Patents Represented by Attorney L. D. Wo-ford, Jr.

Find this attorney in the Justia Lawyer Directory

  • Phase detector for three-phase power factor controller
    Patent number: 4459528
    Abstract: A phase-detector (16, 18, 20) is provided for use in a power factor controller for a three-phase induction motor. The power factor controller includes switching thyristors (10, 12 14) for each motor phase winding and the phase detector for each phase includes an operational amplifier (36) which senses the current phase angle for that phase by sensing the voltage across the phase thyristor. Common mode rejection is achieved by providing positive feedback between the input and output of the voltage sensing operational amplifier.
    Type: Grant
    Filed: December 16, 1982
    Date of Patent: July 10, 1984
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventor: Frank J. Nola