Apparatus and method for dynamically adjusting an electric arc furnace

An apparatus for regulating an electric arc furnace connected to a power supply system with at least one system phase that applies an AC voltage to a furnace electrode and an arc current for melting. A control loop device includes an electrical converter designed for negative feedback of an amplitude and/or frequency of the AC voltage to produce an amplitude and/or frequency of the arc current. The converter includes an input port having a system power supply connected thereto, and an output port having a melting furnace power supply and a primary circuit of a first transformer connected thereto, wherein a secondary circuit of the first transformer is connected to the arc furnace electrode. A primary coil of a second transformer is connected in parallel with the converter input port, and a secondary coil of the first transformer is connected in series with a secondary coil of the second transformer.