Abstract: A synchronous reluctance motor includes a shaft, a rotor, a stator, and multiple magnetic wedges. The stator radially opposes the rotor with a space therebetween. The stator includes a stator core having multiple slots arranged in the circumferential direction and open toward the rotor, and multiple stator coils disposed in the multiple slots. Multiple magnetic wedges close at least some of the multiple slots with the multiple stator coils disposed therein.

Abstract: A stator of an electric machine includes a laminated core on which stator teeth and stator grooves are formed. A conductor bundle is arranged in each stator groove. A groove base channel extends in the axial direction and through which a coolant can flow. The groove base channel is formed between the groove base of the respective stator groove and the conductor bundle. A groove slot channel extends in the axial direction and is formed in the groove slot. The groove slot channel is fluidically connected to the groove base channel at at least one distributor point via a distributor connection that runs in the radial direction. The cooling path of the stator groove is formed such that a cooling flow is forced from the groove slot channel into the groove base channel and/or vice versa via the at least one distributor connection.

Abstract: A clamping device performs a clamping action when performing laser welding to join a first stripped portion, where a coating is absent from a first end, and a second stripped portion, where a coating is absent from a second end. A second claw extends in a radial direction of a second shaft. In a state in which a first shaft and the second shaft are moved toward a stator core such that the first end and the second end are sandwiched between the first shaft and the second shaft, and the first shaft is pressed against a second curved portion and the second shaft is pressed against a first curved portion, the clamping device performs the clamping action by rotating the second shaft about a center axis of the second shaft until the second claw comes into contact with the second end.

Abstract: A slot wedge for a slot in a stator of a dynamoelectric machine, wherein the slot wedge is formed as a longitudinally extending strip of insulating material, where the strip is provided with a punched portion.

Abstract: An x-ray tube includes a housing containing cooling oil and a vacuum envelope disposed within the housing and including a solid envelope wall. The oil is disposed between the housing and wall. An anode and cathode are arranged in a vacuum environment and surrounded by the wall. A rotor connected to the anode is arranged on bearings within the vacuum environment. Additionally, a stator assembly positioned within the oil surrounds the rotor to define an oil-filled annular gap. The stator assembly includes a stator core, stator teeth spaced apart by intervening stator slots, and stator windings disposed within the stator slots. Each stator tooth includes a tooth tip positioned adjacent to the boundary wall and set a distance apart from the stator windings to form an intra-slot cooling channel in fluid communication with the oil-filled annular gap such that the stator teeth inclusive of its tooth tips are immersed in oil.

Abstract: A stator assembly for an electrical machine extends azimuthally around an axis. The assembly includes: a plurality of stator teeth projecting radially from a circumference of the stator assembly, wherein the teeth are spaced azimuthally from each other and extend along a direction parallel to the axis of the stator assembly; a plurality of slots defined by azimuthal spacing of the stator teeth, wherein the plurality of slots extends along a direction parallel to the axis of the stator assembly, wherein the slots are arranged to receive a plurality of stator windings; and one or more dividers positioned within the plurality of slots, wherein the dividers define a plurality of cavities for receiving the plurality of stator windings.

Abstract: A rotor for an electric machine includes at least one rotor laminated core that has at least one coil receiving opening, at least one coil device which is located in the at least one coil receiving opening, and at least one holding device which is joined to the rotor laminated core and prevents an outward movement, brought about by centrifugal force, of the at least one coil device in the radial extension direction of the rotor and out of the at least one coil receiving opening during normal use of the electric machine.

Abstract: A generator rotor including a rotor shaft having a rotor slot includes a rotor winding at least partially disposed within the rotor slot and a wedge coupled to the rotor shaft and extending axially along the rotor shaft, the wedge positioned to inhibit radial movement of the rotor winding from the rotor slot. A seal member is coupled to the wedge and extends axially along the wedge. The seal member cooperates with the wedge and the rotor shaft to define a seal therebetween. The wedge, the seal member, and the rotor shaft cooperate to at least partially define an enclosed space operable to contain a high-pressure coolant.

Abstract: A stator housing assembly includes a stator housing and a stator sleeve. The stator sleeve including a combination of composite layers with different high strength fibers. The stator housing includes a first end section and a second end section that define a stator cavity configured to contain a pressurized cooling fluid. The stator sleeve defines a longitudinal axis and includes a plurality of layers of composite materials that include more than one high strength fiber material. High strength fibers may include carbon and glass fibers. Portions of the stator sleeve may have different combinations of high strength fiber materials and fiber orientations to optimize sleeve properties.

