DIY duct induction oven. Induction furnaces. Types and work. Application and features. Transistor design

Induction furnaces are used for smelting metals and are distinguished by the fact that heating in them occurs through electric current. The current is excited in the inductor, or more precisely in a constant field.

In such structures, energy is converted several times (in this sequence):

into electromagnetic;
electrical;
thermal

Such stoves allow you to use heat with maximum efficiency, which is not surprising, because they are the most advanced of all existing models that run on electricity.

Note! Induction designs come in two types - with or without a core. In the first case, the metal is placed in a tubular trough, which is located around the inductor. The core is located in the inductor itself. The second option is called crucible, because in it the metal and the crucible are already inside the indicator. Of course, there can be no talk of any core in this case.

In today's article we will talk about how to makeDIY induction oven.

Among the many advantages, the following are worth highlighting:

environmental cleanliness and safety;
increased homogeneity of the melt due to active movement of metal;
speed – the oven can be used almost immediately after switching on;
zonal and focused energy orientation;
high melting rate;
no fumes from alloying substances;
possibility of temperature adjustment;
numerous technical possibilities.

But there are also disadvantages.

The slag is heated by the metal, as a result of which it has a low temperature.
If the slag is cold, then it is very difficult to remove phosphorus and sulfur from the metal.
The magnetic field is dissipated between the coil and the melting metal, so a reduction in the thickness of the lining will be required. This will soon lead to the lining itself failing.

Video – Induction oven

Industrial Application

Both designs are used in the smelting of cast iron, aluminum, steel, magnesium, copper and precious metals. The useful volume of such structures can range from several kilograms to several hundred tons.

Industrial furnaces are divided into several types.

Medium frequency designs are commonly used in mechanical engineering and metallurgy. With their help, steel is melted, and when using graphite crucibles, non-ferrous metals are melted.
Industrial frequency designs are used in iron smelting.
Resistance structures are intended for melting aluminum, aluminum alloys, and zinc.

Note! It was induction technology that formed the basis of more popular devices - microwave ovens.

Household use

Due to obvious reasons, an induction furnace for melting is not often used in everyday life. But the technology described in the article is found in almost all modern houses and apartments. These are the microwave ovens mentioned above, and induction cookers, and electric ovens.

Consider, for example, slabs. They heat the dishes due to induction eddy currents, as a result of which heating occurs almost instantly. It is typical that it is impossible to turn on a burner that has no cookware on it.

The efficiency of induction cookers reaches 90%. For comparison: for electric stoves it is approximately 55-65%, and for gas stoves it is no more than 30-50%. But in fairness, it is worth noting that special utensils are required to operate the described stoves.

Homemade induction furnace

Not long ago, domestic radio amateurs clearly demonstrated that you can make an induction furnace yourself. Today there are a lot various schemes and manufacturing technologies, we have listed only the most popular of them, which means the most effective and easy to implement.

Induction furnace made from high frequency generator

Below is the electrical circuit for making homemade device from a high-frequency (27.22 megahertz) generator.

In addition to the generator, four light bulbs will be required during assembly. high power and a heavy lamp for the ready-to-work indicator.

Note! The main difference between a stove made according to this scheme is the condenser handle - in this case it is located outside.

In addition, the metal located in the coil (inductor) will melt in a device of the smallest power.

When making it is necessary to remember some important points, affecting the speed of metal control. This:

power;
frequency;
eddy losses;
heat transfer intensity;
hysteresis losses.

The device will be powered from a standard 220 V network, but with a pre-installed rectifier. If the furnace is intended for heating a room, then it is recommended to use a nichrome spiral, and if for melting, then graphite brushes. Let's take a closer look at each of the designs.

Video - Construction of a welding inverter

The essence of the design is as follows: a pair of graphite brushes is installed, and granite powder is poured between them, after which the connection is made to the step-down transformer. It is characteristic that during smelting there is no need to fear electric shock, since there is no need to use 220 V.

