The smelting industry uses AC & DC processes depending on the arc furnace application. DC Electric Arc Furnace (EAF) Transformers are similar in design to rectifier transformers but have many more taps and on-load tap changers. AC (EAF) transformers are subjected to repeat short circuit conditions that require a more conservative design. They too have many taps and on-load tap changers. The AC (EAF) transformers are generally manufactured as single-phase units, which allow the furnace design and process to be optimized.