Patents Represented by Law Firm Watson, Cole, Grinde & Watson
  • Patent number: 4354215
    Abstract: In a selective safety device for the protection of successive power levels in a power distribution system, a current limiting switch is provided in each of the power levels and includes a current-limiting quick-switching contact which is so positioned at the power supply side in each one of the different power levels such that the current limiting switch immediately in front of a fault is switched off upon occurrence of a fault. A resistor is connected across each of the quick-switching contacts and is serially connected in the interrupted circuit upon the opening action of the quick-switching contact. Additionally, a slow-switching contact is serially connected with each of the quick-switching contacts to be opened after opening of the quick-switching contact with a presettable delay time, which is dependent upon the power levels in which the slow-switching contact is connected.
    Type: Grant
    Filed: June 11, 1980
    Date of Patent: October 12, 1982
    Assignee: Hazemeijer B.V.
    Inventor: Derk van der Scheer