Abstract: A permanent magnet rotating electric machine uses no skewing under a predetermined current and voltage condition to prevent torque from decreasing and to decrease pulsation torque to make the machine less vibrating and less noisy. The permanent magnet rotating electric machine includes a stator with multi-phase stator windings and a rotor with a plurality of permanent magnets internally embedded in a rotor core. The core shape of the rotor is uniform in the depth (longitudinal) direction with no skewing in the arrangement of the permanent magnets. The permanent magnets are symmetrical with respect to the rotation direction, but irregular with respect to the depth direction, for each pole. A magnetic flux generated from the between-pole permanent magnets almost equals a magnetic flux generated from the pole-center permanent magnet.

Abstract: A hybrid-excited rotating machine comprising: a stator winding of a multi-phase Y-connection; a plurality of rotor magnetic poles fixed on a rotor shaft 3 at a predetermined spacing in the circumferential direction and confronting the inner circumference of said stator through a air gap; a plurality of permanent magnets fixed at substantially central portions of said circumferential direction of said individual rotor magnetic poles and magnetized in the radial direction of said rotor shaft; and a plurality of field windings wound individually on said rotor magnetic poles.

Abstract: A rotor for an interior permanent magnet machine has a rotor body having an output shaft and a first cavity filled with magnetic material. Second cavities are disposed inboard of the first cavities and are not filled with magnetic material. Non-magnetic rods extend through the second cavities and protrude beyond end faces of the rotor body. The rods are press-fit in blind bores formed in non-magnetic end plates disposed adjacent the end faces of the rotor body. Shrink disks are shrunk around projecting ends of the output shaft in abutting relation with the end plates. In order to prevent induced voltage from generating current in the cage formed by the rods and end plates, an oxide layer is disposed between the rods and blind bores in the end plates.

Abstract: The present invention provides a rotating electric machine in which damage to a magnet from heat is prevented, eddy current loss is reduced while decreasing an eddy current generated in a permanent magnet, and furthermore, time and cost for manufacturing can be reduced.

Abstract: A rotor for a rotary electric machine includes a rotor core made of magnetic material, and being in the form of a disk, and a plurality of magnet sets each including a pair of permanent magnets whose polarities are identical to each other. The magnet sets are arranged circumferentially in the rotor core so that the polarities of the magnet sets change alternately. The rotor core includes nonmagnetic portions each formed between adjacent two of the magnet sets.

Abstract: A permanent magnet motor having a rotor and a stator and configured such that when the leading edge of each pole of the rotor aligns with a stator tooth the trailing edge of that pole is generally not aligned with a stator tooth.

Abstract: A permanent magnet electrical rotating machine having a permanent magnet rotor and a stator, wherein: a plurality of permanent magnets are disposed in a rotor iron core of the permanent magnet rotor along a periphery of the rotor iron core, polarities thereof being alternately changed; a cooling airflow channel is formed between each pair of adjacent opposite poles on the rotor iron core; and the cooling airflow channel has an approximately trapezoidal shape on an outer periphery side of the rotor iron core; and extends from an end on a central side in a radial direction of the approximately trapezoidal shape to a radial center.

Abstract: A laminated core having a first number of magnetic poles, the first number being a natural number divided by two, of a rotary electric machine, includes a plurality of arc-shaped unit cores each having a second number of magnetic poles, the second number being a natural number except for an aliquot part of the first number. The unit cores are wound and laminated a predetermined number of times in a circumferential direction into a spiral shape in such a manner that an axial lamination amount of the unit cores is obtained by an equation of X=?*t/360, X being the axial lamination amount, ? being a winding angle of the unit cores, and t being a thickness of the unit core. The unit cores are adjacent to each other in the circumferential direction connected to each other at a part of an outer circumference thereof.

Abstract: A magnetic gap is provided between a permanent magnet of a rotor and an auxiliary magnet pole portion which is arranged adjacent to the permanent magnet in a peripheral direction. A gradual change in a magnetic flux density distribution of a surface of the rotor is obtained and a cogging torque and a torque pulsation are restrained. By obtaining a reluctance torque according to the auxiliary magnetic pole, a permanent magnet electric rotating machine in which the cogging torque and the torque pulsation are restrained can be obtained and further an electromotive vehicle having the permanent magnet electric rotating machine can be provided.

