Abstract: The present invention provides a stator and a motor assembly including the same. The stator includes: a stator core disposed outside a rotor core and having an inner surface inclined with respect to a rotation axis of a rotor; a plurality of coil-wound teeth extending from the inner surface of the stator core towards the rotation axis, wherein a coil is wound around each of the plurality of coil-wound teeth; and openings formed by sidewalls of the plurality of coil-wound teeth and the inner surface of the stator core, wherein a cross-sectional area of the openings changes along a direction of the rotation axis.

Abstract: A method and system for operating an electric machine are described. In one example, the system includes a motor stator having a first group of windings and a second group of windings. Each group of the windings is electrically coupled to a different inverter so that the system may have a layer of operational redundancy.

Abstract: A connection structure of a stator of a drive motor is configured to allow coils to be wound in a plurality of slots provided in a stator core and to connect the coils withdrawn from the slots. The coils are wound in the slots to form first-type structures and second-type structures configured such that withdrawal directions of three-phase (U-, W- and V-phase) withdrawal lines and N-phase withdrawal lines withdrawn from the slots of the first-type structures are opposite to withdrawal directions of three-phase (U-, W- and V-phase) withdrawal lines and N-phase withdrawal lines withdrawn from the slots of the second-type structures. The first-type structures and the second-type structures are disposed symmetrically to each other with respect to a reference line formed to divide the slots in half.

Abstract: A magnetically active unit of an electric machine with at least two poles includes a laminated core with slots, and at least one winding for each of the phases. The windings have an electric conductor which forms coil groups in the slots. The coils of the coil groups are formed with at least two sections of the electric conductors of at least one of the windings and are arranged so as to be electrically insulated from each other in the grooves. At least one first coil group of the coil groups of one of the windings has a first number of coils which deviates from a second number of coils of a second coil group of the coil groups of the same winding.

Abstract: The invention relates to a stator (1) for an electric machine, comprising an essentially hollow-cylindrical laminated core (2) with multiple receiving grooves (4) which are arranged distributed. Multiple electric conductor sections (La, Lb) per receiving groove (4) formed by forming rods form a stator winding (14) with at least two part-windings (TWa, TWb).

Abstract: A voltage balanced winding for a stator of an electric machine with a high number of pole pairs is distributed over several circumferential sections and several radial layers of the stator. The winding consists of at least two phases and each phase of the winding comprises a plurality of conductor segments, one conductor segment for each layer in each sector. Each of the conductor segments comprises a plurality of straight conductor portions arranged in an axial direction of the stator and a plurality of end-windings connecting the straight conductor portions to a wave pattern. The voltage balanced winding is characterized in that the plurality of conductor segments is divided into branches of series connected conductor segments, wherein each branch includes at least D conductor segments selected from D different sections d and D different layers j such that (j+d) mod D equals a predefined number, with D being the number of circumferential sections.

Abstract: Provided is a disc-type ironless permanent magnet synchronous generator powered by an auxiliary power supply, which comprises a stator coil disc and a pair of permanent magnet rotor discs (1) positioned on two sides of the stator coil disc and arranged with a gap therebetween, a circle of main coils (3) are fixedly arranged on the stator coil disc around a center of the disc, the main coil is a main winding of an electric motor to output electric energy, an auxiliary winding independent from the main winding is arranged on a circumference formed by the main coils (3) in a surrounding manner, and output power of the auxiliary winding is less than output power of the main winding.

Abstract: A stator assembly includes hairpin coils continuously connected along a circumferential direction to form a coil winding, a plurality of stator cores disposed along the circumferential direction and configured to fix the hairpin coils, and a support ring configured to surround an outer circumferential surface of the stator core, wherein each of the stator cores is inserted into the hairpin coils forming the coil winding in a radial direction.

Abstract: An electric machine comprises a rotor and a stator, wherein the stator comprises a stator body which carries at least one respective winding of at least one phase, wherein the winding of the respective phase or at least one of the windings of the respective phase is conductively connected to a respective contact bridge, which connects the respective winding to an associated power source and/or drain, wherein the respective winding and the contact bridge connected to it each end in a conductor section which extends away from the stator body in the axial direction of the electric machine, these conductor sections being conductively connected to one another, wherein a fixing section of the respective contact bridge is arranged stationary with respect to a housing accommodating the stator by being fixed by an insulation element or directly, on the one hand, to the housing itself and/or, on the other hand, to the power source and/or drain, which, in turn, is fixed to the housing.