Assembly technology

Step 1. The base is assembled - a box made of fireclay bricks measuring 10x10x18 cm, laid on fire-resistant tiles.

Step 2. The box is finished with asbestos cardboard. After wetting with water, the material softens, which allows it to be given any shape. If desired, the structure can be wrapped with steel wire.

Note! The dimensions of the box may vary depending on the power of the transformer.

Step 3. The best option for a graphite furnace - a transformer from a welding machine with a power of 0.63 kW. If the transformer is designed for 380 V, then it can be rewound, although many experienced electricians claim that you can leave everything as is

Step 4. The transformer is wrapped with thin aluminum - this way the structure will not get too hot during operation.

Step 5. Graphite brushes are installed, a clay substrate is installed on the bottom of the box - this way the molten metal will not spread.

The main advantage of such a furnace is its high temperature, which is even suitable for smelting platinum or palladium. But among the disadvantages are the rapid heating of the transformer, small volume (no more than 10 g can be smelted at a time). For this reason, a different design will be required for larger volume melts.

So, to smelt large volumes of metal you will need a furnace with nichrome wire. The operating principle of the design is quite simple: electric current is supplied to a nichrome spiral, which heats up and melts the metal. There are a lot of different formulas on the Internet for calculating the length of a wire, but they are all, in principle, the same.

Step 1. For the spiral, nichrome ø0.3 mm with a length of about 11 m is used.

Step 2. The wire must be wound. To do this, you will need a straight copper tube ø5 mm - the spiral is wound on it.

Step 3. Use a small crucible as a crucible. ceramic pipeø1.6 cm and 15 cm long. One end of the pipe is plugged with asbestos thread - this way the molten metal will not leak out.

Step 4. After checking the functionality, the spiral is laid around the pipe. In this case, the same asbestos thread is placed between the turns - it will prevent short circuits and limit the access of oxygen.

Step 5. The finished coil is placed in a high power lamp socket. Such cartridges are usually ceramic and have the required size.

Advantages of this design:

high productivity (up to 30 g per pass);
fast heating (about five minutes) and long cooling;
ease of use - it is convenient to pour metal into molds;
prompt replacement of the spiral in case of burnout.

But there are, of course, disadvantages:

nichrome burns out, especially if the spiral is poorly insulated;
insecurity - the device is connected to a 220 V power supply.

Note! You cannot add metal to the stove if the previous portion has already been melted there. Otherwise, all the material will scatter throughout the room, moreover, it can injure your eyes.

As a conclusion

As you can see, you can still make an induction furnace yourself. But to be frank, the described design (like all those available on the Internet) is not exactly a stove, but a Kukhtetsky laboratory inverter. It is simply impossible to assemble a full-fledged induction structure at home.

Metal smelting by induction is actively used in various industries, such as mechanical engineering, metallurgical and jewelry production. The material is heated under the influence of electric current, which allows the heat to be used with maximum efficiency. On large factories There are special industrial units for this, while at home you can assemble a simple and small induction furnace with your own hands.

Such furnaces are popular in production

Self-assembly of the stove

There are many technologies and schematic descriptions of this process presented on the Internet and magazines, but when choosing, it is worth choosing one model that is most effective in operation, as well as affordable and easy to implement.

Homemade melting furnaces have quite simple design and usually consist of only three main parts, placed in a sturdy case. These include:

element generating alternating current high frequency;
spiral-shaped piece created from copper tube or thick wire, called an inductor;
crucible - a container in which calcination or melting will be carried out, made of refractory material.

Of course, such equipment is not often used in everyday life, because not all craftsmen need such units. But the technologies found in these devices are present in household appliances, which many people deal with almost every day. This includes microwaves, electric ovens and induction cookers. You can make various equipment with your own hands according to the diagrams, if available necessary knowledge and skills.

In this video you will learn what this oven consists of

Heating in this technique is carried out thanks to induction eddy currents. The temperature rise occurs instantly, unlike other devices of a similar purpose.

