Patent ID: 6040556
Filing Date: 2000-03-21
Classification: B23K

Abstract:
An engine driven arc welder comprising:a welding generator driven by an engine;an output circuit for controlling output of the welding generator in accordance with a control signal to deliver the output to the welding output terminals;a current detector for detecting current flowing in the welding output terminals;an error detector for comparing the output of the current detector with a reference signal to detect error therebetween;a control signal producing circuit which produces a control signal in accordance with the output of the error detector and which delivers the control signal to said output circuit;a voltage detector for detecting the voltage applied to the welding output terminals;said welder showing a welding output characteristic having a constant current control arc characteristic in accordance with the reference signal and exhibiting a drooping characteristic in the vicinity of the arcing voltage and a further constant current control arc characteristic with an increasing current when the arc voltage is lowered; andan adjustment circuit for determining the magnitude of the reference signal to be delivered to the error detector in accordance with the output of said voltage detector,thereby to change the reference signal to allow an inter-characteristic transfer point between the constant current control arc characteristic and the drooping characteristic to be adjustable wherein said adjustment circuit changes the reference signal to allow the inter-characteristic transfer voltage from the constant current control arc characteristic corresponding to arc current to the drooping characteristic to be adjustable, and changes the reference signal to allow inter-characteristic transfer current from the drooping characteristic to the constant current control arc characteristic corresponding to short-circuit current to be adjustable.