Inductors

The inductor is the final step in the induction heating system.  Alternating current flowing through the inductor creates electromagnetic poles, which induce electrical current in conductive materials located inside the inductor coil.  This is basically  a winding based on construction principles made from cooper tubing which is water-cooled.  The shape of this winding must adhere to technological and economic requirements, meaning it must heat the material in the required places incorporating the tightest electromagnetic binds, which creates the highest possible effectivity.

The most effective inductors are solenoidal coils in the shape of a circle, square, or rectangular, which are used for forge-heating of billets or rods.  In this case, the material to be heated is completely surrounding by the inductor winding.  A special shape of this group is a single-winding inductor twisted lengthwise into a double screw used for heating rods that are afterwards send through a wedge roller, where the rod rotates. 

Less effecient are inductors that have a slit-shaped heating core for heating rod-ends, or inductors used for heating flat surfaces that are placed close to the coil.

For standard surface hardening, most of the time a single-winding inductor is used, sometimes with integrated water-cooling.

Unusual inductors are those belonging to a wide spectrum of shapes for specific area heating of various material parts.  Sometimes, when a  concentration of these magnetic poles is required in a specific area on the piece, ferromagnetic sheilds are used.