I worked in a shop once as a welder, this is the same type of machine I used to lay down 1/4 inch rod. These welders are driven with an electric motor the generator end puts out the smoothest DC current in almost any welding machine I've worked with.
Often you'll find these machines at an auction not many people bid on them with the 3 phase power requirement but I have seen machines that have had the electric motor portion removed with a bearing plate made up to support the armature then coupled to an engine of your choice.
Imagine a 600 amp portable welder on the cheap.
The CC/CV square wave machines tops the list, but they probably have better machines out there today.
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