Primary power refers to

• A. The incoming electrical supply from the utility
• B. The output at the welding arc
• C. The energy stored in capacitors
• D. The energy delivered by the arc

Answer: (A)

Primary power is the incoming electrical supply from the utility that feeds the welding equipment. It’s the energy source that the welder draws before any internal conversion, rectification, or transformation occurs inside the machine. The arc energy you weld with is produced after the welder converts that primary power to the appropriate voltage and current on the secondary side. Stored energy in capacitors or the energy delivered by the arc are separate aspects: the capacitors may provide brief bursts or filtering, and the arc energy is the result of the machine’s output settings, not the original supply. So the incoming utility power is the best fit for primary power.