Siemens Aktiengesellschaft

Primetals Technologies Germany Gmbh

Björn Dittmer

Detlef Rieger

Thomas Matschullat

Martin Hergt

Arno Döbbeler

Klaus Krüger

Sascha Leadbetter

An electric arc furnace () operated with alternating current has a converter () which converts mains voltage (U), into primary voltage (U') having a furnace frequency (f&#x2032;). A furnace transformer () transforms the primary voltage (U&#x2032;) into a secondary voltage (U&#x2033;), supplied to electrodes () in a furnace vessel () (). They apply electric arcs () to a melt material () in the vessel (). The secondary voltage (U&#x2033;) is also supplied to a capacitor assembly () on the output side of the furnace transformer () and the furnace transformer () is connected on the output side. A control device () controls the converter () such that a primary voltage (U&#x2032;) output from the converter () to the furnace transformer () has a furnace frequency (f) of least ten times the mains frequency (f) and/or greater than 1 kHz.

Converter-fed electric arc furnace with capacitor assembly in the secondary circuit

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.

Method for controlling a melt process in an arc furnace and signal processing component, program code and data medium for performing said method

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Nuremberg, Germany

Björn Dittmer