Abstract: A compressor (100) includes a compression mechanism part (120) and a motor (200) that are housed in a closed container (110). A stator (300) of the motor (200) includes stator coils (340) respectively wound around teeth of a stator core (310). Each of the stator coils (340) includes first and second protruding portions (340A, 340B) that respectively protrude from the stator core (310) toward first and second sides in an axial direction. First and second surrounding walls (350, 360) are respectively disposed around outer circumferential sides of the first and second protruding portions (340A, 340B) and extend continuously in the axial direction and a circumferential direction so as to surround the entire outer circumferential sides of the first and second protruding portions (340A, 340B).

Abstract: Provided is a semiconductive tape in which semiconductive resin layers in which metal particles are dispersedly mixed are disposed on a fibrous insulation substrate, wherein the metal particles have a melting point higher than the curing temperature of the thermosetting resin to be subjected to an impregnation treatment and lower than the softening point of the fibrous insulation substrate. The semiconductive tape is used for the stator coil of a rotating electric machine to suppress erosion of the thermosetting resin, impairment of semiconductivity thereof, and the like caused by heat generation, discharges and the like during operation of the rotating electric machine, thus exhibiting corona resistance stably over an extended period of time.

Abstract: A coil component for an electric machine, having a carrier and a coil winding accommodated in the carrier at least in sections. The carrier has a ring region with multiple grooves distributed in a circumferential direction, and multiple winding sections of the coil winding are received in each groove. An insulation layer is arranged between the carrier and the winding sections in at least one groove and projects with two extension portions over the winding sections towards a radial opening of the at least one groove. A closure element is received in the carrier in the groove with the insulation layer towards the radial opening, and both extension portions are arranged such that the closure element is spaced apart from the carrier by the extension portions. An electric machine is provided with the coil component.

Abstract: The stator according to the present invention is characterized by comprising a stator core 11 including a base 111 of a circular shape, a teeth part 112 formed radially from the base 111, and a teeth end 113 extending to both sides in the circumferential direction at an end of the teeth part 112; an upper insulator 12 coupled to an upper part of the stator core 11, including an upper base insulating part 121 for insulating an upper part of the base 111, an upper teeth insulating part 122 formed radially in the outer circumferential direction of the upper base insulating part 121, for insulating the upper part of the teeth part 121, and an upper teeth end insulating part 123 located over the teeth end 113, protruding upward at an end of the upper teeth insulating part 122; a lower insulator 13 coupled to a lower part of the stator core 11, including a lower base insulating part 131 for insulating the lower part of the base 111, a lower teeth insulating part 132 formed radially in the outer circumferential dire

Abstract: A motor assembly includes a stator including a stator core, a stator coil, and an insulator, and a rotor. The stator core includes a yoke, a plurality of teeth, and a shoe. The insulator includes an insulator body wrapping and insulating an outer surface of the shoe so that an inner end of the shoe is exposed to outside, and a creepage distance extension portion extending a creepage distance between the stator coil and the inner end of the shoe. The creepage distance extension portion includes an inner extension section extending from the end of the shoe along the circumferential direction, and an outer extension section extending outwardly from the inner extension section. Accordingly, the creepage distances between the stator coil and the stator core in the circumferential direction and the radial direction may be increased, respectively, without increasing the size of the stator in the radial direction.

Abstract: A slot wedge of a dynamoelectric machine which includes a stator having axially extending slots and a winding system disposed in the slots, is configured to cover a corresponding one of the slots in a direction of an air gap and includes a first layer, and a second layer arranged in spaced-apart to the first layer at least in one section to form a flow channel between the first and second layers. The second layer can have a perforation with a different density of holes per unit area, with the density of the holes being greater in a central area of the second layer and/or a perforation having holes defined by a diameter which is greater in a central area of the slot.

Abstract: An electric motor includes a slot insulation member arranged in a slot between adjacent ones of coils in a circumferential direction of a yoke. The slot insulation member is a wedge-shaped spacer and includes a main body and projections. The projections are arranged in the slot and projected from the main body. The coil includes a main coil portion, a coil end, and a bent coil portion. The main coil portion is arranged in the slot and sandwiched between a corresponding one of the projections and a corresponding tooth. The coil end is arranged outside the slot and contacts the main body. The coil end is wider than the main coil portion. The bent coil portion connects the main coil portion and the coil end.

