In modern metallurgical and chemical industry there is an increasing need for electric arc-melting furnaces. Transformer is also one of the vital parts by which power is supplied to furnaces. Because of their technological aspects, Electric arcmelting furnaces, need special transformers different from usual distribution units. The main problem arises from the demand for relatively wide range of regulation on the low voltage side. In this article one of the many principles of voltage regulation is described, nomely, low voltage regulation by means of magnetic flux variations.