Abstract: Some embodiments of the invention provide an electric machine module comprising a housing including a sleeve member and at least one end cap. In some embodiments, the sleeve member can include a first coolant jacket and a second coolant jacket. Also, in some embodiments, the end cap can include an end cap coolant jacket. Also, some embodiments provide an electric machine including stator end turns, housing at least partially enclosing the electric machine, and an end cap coolant jacket positioned substantially axially outward relative to at least one of the stator end turns.

Abstract: A power plant for a jet-type model airplanes and UAVs includes an electric motor and a cover. The cover receives a portion of the electric motor and a sleeve into which the electric motor is inserted. The sleeve has a plurality of fins to dissipate heat and create openings into the cover. Air from the fan rotor passes through the openings to cool an electronic speed control member and exits a rear opening in the cover. The cover may also have additional openings for air to enter into the cover.

Abstract: An exemplary arrangement is disclosed for cooling an electrical machine having an external rotor rotating around its rotation axis and a stator having sheet packs, located inside the rotor at the end of an air gap. In the arrangement, a first part of a coolant flow is conducted from both ends of the stator through axial cooling channels into the stator sheet pack. A second part of the coolant flow is conducted from both ends of the stator into the air gap and from the air gap through at least one radial cooling channel into the stator sheet pack. Both parts of the coolant flow are conductable into at least one heat exchanger placed radially inside and at a distance from the stator sheet pack. At least one fan is placed radially inside the heat exchanger to send the first and the second part of the coolant flow to the ends of the stator.

Abstract: A rotating electrical machine includes: a rotor comprising a rotor core and a field winding wound round the rotor core; and a stator comprising a stator core and a stator winding wound round the stator core. The stator is arranged in opposition to the rotor with a predetermined spacing therebetween. the stator core is formed by punching a split piece, which comprises teeth for insertion of the stator winding thereinto and a core back on an outer periphery thereof, from a magnetic steel sheet, and laminating a plurality of those circular configurations in an axial direction, in which a plurality of the split pieces are arranged in a circle in a circumferential direction. The stator core has magnetic steel sheets, which are different in magnetic permeability in a diametrical direction, laminated at an axial end region of and in an axial central region of the stator core.

Abstract: The electric machine includes a stator. The stator includes stacked lamination plates. The lamination plates form at least two lamination packages. The electric machine includes a first cooling circulation with a first cooling fluid. The stator of the electric machine includes a second cooling circulation with a second cooling fluid. A heat exchanger is part of the second cooling circulation and is arranged to connect the first cooling circulation and the second cooling circulation. Thus heat is transferred from the first cooling fluid to the second cooling fluid. A spacer element is arranged between the two lamination packages. The spacer element is prepared to set a predetermined distance between the lamination packages, thus the first cooling fluid is allowed to flow between the lamination packages. The heat exchanger arrangement is an integral or at least partly integrated part of the spacer elements.

Abstract: A motor having a first portion configured to turn in a forward direction, a second portion coaxially mirrors the first portion; and a central fan between the first and second portions, and forcing air through the portions. A thermoelectric cooler element, thermally coupled to the portion is configured to cool the motor. A motor controller is electrically coupled to the first and second portions, and operates a portion in response to a condition sensed by the motor controller. The condition sensed by the motor controller is a motor torque, a motor speed, a motor casing temperature, or a zoned motor casing temperature. A method includes detecting a motor operational command; selecting a motor operational state using motor portion responsive to the motor command; sensing a heating state of a motor portion; and providing a cooling state to the motor portion responsive to the heating state.

Abstract: An arrangement for cooling an electrical machine is provided. The electrical machine includes a rotor and a stator, an air-gap being between the rotor and the stator. The stator includes a plurality of stacked laminate-plates. The laminate-plates include on a first side, which is facing the air-gap, a plurality of slots containing metal-windings of a stator-coil. The laminate-plates are positioned and fixed by a structural support and by end-plates in relation to a central-part of the stator. A joint cavity is formed by the end-plates, the central-part of the stator and an internal surface of the laminate-plates. The internal surface is defined by a second side of the laminate-plates, the second side being opposite to the first side. The cavity is coupled with an air-cooling-arrangement, which is arranged and used to circulate a cooling gaseous medium from the cavity to the air-gap and the laminate-plates back into the cavity.

