Patent ID: 6815649
Filing Date: 2004-11-09
Classification: H05B

Abstract:
A device for inductive billet heating, comprising a single or multi-layer billet-heating coil (4) for round billets (5), wherein the billet-heating coil (4) comprises one or more consecutive, galvanically separated zones, said zones being supplied with electrical energy from a three-phase network by means of an electrical switching device and a control unit, wherein the billet-heating coil (4) comprises multiple, synchronically regulated zones (Z1, Z2 through Zn) with reference to frequency and phase of inductive field, and wherein for a current feed to each zone (Z1 through Zn) of the billet-heating coil (4), a converter (2) is provided, comprising a plurality of converter modules (M1 through Mn) with variable frequency for a current feed to each separate zone (Z1 through Zn) of the billet-heating coil (4), wherein each converter module (M1 through Mn) forms a closed or self-contained power unit with three-phase network feed and synchronization of phase and frequency of the output voltages, and wherein the separate converter modules (M1 through Mn) are synchronized in such a manner that the produced induction field in each coil zone has no phase displacement to induction of the neighboring zones and is completely independent from power of the converter module.