Patents Examined by Bruce A. Raynolds
  • Patent number: 5438588
    Abstract: The direct current-electric arc furnace system includes a furnace vessel 8, one or more electric arc electrode 7 connected as a cathode, a bottom contact 12 connected as an anode, a furnace transformer 2 and a rectifier assembly 5 for feeding the furnace, an electrode control system E, and a current regulator I. A choke 6 is switched into the direct current main current circuit. A voltage control circuit F underlies the current control circuit I, whereby the output voltage of the current regulator 14 delivers the desired value for the voltage regulator 24. A filter 25 tuned to the flicker frequency follows the voltage regulator 24 with a frequency response, which is tuned to the frequency sensitivity of the human eye. Optionally, an additional control voltage signal U.sub.flick that is delivered by flicker meter can be provided to the voltage control circuit F.
    Type: Grant
    Filed: March 17, 1994
    Date of Patent: August 1, 1995
    Assignee: ABB Management AG
    Inventor: Ernst Wanner