Abstract: A synchronous motor includes a stator, a rotor and permanent magnets. The rotor includes a rotor iron core that is rotatable relative to the stator, and conductor bars accommodated within corresponding slots in the rotor iron core. The conductor bars have their opposite ends short-circuited by respective shortcircuit rings to form a starter cage conductor. The rotor also has a plurality of magnet retaining holes defined therein, in which permanent magnets are embedded. The conductor bar holes are positioned in an axial direction and inwardly from the magnet retaining holes. The conductor bars within the holes protrude outwardly from an axial end of the rotor iron core to form projections for securing an end plate to the end of the rotor iron core, the end plate comprising a non-magnetizable material.

Abstract: A rotor for an interior permanent magnet machine has a rotor body having an output shaft and a first cavity filled with magnetic material. Second cavities are disposed inboard of the first cavities and are not filled with magnetic material. Non-magnetic rods extend through the second cavities and protrude beyond end faces of the rotor body. The rods are press-fit in blind bores formed in non-magnetic end plates disposed adjacent the end faces of the rotor body. Shrink disks are shrunk around projecting ends of the output shaft in abutting relation with the end plates. In order to prevent induced voltage from generating current in the cage formed by the rods and end plates, an oxide layer is disposed between the rods and blind bores in the end plates.

Abstract: An interior permanent magnet rotary motor of the present invention has N slots and P permanent magnet magnetic pole sections, (?<=P/N<= 43/45). Po is an irreducible fraction Po/No of the P/N is an odd number, and a pole arc ratio ?p equals ?pp/?p. ?pp is an angle between two line segments assumed for a pair of flux barriers, each of which connects the center of a rotor core and one of corners of the section of each flux barrier that is closest to the surface of the rotor core. ?p is an angle obtained by dividing 360° by the number of the permanent magnet pole sections. The pole arc ratio indicated by ?p (0<4n<1) is determined by the expression of ?p=2mP/N+P/4LCM (P, N)?2n, where LCM (P, N) is the least common multiple between P and N, m and n are arbitrary natural numbers.

Abstract: A rotor includes a shalt that defines a rotor axis, a first end portion coupled to the shaft, and a pole piece that defines an enclosed aperture therethrough. A second end portion is positioned to dispose the pole piece between the first end portion and the second end portion. A portion of one of the first end portion and the second end portion extends through the aperture and bonds with the other of the first end portion and the second end portion. The portion is integrally-formed as a single piece with one of the first end portion and the second end portion.

Abstract: A rotor (10) for a rotary electric machine (1) comprises a rotation shaft (11), and a plurality of rotor cores (120-129) fixed to the rotation shaft (11) and axially split. The rotor cores (120-129) have outer peripheral surfaces (120A-129A) with a circular cross section. Permanent magnets (13) extending through the rotor cores (120-129) are arranged at equal circumferential intervals. Voids (120B-129B) extending axially through the rotor cores (120-129) are formed between the outer peripheral surfaces (120A-129A) and the permanent magnets (13). The voids (120B-129B) of two adjacent rotor cores (120-129) are formed at circumferentially different positions, thereby being capable of suppressing the cogging torque without introducing a reduction in output torque.

Abstract: A synchronous electric motor including a rotor having a rotation axis, and a stator surrounding the rotor through a gap. The rotor includes a rotor core having an outer circumferential surface extending about the rotation axis and a plurality of permanent magnets attached to the rotor core to form plural poles along the outer circumferential surface of the rotor core. The outer circumferential surface of the rotor core is provided, at each pole, with a contour deviating from a circular arc and bulging out in a radial outward direction, as seen in a cross-section perpendicular to the rotation axis. The permanent magnets include a plurality of magnet sets individually assigned to the plural poles, each set including two or more permanent magnets. The contour of the outer circumferential surface of the rotor core, at each pole, has at least partially a shape represented by a hyperbolic cosine function or a secant function.

Abstract: A rotor for an electric motor includes a base plate (13) made of a magnetic material and coupled to a rotational shaft (12), a rotor core (18) provided on the base plate (13) and including a protrusion protruding axially relative to the base plate and the teeth of the stator, the rotor core having an outer peripheral face and an axial end, a plurality of magnet insertion portions defined in the rotor core, a plurality of rotor magnets provided in the magnet insertion portions respectively, each magnet having a stator side and a counter-stator side both magnetized so as to have poles differing from each other, and a position sensor detecting a rotational position of the rotor core and disposed radially or axially opposite the outer peripheral face or the axial end of the rotor core so as to correspond to the protrusion of the rotor core.

