An electric motor having a rotor with an axis of rotation and an annular stator surrounding the rotor, the stator extending along an axial direction parallel to the axis of rotation and having a first end face and a second end face pointing in opposite axial directions. The stator has exactly two stator teeth extending from an annular circumferential surface that runs between the end faces of the stator, in a radially inward direction to the rotor and facing one another in relation to the axis of rotation, a first stator slot and a second stator slot, which faces the first slot in relation to the axis of rotation, extending along the circumferential surface, between the stator teeth.

A method is described for operating an electric media-flow machine for a compressor and/or a turbine, especially for an exhaust-gas turbocharger of an internal combustion engine, having a shaft rotationally mounted in a housing that has an inlet and an outlet for a medium to be conveyed, a rotor being disposed in rotatably fixed manner on the shaft, having a stator that is fixed in the housing and has at least one polyphase drive winding as well as a plurality of stator teeth projecting radially to the inside, having a covering cap that covers the rotor upstream and to which an inner sleeve is joined surrounding the rotor circumferentially. An outer sleeve is disposed coaxially relative to the inner sleeve, the inner sleeve and the outer sleeve being fixed in the housing, and the stator teeth extending through the outer sleeve at least up to the inner sleeve.

A method is described for operating an electric media-flow machine for a compressor and/or a turbine, especially for an exhaust-gas turbocharger of an internal combustion engine, having a shaft rotationally mounted in a housing that has an inlet and an outlet for a medium to be conveyed, a rotor being disposed in rotatably fixed manner on the shaft, having a stator that is fixed in the housing and has at least one polyphase drive winding as well as a plurality of stator teeth projecting radially to the inside, having a covering cap that covers the rotor upstream and to which an inner sleeve is joined surrounding the rotor circumferentially. An outer sleeve is disposed coaxially relative to the inner sleeve, the inner sleeve and the outer sleeve being fixed in the housing, and the stator teeth extending through the outer sleeve at least up to the inner sleeve.

There is provided an electric machine that includes a rotor comprising a pole and magnet assemblies divided axially in a first subsection and a second subsection. Each of the first and second subsections includes poles and magnets, and the poles and magnets of the first subsection are offset from the poles and magnets of the second subsection.

There is provided an electric machine that includes a rotor comprising a pole and magnet assemblies divided axially in a first subsection and a second subsection. Each of the first and second subsections includes poles and magnets, and the poles and magnets of the first subsection are offset from the poles and magnets of the second subsection.

Described are homopolar bearingless slice motors which include an array arrangement of permanent magnets on stator teeth, and a magnet-free rotor having a unique surface geometry. Also described are related components of such motors. The permanent magnet arrays provide homopolar bias flux to the rotor, and salient features on the rotor surface route the bias flux toward paths desirable for force and torque generation. In an illustrative embodiment, two magnet arrays are placed at the tips of stator teeth, so as to provide the bias flux via relatively short flux paths. By modulating current through windings based upon the rotor radial and angular position measurements, the stator can levitate and rotate the rotor.

Described are homopolar bearingless slice motors which include an array arrangement of permanent magnets on stator teeth, and a magnet-free rotor having a unique surface geometry. Also described are related components of such motors. The permanent magnet arrays provide homopolar bias flux to the rotor, and salient features on the rotor surface route the bias flux toward paths desirable for force and torque generation. In an illustrative embodiment, two magnet arrays are placed at the tips of stator teeth, so as to provide the bias flux via relatively short flux paths. By modulating current through windings based upon the rotor radial and angular position measurements, the stator can levitate and rotate the rotor.

An electromagnetic actuator for non-continuous rotation (cogging-torque actuator (CTA)) (100) comprises a support structure (116), an output shaft (104) rotatable about and defining an axis of rotation (X), a permanent magnet rotor (106) comprising at least two magnetic poles (108a, 108b) attached to the output shaft (104), and a stator device (110) comprising a ferromagnetic pole body (112) attached to the support structure (116) and surrounding the at least two magnetic poles (108a, 108b). The ferromagnetic pole body (112) can have at least four ferromagnetic stator poles (112a-d) each wrapped in a conductive wire (114a-d) to define a stator coil. The at least four ferromagnetic stator poles (112a-d) are sized, and spaced radially from each other, so as to define a maximum cogging torque of the electromagnetic actuator (100). The CTA (100) can operate as an actuator, an elastic spring, a clutch, and/or a load support device.

An electromagnetic actuator for non-continuous rotation (cogging-torque actuator (CTA)) (100) comprises a support structure (116), an output shaft (104) rotatable about and defining an axis of rotation (X), a permanent magnet rotor (106) comprising at least two magnetic poles (108a, 108b) attached to the output shaft (104), and a stator device (110) comprising a ferromagnetic pole body (112) attached to the support structure (116) and surrounding the at least two magnetic poles (108a, 108b). The ferromagnetic pole body (112) can have at least four ferromagnetic stator poles (112a-d) each wrapped in a conductive wire (114a-d) to define a stator coil. The at least four ferromagnetic stator poles (112a-d) are sized, and spaced radially from each other, so as to define a maximum cogging torque of the electromagnetic actuator (100). The CTA (100) can operate as an actuator, an elastic spring, a clutch, and/or a load support device.

Disclosed herein is a rotor for a wound-rotor motor. The rotor for a wound-rotor motor includes: a rotor core including a hollow formed in a central portion thereof and coupled to a shaft; a teeth portion radially formed on an outer side surface of the rotor; and a pole shoe formed to extend from an end portion of the teeth portion in one direction and including a part of a cross section of an outer side surface formed in an arc shape of a first imaginary circle (C1) having a first radius (r1) which is a distance from a central point (CP1) of the hollow to an outermost position (P1) thereof.