A brushless motor includes a stator (26) having six slots (30), and a rotor having two poles. The rotor is adapted to rotate with respect to the stator. By adopting a 6-slots-2-poles structure, the brushless motor effectively reduces operational noise due to iron loss and unbalanced pull. As a result, the working life of the motor can be improved.

A brushless motor includes a stator (26) having six slots (30), and a rotor having two poles. The rotor is adapted to rotate with respect to the stator. By adopting a 6-slots-2-poles structure, the brushless motor effectively reduces operational noise due to iron loss and unbalanced pull. As a result, the working life of the motor can be improved.

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.

A stator for an electric machine comprises: a body; a plurality of stator teeth fixed on the body; anda plurality of tooth windings, which each have a first electrical conductor, which runs from one end portion, via at least one winding portion around at least one stator tooth, to another end portion, and a second electrical conductor, which is electrically insulated from the first electrical conductor and which runs from one end portion, via the at least one winding portion around the same at least one stator tooth, to another end portion; wherein one end portion of each of the first and second electrical conductors of the tooth windings can be or is electrically connected to an inverter, and the other end portions of the first electrical conductors of the tooth windings are electrically interconnected at a star point.

A stator for an electric machine comprises: a body; a plurality of stator teeth fixed on the body; anda plurality of tooth windings, which each have a first electrical conductor, which runs from one end portion, via at least one winding portion around at least one stator tooth, to another end portion, and a second electrical conductor, which is electrically insulated from the first electrical conductor and which runs from one end portion, via the at least one winding portion around the same at least one stator tooth, to another end portion; wherein one end portion of each of the first and second electrical conductors of the tooth windings can be or is electrically connected to an inverter, and the other end portions of the first electrical conductors of the tooth windings are electrically interconnected at a star point.

A vacuum pump (100) includes a rotor (22b), a rotor blade (13), and a magnetic-bearing-integrated stator (22a) including a coil. The rotor includes a pair of spacer members (29), a support member (27), a permanent magnet (26), and a protective ring (28), and in an axial direction of a rotary shaft (11), the support member has a mechanical strength higher than that of the protective ring.

A vacuum pump (100) includes a rotor (22b), a rotor blade (13), and a magnetic-bearing-integrated stator (22a) including a coil. The rotor includes a pair of spacer members (29), a support member (27), a permanent magnet (26), and a protective ring (28), and in an axial direction of a rotary shaft (11), the support member has a mechanical strength higher than that of the protective ring.

An assembly for an electric machine includes: a body; a plurality of teeth fixed to the body; a plurality of tooth windings, wherein each tooth winding includes a first electrical conductor and a second electrical conductor that are wound around the same tooth at least at one winding section along a winding axis and thereby alternate in the direction of the winding axis; and a differential protection device with a plurality of sensors, (e.g., current sensors), wherein each sensor is configured to detect a voltage at, and/or the strength of a current through, the first conductor or the second conductor at least at two points of a tooth winding of the plurality of tooth windings.

An assembly for an electric machine includes: a body; a plurality of teeth fixed to the body; a plurality of tooth windings, wherein each tooth winding includes a first electrical conductor and a second electrical conductor that are wound around the same tooth at least at one winding section along a winding axis and thereby alternate in the direction of the winding axis; and a differential protection device with a plurality of sensors, (e.g., current sensors), wherein each sensor is configured to detect a voltage at, and/or the strength of a current through, the first conductor or the second conductor at least at two points of a tooth winding of the plurality of tooth windings.