On Aug 30, 1:05*pm, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Arc voltage at constant current is a function of the arc gap. *The SW-300
is a constant-current source, and provides high frequency to start the arc.

Lloyd

I do not have a plasma cutter so treat this as opinion not fact.

But the arc voltage is also a function of pressure. See Pachen
curves. So the arc voltage would be higher if the arc gap under
pressure.

Dan