Patents by Inventor Robert D. Pettigrew

Robert D. Pettigrew 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).

  • Remote bias voltage setting LTC control system
    Patent number: 5117175
    Abstract: In a alternating current power distribution system utilizing load tap changing (LTC) transformers having selectively actuable tap selector switches operable in response to an LTC control, system including circuitry for providing remotely adjustable bias voltage for combining with the LTC control voltage to remotely control any change of the center operating level of the band.
    Type: Grant
    Filed: October 16, 1990
    Date of Patent: May 26, 1992
    Inventors: Robert D. Pettigrew, Sanh D. Luong
  • Power factor control with overvoltage and undervoltage override control in a capacitor control system for a distribution system
    Patent number: 4769587
    Abstract: A method and capacitor control apparatus for controlling the power factor and voltage on an electrical distribution line based on the power factor on the line subject to a voltage override control. Hysteresis above an undervoltage limit and below an overvoltage limit prevent undesired oscillation in switching the capacitor controls to and from the distribution line.
    Type: Grant
    Filed: March 9, 1987
    Date of Patent: September 6, 1988
    Assignee: Beckwith Electric Co.
    Inventor: Robert D. Pettigrew
  • RMS Controlled load tap changing transformer
    Patent number: 4323838
    Abstract: A circuit for controlling a load tap changing transformer including a true RMS to D.C. converter for regulating the output of the transformer as a function of the RMS voltage.
    Type: Grant
    Filed: February 9, 1981
    Date of Patent: April 6, 1982
    Assignee: Beckwith Electric Co., Inc.
    Inventor: Robert D. Pettigrew