Which type of power source is ideal for FCAW and GMAW?

• A. Constant Voltage
• B. Constant Current
• C. Pulsed
• D. Variable Current

Answer: (A)

Constant voltage supplies are suited for FCAW and GMAW because these welding processes rely on keeping the arc length stable while the machine controls heat input through the wire feed. A constant voltage power source holds the arc voltage near a set value; as you move faster or slower or as the arc length changes, the current varies automatically through the wire feed to maintain that stable arc. This leads to consistent bead shape, less spatter, and predictable deposition across a range of thicknesses and speeds. Pulsed power can be used in some situations to manage heat, but it’s not the standard setup for routine FCAW/GMAW. Using constant current would make the arc highly sensitive to arc-length changes, causing unstable welding, so it’s not typically the preferred choice for these processes.