Patents by Inventor Joseph C. Fray

Joseph C. Fray 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).

  • High voltage d-c current limiter
    Patent number: 5644461
    Abstract: A current limiter for protecting a circuit at a predetermined driving voltage in excess of 50 volts which includes a plurality of PTC resistors connected in series, with a zener diode connected in parallel with each of the PTC resistors, and wherein each of the PTC resistors has a predetermined voltage capacity limit such that the total of the predetermined capacity limits of the PTC resistors exceeds the predetermined driving voltage, and each of the zener diodes has a zener voltage rating less than the predetermined voltage capacity limit of the individual PTC resistor connected in parallel therewith, and the total of the zener voltage ratings of the zener diodes also exceed the predetermined driving voltage.
    Type: Grant
    Filed: July 30, 1996
    Date of Patent: July 1, 1997
    Assignee: Westinghouse Air Brake Company
    Inventors: Craig A. Miller, Joseph C. Fray