What is the voltage range for open circuit voltage when no welding is being done?

What is the voltage range for open circuit voltage when no welding is being done?

• A. 50-100 volts
• B. 0-20 volts
• C. 120-240 volts
• D. 10-50 volts

Answer: (A)

Open circuit voltage is the voltage present at the welding output when no welding current is flowing. It has to be high enough to start an arc, but not so high as to create a safety hazard. For most welding power sources, that no-load voltage sits roughly in the 50 to 100 volt range. Once welding begins and current flows, the arc voltage drops to a much lower level, usually in the tens of volts.

The other ranges don’t fit typical welding practice: 0–20 volts is too low to reliably start an arc, 120–240 volts is more like mains or heavy equipment voltage and would be unsafe for portable welders, and 10–50 volts is narrower and often misses the common upper end of what many machines provide. So, 50–100 volts best matches standard open-circuit values.