Millwright Level 1 Practice Exam

What is the function of voltage in arc welding?

1. Control heat

2. Start the arc

3. Regulate gas flow

4. Stop the arc

The correct answer is: Start the arc

In the context of arc welding, voltage plays a crucial role in initiating the welding process. The primary function of voltage is to create the necessary conditions for starting the arc between the electrode and the workpiece. When the welding machine is activated, the voltage generates an electrical potential that allows the current to flow and ionizes the air gap, forming a conductive plasma channel. This channel is the arc, which produces the intense heat required to melt the base materials and the filler metal. Once the arc is started, voltage continues to influence the stability and characteristics of the arc but is particularly critical at the outset of the welding process. While other aspects, such as heat control and the regulation of gas flow during processes like MIG welding, are indeed important, the initiation of the arc itself is fundamentally dependent on the voltage supplied. This is why starting the arc is explicitly associated with voltage in the context of welding functions.