Rectifier transformer is a power supply transformer rectifier equipment. Rectifier equipment is characterized by the original input current, while the deputy party through the rectification of the original output dc. Converter is rectifier, reflux and frequency conversion of the three kinds of working mode of general, rectifier is one of the most widely used. Transformer is used as power source of rectifier unit. Most of the industrial rectifier DC power supply is obtained by the AC power grid through the rectifier transformer and rectifier equipment. Due to the rectifier transformer winding current is non sinusoidal containing a lot of harmonic, in order to reduce the harmonic pollution to the power grid, in order to improve the power factor must increasing the number of pulse rectifier equipment.