Abstract: A renewable energy generation system includes a drive motor, a flywheel in mechanical communication with the drive motor, a generator in mechanical communication with the flywheel, a charge controller in electrical communication with the generator, a plurality of charge controller switches in electrical communication with the charge controller, a plurality of batteries in electrical communication with a respective charge controller switch, and a power management module in electrical communication with the plurality of charge controller switches. The drive motor effectuates rotation of the flywheel to generate stored rotational energy which is transferred to the generator as a load is placed upon the generator to maintain a constant speed of the drive motor. The power management module selectively opens or closes a charge controller switch to permit or inhibit the flow of electrical energy to a respective battery to reduce the electrical load placed upon the generator and drive motor.

Abstract: An electrical machine includes a stator assembly coupled to an engine stator component of a propulsion engine. The stator assembly includes a stator support assembly fixedly attached to the engine stator component and a stator disposed on a supporting surface of the stator support structure. The electrical machine also includes a rotor assembly including a rotor support structure connected to a shaft of the propulsion engine and a rotor attached to the rotor support structure such that the rotor is disposed radially inward of the stator. The rotor exchanges rotational energy with the shaft to operate as either an electrical motor or an electrical generator.

Abstract: A kinetic power generation unit improves the magnetic field of an electric motor and the magnetic field of a power generator into a same magnetic field coupling of a same rotor, so that the rotors of electric motor and the power generator have the same rotational direction, and an exciting winding of the electric motor changes and transmits phases sequentially to a phase voltage by a brushless drive controller, so that an interference effect on the counter electromotive force of the electric motor and the counter-electromotive force of the power generator is changed to a positive effect.

Abstract: An electrical power system is provided. The electrical power system involves a battery powered motor which in turn generates electricity using a primary generator and a secondary generator. The secondary generator provides a recycle electricity to the battery, while the primary generator provides an electrical output for powering electrical devices.

Abstract: A method for manufacturing a rotor for an electric machine with a contactless power transmission system, wherein an end winding cover is arranged on one end face of a laminated core of the rotor. The invention provides that a secondary unit (SEC) of the power transmission system is integrated in the end winding cover and, as a result, after the end winding cover has been arranged, the secondary unit (SEC) is held on the rotor indirectly via the end winding cover.

Abstract: A slip ring assembly including a plurality conducting disks spaced-apart and stacked mounted along a common rotation axis, each being electrically connectable and fixedly securable to a generator mounted in a rotatable nacelle of a wind turbine so that a rotation of the rotatable nacelle triggers a rotation of the conducting discs; and a plurality of slip ring devices, each being electrically connectable and mechanically securable to a fixed electrical distribution conductor mounted to a fixed pole so as to have a fixed position relative to the fixed pole, and each of the plurality of the slip ring devices having upper and conducting fingers arranged so as to rotatably receive a respective conducting disk therebetween and to provide an electrical connection between the conducting disks and the slip ring device during rotation of the nacelle.

Abstract: In aspects, the present invention provides a condition monitoring device for monitoring a condition of an electrical machine. The condition monitoring device comprises a housing affixed on a frame of the electrical machine, one or more sensors within the housing, for measuring one or more parameters of the electrical machine, and one or more magnetic coils electrically connected to an electrical energy storage unit located in the housing. The one or more magnetic coils are located within a cavity in the stator core thorough an aperture in the frame of the electrical machine and form an inductive circuit with one or more windings of the electrical machine, for supplying current to the electrical energy storage unit.

Abstract: An axle assembly having a gear reduction unit that is configured to operatively connect an electric motor to a drive pinion. The gear reduction unit includes at least one countershaft gear set. At least one clutch is engageable to provide a torque path between the electric motor and the drive pinion.

Abstract: A method of sensing a rotation speed of an encoder includes generating measurement values by a plurality of sensor elements in response to sensing a magnetic field, where the plurality of sensor elements are grouped into a first shifted pair, a central pair, and a second shifted pair; generating a first shifted differential measurement signal based on the measurement values generated by the first shifted pair, a central differential measurement signal based on the measurement values generated by the central pair, and a second shifted differential measurement signal based on the measurement values generated by the second shifted pair; and generating an output signal based on detecting the first shifted differential measurement signal, the central differential measurement signal, and the second shifted differential measurement signal crossing at least one threshold.

