Plasma cutting power sources and welding machines

Plasma is an effective means of cutting steel and other metals (or sometimes other materials) of different thicknesses. Since plasma cutters produce a very hot and very localized "cone" to cut with, they are extremely useful for cutting sheet metal in curved or angled shapes.
In this process, an inert gas (in some units, compressed air) is blown at high speed out of a nozzle; at the same time an electrical arc is formed through that gas from the nozzle to the surface being cut, turning some of that gas to plasma. The plasma is sufficiently hot to melt the metal being cut and moves sufficiently fast to blow molten metal away from the cut.
To perform plasma cutting, the basic necessary equipment includes a power source; a plasma torch complete with consumables: electrode, diffusor, nozzle, nozzle holder, protection; a ground clamp and compressed air or a gas cylinder.