Question

Straight polarity in arc welding is obtained with

• A. Direct current with the electrode being negative
• B. Direct current with the electrode being positive
• C. Alternating current with the electrode being positive
• D. Alternating current with the electrode being negative

Hint:

Straight polarity (DCEN) in arc welding means the electrode is negative, directing more heat to the workpiece for deeper penetration.

Answer 1

The Correct Option is A

Step 1: Understand polarity in arc welding.
In arc welding, polarity refers to the direction of current flow between the electrode and the workpiece. There are two types of polarity when using direct current (DC):
Straight polarity (DCEN): Direct Current Electrode Negative, where the electrode is the negative terminal, and the workpiece is the positive terminal.
Reverse polarity (DCEP): Direct Current Electrode Positive, where the electrode is the positive terminal, and the workpiece is the negative terminal.
When using alternating current (AC), the polarity alternates, so the electrode is neither consistently positive nor negative. Step 2: Define straight polarity.
Straight polarity specifically refers to Direct Current Electrode Negative (DCEN). In this configuration:
The electrode is connected to the negative terminal of the power source.
The workpiece is connected to the positive terminal.
This setup results in more heat being generated at the workpiece (since electrons flow from the negative electrode to the positive workpiece), making it suitable for deeper penetration in certain welding applications. Step 3: Evaluate the options.
(1) Direct current with the electrode being negative: This is the definition of straight polarity (DCEN). Correct.
(2) Direct current with the electrode being positive: This is reverse polarity (DCEP), not straight polarity. Incorrect.
(3) Alternating current with the electrode being positive: AC does not have a fixed polarity, and the electrode cannot be consistently positive. Incorrect.
(4) Alternating current with the electrode being negative: AC does not have a fixed polarity, and the electrode cannot be consistently negative. Incorrect.
Step 4: Select the correct answer.
Straight polarity in arc welding is obtained with direct current with the electrode being negative, matching option (1).