Patent ID: 7064290

Claim:
An electric arc welder configured to selectively operate in a non-regulated voltage mode and a regulated voltage mode for performing a given weld process with a selected A.C. pulse current waveform performed between an electrode and a workpiece, said current waveform including a positive segment and a negative segment, with at least one segment including a peak current and background current, said welder comprising: a power source with a controller having a digital processor including first program operations operable in the non-regulated voltage mode to calculate the real time power factor of the weld current and weld voltage; and, a circuit to adjust said background current to maintain said power factor at a given level, second program operations operable in the regulated voltage mode to control the waveform voltage by an error circuit having an error output signal generated by a difference between a first input signal representing a desired or set voltage for at least a portion of said waveform and a second input signal representing a sum of an arc voltage and an arc current of said waveform multiplied by a slope constant, and an adjustment operation to reduce said error output signal by adjusting the voltage of said waveform.