Question

why would you use hot start on an smaw welding power supply?

it provides extra amperage for 1/10th of a second to help start the arc
it provides deeper penetration throughout the weld
it optimizes the size and shape of the arc cone
the electrode burns hotter allowing it to melt more quickly into the weld pool

Explanation:

Define the hot start function

Using the Welding Power Sources knowledge point, hot start is a feature designed to assist in establishing an arc during Shielded Metal Arc Welding (SMAW). It temporarily increases the welding current (amperage) at the very beginning of the weld.

Analyze the mechanism of hot start

When the electrode touches the workpiece, the power supply delivers a brief surge of extra amperage. This surge lasts for a fraction of a second (typically around 1/10th of a second) to prevent the electrode from sticking to the metal and to ensure a smooth, reliable arc ignition.

Evaluate the given options

• Option 1: "It provides extra amperage for 1/10th of a second to help start the arc" directly matches the technical definition and timing of the hot start feature.
• Option 2: "It provides deeper penetration throughout the weld" is incorrect because hot start only operates momentarily at the beginning, not throughout the weld.
• Option 3: "It optimizes the size and shape of the arc cone" describes arc control or inductance settings, not hot start.
• Option 4: "The electrode burns hotter allowing it to melt more quickly into the weld pool" is a general description of high current but does not accurately define the specific temporary surge mechanism of the hot start function.

Answer:

• (A) It provides extra amperage for 1/10th of a second to help start the arc (Correct answer)
• (B) It provides deeper penetration throughout the weld
• (C) It optimizes the size and shape of the arc cone
• (D) The electrode burns hotter allowing it to melt more quickly into the weld pool