Plasma torches can operate on DC and AC generators. Dynamos straight polarity are the most popular. They provide the required ampicity for tungsten electrode which is nearly 10 times higher than for the reverse polarity. Metal plasma cutting is is economically more profitable for such installations. In conclusion plasma torches with DC generators have high efficiency, uniform load three-phase network and have very stable arc burning. AC and DC dynamos are more attractive at the same cost for the unit acquisition.