Abstract: An axial field rotary energy device are disclosed. For example, the device can include a printed circuit board (PCB) stator having PCB panels. Each PCB panel can include conductive layers. Selected ones of the conductive layers are coupled to plated vias that extend from one major surface of the PCB stator to an opposite major surface of the PCB stator. In addition, each major surface of the PCB stator can have a layer of a dielectric material that completely covers ends of the plated vias.

Abstract: An electric motor and a compressor having an electric motor are disclosed herein. The electric motor may include a stator having a stator core and a stator coil, and a rotor provided with a rotational shaft and rotatably disposed with respect to the stator. The stator coil may include a main winding and an auxiliary winding connected to each other with a phase difference. The main winding may be divided into a plurality of main windings so as to be connected to each other and disconnected from each other, and the stator coil may further include a winding changeover switch configured to provide connection and disconnection between the plurality of main windings. Such a configuration may allow operating efficiency at a low load to be increased.

Abstract: A rotary electric machine comprises a two-pole rotor, a three-phase armature winding, and a stator core having fifty-four slots. An armature winding is stored as a top coil piece and a bottom coil piece in two layers in the slot of the stator core and has three parallel circuits and two phase belts per one phase. Each phase belt includes two parallel circuits. When a sequence of the first and second parallel circuits of one phase belt is viewed from a side closer to a phase belt center, those parallel circuits are arranged in a sequence of the first, second, first, first, second, first, first, first, and second parallel circuits in the top coil pieces and in a sequence of the first, second, first, first, second, first, first, first, and second parallel circuits in the bottom coil pieces to be connected to the top coil pieces.

Abstract: A coil assembly includes coil units connected to a coil base. Each coil unit includes top, intermediate and bottom coil modules, each of which has spaced-apart first and second interaction sides, and two non-interaction sides connected to the first and second interaction sides to form an accommodating space. The first interaction sides of the intermediate and bottom coil modules are juxtaposed with each other in the accommodating space of the top coil module. The second interaction sides of the top and intermediate coil modules are juxtaposed with each other in the accommodating space of the bottom coil module. An ironless motor includes a magnetic rail assembly and the aforesaid coil assembly.

Abstract: In a motor driving apparatus having an inverter which can drive n (n being an integer not smaller than 2) motors each having a permanent magnet in its rotor, and a connection switching device for switching the connection state of the n motors, the connection switching device is operated to change the number of the motors connected to the inverter thereby to change the impedance as seen from the inverter towards the motors. When i (i being any of 2 to n) motors among the n motors are concurrently driven by the inverter, the voltage outputted by the inverter may be controlled such that the inductance values of the i motors are identical. It is possible to prevent hunting and step-out due to the phase difference between the motors driven by the inverter.

Abstract: An electric motor includes a shaft, and a stator disposed around the outer periphery of the shaft and including a plurality of slots extending toward the shaft. A plurality of coil units are arranged respectively in the plurality of slots. The coil units are each formed of a plurality of wires connected in parallel. One of the coil units that is arranged in at least one of the plurality of slots formed in the stator includes a plurality of winding groups that are connected in series and that have a different number of turns from each other. The winding groups are arranged in the slot in descending order of the number of turns in the direction toward the shaft.

Abstract: An annular stator core in which, out of slots arrayed in a circumferential direction and extending in a radial direction, q slots are formed per pole and per phase; and stator windings, for respective phases, attached to the stator core. For each stator winding, q*n unit coils obtained by winding wire conductors at regular intervals into concentric winding forms are used to obtain n coils in each of which the q unit coils wound in a same direction are connected so as to be shifted from each other in the circumferential direction, and the stator winding is composed of two coil groups each obtained by joining the n/2 coils together. The two coil groups are connected in parallel to each other between power feed portions and neutral points, and two coils that are connected to the power feed portions are disposed so as to share the slot.

Abstract: A motor includes a first inverter electrically connected to a first end of a winding of each phase, and a second inverter electrically connected to a second end of the winding of each phase. Each of the first and second inverters includes low-side switching elements and high-side switching elements. FETs of the first inverter are electrically connected to a first end of a U-phase winding. FETs of the second inverter are electrically connected to a second end of the U-phase winding. At least a portion of a current flowing from one of the FETs of the first inverter to the U-phase winding flows to one of the FETs of the second inverter. One of the FETs of the first inverter and one of the FETs of the second inverter are adjacent to each other.

