The design and performance of multi-megawatt variable width TFX induction heaters for the ultra rapid heat treatment of metal strip

A high power transverse flux induction heater design developed at EA Technology, licensed to Davy International, and marketed under the registered name TFX, has been in successful commercial operation for a number of years at powers up to 3MW. The further development of this reliable design to give a fully continuously variable width capability over at least a two to one strip width range is described. Operating economics, efficiency, power intensity and electromagnetic forces are discussed. The increased operational flexibility of this design allows a very wide range of strip materials, including magnetic strip, to be heated in a common inductor, using commercially available variable frequency power supplies. This extends the use of TFX induction heating to applications such as coating, where steel and aluminium strip may be intermixed in a single line.