For example, induction cookers have an efficiency of 90%, but gas and electric cookers cannot boast of this value; it is only 30-40% and 55-65%, respectively. However, HDTV cookers have a drawback: to use them you will have to prepare special dishes.

Transistor design

There are many different schemes for assembling induction melters at home. A simple and proven oven made from field effect transistors It is quite easy to assemble; many craftsmen familiar with the basics of radio engineering can handle its manufacture according to the diagram shown in the figure. To create an installation need to prepare following materials and details:

two IRFZ44V transistors;
copper wires (for winding) in enamel insulation, 1.2 and 2 mm thick (one piece each);
two rings from chokes, they can be removed from the power supply of an old computer;
one 470 Ohm resistor per 1 W (you can connect two 0.5 W each in series);
two UF4007 diodes (can easily be replaced with the UF4001 model);
250 W film capacitors - one piece with a capacity of 330 nF, four - 220 nF, three - 1 µF, 1 piece - 470 nF.

Before assembling such a stove, do not forget about the tools

Assembly takes place according to the schematic drawing; it is also recommended to check step by step instructions, this will protect you from errors and damage to elements. Creation of induction melting furnace do it yourself using the following algorithm:

Transistors are placed on fairly large heatsinks. The fact is that circuits can get very hot during operation, which is why it is so important to select parts of the appropriate size. All transistors can be placed on one radiator, but in this case you will have to insulate them, preventing them from coming into contact with metal. Washers and gaskets made of plastic and rubber will help with this. The correct pinout of transistors is shown in the picture.
Then they start making chokes; you will need two of them. To do this, take copper wire 1.2 millimeters in diameter and wrap it around rings taken from the power supply. These elements contain ferromagnetic iron in powder form, so it is necessary to make at least 7-15 turns, leaving a small distance between them.
The resulting modules are assembled into one battery with a capacity of 4.6 μF, and the capacitors are connected in parallel.
Copper wire 2 mm thick is used to wind the inductor. It is wrapped 7-8 times around any cylindrical object, its diameter should correspond to the size of the crucible. The excess wire is cut off, but rather long ends are left: they will be needed for connecting to other parts.
All elements are connected on the board, as shown in the figure.

If necessary, you can build a housing for the unit; for this purpose, only heat-resistant materials, such as textolite, are used. The power of the device can be adjusted, for which it is enough to change the number of turns of wire on the inductor and their diameter.

There are several variations of the induction furnace that can be assembled

With graphite brushes

The main element of this design is assembled from graphite brushes, the space between which is filled with granite, crushed to a powder state. Then the finished module is connected to a step-down transformer. When working with such equipment, you do not have to worry about electric shock, since it does not need to use 220 volts.

Manufacturing technology of an induction furnace from graphite brushes:

First, the body is assembled; for this, fire-resistant (fireclay) bricks measuring 10 × 10 × 18 cm are laid on tiles that can withstand high temperatures. The finished box is wrapped in asbestos cardboard. To give this material the desired shape, it is enough to moisten it with a small amount of water. The size of the base directly depends on the power of the transformer used in the design. If desired, the box can be covered with steel wire.
An excellent option for graphite furnaces would be a 0.063 kW transformer taken from a welding machine. If it is designed for 380 V, then for safety reasons it can be subjected to winding, although many experienced radio technicians believe that this procedure can be abandoned without any risk. However, it is recommended to wrap the transformer with thin aluminum so that the finished device does not heat up during operation.
A clay substrate is placed at the bottom of the box so that the liquid metal does not spread, after which graphite brushes and granite sand are placed in the box.

The main advantage of such devices is considered to be the high melting point, which can change the state of aggregation of even palladium and platinum. The disadvantages include too rapid heating of the transformer, as well as small area a furnace that will not allow smelting more than 10 g of metal at a time. Therefore, every master should understand that if the device is assembled to process large volumes, then it is better to make a furnace of a different design.