Abstract: The purpose is to accommodate large axial channels in a slim electric machine without sacrificing its torque density and radial dimensions. This is possible with a rotor (11) provided with permanent magnets (12) and a stator (13) with slots (15) for coils (20A-c), where the slots (15) are separated by teeth (16, 17), which electrical machine include teeth (17) not carrying coils (20A-c), which teeth (17) are provided with axial channels (18, 18?) protruding into the teeth (17) and neighboring back iron so that an area of the channel (18, 18?) inside the tooth (17) is comparable to or even larger than the an area of the channel (18, 18?) in the back iron. The channels serve for transportation of fluids and other substances through the machine and also to integrate a motor protector, which may be required in down-hole applications. There are also novel manufacturing techniques associated with the new concept.

Abstract: In a slowly-running electric machine, such as a bulb turbine generator, air circulation for cooling is supplied by externally driven fans. A cooling device is mounted on the pressure or the suction side of the fan and the rotor and the stator are mounted on the suction side of the fan.

Abstract: A stator arrangement for an electrical machine is provided. The stator arrangement has a stator having a stator stack. The stator stack has a number of adjacently disposed metal plates. A number of radial channels are provided between respective groups of metal plates by spacers. At least one transition area from the stator stack in at least one respective radial channel is provided with a curved and/or chamfered and/or stepped shape.

Abstract: An electric machine with improved cooling efficiency includes a stator, a rotor operating as a rotor fan and comprising a shaft defining an axial direction and having radial and axial cooling channels, and an axial fan configured as a twin axial fan and arranged coaxially with the shaft and supplying a coolant to the axial cooling channels. The axial fan has first and second blade rings and a funnel-shaped tube with a smaller opening directly connected to the axial cooling channels of the rotor to deliver coolant to the axial cooling channels of the rotor, and a larger opening, which is non-rotatably connected to and encloses the first blade ring. The second blade ring is firmly attached at an outer circumference of the funnel-shaped tube to deliver the coolant to the stator. Both the stator and the rotor can be cooled using an efficient coolant flow.

Abstract: An example stator assembly includes a stator for establishing a core side of a channel. A plurality of stator windings are secured relative to portions of the stator core. The plurality of stator windings establish a winding side of the channel. At least a portion of the channel is configured to communicate a cooling fluid from a first axial end of the stator core to an opposing axial end of the stator core.

Abstract: A cooling structure of a stator, including a case that accommodates a rotating electrical machine, and cooling a coil end portion protruding from a stator core included in the stator of the rotating electrical machine. The structure supplies a cooling medium from the stator axial direction toward a gap that is formed between an inner surface of the case and an outer edge of the stator core. The cooling medium introducing gap is formed above a portion of the coil end portion to which the cooling medium is to be supplied. A storage space forming member is provided along an outer peripheral surface of the coil end portion. The storage space forming member has a contact portion having a first contact portion that contacts the inner surface of the case to close the cooling medium storage space on the one side in the stator axial direction.

Abstract: A vehicle alternator comprises a rotor and a stator positioned within a housing. The housing includes a front face, a rear face, and a outer wall extending between the front face and the rear face. The front face includes a plurality of air inlet holes, and the rear face including a plurality of air outlet holes. The outer wall is void of air holes that extend through the outer wall. The rotor is positioned within the housing and configured to rotate about an axis. The stator is positioned within the housing between the rotor and the outer wall of the housing. The stator includes a core with an outer surface, a front end and a rear end. A plurality of substantially axial air passages are positioned between the outer wall of the housing and the outer surface of the stator core.

Abstract: A Stator arrangement for an electric machine includes a stator having a stator yoke with a plurality of stator slots. Each stator slot accommodates at least two adjacently disposed sets of stator windings and at least one cooling device, wherein the at least one cooling device is disposed between the respective adjacently disposed sets of stator windings.

Abstract: An electric drive machine includes an axle assembly having a central axle housing. An electric drive motor, having a motor housing, is oriented along an axis and disposed within the central axle housing. An air cooling system includes a blower fluidly connected to and positioned upstream of an opening of the central axle housing. An airflow path through the central axle housing includes an upstream segment and a downstream segment. The upstream segment extends from the opening to an airflow deflector, and is configured for airflow in a first direction along an axial path. The downstream segment extends from the airflow deflector to the motor housing, and is configured for airflow in a second direction, which is opposite the first direction, along a helical path.