Abstract: An electric machine is provided that includes a stator defining a rotor chamber and a plurality of stator slots disposed circumferentially about the stator. The stator includes a plurality of phase groups each including a plurality of circuits. Each circuit includes a plurality of winding sets of a plurality of phase conductors connected in series for carrying an alternating current voltage. A rotor is disposed in the rotor chamber for rotating relative to the stator. The phase conductors are laid in a plurality of layers of the plurality of stator slots. Stator slots that include phase conductors carrying different phases are shared slots and stator slots that include phase conductors carrying the same phase are same slots. The circuits are arranged with balanced quantities of same slots and shared slots for reducing stator losses at high rotational speeds of the rotor relative to the stator.

Abstract: A pole tooth module for an electric machine is provided. The pole tooth module includes a pole tooth with a pole shoe and a pole head, a coil arranged around a circumferential surface of the pole tooth between the pole shoe and the pole head, and an insulation body enclosing the pole tooth and designed to electrically insulate the pole tooth from the coil. To enclose the pole tooth, the insulation body has a central piece, a first frame element and a second frame element. The central piece is arranged between the coil and the circumferential surface and at least partially surrounds the circumferential surface of the pole tooth. The first frame element adjoins a side of the central piece, which side faces the pole head. The second frame element adjoins an opposite side of the central piece, which opposite side faces the pole shoe, and encloses the pole shoe.

Abstract: Various examples related to shifted fractional pitch wye-delta multilayer windings and their use in AC machines. In one example, a winding includes a first wye-delta winding with first wye and delta windings for each phase and a second wye-delta winding with second wye and delta windings for each phase. The first and second wye windings for each phase are connected in series and the first and second delta windings are connected in series, and formed wye and delta windings are connected in a wye-delta configuration thereby providing an electrical phase shift between the two windings. The windings are interdigitated to provide a physical shift between the first and second wye windings and the first and second delta windings. Such windings can be used in, e.g., permanent magnet synchronous machines, synchronous machines, reluctance machines, and induction machines.

Abstract: A winding electric wire enables a space factor to be increased and an eddy current to be suppressed, despite using an easy winding process. A winding electric wire is configured such that one enameled wire or a plurality of enameled wires bundled in parallel or in a litz form are braided so as to be formed into a belt-like rectangular or square wire shape having flat braided wires forming flatly-molded layers the number that is two or a multiple of two.

Abstract: An assembly for use in an axial flux motor or generator includes a rotor plate and a magnet, the magnet having a surface that is orthogonal to a magnetization direction of the magnet. The rotor plate is adapted to engage a rotor shaft that rotates about an axis of rotation, and the magnet is attached to the rotor plate. The rotor plate and magnet are configured and arranged such that, if the rotor plate and the magnet are separated from all other magnetic field generating components, then a distance between a first plane that intercepts a first point on the surface and to which the axis of rotation is normal and a second plane that intercepts a second point on the surface and to which the axis of rotation is normal is substantially greater than zero.

Abstract: An electric machine includes a stator core defining circumferentially-arranged slots each having radial pin positions arranged to define radial layers and a hairpin winding including a first path of interconnected hairpins disposed in the stator core. The hairpins are arranged such that a leg portion of each hairpin is routed through a radial pin position of each slot wherein at least one uniquely-pitched hairpin is provided along the first path to induce a first shift in a trailing portion of the first path.

Abstract: According to the present invention, a coil is continuously wound in a single pass around each of a series of teeth, and connected to each segment.

Abstract: A stator includes a cylindrical core with a plurality of longitudinally extending slots, a first winding set formed as a first cascaded wire in two radial layers of the slots, a second winding set formed as a second cascaded wire in two other radial layers of the slots, and a jumper connecting the first and second wires. A first winding set may have three cascaded phase wires in first and second layers of the slots, and a second winding set may have three cascaded phase wires in third and fourth layers of the slots. A winding set of a first phase may have a first cascaded wire in two radial layers of a first one of the slots, and a winding set of a second phase may have a second cascaded wire in two other radial layers of the first one of the slots.

