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

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

Answer: (B)

Constant voltage is used for GMAW and FCAW because it keeps the arc voltage essentially steady while the wire feed controls the current. With a constant-voltage source, you maintain a stable arc length, and as you adjust wire feed speed or stickout, the current automatically shifts to preserve that arc length. This stability leads to smoother transfer, consistent bead deposition, and reduced spatter across a range of wire types and shielding conditions. Pulsed power can help manage heat in some cases, but the standard, reliable choice for these processes is constant voltage. Constant current would cause the arc voltage to swing as current changes, making the arc harder to control in GMAW/FCAW.