Generally (but not always) pronouns stand for (pro + noun) or refer to a noun, an individual or individuals or thing or things (the pronoun's antecedent) whose identity is made clear earlier in the text. For instance, we are bewildered by writers who claim something like. They say that eating beef is bad for you.
A wire feeder may be used for machine or automatic welding and must be the constant speed type. The wire feeder must have a speed adjustment covering the range of from 10 in. per minute (254 mm per minute) to 125 in. per minute (3.18 m per minute) feed speed. PAW or plasma arc welding using an automated process.
A Plasma Cutter generates a plasma column that is Hotter than 20,000F...Compare that to 6,000F of an Oxyfuel Torch. see part 2 on the spectrum 625 Xtreme miller plasma cutter How does a plasma cutter work? This short animated video (about 30 seconds) of a miller plasma arc cutting torch explains how it works. Pay attention and dont blink or you will miss something. The plasma cutting torch holds the electrode in a recessed chamber where gas is heated to plasma .