Emerson Electric Company

Other

Nidec Motor Corporation

Alan D Crapo

Todd A Walls

Gary E Horst

Jerry D Lloyd

Richard E Hartsfield, Jr

John H Hussey

Gerald N Baker

Mohamed A Hilal

Thomas M Bourquin

Charles P Ketterer

Ken De Luca

Samuel E Mayberry

An electric induction motor assembly includes a rotor assembly and a stator assembly. The rotor assembly includes an exposed bar rotor comprising a plurality of axially stacked, punched-to-size rotor laminations. The stator assembly includes a plurality of axially stacked, punched-to-size stator laminations. Each of the laminations presents an axial thickness of less than 0.024 inches. The rotor assembly and the stator assembly cooperatively define a radially extending air gap between a radially outer periphery of the rotor assembly and a radially inner periphery of the stator assembly that is less that 0.012 inches.

Exposed bar induction motor with punched-to-size air gap

A stator assembly adapted for use in an electric motor. The assembly includes a stator core having an annular rim and a plurality of teeth extending radially inward from the rim. The stator core has an outer diameter, a root tooth diameter and an inner diameter. Each tooth has a root, a neck extending inward from the root, a head opposite the root, and a length measured from its root to its head. The neck has a width. Each adjacent pair of teeth define a slot having an area. The assembly also includes a winding having aluminum and/or copper wrapped around at least three teeth of the stator core. The stator core and winding have four, six or eight magnetic dipoles. The stator core outer diameter is in a range from about 5.1 inches to about 5.9 inches. The stator core inner diameter is less than about 3.0 inches.

Electric machine

A permanent magnet electric machine includes a stator with salient stator poles. A rotor includes two or more axial rotor sections that are rotationally offset by an offset angle equal to the cogging angle divided by the number of axial rotor sections. The axial rotor sections include rotor poles with permanent magnets. In one embodiment, the permanent magnet electric machine has a 12/10 slot/pole combination. The permanent magnets have a magnet dimension angle between 31 and 35 degrees. An air gap ratio of the electric machine is between 1.35 and 2.5. A slot opening ratio of the electric machine is less than or equal to one. In another embodiment, the permanent magnet electric machine has an 18/12 slot/pole combination. The permanent magnets have a magnet dimension angle that is between 25 and 28 degrees. An air gap ratio of the electric machine is between 1.35 and 2.5. A slot opening ratio of the electric machine is less than or equal to one.

Permanent magnet electric machine having reduced cogging torque

An electric power steering system for a vehicle includes a steering wheel and a steering shaft that is connected to the steering wheel. A worm gear is connected to the steering shaft. A worm is threadably engaged to the worm gear. A permanent magnet motor is connected to the worm. The permanent magnet motor includes a stator with twelve slots and a rotor with ten poles. The rotor includes one or more axial rotor sections. If more than one axial rotor section is employed, the axial rotor sections are rotationally offset. The axial rotor sections are rotationally offset by an offset angle that is equal to a cogging angle divided by the number of axial rotor sections. The rotor includes breadloaf, spoke, radial or arc permanent magnets.

Electric power steering system including a permanent magnet motor

A brushless permanent magnet electric machine includes a stator assembly having a stator core that defines (12&#xd7;n) slots and stator teeth having a generally 'T'-shaped cross section. Winding wire is wound around the stator teeth, wherein a radially outer edge of the stator teeth define a crowned surface. A rotor includes permanent magnets defining (12&#xb1;2)n poles, wherein n is an integer greater than zero.

Brushless permanent magnet motor with high power density, low cogging and low vibration

An interior permanent magnet machine is disclosed that, in one exemplary embodiment, includes a stator defining a number of stator poles, a rotor, a number of permanent magnets positioned within the interior of the rotor and at least two impedance reduction slits associated with each permanent magnet where the impedance reduction slits are positioned radially outward of the permanent magnets. In further embodiments, each impedance reduction slit is positioned such that at least a portion of the slit is within a defined region.

Reduced impedance interior permanent magnet machine

A high torque density interior permanent magnet machine for use in an appliance is provided that includes a stator assembly defining a plurality of stator teeth, a plurality of concentrated phase windings positioned about the stator teeth, a rotor assembly positioned within the prior bore and a plurality of magnets positioned within the interior of the rotor. Also disclosed in a washing machine including such a machine.

