Inductors are needed for all induction heating processes, such as hardening, soldering, melting and annealing. The following designations are also used for the inductor: heating loop, heating coil, heating conductor, working coil and annealing loop. The inductor serves for the transfer of energy from the generator to the material to be treated by means of the alternating magnetic field.

Faulty design or unsuited dimensioning of an inductor will result in serious failures. A lot of skill and know-how is demanded from the design engineer while designing these inductors. Laboratory experiments are often required in order to determine the correct and final shape of an inductor. All sorts of inductor shapes are possible, because they must be adapted to the form of the work piece, or they must be manufactured according to the desired heating patterns. There are inductors with a single or with several loops, round shapes, square shapes, hairpin-shaped forms as well as very complicated forms varied in shape.

The following Design Factors must be kept in Mind:

• Depending on the inductor, current densities of up to 6 kA/mm² may be encountered. This calls for materials of high electrical conductivity. The heat produced must be dissipated by means of a water-cooling system.
• The energy transfer from the inductor to the work piece must be performed with good efficiency.
• The shape of the inductor must correspond with its purpose.
• The inductor must be dimensionally stable, and it must not be deformable either by mechanical or by electrical influences.
• The inductor must be suited for fitting on the generator. Its connections must be designed in such a way, that only low losses will be encountered at the contact points, and that they may easily be exchanged.
• Dependable isolation between the windings must be provided in case of inductors with several loops. Sufficient dimensional stability must thereby be guaranteed.

The shape of an inductor is dictated by the form of the required heating zone and is thus essentially influenced by the shape of the work piece. The form of an inductor may thus be predicted within limits. The mutual influence of the magnetic fields of an inductor of difficult shape and the varied heat flow in a work piece of multiple shapes may often result in unexpected heating zones, if the inductor only follows the work piece form strictly according to the pattern. A brief development time for the inductor requires quite some practical experience and skill of the developer here.

Some pictures of inductors are included below, showing which special shapes are sometimes necessary in order to obtain an optimum power transfer.

Special-coil		Cable-heating-coil		Heavy-duty coil
We make special designs to adapt the coil to your workpiece!		We make "stand-alone" units, to easy fit the coil to your line!		Heating of steel pieces. We make special-coatings/coverings to protect the coil
Coil with shower		Test-coils		Special-coil
We make special designs to optimize your application (pic. hardening of gear wheels)		We have a big assortment of testcoils to make pre-evaluations		Special design with compensation-coil to fit desired frequency
Coils with intensit Intensit is an ferromagnetic material which can focus the heating energy. The coil design with this material is frequently used by hardening and soldering applications.
Intensit-coils