Electrode control system for electric arc furnace - monitors electrode currents and voltages for control signals for depth of electrode immersion

摘要

The system controlling the depth of immersion of the electrodes (1,2,3) in the melt of an electric arc furnace uses a control system which monitors the change of inductivity due to the current passing through them. Each electrode receives current from the secondary winding of a transformer in a circuit known as a knapsack circuit. Each electrode is connected with a measuring line, with a common point (0) formed by the molten bath, and with outer connections to a switching point (8) so that the outputs can be connected to the electronic control unit. Correction values are obtained from the shift of the arc voltages and currents which are added and the differences formed with the quotient of the bath voltages are used as a value for adjusting in the depth of immersion. In each high current path is a magnetic voltage measuring device, each connected to an amplifier and a multiplier. The measuring transformers for each high current path are connected in pairs to an integrator followed by the equalising circuit.