Abstract: Conventional APUs for diesel-electric locomotives may include an AC electric generator and typically require additional hardware to be installed to convert the AC power output by the generator to DC power that can power electrical systems or charge batteries in the locomotive. According to some embodiments, there is provided an auxiliary power unit (APU) or system for operation in cooperation with a primary engine. The APU includes a secondary engine; a primary engine coolant heating system, or a primary engine lubricant heating system; a control system that automatically shuts down the primary engine and starts the secondary engine responsive to a predetermined condition; and a Direct Current (DC) power generator that generates an output voltage, the DC power generator being driven by the secondary engine.

Abstract: A brushless starter-generator system is contained within a single housing. The housing has a first end with an opening to receive a drive spline from a motive source and an opposing second end. A brushless, rotating machine is located adjacent the first end and is kinetically connectable to the drive spline. A power control unit is adjacent the second end and electrically coupled to the brushless, rotating machine. The brushless, rotating machine is selected from the group consisting of a synchronous machine, a permanent magnet machine, and an induction machine. Electrical and mechanical interfaces are identical to a like-rated brushed version for a true “drop-in” replacement capability to facilitate replacements and up-grades.

Abstract: An electromechanical actuator for electrical flight controls of an aircraft, the actuator comprising a transmission shaft, four electromechanical conversion members, each having a respective stator and rotor secured to the transmission shaft, and four control systems, each dedicated to respective ones of the electromechanical conversion members. The stator has teeth and windings surrounding at least one tooth, whereas the rotor is provided with permanent magnets. Each electromechanical conversion member is a flux-concentrating member and each winding is concentric and has a single layer. The electromechanical actuator is intended in particularly for controlling a hydraulic actuator via a mechanical transmission within an electrical flight control device of an aircraft.

Abstract: This disclosure details transmission systems for electrified vehicles. Exemplary transmission systems may include a crankshaft integrated starter-generator. The crankshaft integrated starter-generator may include an electric machine and an integrated rotor carrier/input shaft assembly. The integrated rotor carrier/input shaft assembly is configured to support the electric machine and provide an interface for mounting the crankshaft integrated starter-generator relative to a torque converter. The torque converter may be mounted to a flange of the integrated rotor carrier/input shaft assembly that is inside the diameter of a rotor of the electric machine.

Abstract: A DC monitoring system is configured to measure and analyze VFD (Variable Frequency Drive) operational characteristics. The VFD is configured to receive three-phase input power from a standardized source and to provide variable frequency three-phase output power to a three-phase motor. In some applications, the VFD and motor operate at a medium voltage. The VFD can include multiple inverter modules consisting of a DC section and switching section, also referred to as a multiple bus configuration. The DC monitoring system includes a measurement module coupled to each DC bus of the VFD, a data communication network, and a PQube monitoring device for transmitting data signals corresponding to voltage values of the VFD DC bus obtained in a medium voltage compartment to a low voltage compartment for processing and analysis. Processing of the data signals enables comparative and predictive analysis to determine early warning for possible capacitance failure in the VFD.

Abstract: A motor unit includes a motor including a shaft to rotate about a motor axis, and a stator, a reduction gear, and a housing. The shaft includes a first shaft portion, a connecting shaft portion, and a second shaft portion arranged coaxially with one another, and a separating mechanism between the connecting shaft portion and the second shaft portion. The first shaft portion includes a first end portion. The connecting shaft portion includes a second end portion coupled to the first end portion, a third end portion located on a side opposite to the second end portion, and a connection flange portion extending radially outward. The second shaft portion includes a fourth end portion. The separating mechanism selectively separates the connection flange portion and the fourth end portion from each other.

Abstract: A hybrid steam power drive system that uses electrical motors to power any type of vehicle. It includes a steam unit that drives a steam turbine that turns a generator to provide electricity directly to the electrical drive motors and continually charge a battery/capacitor bank which can also provide energy to the electrical drive motor(s). With this system the battery/capacitor bank is continually being charged and does not have to periodically be plugged into a power source to charge the battery/capacitor bank. It also provides an accessory outlet to power external needs when the vehicle is not in motion.