Abstract: Disclosed herein is an apparatus relating to a magnet member for a dynamoelectric machine comprising, a first portion of the magnet member made of a first magnetic material and a second portion of the magnet member made of a second magnetic material. Further disclosed is a method that relates to increasing performance of an electric machine comprising, determining locations of high demagnetization fields at the dynamoelectric machine, and positioning a magnetic member having a first portion having a higher level of coercivity and a second portion having a lower level of coercivity in the machine such that the portion having a higher level of coercivity is more proximate the location of high demagnetization fields than the portion having the lower level of coercivity.

Abstract: This electric motor includes first permanent magnets secured integrally to an outer periphery side rotor and second permanent magnets secured integrally to an inner periphery side rotor. The first permanent magnets and the second permanent magnets are arranged so as to offset the relative torque produced between the outer periphery side rotor and the inner periphery side rotor based on the magnetic flux of the inner peripheral permanent magnets and the outer peripheral permanent magnets.

Abstract: Disclosed is a rotor of a generator or motor having an auxiliary coil provided around a rotor body, thereby preventing the distortion of output voltage waveforms according to the variation of load, and thereby allowing the fine adjustment of the output voltages of the generator by the control of the current flowing to the auxiliary coil. The rotor of a generator or motor includes: a rotor body adapted to axially rotate together with a rotor shaft; at least one set of N-polar and S-polar permanent magnet groups arranged along the circumferential direction of the rotor body at predetermined intervals; and a plurality of magnetic flux-increasing elements formed on the lines of magnetic force formed by the N-polar and S-polar permanent magnet groups around one side of the rotor body.

Abstract: Disclosed is a rotary device of a generator or motor which includes: a stator having a hollow portion formed at the inside thereof and a plurality of slots formed to wind coils therearound, each of the plurality of slots being skewed at a predetermined angle; a rotor shaft formed of a nonmagnetic material; a cylindrical rotor body adapted to axially rotate together with the rotor shaft; a plurality of N-polar and S-polar permanent magnet groups insertedly coupled radially along the outside of the center portion of the rotor body in an alternating arrangement; a plurality of magnetic flux-increasing magnets insertedly coupled along the inside of the rotor body and arranged on the lines of magnetic force formed by the N-polar and S-polar permanent magnet groups, for increasing magnetic flux; and a rotor adapted to be rotatably inserted into the hollow portion of the stator.

Abstract: A motor generator is provided with a stator having a winding around each of a plurality of stator teeth, and a rotor having a plurality of permanent magnets by the number larger than that of the stator teeth, arranged in the circumferential direction at equal intervals. The stator teeth are formed of a first stator teeth section including a plurality of stator teeth groups I, II, and III each including the adjacent stator teeth around which a winding to which the same phase voltage is applied is wound and in which winding directions of the stator teeth are opposite to each other, and a second stator teeth section including a stator teeth having a winding wound therearound and being placed among stator teeth groups of different phases such that electric power is independently input and output with respect to the first and second winding sections.

Abstract: A rotor of an electric motor includes lamination core formed by laminating a plurality of individual cores, and at least one pair of magnet members that generate rotating torque by electromagnetic interaction with a stator, are provided at the lamination core such that a magnetic sensor can sense magnetic flux, and have magnetic poles opposite to each other, such that a position of the rotor of the electric motor can be accurately detected and a process of manufacturing the electric motor can be simplified.

Abstract: A permanent magnet motor has permanent-magnet-holding slots 5 formed in those parts of a rotor core 2A which correspond to sides of an approximately regular polygon centered on an axis of the rotor core 2A, permanent magnets 4 inserted in the respective permanent-magnet-holding slots, and four or more radially elongated slits 6 arranged apart from each other along each of the permanent-magnet-holding slots on an outer core outside the permanent-magnet-holding slots, characterized in that at a radially outer end, the slits are spaced approximately equally while at a radially inner end, spacing between the slits is reduced with increasing distance from a center of each permanent magnet, with the spacing at the center being the largest.

Abstract: A motor includes a rotor, a rotor core included in the rotor, the rotor core being configured to be embedded, therein, with at least one first magnet, a pair of end plates, one of the pair of end plates being positioned at an axial end of the motor, an other one of the pair of end plates being positioned at an other axial end of the motor, and the pair of end plates holding the rotor core at axial ends of the rotor core, and at least one second magnet embedded in the pair of end plates and supplying magnetic fields in an axial direction of the motor.

