Patents by Inventor Michael O. Hall

Michael O. Hall 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: 4857819
    Abstract: The present invention is directed to a method and apparatus for connecting a static inverter to a free-running motor, wherein the inverter is supplied with D.C. power by a regulator-controlled rectifier. An oscillator connected to both the rectifier regulator and the inverter governs the frequency of the three-phase inverter output, while voltage feedback from the inverter output to the rectifier regulator is employed to establish a proper volts/hertz output characteristic in the inverter output waveform. During the connection process, a synchronizing circuit causes the oscillator to generate a high pulse rate signal which raises the inverter output frequency to a level above that associated with the rotational speed of the free-running motor. Simultaneously, the D.C. output of the rectifier is clamped by the current regulator to current-limit the inverter output. The inverter is subsequently connected to the free-running motor and the inverter output frequency is allowed to decrease gradually.
    Type: Grant
    Filed: October 1, 1981
    Date of Patent: August 15, 1989
    Assignee: Emerson Electric Co.
    Inventors: James Maurice, David J. Collins, Michael O. Hall, Peter D. McLoughlin