Abstract: The present invention may provide a motor including a shaft, a rotor coupled to the shaft, and a stator disposed to correspond to the rotor, wherein the stator includes a stator core, an insulator coupled to the stator core, and a coil disposed on the insulator, the coil is electrically connected to a busbar, the busbar is supported by a busbar holder, the insulator includes a first spherical surface, the busbar holder includes a second spherical surface in contact with the first spherical surface, and the first spherical surface and the second spherical surface are disposed in an overlapping region of the insulator and the busbar holder in a radial direction.

Abstract: A rotor of a rotating electrical machine includes a plurality of poles each extending on a first axis that is radial with respect to the rotor and on a second axis parallel to the rotor with respect to the rotor, each pole comprising a pole body, a rotor winding for each pole, positioned against the body of the pole, the rotor winding taking the form of a strip extending over the length of the pole body on the radial first axis wound against the pole body, a plurality of closure shims, a closure shim of the plurality of closure shims being in contact with a rotor winding associated with a pole body, the closure shim being configured to exert a pressure on the rotor winding towards the pole body.

Abstract: A stator includes: a stator core including a plurality of stator teeth in a circumferential direction with respect to a center of rotation of a rotary electric machine; a stator coil disposed on a bottom portion side of each of a plurality of stator slots formed between the stator teeth; and a stator magnet disposed on an opening side of each of the plurality of stator slots and having the same polarity in a radial direction. In each of the stator slots, a plate-shaped fixing member is provided between the stator coil and the stator magnet so as to be fitted to opposed two wall surfaces of the stator slot, and a magnetic body is provided between the stator coil and the stator magnet.

Abstract: A stator includes: a stator core including a plurality of stator teeth in a circumferential direction with respect to a center of rotation of a rotary electric machine; a stator coil disposed on a bottom portion side of each of a plurality of stator slots formed between the stator teeth; and a stator magnet disposed on an opening side of each of the plurality of stator slots and having the same polarity in a radial direction. In each of the stator slots, a cooling portion is provided between the stator coil and the stator magnet.

Abstract: A stator according to an aspect of the present disclosure includes a connector molding portion including a base portion and a mounting portion and a receiver side terminal. The connector molding portion is provided with a communication hole which includes a first concave portion including an inner opening inside a housing extending through the base portion in an X direction and a second concave portion including a bottom surface opening on a bottom surface of the mounting portion extending through the base portion in a Y direction and communicates the inside and outside of the housing through the first concave portion and the second concave portion. The first concave portion penetrates the base portion in the X direction through an outer opening. A rear surface covering portion is provided to close the outer opening.

Abstract: A wedge for a wound rotor includes a wedge body. The wedge body has a first layer and one or more second layers interfused with one another to provide structural support and limit resistive heating of the wedge from current flow within the wedge body by windings spaced apart by the rotor wedge. Generator rotors and methods of making generator rotors are also described.

Abstract: A slotless electric motor provides a phase change material that may communicate thermally through the sides of coils directly attached to the outer circumference of the central stator. A control system modeling the motor allows effective operation for short durations.

Abstract: A wound field rotor includes a shaft having an outer surface, an inner surface defining a flow path, and an opening defining a passage extending from the flow path through the outer surface. A plurality of laminations is mounted to the outer surface. The plurality of laminations includes an inner annular surface disposed on the shaft and an outer annular surface defining a plurality of rotor teeth. A plurality of field windings is disposed about corresponding ones of the plurality of rotor teeth. A first portion of the plurality of rotor laminations includes a first passage portion that extends from the inner annular surface radially outwardly and is fluidically connected to the passage, and a second portion of the plurality or rotor laminations adjacent the first portion includes a second passage portion that includes a first end that registers with the first passage portion and a second end.

Abstract: Methods and systems for cooling an electric motor are provided. An electric motor system, in one example, comprises a rotor with a plurality of axial air conduits, a first balancing plate positioned on a first axial side of the rotor, the first balancing plate comprising an inlet air duct and an outlet air duct, and a second balancing plate positioned on a second axial side of the rotor, the second balancing plate comprising an inlet air duct and an outlet air duct. In the electric motor system, the inlet air duct in the first balancing plate is radially offset from the inlet air duct in the second balancing plate.

