Operating, welding, or Closed-circuit voltage, is the voltage at the arc during welding. Operating voltage is much like the water pressure observed as the water hose is being used. The operating voltage will vary with arc length, type of electrode being used, type of current, and polarity. The welding voltage will be between 17 and 40 V.
What if Operating Voltage is too High? –> See:Welding Voltage & Arc Length Relationship