Reduction of spark generation voltage in induction heating

On the operation of coil winding shaped induction heating process, a spark phenomenon often generates and makes a serious problem which affects not only the product quality and equipment damage but also the safety operation. Since the cause of the spark generation is considered to be an induced voltage which induced by the time variation of the width direction magnetic flux, in order to reduce it, we proposed a new type coil winding shape in which the winding coils are rectangular to the running direction of the steel sheet and the return coil is parallel to it. The usefulness of the proposed shape is confirmed by using numerical calculation in electromagnetic field. The induced voltage by the proposed induction heating coil is reduced 84%, though the heating capacity and inductance of the proposed coil is the same as the conventional one.