Abstract: In this armature, a joint portion is insulated by a joint portion insulating member that has a sheet shape and that includes a facing surface insulating part that covers a facing surface of the joint portion and a circumferential surface insulating part that covers a circumferential surface of the joint portion. The facing surface insulating parts adjacent to each other in a radial direction are connected by the circumferential surface insulating part on one side or another side in the circumferential direction.

Abstract: A stator includes a stator core that includes a core back portion having an annular shape and with a central axis as a center and tooth portions extending from the core back portion to an inside in a radial direction and arranged in a circumferential direction, insulators that are attached to the tooth portions from the inside in the radial direction, a coil that is wound around the insulator, and a cover that supports an inner surface of the insulator opposing the inside in the radial direction from the inside in the radial direction.

Abstract: A stator includes a terminal unit disposed on a first side in an axial direction with respect to a stator main body, and the terminal unit includes a base extending in an arc shape in a circumferential direction following the stator main body, a first inner side engaging portion provided on an inner circumferential edge of the base, an outer side engaging portion provided on an outer circumferential edge of the base, and an arm extending from the outer circumferential edge of the base in the radial direction and continuous with the outer side engaging portion.

Abstract: A winding arrangement provided on a stator of an electric machine. The winding arrangement includes at least four windings. A first winding and a second winding occupied a first subset of slots; and a third winding and a fourth winding occupied a second subset of the slots. The first subset and the second subset of the plurality of slots are adjoined to each other. A span between two adjacent slots concerning the first winding, the second winding, the third winding, and the fourth winding is chosen from a full-pitch, a short-pitch, and a long-pitch to result in the winding arrangement where the first subsets in a first half of the slots is diagonal to the second subset in a second half of the slots, and the second subset in the first half of the slots is diagonal to the first subset in the second half of the slots.

Abstract: A stator includes a stator core including a plurality of teeth and a plurality of slots, a coil wound around the plurality of slots, and a spacer disposed on an end portion in an axial direction of the stator core. The coil includes a plurality of coil segments, each including a bent portion and a pair of legs. The spacer includes a coil support portion that is disposed between an end portion of each of the teeth and the bent portion of the coil segment and that has a support surface. A distance from the end portion of each of the teeth to the support surface on an inner side in a radial direction of the stator core is longer than a distance from the end portion of each of the teeth to the support surface on an outer side in the radial direction of the stator core.

Abstract: A stator and a rotor suitable for use in an electric motor or generator. The stator comprises a plurality of stator cons and a support for holding the coils around a rotor of the motor. A cylindrical sleeve is mounted radially inwardly on the support to form a barrier in use between cooling fluid passing over the coils and a rotor located within the stator. The rotor comprises a hub, a plurality of rotor segments, and a plurality of permanent magnets. The segments are arranged around the hub in a ring, with the permanent magnets disposed between the segments. A radially outwardly facing exposed surface of each magnet is spaced radially inwardly from an outer cylindrical profile defined by the segments.

Abstract: A stator core design and motor winding method maximizing slot fill are provided. A stator core ring section and open U-shaped slot elements are each formed of multiple layers of lamination steel. Laminations forming the slots have a U-shaped profile corresponding to that of the slots. A straight portion of each lamination adjacent to the slot opening is folded to form stator teeth. Laminations forming the ring section and the slots may have a uniform or variable axial thicknesses and materials. A movable jig configures conducting wire and insulating material into a desired configuration for insertion into the open slots, fills each slot with the wire and insulating material, and partially crimps the open end of the filled slot, leaving an opening. When all slots are filled, the stator core is compressed to a final diameter, inserted into a ring-shaped stator element, and sealed to form a complete stator assembly.

Abstract: An apparatus for manufacturing a stator includes a placement table, a supporting member and a resistance heating device. The placement table is configured to have a stator core, which has coil segments and insulators inserted in slots thereof, placed thereon. The stator core is formed of steel sheets that are laminated in an axial direction of the stator core. The coil segments together form a stator coil. The insulators are formed of a material that is foamable upon being heated. The supporting member is configured to support, in the axial direction of the stator core, distal end portions of teeth of the stator core so as to prevent gaps from being formed between the steel sheets forming the stator core. The resistance heating device is configured to heat, through energization of the stator coil, the insulators along with the stator coil and thereby cause the insulators to foam.