Abstract: There is provided a permanent magnet rotary motor in which manufacture of a stator core is facilitated. The permanent magnet rotary motor includes P rotor magnetic pole sections and N slots. In this permanent magnet rotary motor, a least common multiple LCM (P, N) is set to be different from a least common multiple LCM (P/2, N), and an exciting winding is wound on each of N stator magnetic pole sections arranged in a peripheral direction so that a 120° current phase difference is obtained. N/2 divided cores 13A, 13C, 13E, 13G, 13I, and 13K of a first divided core group and N/2 divided cores 13B, 13D, 13F, 13H, 13J, and 13L of a second divided core group constitute a stator core 2.

Abstract: A motor includes a stator which generates a rotating magnetic field, and a rotor. The rotor includes a plurality of permanent magnets and a hysteresis band disposed on an outer periphery of the rotor.

Abstract: A plurality of convex portions are located inside of a virtual circumferential surface. Each convex portion connects an adjacent pair of circumferential portions with each other. Each convex portion is an arcuate curve bulging radially outward. Each convex portion defines a minimum radius. A difference between a radius R and the minimum radius is a depth Dh. Dhr=Dh×25.5/R. A range of an angular width A in relation to circumferential portion and a range of the depth Dh are set by the following expression, (5.6×Dhr+11.3)°×6/p?A<35°×6/p and A<[360/p?2×arccos]° ??(1) Therefore, decrease in torque is prevented. Torque pulsation is suppressed.

Abstract: A rotor for a permanent magnet motor of an outer rotor type having a plurality of permanent magnets and disposed around a stator includes a frame, an annular iron core combined integrally with the frame, and a plurality of insertion holes formed in the core so that the permanent magnets are inserted in the insertion holes respectively. The frame, the core and the permanent magnets are combined integrally with one another by a synthetic resin. Each insertion hole includes a magnet disposing portion in which the permanent magnet is disposed, a space portion located in at least one of circumferential both ends of each permanent magnet disposed in the magnet disposing portion, and a positioning portion positioning each permanent magnet in the magnet disposing portion, and the molten synthetic resin is poured into the space portion.

Abstract: A permanent magnet motor includes a rotor core having magnetic pole faces including first to third faces. The first face is formed on a peripherally central part and has a peripherally uniform width of the gap. Each of the second and third faces is formed on both peripheral ends respectively and has a width of a gap rendered larger as each of the second and third faces comes close to a boundary between magnetic poles. The first face ranges from ±15 degrees to ±35 degrees in electrical angle about a center of the magnetic pole and has such a circular arc shape that the gap width is increased by about 10% relative to a minimum gap width.

Abstract: An interior permanent magnet electric motor. A lobed rotor comprising composite slots and non-composite slots radially spaced from its longitudinal axis of rotation extending parallel to the axis. Ferrite magnets are positioned in both the composite and non-composite slots and neo magnets are positioned in the composite slots only.

Abstract: A permanent magnet rotating electric machine uses no skewing under a predetermined current and voltage condition to prevent torque from decreasing and to decrease pulsation torque to make the machine less vibrating and less noisy. The permanent magnet rotating electric machine includes a stator with multi-phase stator windings and a rotor with a plurality of permanent magnets internally embedded in a rotor core. The core shape of the rotor is uniform in the depth (longitudinal) direction with no skewing in the arrangement of the permanent magnets. The permanent magnets are symmetrical with respect to the rotation direction, but irregular with respect to the depth direction, for each pole. A magnetic flux generated from the between-pole permanent magnets almost equals a magnetic flux generated from the pole-center permanent magnet.

Abstract: An electric motor has a rotor (36) and a stator (28) having a lamination stack formed with slots (126). The slots have a predetermined slot pitch (?s), and a multi-phase stator winding is arranged in them. The rotor (36) has salient poles having pole shoes (136) and a magnetic return path (130). Between the return path (130) and each pole shoe (136), a recess (138, 140) is formed for receiving a permanent magnet (38). On each side of such a permanent magnet (38), a region (146a, 146b) of poor magnetic conductivity is arranged, in order to make the flux distribution in the air gap more sinusoidal. Measuring in a circumferential direction, the width (?) of a pole shoe (136) decreases with increasing distance from an interface (138) between said return path and said permanent magnet (38), and, at a place of lowest width, the pole shoe has an angular extent (?c) which has, with respect to the slot pitch (?s) between said stator slots (126), the following relationship: ?c=n*?s*(1?0.02) . . . n*?s*(1?0.