Interior permanent magnet motor for use in washing machines

A permanent magnet electric machine with reduced cogging torque includes a plurality of axial rotor sections that are defined on a radially outer surface of a rotor. The axial rotor sections include a set of permanent magnets that are in an unmagnetized state and that have opposite edges that are aligned with an axis of the rotor. The axial rotor sections are rotationally offset such that the edges of the permanent magnets create stair step interfaces. The n sets of permanent magnets are magnetized using a magnetizing fixture. The permanent magnets have a generally rectangular shape and are preferably arc magnets or breadloaf magnets. The conductors of the magnetizing fixture are aligned with the stair step interfaces. A magnetic field induced in the permanent magnets is substantially reduced along the stair step interfaces.

Reduced cogging torque permanent magnet electric machine with rotor having offset sections

In a refrigerator motor with a hollow base-housing with an open mouth defined by a side wall, and a cover for the mouth, one of the housing and cover has integral with it at least one deflectable finger, one end of which is integral with one of said cover and housing and a free end of which is provided with a lip. The other of the housing and cover has integral with it a complementary ledge, spaced and shaped to receive and to be engaged by the lip. In either case, the cover carries, preferably integral with it, a motor mounting bracket by which the motor is mounted in a refrigeration unit. In a preferred embodiment, the finger is integral with the cover and the ledge is integral with the housing, and the mounting bracket has arms that extend beyond a lower perimeter of the housing.

Mounting of motor for refrigeration

A motor, described as a brushless permanent magnet (BPM) motor, has a cup-shaped, open bottomed enclosure having a side wall and a top wall defining a lower interior space. The side wall has a port interrupting a bottom edge. A printed circuit board or other motor electric circuit is positioned above the top wall, below the stator. Electrical conductors electrically connected to the electric motor circuit extend through the top wall and into the interior space. Current supply conductors extend through the side wall port and are electrically connected to the electrical conductors from the circuit. An enclosure cover member has, projecting into the interior space, at least one deflectable prong with an overhanging lip, and a strain relief block positioned adjacent but spaced from the side wall port. The cover has a tool-receiving aperture to permit engagement of a tool with the prong. A ledge, carried by an inner surface of the enclosure, is positioned complementarily to the prong lip to permit the lip to engage a surface of the ledge remote from an inner surface of the cover to hold the cover in position, but to permit the displacement of the prong by a tool inserted through the cover aperture to release the prong and the cover. In the illustrative embodiment, conductor wires from a circuit board mounted above the top wall are mounted in a connector block within the enclosure, and the lip-engaging ledge is part of the connector block. The enclosure and the cover preferably are constructed from electrically insulative material.

Brushless permanent magnet condenser motor for refrigeration

A motor (10) comprises a stator (14) having an associated stator winding (24) formed of a conventional material such as copper, or of a superconductive material. A rotor (12) for the motor is also formed of a superconductive material. The rotor is placed in a cryostat (16) and cooled from a first temperature which is above a critical level to a second temperature which is below the level. The stator is placed in a second and separate cryostat (18) and the stator winding is energized while the rotor temperature is being lowered to below the critical level. Once the superconductive material of the rotor has been cooled to a level below the critical level, the stator winding is de-energized. Currents are now induced in the superconductive material of the rotor to trap or maintain magnetic flux therein. Thereafter, the rotor acts as a permanent magnet so long as it is maintained below the critical temperature.

Flux trapped superconductor motor and method therefor

A brushless homopolar dynamoelectric machine motor (1) has a rotor (3) with a least one winding (5) having multiple turns. The rotor is inductively charged using a flux pump or a rectifier. Solenoid pairs (15a, 15b, 17a, 17b) comprise field windings for the motor and compensate for winding and field losses. The motor is an axisymmetric motor in which superconductive materials are used.

Superconducting brushless homopolar motor with multiple winding rotor

A superconductor motor (10) comprises a stator assembly (14) which includes a plurality of solenoids (40-44). A rotor assembly (12) includes a disk (20) of superconductive material in which are entrapped magnetic lines of flux which cause the rotor to function as a magnet. The lines of flux tend to creep throughout the disk over time thereby reducing the magnetic properties of the rotor assembly and decreasing motor performance. A plurality of coils (48a-48l) are carried by the disk. The stator solenoids are energized to produce rotation of the rotor, and the coils are energized in a predetermined manner to compensate for the flux creep in the disk and to restore the rotor assembly's magnetic properties thus to prevent deterioration in motor performance.

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Florissant, MO, United States of America

Alan D Crapo