Abstract: Embodiments of a small brushless motor include a two-pole rotor and a stator having four slots into which electrical coils are placed. Additional embodiments of a small brushless motor include a two-pole rotor and stator having eight slots into which four, six, or eight electrical coils are placed. The stator may include a means for limiting cogging. The small brushless motor having a high torque constant, low coil resistance, low coil inductance, and high thermal conductivity is provided.

Abstract: An electric motor assembly includes a stator and a rotor configured to rotate relative to the stator. The stator includes a stator core including a yoke that has a ring shape and a plurality of teeth radially coupled to an inner surface of the yoke, a stator coil that is wound around the stator core, and an insulator disposed between the stator core and the stator coil. The insulator includes a yoke insulator that is coupled to the yoke with a first coupling tolerance defined between the yoke insulator and the plurality of tooth insulators, and a plurality of tooth insulators that are coupled to the plurality of teeth, respectively, with a second coupling tolerance defined between the yoke and the plurality of teeth. The first coupling tolerance is less than the second coupling tolerance.

Abstract: The invention relates to a device for driving a compressor of a vaporous fluid, particularly an electric motor. The device has a rotor and a stator, which are extended along a common longitudinal axis, as well as an insulation element. The insulation element is designed as a single part and connected with a stator core of the stator in a form-fitting manner such that the stator core and the insulation element form an integral and single-part component of the stator. The invention further relates to a method for producing a stator of the device, particularly the stator core with the insulation element.

Abstract: An electric machine comprising a rotor having a rotor body. The rotor body has multiple poles each carrying at least one rotor winding formed from multiple conductor loops. The poles extend in a radial direction of the rotor and the conductor loops pass through slots each formed between two adjacent poles. A support element extending in the radial direction is arranged in each of the slots between the rotor windings of the adjacent poles. The support element applies pressure to the conductor loops when the rotor rotates and/or heats up. A pressure distribution element extending at least in portions in the radial direction along the support element and the adjacent rotor winding is arranged between the support element and the rotor windings, which pressure distribution element distributes the pressure applied by the support element onto the adjacent rotor winding.

Abstract: A fuel injector includes an injector housing defining a longitudinal axis extending between a first axial injector end and a second axial injector end. The injector housing includes an upper body piece forming the first axial injector end and including a fuel connector defining a connector axis intersecting the longitudinal axis. The injector housing further includes a nozzle having formed therein a plurality of spray outlets, and including a nozzle terminal tip. An injector full diameter (FD) is defined by the upper body piece. An axial distance (AD) is defined between an intersection of the connector axis and the longitudinal axis, and the nozzle terminal tip. A ratio of AD to FD is from 4.8 to 5.1.

Abstract: A rotor shaft for an electric machine includes a rotor shaft main body and a rotor shaft core which is arranged therein and which is connected to the rotor shaft main body. The rotor shaft comprises a substantially axially running cooling cavity configured to conduct a cooling fluid, and the rotor shaft core is composed of a different material than the rotor shaft main body.

Abstract: A step of inserting an insulating paper into a slot of a stator core (second step) is performed, a step of placing a jig at a position that is on a side opposite to a side from which a segment coil is inserted into the slot of the stator core and that overlaps with a protrusion when viewed in an inserting direction of the segment coil (third step) is performed, and then a step of inserting the segment coil into the slot (fourth step) is performed. Therefore, even when the insulating paper is dragged by the segment coil in the process of inserting the segment coil into the slot, the insulating paper abuts the jig and the movement of the insulating paper is restricted, thereby suppressing displacement of the insulating paper from the slot.

Abstract: An electric motor including a rotor rotatably mounted about a rotational axis extending in the axial direction, and a stator including stator teeth widened in a T shape at the tooth-base side to form pole tabs and extending in the circumferential direction. The pole tabs may form a bearing shoulder. A respective stator slot for receiving coils of a stator winding is formed between adjacent stator teeth and a slot opening formed between mutually facing pole tabs. A reinforcing element may be inserted into a slot opening. The reinforcing element are held on mutually facing pole tabs of adjacent stator teeth by the bearing shoulders. The reinforcing element includes a contour that engages a bearing region to reduce a contact area with the bearing shoulders.

