Patents by Inventor Geoffrey T. Brown

Geoffrey T. Brown 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: 5857496
    Abstract: Weaving apparatus comprises a warp beam bearing warp threads, a loom on which the warp threads are woven with weft threads, and a take-up roller for taking up the woven material. The loom is powered by a main loom motor. Either or both of the take-up roller and the warp beam are controlled by switched reluctance motors. The switched reluctance motor is able to maintain correct tension in the warp threads or the woven material without generating excessive heat in maintaining a desired position.
    Type: Grant
    Filed: April 18, 1997
    Date of Patent: January 12, 1999
    Assignee: Switched Reluctance Drives Limited
    Inventors: Geoffrey T. Brown, Michael J. Turner
  • Patent number: 5739663
    Abstract: An angle interpolation circuit for a phase energisation controller receives absolute positions from sensors and interpolates conduction angles for each phase in a switched reluctance machine having one or more phases. It uses a frequency multiplier to generate an integer number of pulses between the edges of the sensor signal for clocking a corresponding counter for each machine phase. The circuit adjusts for variations in the mark/space ratio of sensor inputs by setting the counters' expected values at each sensor edge.
    Type: Grant
    Filed: November 6, 1996
    Date of Patent: April 14, 1998
    Assignee: Switched Reluctance Drives Limited
    Inventor: Geoffrey T. Brown
  • Patent number: 5637972
    Abstract: A rotor position encoder for an electric motor includes a discate member mounted to rotate with the rotor shaft. The encoder has a set of radially extending features formed with angularly evenly spaced leading edges and unevenly spaced trailing edges. The leading edges induce a signal in a sensor that corresponds to the relative timing of power switches for each motor phase, The trailing edges define a cyclical code by which motor controlling circuitry is able to determine the phase of rotation of the rotor and thus establish the correct power switch actuation sequence. An electric motor control system and methods of starting electric motors also provide significant advantages.
    Type: Grant
    Filed: January 16, 1996
    Date of Patent: June 10, 1997
    Assignee: Switched Reluctance Drives, Ltd.
    Inventors: Steven P. Randall, David M. Sudgen, William Vail, Geoffrey T. Brown
  • Patent number: 5539293
    Abstract: A rotor position encoder for an electric motor includes a discate member mounted to rotate with the rotor shaft. The encoder has a set of radially extending features formed with angularly evenly spaced leading edges and unevenly spaced trailing edges. The leading edges induce a signal in a sensor that corresponds to the relative timing of power switches for each motor phase. The trailing edges define a cyclical code by which motor controlling circuitry is able to determine the phase of rotation of the rotor and thus establish the correct power switch actuation sequence. An electric motor control system and methods of starting electric motors are also shown.
    Type: Grant
    Filed: June 7, 1994
    Date of Patent: July 23, 1996
    Assignee: Switched Reluctance Drives Limited
    Inventors: Steven P. Randall, David M. Sudgen, Willliam Vail, Geoffrey T. Brown
  • Patent number: 4137199
    Abstract: Composite materials composed of an organic polymer containing a fire-retardant together with a blowing agent and a hydroxy group-containing organic acid or a salt thereof, or a reaction product of the blowing agent and said acid or salt.
    Type: Grant
    Filed: July 7, 1975
    Date of Patent: January 30, 1979
    Assignee: Imperial Chemical Industries Limited
    Inventors: Geoffrey T. Brown, John R. Case