Multi-wire induction heating

Abstract From the Canadian patent

Induction Heating", In the induction heating of thin (e.g. 0.5 to 3 mm diameter) steel wires (W) in continuous heating processes, relatively low field strengths of e.g. up to 20,000 Am-1 are employed but are chosen so as to set the relative magnetic permeability µr at 40 or more. The wire are passed through coil blocks (1), which are wound flat around a row of ceramic tubes (3) to guide and insulate the wires. The coil blocks are energised at frequencies typically up to 30 kHz. The direction of winding and/or the phase of the current is changed between adjacent coil blocks (1), or groups of blocks, to reduce voltage build-up along the wires.