What are the induced voltage requirements

What is induction

The Inductotherm Group companies primarily deal with inductive melting, heating or welding for a wide range of industrial applications. But what exactly is induction and how does it differ from other heating processes?

It is fascinating how a piece of metal is heated to red heat within a few seconds under the influence of induction. Understanding this process requires understanding a variety of subject areas: physics, electromagnetism, power electronics, and process control. However, the basics of induction are easy to understand.


Discovered by Michael Faraday, induction is based on a coil made of conductive material such as B. copper. When an electric current flows through the coil, a magnetic field is created in and around the coil. The effects of the magnetic field depend on the structure of the coil and the strength of the current.

The direction of the magnetic field depends on the direction of flow of the current; an alternating current causes an alternating magnetic field, the direction of which changes analogously to the alternating current frequency. An alternating current at 50 Hz causes a change of direction in the magnetic field 50 times per second; a 400 kHz alternating current causes 400,000 changes of direction of the magnetic field per second.

If an electrically conductive material is exposed to this magnetic field, a voltage is induced (Faraday's law). The induced voltage in turn causes a current to flow in the metallic input material; the current flow in the material is opposite to the current flow in the coil. This means that it allows the frequency of the current in the metallic feedstock to be controlled by the frequency of the coil.

When current flows through a medium, the flow of electrons is exposed to a material-specific resistance. This resistance occurs in the form of heat (Joule heating effect). The higher the specific resistance of the material through which it flows, the greater the heat development. This phenomenon is crucial for inductive heating.

What do you need for inductive heating?

Basically, two basic things are needed for the inductive heating process:

  1. An alternating magnetic field
  2. An electrically conductive material that is exposed to the alternating magnetic field

How does inductive heating work in contrast to other heating methods?

There are many different ways to heat an object without induction. Fuel-heated or electrical systems are often used in the industrial sector. These methods are all based on the heat transfer from the heat source (burner, heating rod, etc.) to the product by convection or radiation. As soon as the surface of the product is heated, the rest of the body heats up due to its thermal conductivity.

With induction, on the other hand, the heat is induced directly into the workpiece by the eddy currents that occur. The depth of penetration depends on the alternating current frequency used.

A high frequency results in a comparatively low penetration depth; low frequencies, on the other hand, result in a high penetration depth. In addition, this of course also depends on the electromagnetic properties of the workpiece.

Inductotherm Group companies use this physical and electrical phenomenon to their advantage to develop innovative solutions in the field of inductive heating and inductive melting for different products and applications. The precise control of the electrical power and frequency, as well as the design of the coil geometry, enable Inductotherm to design systems for various applications that offer the highest level of process control and availability.

Inductive melting

For many applications, the melting process is the first step in the production of a corresponding end product. Inductive melting is the fastest and most efficient solution for this. By adapting the coil geometry, furnaces with a capacity of a few kg up to 100 tons of molten material are now being built. By adjusting the frequency and electrical power, Inductotherm can offer melting systems for almost any application or metal, with the main areas of activity being in the field of iron, steel, stainless steel, copper and copper alloys, aluminum and silicon. The melting systems are adapted by Inductotherm to the specific requirements of the customers and thus achieve optimum efficiency.

The future

For the ever higher material requirements, the use of regenerative energies and global progress, engineers are offered a fast, efficient and precise form of heating with the use of induction.