permanent magnet. The dimensions and various other parameters associated with the permanent magnets are adjustable.

Abstract: Disclosed therein is a motor with a variable magnetic flux, which includes a rotor and a stator located inside the rotor. The rotor includes a rotor housing, a plurality of unit rotor cores and magnets which are attached to the inner wall surface of the rotor housing, and the unit rotor cores and the magnets are arranged in turn. The stator includes a stator core base and a plurality of teeth radially formed on the outer peripheral surface of the stator core base at equal intervals, and each of the teeth has ears formed at both sides of an end thereof.

Abstract: A washing machine includes a water tub, an electric motor, and a control device. The motor comprises a stator including a stator coil, a rotor magnet arranged circumferentially with respect to the rotor, and a control device. The rotor magnet includes a permanent magnet. When the control device applies a first voltage to the stator coil in a wash step of the washing operation, the rotor magnet is magnetized so that a magnetic flux of the rotor magnet acting on the stator is increased without reversal of a direction of magnetization. When the control device applies a second voltage to the stator soil in a dehydration step of the washing operation, the rotor magnet is magnetized so that a magnetic flux of the rotor magnet acting on the stator is reduced without reversal of a direction of magnetization as compared with the magnetic flux in the wash step.

Abstract: A magnet that includes a composite body and at least one reinforcing element. The reinforcing element is embedded within the body and increases the radial strength of the body. As a result, the magnet is able to rotate at higher speeds without fracturing. Additionally, methods of manufacturing the magnet are described.

Abstract: In one embodiment, a permanent magnet includes: a composition expressed by RpFeqMrCusCo100-p-q-r-s (R is a rare-earth element, M is at least one element selected from Zr, Ti, and Hf, 10?p?13.5 at %, 25?q?40 at %, 1.35?r?1.75 at %, and 0.88?s?13.5 at %); and a metallic structure including Th2Zn17 crystal phases each having a Fe concentration of 25 at % or more, and Cu-rich crystal phases each having a Cu concentration of from 25 at % to 70 at %. An average thickness of the Cu-rich crystal phases is 20 nm or less, and an average distance between the Cu-rich crystal phases is 200 nm or less.

Abstract: In one embodiment, a permanent magnet includes a sintered compact including: a composition expressed by a composition formula: RpFeqMrCusCo100-p-q-r-s (R is at least one element selected from rare-earth elements, M is at least one element selected from Zr, Ti, and Hf, 10?p?13.3 at %, 25?q?40 at %, 0.87?r?5.4 at %, and 3.5?s?13.5 at %); and a metallic structure having a main phase including a Th2Zn17 crystal phase, and an R-M-rich phase containing the element R whose concentration is 1.2 times or more an R concentration in the main phase and the element M whose concentration is 1.2 times or more an M concentration in the main phase. A volume fraction of the R-M-rich phase in the metallic structure is from 0.2% to 15%.

Abstract: A spindle motor according to an aspect of the invention may include: a base on which a sleeve is mounted; a rotor bound together with a shaft rotatably mounted on the sleeve and rotating by electromagnetic interaction with the stator; a pulling plate mounted on the base to generate a magnetic force in a rotary axis direction of the rotor; and an escape portion provided on the base at a position corresponding to the pulling plate and providing a space into which an adhesive may escape when bonding the pulling plate.

Abstract: The invention relates to an electric motor having a rotatably mounted rotor magnet and a stator enclosing the rotor magnet, said stator comprising at least three coil windings and a winding carrier, wherein coil axes of the at least three coil windings are disposed radially to an axis of rotation of the rotor magnet in various radial directions. The coil windings of the electric motor are designed so that a gap that is parallel to the axis of rotation of the rotor magnet extends between at least two adjacent coil windings, in which at least one media line extending in the longitudinal direction is provided.

