Arc operating voltage

Arc voltage is the voltage across the arc during welding when current flows. It depends on arc length, shielding gas, and electrode material. If you change the distance between electrode and workpiece, the voltage changes too: larger distance means higher voltage, smaller distance lower. In practice, set the arc so it burns quietly and stably, without crackling or going out. Too long an arc makes the weld dirty and spatters, too short can stick to the electrode. You need to get a feel for the right arc length, then the voltage will be fine.