AWS Tools & Equipment Operation 3

Question 1

What is the purpose of the ground clamp in an arc welding circuit?

Accepted Answer

To complete the electrical circuit by connecting the workpiece to the power source's work terminal

Answer

The work clamp (ground clamp) provides the return path for welding current from the workpiece back to the power source.

Question 2

Which lens shade number is generally recommended for GMAW (MIG) welding at 150–250 amperes?

Accepted Answer

Shade 10

Answer

AWS Z49.1 recommends shade 10 for GMAW at 150–250 amps to protect the eyes from arc radiation at that amperage range.

Question 3

What happens if MIG welding contact tips become worn or oversized?

Accepted Answer

The wire develops poor electrical contact, causing erratic arc starts and inconsistent bead quality

Answer

An enlarged contact tip bore creates electrical resistance variations, leading to arc instability and poor fusion.

Question 4

On a TIG welding machine, the high-frequency (HF) start function is used to:

Accepted Answer

Initiate the arc without touching the tungsten electrode to the base metal

Answer

HF start ionizes the shielding gas gap, allowing arc ignition without contaminating the tungsten by touching the workpiece.

Question 5

What does the term 'open circuit voltage' (OCV) refer to on a welding machine?

Accepted Answer

The voltage at the output terminals when no arc is established and no current is flowing

Answer

OCV is the no-load output voltage; it must be high enough to establish the arc but drops significantly once welding current flows.

AWS Practice Test