Patents by Inventor Jan H. W. Kuhlefelt

Jan H. W. Kuhlefelt 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: 5990778
    Abstract: The current-limiting resistor has two connection electrodes (1, 2) which are arranged parallel to one another, a resistance body (3) which has PTC behavior and with which large-area contact is made by the connection electrodes (1, 2) and at least one varistor (4) which is in electrically conductive contact with the resistance body (3). The varistor (4) is of pillar-shaped design and has at least two first portions (4a) routed predominantly perpendicularly to the varistor axis and, arranged between said portions, a second portion (4b) having a reduced cross section compared with each of the first portions (4a). The material of the resistance body (3) fills an interspace (6), which is formed by the at least two first portions (4a) and the second portion (4b), and encloses the outwardly pointing edges (4c) of the at least two portions.This resistor can be operated at high voltages, for example 5 or 10 kV, and advantageously has a single resistance body 3 and a single varistor.
    Type: Grant
    Filed: June 17, 1998
    Date of Patent: November 23, 1999
    Assignee: ABB Research Ltd.
    Inventors: Ralf Strumpler, Jan H. W. Kuhlefelt