Patents by Inventor Kazuhiko Hanasawa

Kazuhiko Hanasawa 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).

  • Method for diagnosing an insulation deterioration of a power cable
    Patent number: 4721916
    Abstract: A method for diagnosing an insulation deterioration of a power cable comprising a step of measuring a DC current component in the AC voltage applied to said power cable, by using a filter circuit for cutting off an AC current and a DC current measuring apparatus for measuring small magnitude of DC current. According to the present invention, said filter circuit and said DC current measuring apparatus are joined in parallel each other and connected between a power source and one end portion of said power cable to be diagnosed. The DC current measuring apparatus can detect the polarity, magnitude, and time lapse characteristics of said DC current component for analyzing and estimating the insulation deterioration.
    Type: Grant
    Filed: February 27, 1986
    Date of Patent: January 26, 1988
    Assignee: Hitachi Cable, Ltd.
    Inventors: Kazuhiko Hanasawa, Kenichiro Soma, Kazuo Kotani