Patents by Inventor Sadao Nanba

Sadao Nanba 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 of diagnosing deterioration of insulating paper in oil-filled electric apparatus
    Patent number: 5309776
    Abstract: In a method of diagnosing the deterioration of the insulating paper in an oil-filled electric apparatus, the total amount of furfural is determined by adding the amount of furfural adsorbed on the insulating paper to the amount of furfural dissolved in insulating oil in an oil-filled electric apparatus, and the deterioration of the insulating paper is diagnosed by the correlation between the total amount of furfural determined and the polymerization degree of the insulating paper, which indicates the degree of deterioration thereof. The method thus permits the precise diagnosis of the deterioration of the insulating paper.
    Type: Grant
    Filed: January 10, 1992
    Date of Patent: May 10, 1994
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Sadao Nanba, Teruo Miyamoto