Mannesmann Aktiengesellschaft

Fried. Krupp Gesellschaft MIT Beschrankter Haftung

Bernhard Espendiller

Hans J Bebber

Heinrich-Otto Rossner

Ulrich Katschinski

Klaus Giertz

Karsten Brabandt

A device for coupling a flexible current feed (50) to a bottom electrode of a metallurgical vessel (10) having a first electrical coupling (20), including a second electrical coupling (30) for operatively engaging the first coupling (20), being connected to the current feed (50), a carrier element (60) and a compensating element (40) between the carrier element (60) and the second electrical coupling (30), the compensating element (40) balancing a force of the flexible current feed (50) on the first electrical coupling. The compensating element (40) may include a damper (42) in parallel to a spring (41), so that a movement of the second electrical coupling (30) with respect to the carrier element (60) is damped.

Device for coupling the current feed to a metallurgical vessel

A method of controlling the course over time of a target temperature of a molten metal in a ladle, for example, in which the required heating power is produced by at least one plasma torch. Determination is made of the variation with time of a target temperature, the mass of an outwardly flowing melt, and a specific heat value of the melt present in the ladle. From the foregoing values there is ascertained the course of a corresponding setting signal for obtaining the heating power necessary to obtain the desired temperature course. Simultaneously and continuously the actual temperature of the melt is measured. When the actual temperature of the melt deviates from its target temperature in excess of a predetermined tolerance, the setting signal for the heating power is changed by decreasing such setting when an actual temperature exceeds the target temperature, and increasing such setting when an actual temperature is less than the target temperature.

Method of controlling a temperature of a molten metal

A power supply for a three-phase plasma heating unit includes a three-phase transformer having a primary winding group with taps which are switched under load. The transformer also has secondary winding groups which are offset by a 60.degree. phase angle, the secondary winding groups being connected to the three-phase plasma heating unit. Converter units are also connected to the secondary winding groups. Each converter unit includes a three-phase thyristor bridge and a choke connected to the bridge. Another embodiment employs two three-phase transformers. The first transformer has a secondary winding group with taps which are switched under load. The second transformer has a primary winding group which is connected to the secondary winding group of the first transformer. The second transformer also has secondary winding groups which are offset by a 60.degree. phase angle, the secondary winding groups being connected to the three-phase plasma heating unit. Converter units, each including a three-phase thyristor bridge and a choke, are connected to the secondary winding groups.

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Dulmen, Germany

Bernhard Espendiller