Abstract: The electric machine (M) comprises an armature (A) and an inductor (B), the inductor (B) having for each pair of poles (N, S) of the armature (A), n teeth (20) identical to one another and n slots (21) and being provided with a winding (W) housed in the said n slots. The armature (A) has its surface facing the air gap (G) divided into 2N elements or samples (1–12) with N being a whole multiple of n, having substantially the same extent in the said direction of relative displacement, and having a respective magnetic potential value. Each sample (1–12) of the armature (A) is associated with a value of total magnetic permeance (pi) at the air gap (G) in a predetermined alignment condition between the inductor (B) and the armature (A). The armature (A) comprises a plurality of magnetically distinct ferromagnetic bodies (30, 31, 32; . . . ) each of which couples at least two armature samples in such a way as to ensure a substantial magnetic equipotentiality.

Abstract: A rotating electric machine comprises a stator having stator salient poles, three-phase windings wound around said stator salient poles, a rotor rotatable held inside the said stator, and permanent magnets inserted into said rotor and positioned opposite to said stator salient poles. The three-phase windings are concentratively wound around each of the stator salient poles, with windings of each phase wound around more than one stator salient pole. The windings of each phase have a phase difference of voltage between at least one of the windings and the other.

Abstract: A method for fabricating a rotor arrangement for an electric machine in which a rotor body is provided and permanent magnets made from an isotropic magnetic material are embedded in the rotor body, the permanent magnets being magnetized by an external magnetizing device with a magnetization that corresponds at least approximately to a Halbach magnetic field distribution.

Abstract: A rotating electric machine comprises a stator having stator salient poles, three-phases windings wound around the stator salient poles, a rotor rotatable held inside the stator, and permanent magnets inserted into the rotor and positioned opposite to the stator salient poles. Three-phase windings, which are concentratively wound around each of the stator salient poles, are wound around more than one stator salient pole. The windings of each phase have a phase difference of voltage between at least one of the windings and the other.

Abstract: The invention relates to a rotor for an electric motor comprising an essentially cylindrical rotor core having a central aperture, and comprising permanent magnets which are embedded in the rotor core and extend essentially like spokes through the rotor core, the radially inner ends of selected adjacent permanent magnets being magnetically coupled by at least one auxiliary magnet.

Abstract: The invention relates to a rotor for an electric motor, particularly an electric line-start motor, comprising axially accommodating spaces (4 to 6) for conductor rods, and axially extending receiving spaces (10, 11) for permanent magnets (14, 15), which are-designed and located in such a way that they generate a permanent magnet field with a magnet axis (22) and a neutral axis (23). The aim of the invention is to ensure that the rotor runs as regularly as possible during the operation of the electric motor. To this end, the diameter of the rotor along the magnet axis is larger than that along the neutral axis (23).

Abstract: A synchronous motor includes a stator, a rotor and permanent magnets. The rotor includes a rotor iron core that is rotatable relative to the stator, and a plurality of conductor bars accommodated within corresponding slots in the rotor iron core. The conductor bars have their opposite ends shortcircuited by respective shortcircuit rings to form a starter cage conductor. The rotor also has a plurality of magnet retaining slots defined therein at a location on an inner side of the conductor bars, in which hole permanent magnets are embedded.

Abstract: A rotor for a reluctance type rotating machine includes a rotor core formed by stacking a number of annular core materials each of which includes magnetic concave and convex portions. The rotor core has two keys which are formed at two positions on an inner circumference of the rotor core. The positions are spaced 180 degrees apart from each other with respect to the rotor core. The rotor core is divided into a plurality of blocks and the core materials constituting at least one block have the magnetic concave and convex portions shifted by a predetermined angle relative to the core materials constituting the other or another block on the basis of a center line passing through the keys. A whole or part of the core materials of at least one block are located circumferentially 180 degrees apart form the core materials constituting the other or another block.

Abstract: A spoke permanent magnet rotor that includes a shaft defining a rotor axis. A first non-magnetic end portion is coupled to the shaft and a ferromagnetic pole piece defines an aperture therethrough. A second non-magnetic end portion is positioned to dispose the pole piece between the first end portion and the second end portion. A portion of one of the first end portion and the second end portion extends through the aperture and bonds with the other of the first end portion and the second end portion.

Abstract: A plurality of projections are provided abutted with an outer circumference of a columnar axis inserted to an inner circumference of a rotor. The projections are provided in the direction of a magnetic pole in the rotor. When the rotor is fixed to the columnar axis, the projection parts are fixed by “plunge-in” and the other rotor inner circumference parts have an uniform clearance to the columnar axis. The clearance is filled with an adhesive agent, thereby fixing the rotor to the columnar axis.