Lamp-based device

A powerful melting stove can be assembled from electronic light bulbs. As can be seen in the diagram, to obtain high-frequency current, beam lamps must be connected in parallel. Instead of an inductor, this device uses a copper tube with a diameter of 10 mm. The design is also equipped with a tuning capacitor in order to be able to regulate the power of the furnace. For assembly you need to prepare:

four lamps (tetrodes) L6, 6P3 or G807;
trimmer capacitor;
4 chokes at 100-1000 µH;
neon indicator light;
four 0.01 µF capacitors.

To begin with, the copper tube is shaped into a spiral - this will be the inductor of the device. In this case, a distance of at least 5 mm is left between the turns, and their diameter should be 8-15 cm. The ends of the spiral are processed for attachment to the circuit. The thickness of the resulting inductor should be 10 mm greater than that of the crucible (it is placed inside).

The finished part is placed in the housing. For its manufacture, you should use a material that will provide electrical and thermal insulation for the filling of the device. Then a cascade is assembled from lamps, chokes and capacitors, as shown in the figure, the latter being connected in a straight line.

It's time to connect the neon indicator: it is needed so that the master can find out when the device is ready for work. This light bulb is connected to the furnace body along with the handle of the variable capacitor.

Cooling system equipment

Industrial units for metal melting are equipped with special systems cooling with antifreeze or water. Equipping these important installations in homemade HDTV stoves will require additional costs, which is why the assembly can put a significant dent in your wallet. Therefore, it is better to provide a household unit with a cheaper system consisting of fans.

Air cooling with these devices is possible when they are located remotely from the furnace. Otherwise, the metal windings and fan parts can serve as a loop for short-circuiting eddy currents, which will significantly reduce the efficiency of the equipment.

Lamp and electronic circuits also tend to actively heat up during operation of the unit. Heat sinks are usually used to cool them.

Terms of use

For experienced radio technicians, assembling an induction furnace according to the diagrams with your own hands may seem like an easy task, so the device will be ready quite quickly, and the master will want to try his creation in action. It is worth remembering that when working with homemade installation It is important to follow safety precautions and not forget about the main threats that may arise during operation of an inertial furnace:

Liquid metal and heating elements devices can cause severe burns.
Tube circuits consist of parts with high voltage, therefore, during assembly of the unit, they must be placed in a closed box, thus eliminating the possibility of accidentally touching these elements.
The electromagnetic field can influence even those things that are outside the installation box. Therefore, before turning on the device, you need to remove all complex technical devices, such as Cell phones, digital cameras, MP3 players, and also remove all metal jewelry. People with pacemakers are also at risk: they should never use such equipment.

These furnaces can be used not only for melting, but also for rapid heating metal objects during forming and tinning. By changing the output signal of the installation and the parameters of the inductor, you can configure the device for a specific task.

For melting small volumes of iron, homemade stoves are used; these effective devices can operate from ordinary sockets. The device does not take up much space, it can be placed on a desktop in a workshop or garage. If a person can read simple electrical circuits, then he does not need to purchase similar equipment in the store, because he can assemble a small stove with his own hands in just a few hours.

Radio amateurs have long discovered that they can make induction furnaces for melting metal with their own hands. These simple diagrams will help you make a HDTV installation for home use. However, it would be more correct to call all the described designs “Kukhtetsky’s laboratory inverters,” since it is simply impossible to independently assemble a full-fledged stove of this type.

For many years people have been smelting metal. Each material has its own melting point, which can only be achieved using special equipment. The first furnaces for melting metal were quite large and were installed exclusively in the workshops of large organizations. Today, a modern induction furnace can be installed in small workshops when setting up jewelry production. It is small, easy to use and highly effective.

Operating principle

The melting unit of an induction furnace is used to heat a wide variety of metals and alloys. The classic design consists of the following elements:

Drain pump.
Water cooled inductor.
Frame made of of stainless steel or aluminum.
Contact area.
The hearth is made of heat-resistant concrete.
Support with hydraulic cylinder and bearing unit.

The operating principle is based on the creation of Foucault eddy induction currents. As a rule, when working household appliances Such currents cause failures, but in this case they are used to heat the charge to the required temperature. Almost all electronics begin to heat up during operation. This negative factor electricity is used at full capacity.