Abstract: In one embodiment, an electric motor. A first bracket is fixed to the first side of a stator core in an axial direction, and is fixed to first bearing housing. A second bracket is fixed to the second side of the stator core, and is fixed to second bearing housing. The rotor includes a shaft rotatably supported by bearings, and an attached rotor core. Rotor core faces the inside of the stator core. A fan is attached to the shaft between the rotor core and the first housing. A flue formed between the first housing and the first bracket is configured to draw air from a port to a part of the first bracket. A rotation detection circuit includes a detected part fixed to the fan, and is within the flue. A sensor operable to detect the part is set in the flue, counter to the detected part.

Abstract: A permanent magnetic machine includes a stator body having a first end, a second end, and a plurality of generally radial slots formed therein for accepting a set of windings having a first set of end-turns at the first end and a second set of end-turns at the second end. The stator body has a plurality of channels adjacent to the slots and extending from the first end of the stator body to the second end of the stator body, wherein the channels are configured to allow the flow of a cooling fluid therethrough. A plurality of nozzles in fluid communication with the plurality of channels are configured to spray the cooling fluid onto the first and second set of end turns.

Abstract: This invention relates to a magnetic gearbox, comprising: an inner rotor having a first plurality of magnetic flux sources; an outer rotor having a second plurality of magnetic flux sources; and, a modulator having a plurality of pole pieces positioned between the first and second magnetic flux sources and separated from each by an air gap, wherein upon relative rotation of the inner rotor, outer rotor and modulator the first and second magnetic flux sources and pole pieces are arranged to provide a modulated magnetic field in the air gap adjacent each rotor; wherein either or both of the modulator and inner rotor include at least one nozzle for directing fluid radially across the respective air gap so as to impinge on the adjacent rotor or modulator.

Abstract: An air-cooled electric machine, such as an alternating current motor, having a housing containing a rotating shaft and a housing airflow cooling path has cooling vents on the housing periphery. An external cooling system having a duct enclosure is coupled to the housing exterior, and defines a duct airflow cooling path that is in communication with the housing airflow cooling vent and housing airflow cooling path. A duct fan within the duct enclosure external the housing is coupled to and driven by the shaft. The duct fan circulates air at above ambient pressure into the housing airflow cooling path.

Abstract: An induction motor has a rotation detector, a heat dissipating disc for dissipating heat generated from a rotor, and a cooling fan for forcibly cooling the heat dissipating disc with outside air. The heat dissipating disc is disposed between the rotation detector and the cooling fan.

Abstract: The present invention relates to a disk-type motor using a permanent magnet, wherein the permanent magnet is arranged on a disk-type rotor (300), and a stator core (202) and a power-generating coil (204) are arranged on a stator (200) to obtain a high-efficiency motor which self-generates power upon being driven. (2) A special device is needed to reduce the consumption of electrical energy for driving a motor, and a special circuit for bypassing the magnetic force of a magnet is also needed. (3) To bypass the magnetic force, a bypass core (101.205) and a magnetic core (301) are employed to constitute a circuit for bypassing the magnetic force, and a magnetic flux path for bypassing the magnetic force is formed. Thus, a special circuit which can significantly reduce the consumption of electrical energy is obtained.

Abstract: An apparatus for venting a stator core having a plurality of slots through which stator windings extend is provided. The apparatus includes a first ventilation layer for positioning at an end of the stator core. The first ventilation layer includes an inner set of circumferentially spaced slots that correspond to the plurality of slots and through which the stator windings extend, and an outer set of slots radially distanced from the inner set of slots. A second ventilation layer for positioning between the first ventilation layer and a stator core flange of the stator core is also provided. The second ventilation layer includes a set of ventilation slots providing a flow path between the stator windings to the outer set of slots.

Abstract: The invention discloses a motor casing including a frame assembly and a motor base. The frame assembly includes a frame having an inner face defining an air channel, and a plurality of connection members disposed in the air channel. Each connection member has first and second ends. The first ends of the connection members are coupled to the inner face of the frame. The motor base includes a supporting member and a covering member. The supporting member has an inner surface defining a through-hole, and an outer surface coupled with the second ends of the connection members. An opening portion and a coupling portion are formed at two sides of the through-hole. The covering member is coupled to the opening portion of the supporting member and has first and second surfaces. The first surface faces the through-hole of the supporting member. The covering member includes at least one vent.

