Patents Represented by Attorney Thomas A. Miller
  • Patent number: 5656912
    Abstract: A controller for a motor having at least one stator phase and a method for controlling the motor, the controller including a drive signal generator for producing an electrical drive signal in the stator phase, the drive signal resulting in a current flow in the stator phase such that the current flow varies in response to varying load conditions for the motor, a current sensor for monitoring the current flow in the stator phase, an error detector for producing an error signal related to changes in the current flow, and a manipulation circuit electrically connected to the error detector and to the drive signal generator for changing the electrical stimulus in response to the error detector.
    Type: Grant
    Filed: September 29, 1995
    Date of Patent: August 12, 1997
    Assignee: A. O. Smith Corporation
    Inventor: Sheng Ming Yang
  • Patent number: 5525887
    Abstract: A switched reluctance motor includes a rotor mounted for rotation about a rotor shaft axis and a stator surrounding the rotor and having at least three electrically independent stator phases. The motor includes an electronic circuit for selectively energizing the phases in succession with a run current to generate a torque on the rotor and thereby rotate the rotor. The circuit includes switch operating means for selectively operating switches connecting an energy source to the phases. The circuit also includes current sensing means for sensing the amount of current in each of the phases, and timing means for determining the amount of time for the current in each phase to reach a predetermined current level threshold.
    Type: Grant
    Filed: March 14, 1995
    Date of Patent: June 11, 1996
    Assignee: A. O. Smith Corporation
    Inventor: Thomas G. Van Sistine
  • Patent number: 5497064
    Abstract: A switched reluctance electronic motor includes a rotor mounted for rotation about an axis and including a plurality of rotor poles. A stator surrounds the rotor and includes at least three stator phases. The motor also includes a circuit for controlling the motor, the circuit includes a pulse generator for supplying a seek current to each of the phases of the motor without causing rotation of the rotor. The seek currents in the phases each have a respective seek current rise time. The rise time is a function of the proximity of the rotor poles to the respective phases.
    Type: Grant
    Filed: March 14, 1995
    Date of Patent: March 5, 1996
    Assignee: A. O. Smith Corporation
    Inventor: Thomas G. Van Sistine