Patent ID: 6291798
Filing Date: 2001-09-18
Classification: B23K

Abstract:
An electric arc welder comprising plurality of power supplies for creating a D.C. current of a given magnitude controlled by an adjustable command signal for use by a welding station having a D.C. input current and an output to pass an arc welding current between an electrode and workpiece and an arc current sensor, said plurality of power supplies including a first master power supply and at least one slave power supply, said first master power supply and said at least one slave power supply simultaneously providing current to said D.C. input current, said first master power supply including a first high speed switching type inverter having an output transformer and an output rectifier to produce a first D.C. current having a magnitude determined by a master current signal and a first pulse width modulator operated at a high frequency and having a current control voltage input connected to said master current signal, and an error amplifier for creating said master current signal based upon a comparison of said command signal and said sensed arc current, said at least one slave power supply including a second high speed switching type inverter having an output transformer and an output rectifier to produce a second D.C. current having a magnitude determined by said master current signal and a second pulse width modulator operated at a high frequency and having a current control voltage input connected to said master current signal of said master power supply whereby said first and second D.C. currents combine to form at least a portion of said D.C. input current.