A method and device for regulation of the electrode gap in a light arc melting furnace

摘要

1,048,436. Automatic arc furnace control. ALLEGHENY LUDLUM STEEL CORPORATION. April 2, 1964 [April 2, 1963], No. 13743/64. Heading G3R. In an automatic arc furnace control system wherein the arc length is controlled by arc voltage, within defined high and low limits arc voltage or current transients below 30 cps are utilized to control the arc length which transients increase in frequency as the arc shortens. The arc length may be controlled according to the frequency of the transients, or they may be integrated over a period of time. Alternatively transient amplitude may be the criteria of operation. The arc voltage is sensed by high and low voltage circuits 46 comprising magnetic amplifiers and if inside these limits the arc control is switched by a relay 88, 90, 92 to transient control comprising a filter 58 to eliminate d.c. ripple and a timing control counter 84. If the count is less than a first given amount in a predetermined period the arc length is shortened by a fixed amount successively until the count increases. If the count reaches a second given amount the arc voltage will be lengthened until stopped by the high voltage circuit 46.