Abstract: A method of making a magnetically loaded pre-impregnated tape uses a drum 1 that is heated and which is associated with a heated bath 2 containing a thermo-plastic resin solution. A fibre tape material 4 is fed onto the drum 1 and, just prior to the fibre tape material meeting the periphery of the drum, the fibre tape material 4 is impregnated with an isotropic magnetic particle material 6 to form a pre-impregnated tape 8. The pre-impregnated tape is fed to a heating station where it is bonded with a thermoplastic resin impregnated fibre tow to produce a magnetically loaded composite tape. The heating station includes a rotatably driven heated mandrel (20) having a magnetic field (41, 42) embedded therein to provide the pre-impregnated tape (8) with a desired magnetic configuration.

Abstract: A rotor includes a rotor core having an outer circumferential surface provided with projections extending in a direction of a rotational axis and projecting outwardly in a radial direction, and a plurality of permanent magnets arranged between the projections. The projections extend at an angle with respect to the direction of a rotational axis. The permanent magnets have inclined sides on both side faces, which incline with respect to the direction of a rotational axis. Side faces of the projections and the inclined side of the permanent magnets which face each other incline so as to define the same angle with respect to the direction of a rotational axis. An electric motor including such a rotor is also provided.

Abstract: An actuator motor described herein has fast dynamic response capability, high torque density, high efficiency, and improved thermal and mechanical stability at high speed while minimizing weight. According to one aspect of the disclosure provided herein, an actuator motor has a rotor shaft with an array of permanent magnets attached according to a Halbach array configuration. A stator includes windings that induce a torque on the rotor shaft when rotating magnetic fields interact with the optimized magnetic flux distributions of the magnets of the Halbach array. According to various embodiments, the rotor shaft is hollow, reducing weight and rotational inertia, while improving ambient cooling characteristics of the motor.

Abstract: An Nd—Fe—B permanent magnet is disclosed. The Nd—Fe—B permanent magnet includes 28-34 weight % of rare earth elements, where the content of Dy is smaller than 0.1 weight % and the Nd—Fe—B permanent magnet has a spatial extension parallel to a magnetization direction of the Nd—Fe—B permanent magnet which is larger than 30 mm. Further described is a rotor assembly for an electro-mechanical transducer. The rotor assembly includes at least one of such an Nd—Fe—B permanent magnet. Further described is an electromechanical transducer including such a rotor assembly and a wind turbine including said electromechanical transducer.

Abstract: An AC electric motor includes an annular A-phase winding WA wound in the circumferential direction of a stator, a stator pole group SPGA configured to generate magnetic flux ?A to interlink with the A-phase winding WA, an annular B-phase winding WB wound in the circumferential direction, and a stator pole group SPGB configured to generate magnetic flux ?B to interlink with the B-phase winding WB. The motor additionally includes a third stator pole group SPGC, N and S magnetic poles of the rotor, and X magnetic poles, which serve as third rotor poles, showing magnetic characteristics between the N and S magnetic poles of the rotor. DC currents are supplied to the A-phase and B-phase windings WA and WB to generate rotational torque.

Abstract: In an electrically driven motor and an electrically driven pump using the electrically driven motor which can reduce a cogging torque in a simple structure not using a magnetized skew, the electrically driven motor includes a motor rotor in which a plurality of permanent magnets are attached onto an outer circumferential portion of rotor core and a stator having a plurality of slots and a plurality of projections are disposed on positions including a magnetic pole center of at least one of the permanent magnets at predetermined intervals of distance in a peripheral direction of an outer circumferential portion of the rotor core.

Abstract: The electric rotating machine includes a stator having an inner hole, a rotor disposed in the inner hole of the stator with a gap with an inner periphery of the stator and formed with magnet housing holes each housing a permanent magnet as a magnetic pole embedded in the outer periphery of the rotor, and a shaft pressure-inserted into a center hole of the rotor. The rotor includes, for each adjacent two of the magnet housing holes, a beam portion formed radially outside the magnet housing holes, a projecting portion projecting radially inward to define the center hole, an extension portion formed radially outside the projecting portion and radially outside the magnet holes, and a plate-shaped bridge portion connecting the beam portion and the extension portion.

