A motor device for a vehicle includes a stator, a rotor, a bearing, an inverter, and a controller. The stator is attached into a housing and includes a concentrated winding coil. The rotor includes a permanent magnet. The bearing supports a rotating shaft of the rotor. The inverter controls an energization state of the concentrated winding coil. If a rotational speed of the rotor is greater than a threshold, the controller outputs a control signal to the inverter to execute field weakening control, and thereby makes a potential difference between the housing and the rotating shaft lower than a withstand voltage of the bearing. The control signal controls the energization state of the concentrated winding coil. The field weakening control generates magnetic flux of the concentrated winding coil in a direction of weakening magnetic flux of the permanent magnet.

An actuator device (1) for generating a longitudinal positioning movement to engage a shift element includes an actuator housing (2) and an electric motor (3). The electric motor (3) has a stator (4) and a rotor (5), the stator (4) being stationarily fixed at the housing (2), and the rotor (5) being rotatable relative to the stator (4) and rotationally fixed to a rotor carrier (6) supported relative to the housing (2) via a fixed bearing (7). The actuator device (1) further includes a threaded drive (8) having a nut (9) and a threaded spindle (10), with the nut (9) being rotationally driveable and axially fixed, and the threaded spindle (10) being axially displaceable along the threaded nut (9) and secured against rotation. The threaded nut (9) is rotationally fixed to the rotor carrier (6) and is at least partially radially within the fixed bearing (7).

A drive device includes a motor and an inverter. A motor axis is parallel to an output axis. The inverter is located in a second direction orthogonal to a first direction with respect to the motor axis and extends in a third direction orthogonal to the first and second directions. When viewed from the first direction, a virtual straight line passing through the axes extends in the third direction. An inverter housing portion overlaps the axes when viewed from the second direction, and has a boundary wall on the virtual straight line side in the second direction. In the second direction, a distance between the boundary wall and the output axis is smaller than a distance between the boundary wall and the motor axis. A motor side connection portion has a portion closer to the side opposite to the output axis than the motor axis in the third direction.

A method of assembling an electric motor comprises axially translating a rotor of a rotor assembly in a first direction through a longitudinal bore of a stator, a first centering ring of the rotor assembly preventing a first end of the rotor from contacting an internal surface of the longitudinal bore; rotatably supporting a first end of the rotor assembly longitudinally extending from the rotor with a first support member; resting a second centering ring of the rotor assembly on the internal surface of the longitudinal bore; rotatably supporting a second end of the rotor assembly longitudinally extending from the rotor with a second support member; and axially translating the rotor assembly in a second direction, opposite the first direction, to place the rotor assembly in a position in which both the first centering ring and the second centering ring are outside the longitudinal bore.

A compressor or pump stage is provided. The compressor or pump stage at least comprising a central shaft (8) and one rotor (3), where the axis of rotation of the rotor (3) is the central shaft (8) and where the rotor comprises a number, n, of rows of impellers (5) arranged at an outer perimeter of the rotor with an axial distance between neighbouring rows of impellers (5), where n={2, 3, 4...}.

A gyroscopic roll stabilizer comprises a gimbal having a support frame and enclosure configured to maintain a below-ambient pressure, a flywheel assembly including a flywheel and flywheel shaft, one or more bearings for rotatably mounting the flywheel inside the enclosure, a motor for rotating the flywheel, and bearing cooling system for cooling the bearings supporting the flywheel. For smaller units, the bearing cooling system is effective to enable a flywheel with a moment of inertia less than 40,000 lb in.sup.2 to be accelerated at a rate of 5 rpm/s or greater. For larger units, the bearing cooling system is effective to enable a flywheel with a moment of inertia greater than 40,000 lb in.sup.2 to be accelerated at a rate of 2.5 rpm/s or greater.

An electric work machine, such as a lawn mower includes a motor case (22) fixed inside a main-body housing (10). A brushless motor (21) is housed inside the motor case (22) and includes a stator (23) having a stator core (40), coils (45), and upper and lower insulators (42, 43), and a rotor (24) disposed inward of the stator (23) and having a rotary shaft (25). A spindle (17) is driven by the rotary shaft (25). The motor case (22) holds the stator (23) and axially supports the rotary shaft (25) via bearings (68, 76). One or more insulating members, such as an insulating cap (67) and/or a resin layer (78), provide electrical insulation between the stator core (40) and the rotary shaft (25).

A motor includes: an electrically conductive case; a shaft stored in the case and placed such that a part of the shaft penetrates the case; and a bearing via which the shaft is rotatably attached to the case. The shaft has an electrically conductive shaft material, and a high-resistance layer covering a surface of the shaft material and having a higher electric resistance than the shaft material.

A starter-generator module for a gas turbine engine includes an inner stator portion with an armature defining a rotation axis and an outer rotor portion disposed about the rotation axis. The outer rotor portion includes a permanent magnet and a gear teeth member. The permanent magnet is disposed about the rotation axis and the gear teeth member is defined on the outer rotor portion such that the gear teeth member transmits rotational energy to an accessory gearbox in a start mode and receives rotational energy from the accessory gearbox in a generate mode.

A rotary electric machine includes a rotor shaft, a rotor attached to the rotor shaft, a stator, and a case that houses the rotor and the stator. One end side and the other end side of the rotor shaft in an axial direction are respectively supported by the case via bearings with the rotor interposed therebetween. The bearings electrically insulate the rotor shaft and the case from each other.