Advantages of the device

The induction melting furnace began to be used relatively recently. The famous open-hearth furnaces, blast furnaces and other types of equipment are installed at production sites. Such a furnace for melting metal has the following advantages:

It is this last advantage that determines the spread of induction furnaces in jewelry, since even a small concentration of foreign impurities can negatively affect the result obtained.

Depending on the design features, floor-standing and tabletop induction furnaces are distinguished. Regardless of which option was chosen, there are several basic rules for installation:

The device may become very hot during operation. That is why there should be no flammable or explosive substances nearby. In addition, according to technology fire safety close should a fire shield must be installed.

Only two types of furnaces are widely used: crucible and channel. They have similar advantages and disadvantages, the differences lie only in the method of operation used:

The most popular type of induction furnace is the crucible type. This is due to their high performance and ease of operation. In addition, if necessary, such a design can be made independently.

Homemade versions are quite common. To create them you need:

Generator.
Crucible.
Inductor.

An experienced electrician, if necessary, can make an inductor with his own hands. This structural element is represented by a winding of copper wire. The crucible can be purchased at the store, but a lamp circuit, a self-assembled battery of transistors, or a welding inverter are used as a generator.

Using a welding inverter

An induction furnace for melting metal with your own hands can be created using welding inverter as a generator. This option is the most widely used since the efforts made concern only the manufacture of the inductor:

Thin-walled copper tube is used as the main material. The recommended diameter is 8-10 cm.
The tube is bent according to the desired pattern, which depends on the characteristics of the housing used.
There should be a distance of no more than 8 mm between the turns.
The inductor is placed in a textolite or graphite housing.

After creating the inductor and placing it in the housing, all that remains is to install the purchased crucible in its place.

Such a circuit is quite complex in execution, it involves the use of resistors, several diodes, transistors of various capacities, a film capacitor, copper wire with two different diameters and throttle rings. Assembly recommendations are as follows:

The created circuit is placed in a textolite or graphite case, which are dielectrics. Scheme, involving the use of transistors, quite difficult to implement. Therefore, you should undertake the manufacture of such a stove only if you have certain work skills.

Lamp stove

Lately, lamp-based stoves have been created less and less frequently, as they require careful handling. The circuit used is simpler compared to the case of using transistors. Assembly can be carried out in several stages:

The llamas used must be protected from mechanical impact.

Equipment cooling

When creating an induction furnace with your own hands, the biggest problem that arises is cooling. This is due to the following points:

During operation, not only the molten metal is heated, but also some elements of the equipment. That's why for long work efficient cooling is required.
Application based method air flow, characterized by low efficiency. In addition, it is not recommended to install fans near the stove. This is due to the fact that metal elements can influence the eddy currents generated.

Typically, cooling is carried out by supplying water. Creating a water cooling circuit at home is not only difficult, but also economically unprofitable. Industrial versions of the furnace already have a built-in circuit, to which it is enough to connect cold water.

Safety precautions

When using an induction furnace, certain safety precautions must be followed. Basic recommendations:

When installing equipment, you should consider how the charge will be loaded and the molten metal will be extracted. It is recommended to set aside a separate prepared room for installing an induction furnace.

Induction melting furnace has been used for melting metals and alloys for the past few decades. The device has become widespread in the metallurgical and mechanical engineering fields, as well as in jewelry. If you wish, you can make a simple version of this equipment yourself. Let's take a closer look at the operating principle and features of using an induction furnace.

Induction heating principle

In order for a metal to move from one state of aggregation to another, it must be heated to sufficiently high temperature. Moreover, each metal and alloy has its own melting point, which depends on chemical composition and other points. An induction melting furnace heats the material from the inside by creating eddy currents that pass through crystal lattice. The process under consideration is associated with the phenomenon of resonance, which causes an increase in the strength of eddy currents.

