Patents by Inventor Alan D. Crapo
Alan D. Crapo has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 8288913Abstract: 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.Type: GrantFiled: April 20, 2010Date of Patent: October 16, 2012Assignee: Nidec Motor CorporationInventors: Thomas M. Bourquin, Samuel E. Mayberry, John H. Hussey, Alan D. Crapo
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Patent number: 7709992Abstract: 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.Type: GrantFiled: July 31, 2008Date of Patent: May 4, 2010Assignee: Emerson Electric Co.Inventors: John H. Hussey, Alan D. Crapo, Thomas M. Bourquin
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Publication number: 20100026135Abstract: 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.Type: ApplicationFiled: July 31, 2008Publication date: February 4, 2010Applicant: EMERSON ELECTRIC CO.Inventors: John H. Hussey, Alan D. Crapo, Thomas M. Bourquin
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Patent number: 7245054Abstract: 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.Type: GrantFiled: November 1, 2000Date of Patent: July 17, 2007Assignee: Emerson Electric Co.Inventors: Todd A. Walls, Alan D. Crapo
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Patent number: 7034423Abstract: 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.Type: GrantFiled: May 7, 2003Date of Patent: April 25, 2006Inventors: Alan D. Crapo, Todd A. Walls, Richard E. Hartsfield, Jr.
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Patent number: 6946760Abstract: A brushless permanent magnet electric machine includes a stator assembly having a stator core that defines (12×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±2)n poles, wherein n is an integer greater than zero.Type: GrantFiled: October 22, 2003Date of Patent: September 20, 2005Assignee: Emerson Electric Co.Inventors: Alan D. Crapo, Gary E. Horst
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Patent number: 6727623Abstract: 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.Type: GrantFiled: August 28, 2002Date of Patent: April 27, 2004Assignee: Emerson Electric Co.Inventors: Gary E. Horst, Alan D. Crapo
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Patent number: 6717314Abstract: 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.Type: GrantFiled: August 28, 2002Date of Patent: April 6, 2004Assignee: Emerson Electric Co.Inventors: Gary E. Horst, Alan D. Crapo
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Patent number: 6707209Abstract: 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.Type: GrantFiled: May 9, 2001Date of Patent: March 16, 2004Assignee: Emerson Electric Co.Inventors: Alan D. Crapo, Todd A. Walls, Richard E. Hartsfield, Jr., Charles P. Ketterer, Ken De Luca
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Publication number: 20040041484Abstract: 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.Type: ApplicationFiled: August 28, 2002Publication date: March 4, 2004Inventors: Gary E. Horst, Alan D. Crapo
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Publication number: 20040041489Abstract: 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 interior bore and a plurality of magnets positioned within the interior of the rotor. Also disclosed in a washing machine including such a machine.Type: ApplicationFiled: August 28, 2002Publication date: March 4, 2004Inventors: Gary E. Horst, Alan D. Crapo
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Publication number: 20030201137Abstract: 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.Type: ApplicationFiled: May 7, 2003Publication date: October 30, 2003Inventors: Alan D. Crapo, Todd A. Walls, Richard E. Hartsfield
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Patent number: 6597078Abstract: 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.Type: GrantFiled: January 30, 2001Date of Patent: July 22, 2003Assignee: Emerson Electric Co.Inventors: Alan D. Crapo, Todd A. Walls, Richard E. Hartsfield, Jr.
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Publication number: 20020101126Abstract: 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.Type: ApplicationFiled: January 30, 2001Publication date: August 1, 2002Inventors: Alan D. Crapo, Todd A. Walls, Richard E. Hartsfield
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Publication number: 20020067092Abstract: 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.Type: ApplicationFiled: May 9, 2001Publication date: June 6, 2002Inventors: Alan D. Crapo, Todd A. Walls, Richard E. Hartsfield, Charles P. Ketterer, Ken De Luca
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Patent number: 5696416Abstract: 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.Type: GrantFiled: August 19, 1994Date of Patent: December 9, 1997Assignee: Emerson Electric Co.Inventors: Gerald N. Baker, Alan D. Crapo
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Patent number: 5532534Abstract: 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.Type: GrantFiled: May 11, 1994Date of Patent: July 2, 1996Assignee: Emerson Electric Co.Inventors: Gerald N. Baker, Alan D. Crapo
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Patent number: 5177054Abstract: 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.Type: GrantFiled: April 8, 1991Date of Patent: January 5, 1993Assignee: Emerson Electric Co.Inventors: Jerry D. Lloyd, Alan D. Crapo
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Patent number: 5144179Abstract: 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.Type: GrantFiled: April 3, 1991Date of Patent: September 1, 1992Assignee: Emerson Electric Co.Inventors: Mohamed A. Hilal, Jerry D. Lloyd, Alan D. Crapo
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Patent number: 5138207Abstract: 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.Type: GrantFiled: April 4, 1991Date of Patent: August 11, 1992Assignee: Emerson Electric Co.Inventors: Mohamed A. Hilal, Jerry D. Lloyd, Alan D. Crapo