Abstract: A rotating electric machine includes a stator and a rotor. The stator includes a stator core and an armature coil wound on the stator core. The rotor is arranged radially inside the stator to radially face the stator. The rotor includes: a field core having a plurality of magnetic pole portions for respectively forming a plurality of magnetic poles the polarities of which are alternately different in a circumferential direction; a field coil wound on the field core; and a tubular short-circuiting member that is arranged radially outside the magnetic pole portions to cover radially outer surfaces of the magnetic pole portions and magnetically connects each circumferentially-adjacent pair of the magnetic pole portions. The short-circuiting member is provided within an axial range between two axial ends of the stator core.

Abstract: A hand vacuum cleaner has an air flow path extending from a dirty air inlet to a clean air outlet and a suction motor positioned in the air flow path. A cyclone chamber positioned in the air flow path has a cyclone air inlet and a cyclone air outlet. A longitudinally extending battery pack which extend upwardly and forwardly when the upper end of the hand vacuum cleaner is positioned above the lower end of the hand vacuum cleaner. A portion of the dirt collection region is located below a portion of the battery pack.

Abstract: Magnetic sensor modules, systems and methods are provided, configured to detect a rotation speed of an object. A magnetic sensor module includes a plurality of sensor elements configured to generate measurement values in response to sensing a magnetic field, the plurality of sensor elements being grouped into three pairs; and a sensor circuit configured to generate a first shifted differential measurement signal based on the measurement values received from a first shifted pair of sensor elements, a central differential measurement signal based on the measurement values received from a central pair of sensor elements, and a second shifted differential measurement signal based on the measurement values received from a second shifted pair of sensor elements, and generate an output signal based on detecting the first shifted differential measurement signal, the central differential measurement signal, and the second shifted differential measurement signal crossing at least one threshold.

Abstract: A hand vacuum cleaner has an air flow path extending from a dirty air inlet to a clean air outlet and a suction motor positioned in the air flow path. A cyclone chamber positioned in the air flow path has a cyclone air inlet and a cyclone air outlet. At least one energy storage member is positioned in an energy storage chamber having an energy storage chamber wall. The cyclone air outlet faces the energy storage chamber wall whereby air exiting the cyclone chamber impinges on the energy storage chamber wall.

Abstract: Various embodiments associated with a segmented magnetic core are described. The segmented magnetic core can be made up of multiple singular structures so as to allow an individual singular structure to be removed with ease and without disturbing another magnetic core. This modular core design allows for a significant reduction in motor housing weight due to compatibility of the design with lightweight materials and the potential absence of extensive housing when so designed. This modular core design can be incorporated into a motor or a generator and this modular core design can be accomplished, in one example, by way of stacking and/or interlocking employing low cost assembly. In one example, a motor or a generator uses sensors to detect an operational failure in a magnetic core, notifying a user early of the failure.

Abstract: A hand vacuum cleaner has an air flow path extending from a dirty air inlet to a clean air outlet. A cyclone assembly including a dirt collection region is positioned in the air flow path, a pre-motor filter is positioned downstream from the cyclone chamber and a suction motor is positioned upstream of a clean air outlet. A battery pack is positioned such that at least a portion of the battery pack is positioned rearward of the dirt collection region and at least a portion of the battery pack underlies at least a portion of one or both of the cyclone assembly and the pre-motor filter.

Abstract: A motor with self power generation includes a motor body, at least one magnetic element, a shield case, an induction element, a transfer circuit board and a working module. The motor body includes a shaft member. The at least one magnetic element, located at the shaft member, is to generate a dynamic electromagnetic induction space while the shaft member rotates. The shield case, located close to the shaft member, is to shield the shaft member. The induction element, fixed at the shield case, has a portion located inside the dynamic electromagnetic induction space to generate an induction power while the shaft member rotates. The transfer circuit board has a transfer circuit electrically coupled with the induction element to receive the induction power to further generate a working power. The working module, electrically coupled with the transfer circuit, is to receive the working power to execute a default work.

Abstract: Provided is a field winding type motor capable of having high efficiency and reinforcing a portion having low stiffness during high speed rotation by respectively assembling metal cores in axial directions of a stator bobbin and a rotor bobbin.

Abstract: A vehicle includes an engine and a controller. The controller may be configured to, responsive to indication of a temperature of a starter-generator exceeding a de-rated threshold, command the engine to start and disable engine automatic shut-off. And the controller may be configured to, responsive to indication of the temperature exceeding a disabled threshold, or the temperature exceeding the de-rated threshold and a traction battery discharge power being less than a threshold, command the engine to start and shed a load.