The operating principle of the device has the following features:

The space that is formed inside the coil serves to accommodate the workpiece. This heating method can be used in industrial conditions only if a large device is created into which mixtures of various sizes can be placed.
The installed coil may have different shape, for example, eights, but the spiral is most widespread. It is worth considering that the shape of the coil is selected depending on the characteristics of the workpiece being heated.

In order to create an alternating magnetic field, the device is connected to a household power supply network. To improve the quality of the resulting alloy with high fluidity, high-frequency generators are used.

Design and use of an induction furnace

If desired, you can create an induction furnace for melting metal from scrap materials. The classic design has three blocks:

A generator that creates high frequency alternating current. It is he who creates an electric current, which is converted into a magnetic field passing through the material and accelerating the movement of particles. Due to this, the transition of metal or alloys from solid state into liquid.
The inductor is responsible for creating magnetic field, which heats the metal.
The crucible is designed for melting material. It is placed in an inductor, and the winding is connected to current sources.

The process of converting electric current into a magnetic field is used today in a wide variety of industries.

The main advantages of the inductor include the following points:

A modern device is capable of directing a magnetic field, thereby increasing efficiency. In other words, the charge is heated, not the device.
Due to the uniform distribution of the magnetic field, the workpiece is heated evenly. In this case, from the moment the device is turned on until the charge is melted, it takes about a large number of time.
The homogeneity of the resulting alloy, as well as its high quality.
When heating and melting the metal, no evaporation is formed.
The installation itself is safe to use and does not cause the formation of toxic substances.

There is simply great amount various options designs of homemade induction furnaces, each with its own specific features.

Types of induction furnaces

Considering the classification of devices, we note that the workpieces can be heated both inside and outside the coil. That is why there are two types of induction furnaces:

Channel. This kind of device has small channels that are located around the inductor. To generate an alternating magnetic field, a core is located inside.
Crucible. This design is characterized by the presence of a special container called a crucible. It is made from refractory metal with a high melting point.

It is important that channel induction furnaces have large overall dimensions and are intended for industrial metal melting. Due to the continuous melting process, a large volume of molten metal can be obtained. Channel induction furnaces are used for melting aluminum and cast iron, as well as other non-ferrous alloys.
Crucible induction furnaces are characterized by relatively small in size. In most cases, this type of device is used in jewelry making, as well as when melting metal at home.
When creating a furnace with your own hands, you can adjust the power by changing the number of turns. It is worth considering that as the power of the device increases, a larger battery is required, as the energy consumption increases. In order to reduce the temperature of the main structural elements, a fan is installed. During long-term operation of the stove, its main elements can heat up significantly, which is worth taking into account.
Lamp-based induction furnaces have become even more widespread. You can make a similar design yourself. The assembly process has the following features:
A copper tube is used to create an inductor, for which it is bent in a spiral. The ends must also be large, which is required to connect the device to a current source.
The inductor should be placed in the housing. It is made of heat-resistant material that can reflect heat.
The lamp cascades are connected according to a circuit with capacitors and chokes.
The neon indicator lamp is connected. It is included in the circuit to indicate that the device is ready for operation.
A variable capacitor is connected to the system.

An important point is how the system can be cooled. When operating almost all induction furnaces, the main structural elements can heat up to high temperatures. Industrial equipment has a forced cooling system that runs on water or antifreeze. In order to create a water cooling design with your own hands, quite a lot of money is required.
The system is installed at home air cooling. For this purpose, fans are installed. They should be positioned so as to ensure a continuous flow of cold air to the main structural elements of the furnace.

Induction furnaces were invented back in 1887. And just three years later, the first industrial development appeared, with the help of which they smelted various metals. I would like to note that in those distant years these stoves were a novelty. The thing is that scientists of that time did not quite understand what processes were occurring in it. Today we figured it out. In this article we will be interested in the topic - do-it-yourself induction furnace. How simple is its design, is it possible to assemble this unit at home?

Principle of operation

You need to start assembling by understanding the principle of operation and structure of the device. Let's start with this. Pay attention to the figure above, we will understand it according to it.

