Abstract: An electric arc furnace (1) operated with alternating current has a converter (2) which converts mains voltage (U), into primary voltage (U?) having a furnace frequency (f?). A furnace transformer (4) transforms the primary voltage (U?) into a secondary voltage (U?), supplied to electrodes (6) in a furnace vessel (8) (1). They apply electric arcs (10) to a melt material (9) in the vessel (8). The secondary voltage (U?) is also supplied to a capacitor assembly (7) on the output side of the furnace transformer (4) and the furnace transformer (4) is connected on the output side. A control device (5) controls the converter (2) such that a primary voltage (U?) output from the converter (2) to the furnace transformer (4) has a furnace frequency (f) of least ten times the mains frequency (f) and/or greater than 1 kHz.

Abstract: An electrical arrangement for an electric arc furnace (1) operated with alternating current has a converter (2) which converts mains voltage (U), having a mains frequency (f), of a supply grid (3) into primary voltage (U?) having a furnace frequency (f?). A furnace transformer (4) of the electrical arrangement transforms the primary voltage (U?) into a secondary voltage (U?). The secondary voltage (U?) is supplied to a number of electrodes (6) of the electric arc furnace (1). The electrodes (6) are arranged in a furnace vessel (8) of the electric arc furnace (1). They apply electric arcs (10) to a melt material (9) in the furnace vessel (8). The secondary voltage (U?) is also supplied to a capacitor assembly (7) which is on the output side of the furnace transformer (4) and to which the furnace transformer (4) is connected on the output side.

Abstract: A method for controlling a melt process in an arc furnace, including a signal processing component, program code, and data medium for performing the method. Sound signals or vibrations from the interior of the furnace container are captured by solid-borne sound sensors, from which characteristic values can be derived representing the distribution of melting material, melt, and slag in the furnace fill. A characteristic values are generated in priority sequence for: thermal radiation impinging on the furnace wall of the container, the lumpiness of the melting material in the volume of furnace fill, and the change to the portion of solid melting material contacting the furnace wall. The energy distribution at the electrodes is chanced by a control system based on the characteristic values in priority sequence, such that thermal load peaks are dampened or even completely prevented.

Abstract: A basic materials industry facility having a type 1 electrical consumer with at least three working points that each have a respective expected power consumption is disclosed. The facility can also have type 2 or type 3 consumers, each having only two working points or a single expected power consumption assigned to them, respectively. Schedule diagrams for type 1 and 2 consumers define their working points as a function of time, taking into account technological criteria for the operation of the facility, and are continuously updated using actual energy consumption data in such a way that the expected total energy consumption between starting time point and a predefined end time point does not exceed a maximum permissible total energy consumption. Preferably the consumers are controlled so that the expected total energy consumption is brought close to the maximum permissible energy consumption.

Abstract: An electric arc furnace, signal processing device, storage medium, machine-readable program code, and method for determining a time for charging (e.g., recharging) an electric arc furnace with material to be melted (e.g., scrap) are provided. The electric arc furnace may include electrode(s) for heating material inside the electric arc furnace by an electric arc. By detecting a signal for determining a phase state of an electric arc root on the side of the material to be melted based on a captured electrode current, by checking whether the signal exceeds a predetermined threshold value for a predetermined minimum duration, and by ensuring that the charging time is reached at the earliest when the signal exceeds the predetermined minimum duration threshold value, a state-oriented charging time for an electric arc furnace can be determined to reduce energy use, resource use, and production time for a production cycle to reach a tap weight.

Abstract: An arc furnace, a control and/or regulating device for an arc furnace, and a method for operating an arc furnace are provided, wherein an arc for melting metal is generated by at least one electrode, wherein an arc associated with the electrode(s) has a first radiation power based on preselected operating parameters, wherein the arc furnace is operated according to a predefined operating program based on an expected process sequence, wherein monitoring is performed to detect whether an undesirable deviation exists between the actual process sequence and the expected process sequence. Because a modified second radiation power is specified if a deviation is present, and a modified second set of operating parameters, e.g., impedance value(s), is determined based on the modified second radiation power, a method is provided that permits a minimal melting time while minimizing consumption of operating resources, e.g., with respect to arc furnace cooling.

Abstract: A method for controlling a melt process in an arc furnace and signal processing component, program code, and data medium for performing said method are provided. According to the method, sound signals or vibrations from the interior of the furnace container are captured by solid-borne sound sensors, from which characteristic values can be derived for the distribution of melting material, melt, and slag in the furnace fill. A characteristic value SM for thermal radiation impinging on the furnace wall of the container, a characteristic value M for the lumpiness of the melting material in the volume of furnace fill, and a characteristic value MM for the change to the portion of solid melting material contacting the furnace wall are generated in priority sequence. The energy distribution at the electrodes is changed by a control system analyzing the characteristic values in priority sequence, such that thermal load peaks are dampened or even completely prevented.