In AC welding using the GTAW process, part of which half cycle is reduced?

In AC welding using the GTAW process, part of which half cycle is reduced?

• A. Direct Current Electrode Positive
• B. Direct Current Electrode Negative
• C. Alternating Current High Frequency
• D. Direct Current High Frequency

Answer: (A)

In AC GTAW, the current alternates between the electrode positive and electrode negative halves, and the balance control determines how long the arc stays in each half. Reducing the electrode-positive half-cycle lowers the cleaning action on the workpiece surface and shifts more of the heat into the weld during the negative half-cycle. That’s why the part of the cycle being reduced is the electrode-positive half-cycle. The other options refer to polarities or high-frequency use, which aren’t about reducing a half-cycle in the AC balance sense.

In AC GTAW, the current alternates between the electrode positive and electrode negative halves, and the balance control determines how long the arc stays in each half. Reducing the electrode-positive half-cycle lowers the cleaning action on the workpiece surface and shifts more of the heat into the weld during the negative half-cycle. That’s why the part of the cycle being reduced is the electrode-positive half-cycle. The other options refer to polarities or high-frequency use, which aren’t about reducing a half-cycle in the AC balance sense.