Abstract: A light ranging system including a shaft; a first circuit board assembly that includes a stator assembly comprising a plurality of stator elements arranged about the shaft on a surface of the first circuit board assembly; a second circuit board assembly rotationally coupled to the shaft, wherein the second circuit board assembly includes a rotor assembly comprising a plurality of rotor elements arranged about the shaft on a surface of the second circuit board assembly such that the plurality of rotor elements are aligned with and spaced apart from the plurality of stator elements; a stator driver circuit disposed on either the second or the first circuit board assemblies and configured to provide a drive signal to the plurality of stator elements, thereby imparting an electromagnetic force on the plurality of rotor elements to drive a rotation of the second circuit board assembly about the shaft; and a light ranging device mechanically coupled to the second circuit board assembly such that the light ranging d

Abstract: The present application discloses a fuel system for a gas turbine engine. The engine includes a main alternating current electrical generator driven by an engine shaft such that the electrical output frequency of the electrical generator varies in dependence on shaft rotational speed. The fuel system includes a variable flow fuel pump for providing a fuel flow to the engine, a frequency and/or voltage controller configured to provide electrical power having at least one of a predetermined output frequency and a predetermined voltage, and a variable speed electric motor configured to drive the fuel pump. The electric motor includes an induction motor having a stator and at least a first rotor, the stator having first and second sets of stator windings. Each set of stator windings is configured to impart a torque on the rotor in use.

Abstract: A rotation angle detection device detects a rotation angle of a motor having a shaft passing through a heat-dissipation plate. The rotation angle detection device includes: a permanent magnet attached to a base end of the shaft; a board that is disposed above the heat-dissipation plate and on which a drive circuit of the motor and a control circuit of the drive circuit are mounted; a magnetic sensor that is provided on the board so as to face the permanent magnet; and a magnetic shielding member that has a tubular shape and is disposed between the heat-dissipation plate and the board to surround the permanent magnet in plan view.

Abstract: In various example embodiments disclosed herein, physical architectures, systems, processes and methods for security are described that, at their core are adaptive and changing at determined intervals so as to present a different attack surface. In one aspect is described improvements in the improved security architecture, system and methods based upon multiple processors, operating systems, communication channels and batteries, Power Distribution Units, and Faraday cages (Faraday shielding), which can combat electromagnetic pulse (EMP) attacks.

Abstract: Alternator/starters and methods for providing electrical power to a vehicle and rotating an engine are disclosed. In one example, the alternator/starter provides a differential action whereby torque on an input side of the alternator may be maintained while speed of an output side of the alternator may be varied. The alternator/starter includes two armature windings and two field windings.

Abstract: A vehicle supercharger assembly (110) comprises a dual generator comprising first and second co-axial relatively rotatable armatures (14a, 14b), and a first disengageable clutch (32) between the armatures (14a, 14), said first armature (14a) being adapted for permanent drive from a source of motive power, and said second armature (14b) being driven by said first armature (14a) on engagement of said first clutch (32); a supercharcharger impeller (24), the second armature (14b) driving the impeller (24) mechanically via a gear train; an electric motor coupled to the gear train and operable to adjust the rotational speed of the impeller (24); wherein, in use, the electric motor is electrically driven on demand from a generator comprising the second armature (14b).

Abstract: A system for reducing inrush loading when a source power is restored includes a device for switching power that selectively connects a load to the source of power and a circuit for measuring the AC voltage at the source and for determining when the AC voltage is within operating range. Responsive to the AC voltage being within operating range, the system delays for a time period then connects the load to the source of power by way of the device for switching power.

Abstract: An electric motor includes a rotor shaft, and the rotor shaft has a shaft-core oil passage and radial oil passages. The shaft-core oil passage includes an inner wall facing radially inward. The radial oil passages are provided toward a radial outer side of the rotor shaft from the shaft-core oil passage. The radial oil passages penetrate through the rotor shaft. The radial oil passages have corresponding one of first connection openings connected to the shaft-core oil passage, so that oil that is not discharged from the first connection openings to the radial oil passage is supplied to other supply destinations. A distance of the first connection openings from the shaft core is shorter than a distance, from the shaft core, of that part of the inner wall which is not provided with the first connection openings.

