DESCRIPTION Medium Frequency Direct Current machines use an inverter, powered from a 3 phase supply in which the current is rectified using diodes and then chopped by means of IGBT’s into high frequency alternating current. This alternating current is then transformed by the welding transformer and again rectified. DC current is thus obtained at the secondary side in to the parts to be welded. The MFDC welding machine load is evenly distributed across all three phases. This