Abstract: A motor for an electric vehicle includes a frame, a stator disposed in the frame, a rotor disposed to be rotatable with respect to the stator; and an engaging portion that restricts the stator from moving with respect to the frame in a circumferential direction, the engaging portion including at least one rib protruding from one of the surfaces of the frame and the stator, and at least one rib accommodation portion formed at other of the surfaces of the frame and the stator, wherein the at least one rib and the at least one accommodation portion are engaged to allow heat to be transferred therebetween. Under this configuration, a cooling performance may be improved and durability may be enhanced.

Abstract: A permanent magnet rotating electrical machine comprises a stator with a stator coil applied in a plurality of slots provided in a stator core, a rotor disposed opposite to the stator with a predetermined gap interposed therebetween, the rotor including a permanent magnet embedded in each of magnet-insertion holes provided in a rotor core of the rotor while polarity of the permanent magnet being varied on a pole-by-pole basis, and end plates disposed at ends of the rotor core, in the axial direction thereof, respectively, in which one end plate of the end plates disposed at the ends of the rotor core, in the axial direction thereof, respectively, is also provided with magnet-insertion holes, and each of the magnet-insertion holes provided in the one endplate is filled up with a non-magnetic material, thereby stopping up each of the magnet-insertion holes provided in the end plate.

Abstract: An air-gap is between a rotor and a stator. The stator comprises a number of stacked laminate-plates. The laminate-plates are positioned and fixed by a structural support and by end-plates in relation to a central-part of the stator to achieve the air-gap. A cavity is formed by the end-plates, the central-part of the stator, the air-gap and an internal surface of the rotor. An air-cooling arrangement is arranged and used to circulate a gaseous medium for cooling purposes inside the cavity.

Abstract: Braces that can be placed in the gap between adjacent rotor field windings to help secure the rotor field windings in place during operation and that help cool those windings. Rotor assemblies with cooling ducts, such as rotor body cooling ducts and pole body cooling ducts, that help cool rotor field windings.

Abstract: A cooling electric generator with pipes embedded in its housing which includes mechanisms for generating electrical power from the motor torque provided by a wind turbine rotor, and with an external housing comprised of a cylindrical casing (23) and side shields (25) made of cast iron and have embedded conduits configured to form a refrigeration circuit (31, 41) for the generator with routes for entry and exit (33, 35, 43, 45) of the refrigeration liquid to and from the generator exterior. Preferably, the circuit (31) embedded in the cylindrical casing (23) has a helicoidal form and the circuits (41) embedded in the shields (25) have a spiral form.

Abstract: A wind turbine having a generator is provided. The generator includes a rotor and a stator having a stator lamination, one or more flange rings and one or more core rings. The stator lamination includes a plurality of axial flow passages and the one or more core rings include a plurality of core ring axial flow passages that are aligned with the plurality of axial flow passages in the stator lamination. The plurality of axial flow passages in the stator lamination have a substantially triangular cross-sectional shape.

Abstract: An electric machine system including an alternating current (AC) electric machine. The AC electric machine includes a machine housing having a machine portion and a switch portion. A stator is fixedly mounted in the machine portion of the machine housing, and a rotor rotatably mounted relative to the stator. A switch assembly is arranged within the switch portion of the machine housing and electrically connected to the stator. The switch assembly includes a switch module having a switch member. The switch module is configured and disposed to be detachably mounted in the switch portion of the machine housing. A cooling system that includes an expandable coolant manifold is arranged in the switch portion of the machine housing. The expandable coolant manifold is fluidly connected to the switch module.

Abstract: Some embodiments of the invention provide an electric machine module including a rotor assembly. The rotor assembly can include a rotor hub, a first set of rotor laminations which can include a portion having a first inner radius, and a second set of rotor laminations which can include a portion having a second inner radius larger than the first inner radius. At least one circumferential flow channel defined by the first set of rotor laminations, the second set of rotor laminations, and the rotor hub can at least partially circumscribe the rotor hub.

Abstract: A rotating electrical machine includes: a rotor comprising a rotor core and a field winding wound round the rotor core; and a stator comprising a stator core and a stator winding wound round the stator core. The stator is arranged in opposition to the rotor with a predetermined spacing therebetween. the stator core is formed by punching a split piece, which comprises teeth for insertion of the stator winding thereinto and a core back on an outer periphery thereof, from a magnetic steel sheet, and laminating a plurality of those circular configurations in an axial direction, in which a plurality of the split pieces are arranged in a circle in a circumferential direction. The stator core has magnetic steel sheets, which are different in magnetic permeability in a diametrical direction, laminated at an axial end region of and in an axial central region of the stator core.

