| 摘要 |
The invention concerns an induction furnace, containing a crucible 3 with vertical axis, containing a molten metal bath 2 and surrounded by a multiphase winding of several coils A-F along the crucible, wherein parts of the winding are arranged to produce motions in the metal bath. According to the invention, the coils in the multiphase winding are arranged in two groups of n coils A-C for the upper part and n' coils D-F for the lower part of the crucible, wherein the n upper coils are energised from a multiphase system with n voltages U1 ... Un, which has an inverse component Ui with is negligible compared to a direct component Ud and a homopolar component Uo, and the ratio Uo/Ud is chosen such that the tangential eddy components produced by the homopolar and the direct component are of opposite sign and have amplitudes preferably equal to or at least of the same order of magnitude for at least the upper part of the bath, and at the same time the n' lower coils are energised by a multiphase system with n' voltages U'1 ... U'n, which has a direct component U'd that is negligible in relation to an inverse component U'i and a homopolar component U'o, wherein the ratio U'o/U'i is chosen such that the tangential eddy components produced by the homopolar and the inverse component are of opposite sign and have amplitudes which are preferably equal to or at least of the same order of magnitude, at least in the lower part of the bath. <IMAGE> |