Abstract: Rotating machinery includes a two-pole rotor, a stator core with seventy-two slots, and three-phase armature windings, as an example. The armature winding has two phase belts per phase. The phase belt includes a first parallel winding and a second parallel winding which are arranged in the stator slots as top coils and bottom coils. When a circumferential mean position of all top coils and bottom coils included in the phase belt is defined as a phase belt center, an arrangement of the first and second parallel windings in the phase belt, as viewed in order of proximity to the phase belt center, is such that the first and second parallel windings are arranged in order of second/first/second/first/first/second/first/second/first/second/second/first parallel windings as the top coils, and the first and second parallel windings are arranged in order of first/second/second/first/second/first/first/second/first/second/second/first parallel windings as the bottom coils connected to the top coils.

Abstract: An electric machine includes a stator core defining slots and hairpins disposed in the slots. The hairpins are selectively joined at connections to form windings that include at least first and second radial layers. Each connection is disposed in one of the layers. The connections are staggered such that the connections of the first layer are circumferentially offset from the connections of the second layer to increase clearance for tooling that forms the connections.

Abstract: An electric machine includes a stator core defining slots and a hairpin winding path disposed in the slots. The winding path includes first and second hairpins having legs with same slot spans and twist with same slot spans. The hairpins are installed in the core such that one of the twists of the first hairpin crisscrosses with one of the twists of the second hairpin. A reverse jumper joins the twists that crisscross.

Abstract: Solar Motor Controller is an electronic device with DC power input terminals that may connect directly to solar PV panels, and output terminals that may connect directly to single or multiphase phase AC electric motors without requiring an energy storage subsystem. The Controller runs electric motors of many frequencies and is capable of interfacing to multiple voltages of solar PV panels with or without maximum power point tracking. The Controller may drive motors in water pumping, HVAC, refrigeration, compressors operation, blowers, machine tools, and many other applications; some controller applications may operate at motor speeds adjusted to conform to power available from attached solar panels.

Abstract: A two-pole brush-commutated DC electric motor with a stator and a rotor with a hollow-cylindrical ironless winding having n coil segments and a commutator having n commutator segments. Each coil segment being electrically connected to two adjacent commutator segments. An axis of gravity intersects the rotor axis perpendicularly and passes through the center of gravity of a coil segment or a center line of the coil segment that passes through the center of gravity and the rotor axis spanning a coil plane that defines the angular position of the associated coil segment. Two brush contact surfaces of the commutator segments are electrically connected to this coil segment have a distance bisector intersecting the rotor axis perpendicularly. The distance bisector and the rotor axis span a commutator plane which defines the angular position of the associated commutator segments.

Abstract: According to one embodiment, there is provided a rotating electrical machine coil with a conductor and an insulation layer that is provided around the conductor to cover the conductor, the rotating electrical machine coil including a linear part of the coil and a coil end that is separable from and electrically connectable to the linear part of the coil.

Abstract: A method and apparatus for cooling a rotor assembly includes a rotor core having a rotatable shaft and defining at least one rotor post, a winding wound around the post, and at least one coolant conduit supported by the rotor core and in a thermally conductive relationship with a portion of the winding.

Abstract: Stators for an electrical machine which are fitted with a polyphase winding which is in the form of a plug-type winding and the winding sections of which run through slots of the stator and comprise a plurality of different conductor elements are already known. At least some of the said conductor elements have in each case two conductor limbs and in each case one connecting conductor which connects the two conductor limbs, wherein an even number of n conductor limbs is arranged one above the other in the radial direction with respect to a stator axis in each slot. Each conductor limb of one of the conductor elements is provided in its slot in a specific position with respect to a slot base of the slot. These polyphase windings comprise a comparatively large number of different conductor elements, in particular so-called special conductors which differ from the standard conductor elements. These special conductors increase the manufacturing costs.

Abstract: A stator operable to generate a rotating magnetic field for an electrical rotating machine, the stator comprising at least one circuit board with electrically conductive portions formed thereon, the electrically conductive portions connected with a multiphase configuration, wherein a phase comprises: on a first face of the circuit board(s) electrically conductive portions arranged as a plurality of elements, an element comprising a radially extending radial portion having: connected at a proximal end thereof a proximal portion, the proximal portion extending therefrom with a directional component in a first angular direction; and connected at a distal end thereof a distal portion, the distal portion extending therefrom with a directional component in a second opposed angular direction, whereby proximal and distal are defined relative the centre of rotation of the magnetic field and said angular direction is defined about said centre of rotation; and on a second face of the circuit board(s) electrically conduc

Abstract: An electric machine includes a stator core defining slots having radial layers that each include adjacent first and second pin positions. Pins are disposed in corresponding ones of the slots and are interconnected to form a winding path. The path occupies the first and second positions of each layer, and, for each of the corresponding slots, the pins are in a same layer.

