Induction heater, device and principle of operation

Today, the principle of induction heating is used quite widely and this is not only huge smelting furnaces in steel mills, but also fairly compact devices for home application.

In this article I want to tell you on what principle this product functions, as well as how you can use it at home. So, let's begin.

Induction heater working principle

The principle of operation is as follows: the workpiece placed inside the inductor is heated by the eddy current induced in it.

The inductor is a coil in which an alternating current flows. This creates a high frequency alternating electromagnetic field.

And the field already generated by the coil has a direct effect on the workpiece made of a conductive material, inside which a closed current of increased density is induced. Due to this, the workpiece is heated and further melted.

This phenomenon was discovered back in 1931 by M. Faraday when he described such a phenomenon as electromagnetic induction.

An alternating magnetic field creates an alternating EMF in the conductor that it penetrates. And such a conductor can be, for example, a transformer winding, a transformer core or any piece of metal.

And it turns out that the induced EMF in a closed winding or magnetic circuit starts the heating process.

That is, in essence, an induction heater is nothing more than a transformer with a short-circuited secondary winding, which consists of only one turn.

And since the internal resistance of the workpiece is quite small, even the smallest induced eddy current is quite enough to form a current of increased density. And he, in turn, performs the work of heating and melting the workpiece.

The very first channel type furnace was put into operation in 1900 in Sweden. This installation operated on alternating current with a frequency of 50-60 Hertz. And this installation had a coefficient of efficiency slightly less than 50%

Modern furnaces, on the other hand, are coreless transformers, which are made of several turns of a thick copper tube. And inside it circulates an active cooling liquid.

In this case, an alternating current with an increased frequency is supplied to this copper tube in the range from a couple of kilohertz to several megahertz. The value of the frequency is directly dependent on what material needs to be heated and melted.

Such a high frequency is used because at such values, such an effect is observed as the displacement of the eddy current to the surface of the heated conductor. This phenomenon is called the Skin Effect.

And it would seem that such heaters are especially large units installed at enterprises in large workshops, and it is difficult to imagine such equipment at home.

Home Induction Heater

But progress does not stand still, and now in stores you can find compact induction heaters, one of which I purchased in order to experiment with it.

Its external dimensions are rather modest: 55 x 40 x 20 millimeters. In this case, power is supplied from a source of 5-12 Volts with a maximum current of 5 Amperes.

In other words, the maximum that this "baby" can consume is 60 watts. But you may well ask the pig: why is it needed in the house at all?

In fact, you can think of a large number of options for using such a heater at home.

The first thing that came to my mind was warming up strongly stuck nuts in order to unscrew them.

For experimentation and home use, you can order a cheap sample, for example, here at this seller.

Conclusion

This is such an induction heater that works both in large factories and in small home workshops. Share your ideas for using such a gadget in your home workshop.

Thank you for your time!