Patents by Inventor Gerald D. Duncan

Gerald D. Duncan 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).

  • Patent number: 9634529
    Abstract: A method of making generally symmetrical lamination stacks for electrical machines comprises producing generally symmetrical pole tips from alternating asymmetrical pieces that each have an additional layer in the asymmetrical portion. With the alternating asymmetrical pieces combined, the resulting pole tip is generally symmetrical with a larger possible pole tip width compared with currently-used interleaved stamping techniques.
    Type: Grant
    Filed: December 4, 2012
    Date of Patent: April 25, 2017
    Assignee: Fisher & Paykel Appliances Ltd.
    Inventors: Gregory P. Hill, John Julian A. Williams, Gerald D. Duncan, Kerrin E. Burnnand, Mark G. Benson
  • Patent number: 5353613
    Abstract: An electric motor (2) for a clothes washing machine including the motor and a drive, the motor having a stator (25) held outboard of a frame carrying bearings (37, 38) in which a shaft (11) rotates, the shaft carrying the rotor (21) outboard of the stator (25), and permanent magnets (17) on an inner face of the rotor. The stator (25) is formed as an annular helical yoke edgewise wound from a strip of magnetic material and having an inner face and an outer face, the strip having pole pieces (8) formed integrally therewith extending from one edge of the strip and the strip being edgewise wound whereby the pole pieces coincide in stacked groups to form a plurality of poles arranged at equally spaced intervals extending radially outwardly from the outer face of the yoke.
    Type: Grant
    Filed: April 27, 1993
    Date of Patent: October 11, 1994
    Assignee: Fisher & Paykel, Limited
    Inventors: Dennis E. Smith, John J. A. Williams, Gerald D. Duncan, Graeme D. Thomas, John G. Borrows, Frank W. Shacklock
  • Patent number: 5266855
    Abstract: An electric motor (2) for a clothes washing machine including the motor and a drive, the motor having a stator (25) held outboard of a frame carrying bearings (37, 38) in which a shaft (11) rotates, the shaft carrying the rotor (21) outboard of the stator (25), and permanent magnets (17) on an inner face of the rotor. The stator (25) is formed as an annular helical yoke edgewise wound from a strip of magnetic material and having an inner face and an outer face, the strip having pole pieces (8) formed integrally therewith extending from one edge of the strip and the strip being edgewise wound whereby the pole pieces coincide in stacked groups to form a plurality of poles arranged at equally spaced intervals extending radially outwardly from the outer face of the yoke.
    Type: Grant
    Filed: August 14, 1990
    Date of Patent: November 30, 1993
    Assignee: Fisher & Paykel, Limited
    Inventors: Dennis E. Smith, John J. A. Williams, Gerald D. Duncan, Graeme D. Thomas, Frank W. Shacklock
  • Patent number: 4857814
    Abstract: A control apparatus and method for an electric motor having sensing devices which sense the frequency and polarity of EMFs in the rotor windings down to a condition where the rotor is in condition for reversing, and causing reversing of the motor when the frequency is such as to allow reversing and the polarits of a selected winding is at or near a zero crossing between positive and negative polarities. Cyclical reversal is effected by measuring the time the rotor takes to coast from a "power off" condition to the condition for reversing and with an electronically commutated motor reversing can usually be effected in one commutation period. The motor is used in a clothes washing machine or similar application where rapid reversal is required or timing of the time from one reversal to the next is required to be constant.
    Type: Grant
    Filed: September 16, 1986
    Date of Patent: August 15, 1989
    Assignee: Fisher & Paykel
    Inventor: Gerald D. Duncan
  • Patent number: 4853571
    Abstract: An electric motor, a drive and a clothes washing machine including the motor and drive, the motor having a stator held outboard of a frame carrying bearings in which a shaft rotates, the shaft carrying the rotor outboard of the stator, the rotor having permanent magnets on an inner face thereof.
    Type: Grant
    Filed: February 9, 1988
    Date of Patent: August 1, 1989
    Assignee: Fisher & Paykel Limited
    Inventors: Dennis E. Smith, John J. A. Williams, Gerald D. Duncan, Graeme D. Thomas, John G. Borrows, Frank W. Shacklock
  • Patent number: 4813248
    Abstract: An electric motor, a drive and a clothes washing machine including the motor and drive are described, the motor having a stator held outboard of a frame carrying bearings in which a shaft rotates, the shaft carrying the rotor outboard of the stator, the rotor having permanent magnets on an inner face thereof.
    Type: Grant
    Filed: May 2, 1988
    Date of Patent: March 21, 1989
    Assignee: Fisher & Paykel Limited
    Inventors: Dennis E. Smith, John J. A. Williams, Gerald D. Duncan, Graeme D. Thomas, John G. Borrows, Frank W. Shacklock
  • Patent number: RE37360
    Abstract: A control apparatus and method for an electric motor having sensing devices which sense the frequency and polarity of EMFs in the rotor windings down to a condition where the rotor is in condition for reversing, and causing reversing of the motor when the frequency is such as to allow reversing and the polarits polarity of a selected winding is at or near a zero crossing between positive and negative polarities. Cyclical reversal is effected by measuring the time the rotor takes to coast from a “power off” condition to the condition for reversing and with an electronically commutated motor reversing can usually be effected in one commutation period. The motor is used in a clothes washing machine or similar application where rapid reversal is required or timing of the time from one reversal to the next is required to be constant.
    Type: Grant
    Filed: February 18, 1992
    Date of Patent: September 11, 2001
    Assignee: Fisher & Paykel
    Inventor: Gerald D. Duncan