>>My question is if the welding supply has any other circuitry such as
>>SCR/Triacs for conduction angle modulation in series with the primary?

>My understanding of welders is that the more "exotic" circuitry is usually
>found on the more expensive welders, and is more for MIG and TIG welders,
>and not the typical home type welder.  I have a Lincoln 225A AC welder that 
>cost ~$200 new.  I don't have any qualms about using this one for coil use,
>and then later using it for welding.  I do know that TIG welders have a
>high frequency start, as well as other circuitry to condition the electricity
>which may be affected by coil usage.

	Having once done some emi studies on low-mid end industrial rf
	stabilized welders (tho this was two decades back...)...

	They were nearly straight autotransformers.

	The "rf" (in these), well, the maintainance instructions for the
	RF source were how to use a feeler gauge on the gap, with cautions
	on NOT trying to file it as the gap was tungsten & would ruin the file.