Abstract: An electric machine including a rotor operably coupled with a stator having a plurality of stator windings. Each stator winding defines has a plurality of axially extending segments disposed within the stator slots and a plurality of end turn segments. At least one first axially extending segment defining a first cross sectional area and at least two second axially extending segments defining a smaller second cross sectional area are disposed in each of the stator slots. At least one of the plurality of end turn segments conductively couples a single first axially extending segment in a first one of the plurality of slots to at least two second axially extending segments in a second one of the plurality of slots. In some embodiments, the larger first axially extending segments are all disposed radially outwardly of the smaller second axially extending segments. The windings may be formed using hairpin conductors.

Abstract: An electric drive apparatus includes a DC motor for driving the electric device; a DC power source for outputting constant-voltage DC power to the DC motor; and a chopper for converting the constant-voltage DC power into variable-voltage DC power according to a driving signal and providing the variable-voltage DC power to the DC motor. The DC motor has 2j armature winding branches, each of which consists of m windings, 2j×m commutator segments connected to the windings, and two brush sets respectively connected to two power line sets of the DC motor and in contact with the commutator segments.

Abstract: An electric machine with a stator operably coupled with a rotor. The stator includes a stator core defining a plurality of slots. Each of the slots defines a plurality of layer positions located at different radial distances from a rotational axis of the electric machine. At least three windings are associated with each of the phases of the machine. In a first slot, a first winding is disposed in a first layer position. A second winding is disposed in a second layer position. A third winding is disposed in a third layer position. The first winding includes a first outside lead wire extending from the first slot. The second winding includes a second outside lead wire extending from a second slot. The third winding includes a third outside lead wire extending from a third slot. Each of the outside lead wires are in the first layer position.

Abstract: Each of phase windings includes parallel windings for each phase connected together in parallel, and the parallel windings include power-wire partial windings connected to a power supply side, neutral-line partial windings connected to a neutral point, and at least one of a set of 5-pitch and 7-pitch jumper wires, the power-wire partial windings, the neutral-wire partial windings, and the jumper wires being included in the plurality of partial windings forming the parallel windings. For two of the three phases, each of the 5-pitch jumper wires and a corresponding one of the 7-pitch jumper wires overlap each other, and for the remaining single phase, two of the 5-pitch jumper wires are spaced from each other in the circumferential direction, and each of the power-wire partial windings is adjacent to another power-wire partial winding for an identical phase or to a corresponding one of the neutral-line partial windings for a different phase.

Abstract: A rotating electric machine of one embodiment includes a stator provided with a stator core having windings of each pole of each phase lap wound thereto; and a rotor provided rotatably with respect to the stator. The stator core is provided with slots each having two or more parallelly connected windings of equal turns count inserted therein.

Abstract: In a rotating armature, the numbers of teeth straddled by each of plural coil portions are all the same as each other, three. In plural windings that form the plural coil portions, three individual coil portions that, out of the plural coil portions, are disposed at uniform intervals around the circumferential direction of the armature core and are connected together in series are formed in each of the windings. In each of the windings including the three individual coil portions, one segment out of the plural segments is connected to another segment that has the same phase as the one segment out of the plural segments.

Abstract: In a rotating armature, the numbers of teeth straddled by each of plural coil portions are all the same as each other, three. In plural windings that form the plural coil portions, three individual coil portions that, out of the plural coil portions, are disposed at uniform intervals around the circumferential direction of the armature core and are connected together in series are formed in each of the windings. In each of the windings including the three individual coil portions, one segment out of the plural segments is connected to another segment that has the same phase as the one segment out of the plural segments.

Abstract: A rotating electrical machine includes a stator having a stator core, coil groups, and a rotor. The coil groups include a first coil group located at an outer circumference side of the stator core and a second coil group located at an inner circumference side of the stator core. The first and second coil groups are formed into an annular shape by inserting unit coils into stator core slots so that the coils adjacent in a circumferential direction overlap alternately in a radial direction and so that an inside and an outside of the overlap alternate with each other. The first coil group is disposed to surround an outside of the second coil group. The first and second coil groups are disposed in a concentric manner. The unit coils constituting the second coil group have shorter circumferential lengths than the unit coils constituting the first coil group.

