Patent ID: 6051810
Filing Date: 2000-04-18
Classification: B23K

Abstract:
An apparatus for electric arc welding two spaced ends of two metal plates at a groove between said two metal plates by melting an advancing welding wire and depositing said melted wire into said groove to join said spaced ends, said apparatus comprising: a switching power supply for creating a series of small width current pulses constituting a welding cycle with a short circuit transfer portion and a plasma arc melting portion, said current pulses in said cycle each having a given electrical polarity of said advancing wire with respect to said two metal plates; and, selector means for selecting the polarity of said pulses in said cycle between a first polarity with said wire being positive and a second polarity with said wire being negative, said power supply includes a center tapped inductor with a first portion creating said first polarity and a second portion creating said second polarity, a first switch for connecting said first portion of said inductor between said wire and said plates, a second switch for connecting said second portion of said inductor between said wire and said plate, and said selector means including means for closing either said first switch or said second switch during a given weld cycle.