Abstract: A method for manufacturing a rotor with permanent magnets may include providing a central core with a desired cross-section; providing a plurality of ferromagnetic discs having a hole shaped in a complementary manner to the cross-section of the central core; stacking up the ferromagnetic discs around the central core to form a cylindrical structure with a longitudinal cavity, wherein the longitudinal cavity is formed by the holes of the stacked-up ferromagnetic discs; integrally blocking together the stacked-up ferromagnetic discs; and removing the central core. A rotor may be manufactured by the method. The rotor may be used in an electric motor.

Abstract: A concentrated winding motor having the combination of the number of poles and the number of slots of 10:12 or 14:12 includes coils in the same phase that are adjacent to each other and have mutually different numbers of coil turns.

Abstract: Method for assembling a rotor with permanent magnets, including the steps of introducing the magnets in 10 recesses of a non-ferromagnetic holder; combining the holder and the permanent magnets with a non-ferromagnetic support plate; attaching the permanent magnets to the support plate; and removing the holder and providing lamellae over the permanent magnets attached to the support plate. A holder and rotor obtained by the method are described.

Abstract: A motor having a structure that enhances durability of the motor. The motor includes a stator and a rotor rotatably disposed at an inside outside of the stator. The rotor includes a plurality of rotor cores radially disposed and a plurality of magnets respectively disposed between rotor cores. The area of a lateral surface of each of the magnets adjoining a lateral surface of a corresponding one of the rotor cores is greater than the area of an imaginary plane connecting one end of an upper end portion of each of the magnets to one end of a lower end portion of each of the magnets.

Abstract: Provided are a device and method of stopping an induction motor. The includes: a frequency commanding unit for generating an operating frequency corresponding to a rotational speed command of the induction motor; a q-axis and d-axis V/F converter for outputting a first q-axis voltage (Vq1) proportional to the generated operating frequency and a first d-axis voltage (Vd1) proportional to a 0 frequency; a q-axis PI current controller for outputting a second q-axis voltage (Vq2) for stopping the induction motor when the operating frequency reaches a stopping frequency; a d-axis PI current controller for outputting a second d-axis voltage (Vd2) for stopping the induction motor when the operating frequency reaches the stopping frequency; and a selection unit for selecting and outputting the first q-axis and d-axis voltages (Vq1 and Vd1) or the second q-axis and d-axis voltages (Vq2 and Vd2) according to the operating frequency generated by the frequency commanding unit.

Abstract: Provided is a permanent magnet type motor capable of improving a demagnetization proof stress almost without lowering a generated torque, and reducing a torque ripple and a cogging torque by improving a gap magnetic flux density distribution. In manufacturing a permanent magnet type motor, portions having a low demagnetization proof stress of a plurality of permanent magnets incorporated into a rotor core are partially and equally demagnetized.

Abstract: Disclosed herein is a rotor for an interior permanent magnet synchronous motor, the rotor including: a rotor core having a through-hole formed in an axial direction so that a shaft is press-fitted thereinto, a permanent magnet receiving part formed at an outer peripheral portion thereof in a circumferential direction so that a permanent magnet is inserted thereinto, and slits formed to be adjacent to the permanent magnet receiving part and be extended toward a circumferential end in a radial direction; and at least one permanent magnet inserted into the permanent magnet receiving part.

Abstract: A magnetic resistance changing mechanism for changing a magnetic resistance of a stator magnetic path including a stator yoke portion and each tooth portion by mechanically changing the stator magnetic path is provided. A pair of side protruded portions are formed on circumferential sides of a rotor side end portion of each tooth portion. The rotor side end face of each tooth portion is shaped so that a gap between the rotor side end face of each tooth portion and an outer periphery of the rotor is increased continuously or stepwisely from a circumferential intermediate portion of the rotor facing end face toward circumferential end portions thereof.