Abstract: A locking wedge system for securing a stator coil in a slot of a stator core includes a slot layer positioned on the stator coil to inhibit movement of the stator coil within the slot, an outer wedge including a first tapered surface, an inner locking wedge positioned on the slot layer, the inner locking wedge including a second tapered face that interfaces with the first tapered face, a locking member configured to lock the inner locking wedge to the stator core, and an interlocking mechanism to couple the outer wedge to the inner locking wedge.

Abstract: An embodiment relates to a stator and a motor including the stator, the stator comprising: a stator core; a coil wound around the stator core; and an insulator disposed between the stator core and the coil, wherein the insulator includes: a body around which the coil is wound; a first guide protruding from the inside of the body; a second guide protruding on the outside of the body a first protrusion protruding outward from the lateral surface of the first guide; and a second protrusion protruding inward from the inner surface of the second guide, and an insulating member radially disposed between the first guide and the second guide is bent in a circumferential direction by means of the first protrusion and the second protrusion. Therefore, the motor can inhibit the movement and separation of insulating paper.

Abstract: The present application relates to a slot wedge element, a stator device, a motor, and a wind turbine. The slot wedge element extends in a first direction and has opposite first and second edges has a first surface and a second surface in the thickness direction thereof, and is attached to a winding of the stator device via the first surface. The second surface includes a first portion, a second portion, and a third portion sequentially distributed in the first direction. A second thickness between the second portion and the first surface is greater than a first thickness between the first portion and the first surface, and the second thickness is greater than or equal to a third thickness between the third portion and the first surface. The first thickness is decreasingly distributed in a direction from the second portion to the first edge.

Abstract: A brushless motor is provided including a rotor rotating around a center axis and a stator including a stator core and stator teeth radially extending from the stator core forming stator slots therebetween. Each stator tooth includes a radial main body and a tooth tip extending substantially laterally from an end of the radial main body opposite the stator core, and stator windings are wound around the stator teeth. Winding retention wedges are axially received within the slots, each winding retention wedge comprising: a first portion received within gaps formed between tooth tips of adjacent stator teeth, and a second portion received at least partially between adjacent stator windings to apply a force substantially in a range of a radially-inward direction to a lateral direction to the adjacent stator windings.

Abstract: The disclosure relates to an electric machine including a stator having a plurality of teeth and on which a winding of the electric machine is arranged, wherein a respective intermediate space is formed between neighboring teeth. The electric machine further includes a rotor that may rotate relative to the stator, wherein an air gap is formed between the stator and the rotor. The electric machine further includes a plurality of closing devices for closing the respective intermediate spaces in relation to the air gap, and wherein a respective closing device of the plurality of closing devices is arranged between neighboring teeth of the stator.

Abstract: Disclosed is an electromagnetic retarder and generator assembly, the assembly including a rotor, a retarder armature carried by the rotor, a generator inductor carried by the rotor, a stator including a sleeve having one outer axial surface and one inner axial surface, a retarder inductor arranged on the outer axial surface of the stator and a generator armature arranged on the inner axial surface of the stator. The sleeve includes several bodies of nonmagnetic material arranged between the inductor of the retarder and the armature of the generator.

Abstract: An electric machine including a rotor and a stator positioned about the rotor. The stator includes a stator core having a plurality of stator teeth and a plurality of stator windings supported by the stator core about the plurality of stator teeth. The plurality of stator windings include a first end turn and a second end turn. The stator includes a plurality of interlocking insulators extending about corresponding ones of the plurality of stator teeth. Each of the plurality of interlocking insulators includes a first base portion extending circumferentially outwardly in a first direction and a second base portion extending circumferentially outwardly in a second direction. The first base portion being configured to inter-engage with a second base portion on an adjacent interlocking insulator to form a coolant passage and a coolant barrier about the air gap.

Abstract: Provided is a covering element for covering a slot between two adjacent teeth of an electromagnetic machine, a stator for an electromagnetic machine and a method of forming a covering element. The covering element comprises a first sub-element and a second sub-element. The first sub-element and the second sub-element are arranged adjacent to each other in a first direction. Further, the second sub-element is made of a different material than the first sub-element.

Abstract: First and second sets of magnet assemblies and magnetic assemblies are alternately arranged in a circumferential direction in a first portion along an axial direction, and the first and second sets are alternately arranged in the circumferential direction in a second portion along the axial direction. When viewed in the axial direction, the first set of the first portion and the second set of the second portion overlap with each other, and the second set of the first portion and the first set of the second portion overlap with each other.