Abstract: Certain exemplary embodiments can comprise a system, which can comprise an electric motor cooling fan. The electric motor cooling fan can be driven by an auxiliary motor distinct from an electric motor adapted to be cooled by the electric motor cooling fan. The system can comprise a motor enclosure of the electric motor. The motor enclosure can be configured in a predetermined ventilation pattern.

Abstract: A dynamoelectric machine includes a rotor having a plurality of adjacent coils; and a spaceblock disposed between adjacent coils so as to define at least a first cavity adjacent the spaceblock and between mutually adjacent coils, the spaceblock including a channel disposed in a coil facing surface of the spaceblock for intercepting and redirecting a circulating coolant flow to the first cavity.

Abstract: A generator includes a housing and a stator arranged within the housing. The stator includes a first end that extends to a second end, and a plurality of axial flow passages extending between the first and second ends. The generator also includes at least one air flow re-direction member provided on at least one of the first and second ends of the stator. The at least one air flow re-direction member fluidly connects adjacent ones of the plurality of axial flow passages. The at least one air flow re-direction member guides an air flow passing though one of the plurality of axial flow passages in a first direction into an adjacent one of the plurality of axial flow passages in a second direction, the second direction being distinct from the first direction.

Abstract: A heat-dissipation structure for a motor including a motor shell, a control box, and a coupling shell. One end of the coupling shell is connected to the bottom of the motor shell and the other end thereof is connected to the top of the control box and a plurality of air vents are arranged on a side wall of the coupling shell. The introduction of the coupling shell enlarges the inner space of the control box and achieves rapid heat dissipation and a better heat dissipation effect. The heat-dissipation structure features rapid heat dissipation, excellent heat dissipation effect, a simple structure, an attractive shape, and great universality.

Abstract: A rotor arrangement with decreased fluid flow impedance and improved rotary motor cooling is mountable on a shaft for rotation relative to the stator of a rotary motor arrangement The rotor arrangement has a plurality of laminations joined together to form a multilayer laminated rotor with a plurality of magnet receptacles. Each of the laminations has a solid central section surrounding an opening within which the shaft is receivable, spokes extending substantially radially outwardly from said solid central section, ribs interposed between adjacent spokes, and bridges interconnecting the spokes and ribs. At least some of the bridges are inset from an outer diameter of the lamination toward the solid central section to decrease fluid flow impedance and improve rotary motor cooling.

Abstract: The present application provides a stator. The stator may include a number of poles and a stator tip and cooling assembly. The stator tip and cooling assembly may include a number of stator tips with a number of cooling tubes adjacent thereto such that the stator tips align with the poles and the cooling tubes cool the poles.

Abstract: A generator housing includes a top portion, a plurality of side portions, and a base portion. The top, sides, and base portions are connected to form an enclosure, such that a generator can be housed inside the enclosure. The top and side portions include an air and exhaust flow structure that facilitates cooling of a generator maintained inside the housing, that provides a sound attenuation function, and that releases exhaust created by a generator. At least one of the side portions and the top portion may be opened and closed to provide access inside the housing. The base portion includes a structure that facilitates installation and transport.

Abstract: According to one embodiment, a traction motor includes a stator core, a rotor core, a first bearing, a second bearing, a rotor shaft, a first ventilation passage made at an outer circumference portion of the stator core, a first fan, and a second ventilation passage to introduce external air. And, in the motor, a first minute gap is provided between an end portion of a first fan main plate and an inner circumference portion of the first bracket, cooling wind is discharged to the motor outside via the second ventilation passage, an outer circumference portion of the first fan, a ventilation portion in the first bracket and the first ventilation passage, and the second ventilation passage is made so that the cooling wind entered from the first air intake port flows around the rotor shaft portion between the first ventilation fan and the first bearing.

Abstract: A motor cooling structure includes a coil end cover interposed between a coil end and a motor case, a liquid passage, in which a cooling liquid flows, formed between the coil end cover and the coil end or the motor case. A micro-gap into which part of the cooling liquid in the liquid passage flows, is formed between the coil end cover and the coil end or the motor case by sandwiching the coil end cover between the coil end and the motor case instead of attaching the coil end cover to the coil end or the motor case.

