Through a contrary electrical source, change the three-phase alternating current into a single-phase DC, and then invert into a medium frequency pulse AC of 500-1000Hz by inverter. Then form a magnetic field through the copper spiral in the furnace. The magnetic field can make quantity of heat in the furnace, so that the furnace can melt the metals.
It is widely used to melt and heat nonferrous metals. Size: 0.25T-3T.