Dynamics of electromagnetic forces rejecting arcs from verticals in a three-phase arc furnace

Knowledge of the nature and behavior of forces acting on an arc is important when designing furnaces, controlling and automating their work. The effect of electromagnetic arc blowing has a negative effect on technical and economic indicators of the furnace, since the arc is removed from dimples in metal and slag. Radiation of the arc on walls and arch increases. And the effective power absorbed by the metal decreases. For this and a number of other tasks, it is necessary to know the dynamic behavior of the arc, which is largely determined by the instantaneous values and directions of the individual forces and the resultant force. The paper discusses the behavior of an electromagnetic force acting on an arc column from currents flowing through a liquid metal and currents flowing through other parallel arcs and graphitized electrodes in a three-phase AC arc furnace. It was assumed that the arcs burn perpendicular to the surface of the metal bath (their axes coincide with the axes of the electrodes) and effective value of the linear currents in different phases is the same. A mathematical model is proposed for calculating the instantaneous values and directions of the main electromagnetic forces acting on arcs in a three-phase arc furnace, allowing to reveal the nature of arcs dynamic behavior. A computer program has been created that makes it possible to visualize the behavior of a hodograph of forces acting on an arc. Hodographs of forces acting on the arc from the currents flowing through the melt are shown; they are ellipses lying in a horizontal plane. The resulting force deflecting an arc is also an even harmonic function with a frequency twice as high as the industrial frequency of the current. Its hodograph is an ellipse lying in a horizontal plane, the big semi-axis of which makes an angle of 20 – 80° with a line connecting the center of decay of the electrodes and the electrode axis.

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