Abstract: An electromagnetic power generator device and a method thereof for using balanced electromagnetic forces to drive one or more flywheel rotor assemblies on a fixed shaft and generating large amount of electrical power are provided. The electromagnetic power generator device includes a non-rotating shaft attached to a support frame, at least one flywheel rotor assembly, and at least one input driver plate assembly which is coupled to the flywheel rotor assembly via the non-rotating shaft penetrating through a first centered hole of a bearing of the flywheel assembly and a second centered hole of the input driver plate assembly.

Abstract: A multi-engine system 10 for use on an aircraft 14 is disclosed. The system 10 may comprise a first aircraft engine 16A and a second aircraft engine 16B configured to drive at least one device 12 of the aircraft 14. A starter 20 may be coupled to one of the first and second aircraft engines 16A, 16B to assist starting of the one of the first and second aircraft engines 16A, 16B. An energy source 24 may be configured to deliver energy to the starter 20 at a rapid rate during rapid starting of the one of the first and the second aircraft engines 16A, 16B, the rapid rate being higher than a regular rate used during regular starting of the one of the first and the second aircraft engines 16A, 16B. The energy source 24 may comprise at least one supercapacitor.

Abstract: An arrangement (1) for driving a wheel of a motor vehicle has an electric machine (6) and a transmission (4). The transmission (4) is downstream of the electric machine (6) and is arranged within the electric machine (6). A common cooling device (14) with a cooling water jacket (15) is utilized for cooling both the electric machine (6) and the transmission (4).

Abstract: A direct current (DC) motor including: a cylindrical frame, at least one end of which is open; a cylindrical end cover including an opening configured to block the at least one open end; a rotor including a rotor shaft supported by the frame and the end cover, and a rotor core installed on the rotor shaft; a commutator installed on the rotor shaft and arranged on one end of the rotor core; a cover unit installed on the rotor shaft, arranged between the rotor and the commutator, and including at least one location detection device; and a rotation detection unit installed in the end cover and configured to detect the at least one location detection device.

Abstract: A coolant flow path structure which cools a rotor is configured of a first coolant flow path forming a radial coolant flow path of the rotor and a second coolant flow path communicating with the first coolant flow path and forming an axial coolant flow path of the rotor, and a negative pressure structure, which brings an exist of the coolant flow path structure into a negative pressure as a result of a rotation of the rotor, is provided at the exit of the second coolant flow path.

Abstract: A system includes an electric motor including a housing enclosing a substantially-sealed internal environment, a pump including an inlet connected to the substantially-sealed internal environment of the electric motor via a first conduit, and a fluid supply storing a makeup fluid, the fluid supply including an outlet connected to the substantially-sealed internal environment of the electric motor via a second conduit. The pump is configured to create a negative pressure within the substantially-sealed internal environment of the electric motor to mitigate potential contamination of an external environment of the electric motor with the makeup fluid.

Abstract: It is an object of the present invention, to provide a rotor-holding structure of a rotating electrical machine for hybrid-vehicle, the structure being capable of ensuring a space is present between a stator and a rotor. A rotating electrical machine includes a stator and a rotor, the stator being fixed to a housing, and the rotor being disposed opposite to stator across a predetermined space, wherein the rotor has a rotor boss section, a rotor core, and a permanent magnet. The rotor boss section is rotatably attached to the housing through a bearing. The rotor core and the permanent magnet are attached to the rotor boss section. Multiple through-holes are provided at the respective corresponding locations of the housing and the rotor boss section. A supporting member is passed through each of the through-holes, thereby holding the rotor boss section.

Abstract: A number of configurations of a high speed electromagnetic turbine (1300) are discussed. The turbine (1300) includes a housing (1301) includes at least superconducting coil (1307) for the generation of a magnetic field, the coil being retained within a cryogenic envelope of a cryogenic body (1306). The turbine (1300) includes also includes rotor assembly including one or more rotors (13091), (13092), (13093), (13094), (13095) and (13096) positioned on shaft (1310). The rotor being received within the bore (1308) formed between the interior walls of the body (1306) such that it is immersed in the magnetic field. As the current is passed through the rotor assembly the induced force due to the interaction of the current with the magnetic is translated into a torque on the shaft (1310).

