ABSTRACT
Duties of rectifier transformers serving special industrial loads are more stringent than conventional transformers. Due to rapid developments in power electronic converters and switching devices, transformers with modern static converters are being widely used for current ratings as high as hundreds of kilo-amperes. Complex winding arrangements, high currents and associated stray field effects, additional losses and heating effects due to harmonics, and the necessity of maintaining constant direct current are some of the special characteristics of the rectifier transformers. Furnace transformers have special features for handling very high currents compared to conventional transformers. The difference between the instantaneous values of direct voltages of the two systems is balanced by the voltage induced in the windings of the interphase transformer. Under the balanced condition of the two paralleled rectifier systems, the currents in both the windings of the interphase transformer are equal.