Abstract: A permanent magnet rotating electric machine comprises a stator having stator windings wound round a stator iron core and a permanent magnet rotor having a plurality of inserted permanent magnets in which the polarity is alternately arranged in the peripheral direction in the rotor iron core. The rotor iron core of the permanent magnets is composed of magnetic pole pieces, auxiliary magnetic poles, and a stator yoke, and furthermore has concavities formed on the air gap face of the magnetic pole pieces of the rotor iron core of the permanent magnets, gently tilting from the central part of the magnetic poles to the end thereof; resulting in a permanent magnet rotating electric machine effects of iron loss are reduced, and an electric car using highly efficient permanent magnet rotating electric machine are realized.

Abstract: A permanent magnet rotating electric machine uses no skewing under a predetermined current and voltage condition to prevent torque from decreasing and to decrease pulsation torque to make the machine less vibrating and less noisy. The permanent magnet rotating electric machine includes a stator with multi-phase stator windings and a rotor with a plurality of permanent magnets internally embedded in a rotor core. The core shape of the rotor is uniform in the depth (longitudinal) direction with no skewing in the arrangement of the permanent magnets. The permanent magnets are symmetrical with respect to the rotation direction, but irregular with respect to the depth direction, for each pole. A magnetic flux generated from the between-pole permanent magnets almost equals a magnetic flux generated from the pole-center permanent magnet.

Abstract: An electric motor including a stator with a plurality of coils wound around a ring-shaped iron core, and a rotor rotatably disposed inside the stator is provided. The rotor includes a rotor shaft and a yoke. The yoke is provided near its periphery with a plurality of plate-like permanent magnets arranged at equal pitches. Heat generated from the rotor is released through a plurality of air holes formed in the yoke between the rotor shaft and the permanent magnets.

Abstract: A magnetic gap is provided between a permanent magnet of a rotor and an auxiliary magnet pole portion which is arranged adjacent to the permanent magnet in a peripheral direction. A gradual change in a magnetic flux density distribution of a surface of the rotor is obtained and a cogging torque and a torque pulsation are restrained. By obtaining a reluctance torque according to the auxiliary magnetic pole, a permanent magnet electric rotating machine in which the cogging torque and the torque pulsation are restrained can be obtained and further an electromotive vehicle having the permanent magnet electric rotating machine can be provided.

Abstract: There are problems in a rotor having a slit that it is difficult to increase the number of rotations of the rotor, since the centrifugal force is received at both ends of the slit, and if the connection part is made thick to increase the number of rotations, the properties of the motor is deteriorated. According to the present invention, a rotor for a synchronous motor includes a slot for generating induction torque and a slit for generating reluctance torque, the slit is filled with a filler, the slit is provided with at least one of a convex and a concave, so that the convex and the concave are formed so as to receive the centrifugal force which is generated by the rotation of the rotor and acts on a part of the rotor outside the slit and the filler so as to bulge toward the outside from the center side of the rotor by mechanical bondage of the filler and the rotor core.

Abstract: A synchronous electric machine includes a stator and a rotor. The stator is provided with teeth, which are wound around to establish electromagnetic fields. The rotor is provided with permanent magnets to generate magnetic fields, so that the rotor can rotate by interaction of the magnetic fields of the windings and the permanent magnets of the magnets. At least one pair of the permanent magnets is dislocated by a predetermined angle from positions where the permanent magnets is arranged at even pitch, and the predetermined angle being set to reduce electromagnetic excitation force acting on said teeth.

Abstract: A synchronous AC motor has a stator with stator poles arranged as a plurality of circumferentially extending stator pole groups, with each stator pole group having a pair of corresponding circumferentially extending loop-configuration stator windings disposed adjacent on either side or a single such winding disposed adjacent at one side, adjacent stator pole groups being mutually circumferentially displaced by a fixed amount corresponding to a specific electrical phase angle. A rotating magnetic field is produced by applying respective polyphase AC voltages to the windings, such that currents of mutually opposite direction flow in each pair.

Abstract: A total of three permanent magnets, installed in a rotor core closely to an outer cylindrical surface of the rotor core, are disposed at predetermined angular pitches in the circumferential direction of the rotor core. All of the permanent magnets are magnetized in such a manner that the direction of magnetization is the same when seen in the radial direction. A plurality of magnet-less holes, extending in the axial direction in the vicinity of the outer cylindrical surface of the rotor core, are provided between two adjacent permanent magnets.