Low-Powered Plasma Arc Cutting In the low-powered plasma arc cutting variation, the maximum current is normally 125 A. The torch is relatively small, usually air cooled, and manually operated. Air is usually used for the plasma. Low powered units can be used with mechanized cutting systems and can utilize special devices to help as an aid for manual cutting. This shows a small circle-cutting attachment which improves the quality of the cut surface. Straight-line attachments are also used. In all cases the cutting, speed is greater than the cutting speed of oxy-acetylene cutting. The cutting speed versus material thickness for low-powered plasma arc cutting is shown in Figure using air.