Patents by Inventor Lawrence J. Koopman

Lawrence J. Koopman 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: 4789834
    Abstract: A method and apparatus for testing the operability of an overload protection device for an induction motor, rapidly and without the need to mechanically load the motor output shaft. A rectifier circuit converts a standard AC input power signal to an unfiltered full wave rectified output power signal which is applied to the input terminals of the motor under test to rapidly heat the overload device to its trip temperature. The output power signal is periodically interrupted for brief periods of sufficient duration to extinguish any arcing occasioned by the opening of the overload device contacts. The period between successive interrupt periods is selected to be short enough to extinguish any such arcing before the contacts are damaged. If the contacts of the protection device fail to open within a predetermined time period, a signal is generated to indicate that the overload device has failed to operate properly.
    Type: Grant
    Filed: December 22, 1986
    Date of Patent: December 6, 1988
    Assignee: General Electric Company
    Inventor: Lawrence J. Koopman