| 摘要 |
<p>DC arc furnaces (8) have a current controller (14) for stabilizing the current of an arc (10), and an electrode controller (18) for influencing the position of an electrode (7) of the arc furnace (8) and thus the length of an arc (10). The control of the position of the electrode (7) is performed by means of a hydraulic electrode adjusting device (21), which is controlled as a function of a difference between a prescribable electrode controller reference variable signal (.alpha.des) and a rectifier manipulated variable signal (.alpha.act) at the output of the current controller (14). As a result, the arc length is regulated such that a rectifier (5) operates on average with a drive level of, for example, 25.degree. electrical, irrespective of the secondary voltage of a furnace transformer (2) and of an adjusted desired current value signal (ides). Limiting values are monitored and undesired frequencies are filtered out by means of a bandpass filter (16) between the output of the current controller (14) and a comparator or summer (17) for forming the difference signal between the electrode controller reference variable signal (.alpha.des) and the rectifier manipulative variable signal (.alpha.act).</p> |
