Patents by Inventor Per-Ake Hellman

Per-Ake Hellman 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).

  • Surge arrester
    Patent number: 4547831
    Abstract: A surge arrester includes an elongated insulating housing comprising one or more stacks of electrically series-connected metal oxide varistor blocks arranged between a top terminal and a bottom terminal. To achieve a more even voltage distribution in the longitudinal direction of the surge arrester, the surge arrester comprises larger varistor blocks at the top terminal than at the bottom terminal.
    Type: Grant
    Filed: February 28, 1983
    Date of Patent: October 15, 1985
    Assignee: ASEA Aktiebolag
    Inventors: Per-Ake Hellman, Lennart Stenstrom