Abstract: The invention relates to an electric machine, which comprises a stator (1) and a rotor (2) that can be moved in relation to the stator. The stator (1) has a first multi-strand winding (I) and at least a second multi-strand winding (II), which each comprise two sub-windings (A1, A2) mechanically shifted in relation to each other. In a slot (3) of the stator, a number of windings (Nw1) of the first sub-winding (A1) of a multi-strand winding is different from a number (Nw2) of windings of the second sub-winding (A2) of said multi-strand winding. The stator (1) has a number of slots (3) that is twice the number of slots minimally required for a given pole pair number p of the rotor (2) for one of the multi-strand windings.

Abstract: An electric motor includes: a rotor having a rotor yoke and a magnet; and a stator formed by stacking, in a rotation axis direction of the rotor, a plurality of electromagnetic steel sheet layers in each of which a plurality of electromagnetic steel sheets each having two teeth is annularly arranged. A core of a coil provided in the stator is formed of the teeth stacked in the rotation axis direction, there are two types of phases for arrangement of a plurality of electromagnetic steel sheets in one electromagnetic steel sheet layer, and the stator includes the electromagnetic steel sheet layers having the two types of phases.

Abstract: A torque sensor coil includes a non-magnetic bobbin that includes first inclined grooves inclined at a predetermined angle relative to an axial direction and second inclined grooves inclined at the predetermined angle relative to the axial direction in a direction opposite to the first inclined grooves, a first detection coil formed by winding an insulated wire around the bobbin along the first inclined grooves, and a second detection coil formed by winding an insulated wire around the bobbin along the second inclined grooves. The bobbin is divided into plural regions along the circumferential direction, side walls of the first and second inclined grooves in each region are all parallel to a mold draw direction set to be different for each region or are inclined with respect to the parallel direction in such a manner that the first and second inclined grooves are widened toward the outside in a radial direction.

Abstract: Rotating machinery includes a rotor of 2n poles, 84n slots, and three-phase stator windings, where n is an integer equal to or greater than 1. A top coil and a bottom coil accommodated at the diametrically inner and outer sides of the slot are connected to each other to form the stator winding. The stator windings have 2n phase belts per one phase, the phase belt including two parallel windings. In at least one of the phase belts, the one coils are disposed in the order of the second, first, first, second, first, second, first, second, second, first, second, first, second, and first parallel windings; the other coils connected to the one coils are disposed in the order of the first, second, second, first, second, first, second, first, second, first, first, second, first, and second parallel windings.

Abstract: According to one embodiment, there is provided a 3-phase even-numbered-pole 2-layered armature winding housed in 45 slots per pole provided in a laminated iron core. The coil pieces corresponding to first, second, and third parallel circuits are placed in the first phase belt, and the coil pieces corresponding to fourth, fifth, and sixth parallel circuits are placed in the second phase belt. The upper coil pieces and the lower coil pieces of each parallel circuit are mutually placed in identical-numbered positions from a pole center.

Abstract: An armature for an electric machine according to the present invention includes: an armature core in which a plurality of slots are arranged in a circumferential direction; and an armature winding that is mounted to the armature core, and includes a plurality of two-lane winding bodies that are each produced by stacking and winding two jointless continuous conductor wires that are coated with insulation such that the two conductor wires are stacked in a radial direction of the armature core, the two-lane winding bodies being arranged at a pitch of one slot in a circumferential direction so as to be mounted into a third slot, a first slot, and a second slot that line up consecutively in the circumferential direction at an angular spacing of six slots.

Abstract: A brush-commutated direct-current motor comprises a stator which includes a plurality of exciter poles, a rotor rotatable relative to the stator about an axis of rotation, a plurality of pole teeth arranged on the rotor, and grooves arranged between the pole teeth, wherein the pole teeth are separated from each other by the grooves along a circumferential direction around the axis of rotation. On the pole teeth coil windings are arranged. A commutator is arranged on the rotor and includes a plurality of lamellae, wherein each coil winding is connected with one of the lamellae via a first connecting arm and is connected with another one of the lamellae via a second connecting arm.