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 compressor including a housing, and a motor including a stator to be interference fitted into and fixed to an inner circumferential surface of the housing and a rotor rotatable inside the stator. The stator includes an annular back yoke disposed inside the housing, a plurality of teeth extending radially inward from the back yoke, and a coil wound on the plurality of teeth. The back yoke includes a deformation portion compressed and deformed by the housing while the stator is interference fitted into the inner circumferential surface of the housing, a contact portion which protrudes radially outward from the deformation portion and being in contact with the housing, and a cavity formed on a radial inner side of the deformation portion into which the deformation portion is deformed.

Systems and methods for producing fluids from a subterranean well include an electrical submersible pump assembly with a motor-pump unit. The motor-pump unit has a motor housing and a stator is located within the motor housing. The stator has a stator body with an interior cavity. A rotor assembly is located within the interior cavity of the stator. The rotor assembly includes a rotor shaft extending along the central axis of the stator, a rotor member, and an intermediate rotor bearing assembly. The rotor member and the intermediate rotor bearing assembly circumscribe the rotor shaft. An impeller is mounted on the rotor shaft and located within the interior cavity of the stator. A liner with a polygonal cross section is located along an interior surface of the interior cavity. The liner is secured to the motor housing and seals the stator body from a wellbore fluid.

A brushless motor is provided that includes a stator assy and a rotor. The stator assy includes a stator, a housing that has a space where the stator is disposed, and an insulating resin disposed in the space. The insulating resin fixes the housing to the stator. The housing includes a first housing member and a second housing member. The insulating resin also fixes first housing member to the second housing member.

A rotor includes a rotor hub including a through-hole to which the shaft is fixed. An upper end and a lower end of an opposing region where an outer peripheral surface of the shaft and an inner peripheral surface of the through-hole oppose each other in a radial direction are respectively provided with an upper gap portion and a lower gap portion opposing each other through a space in the radial direction. The upper gap portion and the lower gap portion each include a bottom portion extending in a direction intersecting the center axis and a peripheral wall portion connected to a radial outer edge of the bottom portion and extending along the center axis.

An electric oil pump includes a motor including a shaft, a pump driven via the shaft, and an inverter assembly located on a rear side of the motor and secured to the motor. The motor includes a rotor, a stator, and a motor housing that houses the rotor and the stator. The pump includes a pump rotor and a pump housing. The motor housing has a bottomed tubular shape that includes a bottom portion on a side of the inverter assembly, and the inverter assembly includes an inverter housing including a circuit board housing that houses a circuit board and a busbar holder. The busbar holder is on a side opposite to a terminal that is electrically connected to the circuit board with respect to the shaft in the circuit board housing.

A hybrid spherical motor includes a first gear box, a second gear box, a yoke arm, a brushless direct current (BLDC) motor, a spherical stator, and a spherical armature. The split armature, in response to the spherical stator being energized, rotates about a first rotational axis, thereby causing the first gear box input connection and the second gear box input connection to rotate about the first rotational axis, and the yoke arm rotates about the first rotational axis in response to the first gear box input connection and the second gear box input connection being rotated about the first rotational axis, whereby the BLDC motor rotates about the first rotational axis.

Provided is an axial gap type motor employing a non-rare earth magnet, and a water pump using same. The axial gap type motor for a water pump (EWP) comprises: a rotor rotatably supported on a fluid flow passage between a pump cover and a body case; a stator arranged in a lower space formed by the body case and an upper cover, so as to generate a rotating magnetic field, thereby rotating the rotor; and a partition arranged on the body case in order to separate the rotor from the stator. The rotor can use a ferrite magnet, which is a non-rare earth magnet.

A brushless motor is provided that includes a rotor, a stator, a bearing member, an attraction magnet, and a yoke. The rotor includes a shaft, a rotor yoke that holds the shaft and covers a peripheral surface of the shaft, and a magnet disposed around an outer periphery of the rotor yoke. The stator is disposed around an outer periphery of the rotor. An inner wall of a housing serving as a bearing member rotatably holds the shaft with a bearing. The attraction magnet is disposed at an end portion of the inner wall at which the rotor yoke holds the shaft, and produces an attraction force to attract the rotor yoke. The yoke supplements and enhances the attraction force produced by the attraction magnet.

A three-phase drainage motor for a washing machine includes a stator, a rotor and an upper cover. The rotor is sealed inside the stator through the upper cover and includes an iron core, a coil bobbin, a three-phase coil and a plastic package portion. The iron core includes a hub, an inner ring and teeth radially connecting the hub to the inner ring, the coil bobbin covers the teeth, the three-phase coil is wound around the coil bobbin. The plastic package portion is wrapped around the coil bobbin, the three-phase coil and the iron core to form a spigot, a rotor cavity and a rotary shaft cavity. The spigot is located above the rotor cavity. The rotary shaft cavity is at a bottom of the rotor cavity, the plastic package portion includes a housing, a wall surface of the rotor cavity and a wall surface of the rotary shaft cavity.