Patents Represented by Attorney, Agent or Law Firm George B. Corrigan
  • Patent number: 6653595
    Abstract: A short circuit arc welding system is disclosed. The control scheme uses a current command signal to drive the output current. The command signal is comprised of a long-term current command that sets the long-term current command level and a real-time or short-by-short current command. Arc voltage feedback is used to determine if the desired arc length is present and to adjust the long-term command. The short-by-short current command is derived from real-time arc current feedback and is used to control the burn-off rate by an instantaneous, or short-by-short, adjustment of the current command. A function of the time derivative of arc power, less the time derivative of arc current, is used to detect, in real time, when the short is about to clear. A stop algorithm is employed that monitors the arc on a short-by-short basis. When the process is ending a very low current level is provided to avoid forming a ball.
    Type: Grant
    Filed: November 5, 2001
    Date of Patent: November 25, 2003
    Assignee: Illinois Tool Works Inc.
    Inventors: Richard Hutchison, Todd Holverson, James Uecker