| 摘要 |
1506020 Electric arc furnaces ASEA AB 22 July 1975 [23 July 1974] 30584/75 Heading H5H In operating a direct arc furnace having an electrode 3 with a through channel, rotation of direct current arc 17 is effected by the magnetic fields from coils 8, 10, Fig. 1, and 11, Fig. 6 energized by alternating current. The necessary rotating magnetic field is obtained with either a two phase or asymmetrical three phase supply. A furnace may have two or four coils 10 fed with 2-phase A.C. in the roof and three coils 8 in the walls and symmetrically arranged with respect to the electrode 3, but one of the 3-phase fed coils must be so connected or wound as to produce the required asymmetric field. These coils 8, 10 may be reversed in position. Alternatively coils 11, Fig. 6 may be mounted at the tip of a cooled (by means of channels 12) non consumable electrode. The A.C. supply may be of 50 to 60 Hz. When coils are mounted beneath the vessel they are preferably of lower frequency, e.g. 1 Hz. When 3-phase fed coils are not arranged symmetrically with respect to the arcing electrode, it is not necessary to wind or connect the coils asymmetrically to produce the asymmetric field. Charge material is fed through the channel of electrode 3. |