The device includes:

Generator G, which produces alternating current.
Capacitor C, together with coil L, creates an oscillating circuit, which provides the installation with high temperature.

Attention! Some designs use a so-called self-oscillating generator. This makes it possible to remove the capacitor from the circuit.
The coil in the surrounding space forms a magnetic field in which there is a voltage, indicated in our figure by the letter “H”. The magnetic field itself exists in free space, or can be short-circuited through a ferromagnetic core.
It also acts on the charge (W), in which it creates magnetic flux(F). By the way, instead of the charge, some kind of blank can be installed.
The magnetic flux induces a secondary voltage of 12 V. But this only happens if W is an electrically conductive element.
If the heated workpiece is large and solid, then the so-called Foucault current begins to operate inside it. It is of the vortex type.
In this case, eddy currents are transmitted from the generator through a magnetic field thermal energy, thereby heating the workpiece.

The electromagnetic field is quite wide. And even the multi-stage energy conversion, which is present in homemade induction furnaces, has maximum efficiency - up to 100%.

Crucible furnace

Varieties

There are two main designs of induction furnaces:

Duct.
Crucible.

We won’t describe them all here. distinctive features. Just note that the duct option is a design that is similar to welding machine. In addition, in order to melt metal in such furnaces, it was necessary to leave a little melt, without which the process simply would not work. The second option is an improved scheme that uses technology without residual melt. That is, the crucible is simply installed directly into the inductor.

How it works

Why do you need such a stove at home?

In general, the question is quite interesting. Let's look at this situation. There is a fairly large number of Soviet electrical and electronic devices that used gold or silver contacts. These metals can be removed different ways. One of them is an induction stove.

That is, you take the contacts, put them in a narrow and long crucible, which you install in the inductor. After 15-20 minutes, reducing the power, cooling the apparatus and breaking the crucible, you will get a rod, at the end of which you will find a gold or silver tip. Cut it off and take it to a pawnshop.

Although it should be noted that with this homemade unit can be carried out various processes with metals. For example, you can harden or temper.

Coil with battery (generator)

Stove components

In the Working Principle section, we have already mentioned all the parts of an induction furnace. And if everything is clear with the generator, then the inductor (coil) needs to be sorted out. A copper tube is suitable for it. If you are assembling a device with a power of 3 kW, then you will need a tube with a diameter of 10 mm. The coil itself is twisted with a diameter of 80-150 mm, with a number of turns from 8 to 10.

Please note that the turns of the copper tube should not touch each other. Optimal distance there are 5-7 mm between them. The coil itself should not touch the screen. The distance between them is 50 mm.

Typically, industrial induction furnaces have a cooling unit. It is impossible to do this at home. But for a 3 kW unit, working for up to half an hour is not dangerous. True, over time, copper scale will form on the tube, which reduces the efficiency of the device. So the coil will have to be changed periodically.

Generator

In principle, making a generator with your own hands is not a problem. But this is only possible if you have sufficient knowledge in radio electronics at the level of an average radio amateur. If you don’t have such knowledge, then forget about the induction stove. The most important thing is that you also need to skillfully operate this device.

If you are faced with the dilemma of choosing a generator circuit, then take one piece of advice - it should not have a hard current spectrum. To make it clearer what we mean we're talking about, we offer the simplest generator circuit for an induction furnace in the photo below.

Generator circuit

Required knowledge

The electromagnetic field affects all living things. An example is microwaved meat. Therefore, it is worth taking care of safety. And it doesn’t matter whether you are assembling the stove and testing it or working on it. There is such an indicator as energy flux density. So it depends on exactly electromagnetic field. And the higher the frequency of radiation, the worse it is for the human body.

Many countries have adopted safety measures that take into account energy flux density. There are developed acceptable limits. This is 1-30 mW per 1 m² of the human body. These indicators are valid if exposure occurs no more than one hour per day. By the way, the installed galvanized screen reduces the density of the ceiling by 50 times.

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