AC balance control in GTAW primarily affects which arc characteristic?

• A. Penetration depth
• B. Cleaning action
• C. Arc length
• D. Current waveform stability

Answer: (B)

AC balance controls how long each AC cycle spends with the tungsten electrode positive versus negative. The positive half-cycle increases the ion bombardment on the workpiece and promotes oxide removal, which is the cleaning action you want when welding aluminum. So, shifting more time to the electrode positive half-cycle enhances cleaning of the surface, making cleaning action the arc characteristic most affected. Penetration depth and arc length are influenced more by current level and technique, while stability is governed by the power supply and waveform design, not primarily by balance.