Abstract: A cleaner includes a BLDC motor and a power unit. The BLDC motor includes a rotor and a stator provided with a DC coil and an AC coil in a separate manner. The power unit is configured to supply DC power and AC power to the DC coil and the AC coil, respectively.

Abstract: An electrical machine includes a rotor located at a central shaft and a stator located radially outboard of the rotor and secured at a back iron. A first baffle is coupled to the central shaft at one axial end of the rotor, the baffle extending radially outwardly from the shaft toward a baffle cavity at the back iron. A flow of coolant is urged toward the baffle cavity along the baffle via centrifugal force. A method of flowing coolant through an electrical machine includes injecting a flow of coolant substantially radially into an electrical machine cavity. The flow of coolant is urged radially outwardly along a rotating baffle located at one axial end of a rotor of the electrical machine via centrifugal force and into a baffle cavity disposed at the back iron at a radial end of the baffle.

Abstract: A drive module for a vehicle has a transmission (12) and an electric machine (11) that is coupled to an input shaft (16) of the transmission (12). An air-filled cavity (23) is formed between the electric machine (11) and the transmission (12). The electric machine (11) is an external-rotor motor with a rotor (24) that surrounds the stator (25). A fan impeller (31) rotates with the rotor (24) and draws air out of the air-filled cavity (23) in an axial direction, draws the air through windings (27) of the stator (25) for cooling, and subsequently conveys the air in the radial direction into a housing-side flow duct (34) in which heated air can be accumulated and via which the air can be returned toward the cavity (23). The heated air can be cooled in the region of the flow duct (34) and/or in the region of the cavity (23).

Abstract: A linear magnetic sensor shield system comprises first and second shield parts. The system may include first and second field sensor assemblies, each having field sensors disposed therein. The first shield part may be disposed adjacent to a first side of the first field sensor assembly, and the second shield part may be disposed adjacent to a second side of the second field sensor assembly. The shield parts may be formed of mu metal or a mu metal and steel composite, by of example. A torque transmitting device is also provided.

Abstract: Apparatus for generating and supplying electrical power to AC loads on an aircraft may include a prime mover, an exciter generator rotatably coupled to the prime mover and a main generator with a main generator rotor electrically coupled to the exciter generator to receive AC power from the exciter generator. One or more capacitors may be electrically coupled to the main generator rotor to increase a power factor of the main generator rotor.

Abstract: It is an object to decrease an amount of a cooling medium which stays in a housing of an electric motor and is not discharged to the outside when cooling the electric motor by the cooling medium. For this reason, an electric motor includes a first discharge port which is provided in a first flange of a housing so that the cooling medium passes therethrough, a second discharge port which is provided in the first flange so that the cooling medium in the housing passing a bearing passes therethrough, and a discharge passageway which discharges the cooling medium passing the first discharge port and the second discharge port to the outside of the housing.

Abstract: A wireless power supply system that wirelessly supplies electric power from a power-supplying coil to a power-receiving coil is provided with a ground power-supplying device having a power-supplying coil, a vehicle having a power-receiving coil, and a power-supplying and a power-receiving covers that shield leakage magnetic flux by covering the periphery of the power-supplying coil and the power-receiving coil and the periphery of space between the coils.

Abstract: A motive power transmission device capable of suppressing deformation of matching surfaces of cases is provided. A motive power transmission device is used as a transmission for a hybrid vehicle containing a first rotating electric machine and a second rotating electric machine as two rotating electric machines. The first rotating electric machine and the second rotating electric machine each serving as a motor/generator are housed in independent first case and second case, and the both are coupled to constitute the transmission for a hybrid vehicle. A first stator and a second stator are fastened and fixed to the first case and the second case on sides opposite to a first matching surface and a second matching surface.

Abstract: A method and apparatus for reducing electromagnetic drag in an electric machine may include a laminated stator having wire slots disposed around the inner periphery spaced into sectors separated by a pole iron support structure. The slots contain induction windings. A series of wound lateral pole irons may be arranged around the inner periphery of the stator, the first ends of which extend into the slots in the sectors. A support structure supports the lateral pole irons by forming a circular opening concentric with the inner periphery of the stator, A rotor may be inserted into the circular opening of the lateral pole iron support structure and supported at the stator lateral pole iron ends by a support means. A plurality of rotor inserts may contain free-wheeling permanent magnet inserts spaced along an outer periphery of the rotor.