A rotor for a permanent magnet machine includes first and second axially successive rotor sections each including permanent magnets generating magnetic field having a pole pitch. The rotor includes a first coupling system for connecting the first rotor section to a shaft and a second coupling system for connecting the second rotor section to the shaft or to the first rotor section. The second rotor section is rotatable with respect to the first rotor section by an angle corresponding to the pole pitch in response to releasing the second coupling system so as to set the stator flux-linkages generated by the first and second rotor sections to be substantially zeroes. Thereafter, the permanent magnets do not substantially induce voltages on the stator windings even if the rotor is rotating during for example an internal fault of stator windings.

The present invention relates to a motor. According to one embodiment of the present invention, a skew angle is changed according to a load condition so that noise and vibration can be reduced as compared to a conventional motor.

An axial flux permanent magnet machine including a pair of axially spaced first components. A second component positioned axially between and equidistant from the first components. Either the pair of first components or the second component is arranged to rotate about a shaft. A translation mechanism coupled to each of the first components. The translation mechanism configured to translate the first components axially away from the second component. Also a method of controlling an axial flux permanent magnet machine.

An electric power supply system configured to supply electric power to an electrical load device in accordance with a current requirement. The electric power supply system includes an engine configured to output rotational power, a generator configured to receive the rotational power and to supply a current to the electrical load device. The generator includes a rotor, and a stator including a winding and a stator core with the winding wound thereon, a magnetic circuit for the winding passing through the stator core, and a supply current adjustment device configured to adjust magnetic resistance of the magnetic circuit for the winding, to thereby change an inductance of the winding to adjust the supplied current. The electric power supply system further includes a control device configured to control the engine to adjust the output rotational power and to control the supply current adjustment device to adjust the inductance of the winding.

A rotary electric machine includes: a stator; a rotor; a control device that causes the stator to generate a rotating magnetic field; and a magnetic flux supply element supported by a rotary shaft so as to be rotatable relative to the rotary shaft, disposed radially inward of the rotor across a gap, and having auxiliary magnets. Each auxiliary magnet is formed such that opposite end portions thereof in the circumferential direction are radially opposed to holding magnets when the relative rotation angle of the magnetic flux supply element is a strengthening angle. The control device executes field weakening control or field strengthening control, thereby changing the relative rotation angle of the magnetic flux supply element.

Various embodiments provide a system for moving optical elements. The system includes a first rotor and a second rotor configured to rotate in opposite directions. The system further includes a first plurality of paddles coupled to the first rotor, each of the plurality of paddles having an aperture configured to receive a first optical element, and a second plurality of paddles coupled to the second rotor, each of the plurality of paddles having an aperture configured to receive a second optical element. The first rotor and the second rotor are configured to move the first optical element between a retracted position and a desired position and to move the second optical element between the desired position and a retracted position substantially simultaneously such that a reaction torque of the first rotor cancels a reaction torque of the second rotor.

A magnetically reconfigurable robot joint motor includes a coil stator, a permanent magnet rotor and a magnetic reconfiguration unit. The magnetic reconfiguration unit is arranged around an outer periphery of the permanent magnet rotor, and a coil connected to a control circuit is wound on an outer layer of the magnetic reconfiguration unit. When it is necessary to execute low rotation speed or zero rotation speed operating conditions, the control circuit inputs current pulses of different strengths, so that the magnetic reconfiguration unit obtains permanent magnetization of corresponding degree, and generates a magnetic field which acts together with a magnetic field of the permanent magnet rotor, so as to maintain a torque required for output.

A rotating electrical machine equipped with a magnet unit and a magnetic body. The magnet unit is also equipped with magnet covers wrapped about armature-facing peripheral surfaces of the magnets. Each of the magnets has recesses formed in portions of the armature-facing peripheral surface which are located close to q-axes each of which lies at a boundary between magnetic poles. Each of the magnet covers is recessed in the radial direction in accordance with the shape of the magnet recesses. If the armature-facing peripheral surface of the magnets is between a circumferentially adjacent two of the magnet recesses is defined as a main magnetic pole surface, and an angle representing a circumferential range occupied by the main magnetic pole surface is defined as a main magnetic pole angle θa, the main magnetic pole angle θa is selected to be 2π/5<θa<2π/3.

An electrical machine with two or more stators is proposed. One stator (1) is stationary and is fixed to the body (4) of the machine, and the second stator (6) is movable and can rotate freely to both the rotor (2) and the stationary stator (1). The movable stator (6) is self-orienting according to the lines of the magnetic field created by the electric windings and/or permanent magnets of the stationary stator (1). The movable stator (6) concentrates and shapes up the magnetic field B so that the magnetic lines are almost perpendicular to the rotor windings. The movable stator (6) does not rotate relative to the magnetic field of the stationary stator (1) and the magnetic field in it does not change, there is no continuous re-magnetization, magnetic hysteresis is avoided and no eddy currents are generated, due to which the losses and heating of the machine are reduced. The movable stator (6) may comprise permanent magnets to increase the magnetic field in the rotor active zones (2).

A downhole rotating machine includes a stator having stator windings and corresponding magnetic flux guides and a rotor having a plurality of magnets configured to cooperate with the stator windings and the corresponding magnetic flux guides to generate a magnetic field in a magnetic gap that is substantially parallel to an axis of rotation of the rotor, wherein the magnetic gap provides a magnetic gap separation between the plurality of magnets and the corresponding magnetic flux guides that is at least five percent of an overall diameter of the downhole rotating machine. A method of operating a downhole tool in a wellbore and a downhole tool are also provided.