Furnace Transformers

CG offers various types of furnace transformers like arc furnace and laddle furnace transformers. Mainly the application of electrical air furnace is limited only for melting and refining carried out in next stage. The range of voltages are small for melting operations since furnaces are designed with specific apparent power density in the order of 600-800 kVA ton. The laddle furnace transformers are used in refining molten steel. The range of voltage required is smaller and lower than those of electrical arc furnace transformers. Normal range arc has low specific apparent average power density in the order of 200-400 kVA ton. A transformer supplying power to a furnace has to handle extremely high value currents in the order of kAmps. (10 to 60 or higher depending upon furnace ratings).
The furnace transformer thus has special features to handle such high currents as compared to conventional transformers. The electric arc furnace has 3 electrodes connected to the secondary terminals of the furnace transformers. The secondary terminals of the transformers are subject to frequent short circuits during the melting process through the charge and arc. Hence the furnace transformer needs to be specially designed to withstand the frequent short circuits.