Abstract: In one aspect, an arrangement for cooling of an electrical machine is provided. A rotor and a stator include an air-gap arranged between the rotor and the stator. The rotor and the stator include a circulation arrangement to allow the circulation of air for cooling-purposes of the rotor and of the stator. The rotor and the stator are encapsulated by a shell which is formed to allow the flow of hot air from the rotor and the stator to a heat-exchanger. The shell is formed to allow the flow of cool air from the heat-exchanger back to the rotor and the stator for cooling-purposes. The shell includes a number of corners, while each corner is used to gather the hot air before it is guided to the heat-exchanger.

Abstract: The invention provides systems and methods for cooling and lubrication of high power density electric machines with an enhanced fluid injection system. A plurality of fluid flow passages may be provided within the electric machine. A method for fluid distribution for cooling and lubrication of the electric machine may comprise providing a fluid distribution manifold with at least one inlet and a plurality of distribution openings leading to a plurality of fluid flow passages within the machine. The fluid within the electric machine may be used to cool and/or lubricate internal components of the electric machine.

Abstract: The invention provides systems and methods for cooling and lubrication of high power density electric machines with an enhanced fluid injection system. Multiple fluid flow passages may be provided within the electric machine, which may comprise a stator fluid flow pathway, a rotor fluid flow pathway, and a bearing fluid flow pathway. The fluid within the electric machine may be used to cool and/or lubricate internal components of the electric machine.

Abstract: A permanent magnet rotating machine has a stator, in which armature windings are formed in a plurality of slots formed in a stator iron core, and also has a rotor, in which two magnet insertion slots are formed for each pole in a rotor iron core in a V shape when viewed from the outer circumference of the rotor and one permanent magnet is embedded in each magnet insertion slot with polarity alternating for each pole; a wall at one end of the magnet insertion slot on the external diameter side of the rotor is formed with three arcs having different curvatures, one of the three arcs being parallel to the outer circumference of the rotor, and a wall at the other end of the magnet insertion slot on the internal diameter side of the rotor is formed in an arc shape.

Abstract: To provide a rotating electric machine capable of accurate detection of coil temperature by causing refrigerant to flow so as not to contact a temperature detecting element provided on a coil end portion. A rotating electric machine (10) comprises: a cylindrical stator core (12); coils (16) wound around a plurality of teeth (14) projecting from an inner circumferential surface of the stator core (12) and having coil end portions (18) protruding beyond respective end portions in an axial direction of the stator core (12); a cooling part (50) to cool the coil (16) by dropping refrigerant onto the coil end portions (18); and a temperature detecting element (30) placed in contact with the coil end portion (18), for detecting coil temperature. The temperature detecting element (30) is provided so as not to directly contact the refrigerant flowing on the coil end portion.

Abstract: In a slowly-running electric machine, such as a bulb turbine generator, air circulation for cooling is supplied by externally driven fans. A cooling device is mounted on the pressure or the suction side of the fan and the rotor and the stator are mounted on the suction side of the fan.

Abstract: A motor including a housing, a stator assembly, a rotor assembly, a controller, and a top end cover. The housing includes a cavity. The stator assembly includes a stator core and a stator winding and is housed in the cavity. The top end cover is disposed on the top of the housing. The rotor assembly includes a permanent magnet, a revolving shaft, and a rotor support. A bearing support extends inward from the center of a top end face of the top end cover, with a bearing chamber respectively provided on both ends thereof. The revolving shaft is disposed into and supports the bearing. A connection kit extends from the edge of the rotor support and outside the bearing support. The permanent magnet is disposed on the connection kit. The motor is characterized by simple and compact structure, lower cost, easy thermal dissipation, smaller axial dimension, and convenient assembly.

Abstract: A cooling system of a AC generator for vehicles has a stator with a stator winding, a rotor that is arranged in an inner circumferential side of the stator, a rectifier that converts an alternating current voltage generated in the stator winding into direct current, and a rear cover that covers the rectifier. The rear cover has an intake duct connecting portion that projects outside and an air intake duct is attached to a tip portion of the intake duct connecting portion. A dividing wall that divides an internal space of the rear cover into a plurality of spaces along a direction extending from the rectifier backwardly relative to the direction of rotation is disposed in the intake duct connecting portion.