Do-it-yourself induction furnace scheme. Do-it-yourself assembly of induction melting furnaces. Do it yourself

Induction furnaces are used for smelting metals and are distinguished by the fact that they are heated by means of electric current. The excitation of the current occurs in the inductor, or rather in a non-variable field.

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

into the 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 are of two types - with or without a core. In the first case, the metal is placed in a tubular chute, which is located around the inductor. The core is located in the inductor itself. The second option is called the crucible, because in it the metal with the crucible is 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 benefits are the following:

environmental cleanliness and safety;
increased homogeneity of the melt due to the active movement of the metal;
speed - the oven can be used almost immediately after switching on;
zone and focused orientation of energy;
high melting rate;
lack of waste from alloying substances;
the ability to adjust the temperature;
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.
Between the coil and the melting metal, the magnetic field dissipates, so a reduction in lining thickness will be required. This will soon lead to the fact that the lining itself will fail.

Video - Induction furnace

Industrial Application

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

Furnaces for industrial use 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 also melted.
Industrial frequency designs are used in iron smelting.
Resistance structures are intended for melting aluminum, aluminum alloys, zinc.

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

domestic use

For obvious reasons, the induction melting furnace is rarely used in the home. But the technology described in the article is found in almost all modern houses and apartments. These are the microwaves mentioned above, and induction cookers, and electric ovens.

Consider, for example, plates. They heat the dishes due to inductive eddy currents, as a result of which the heating occurs almost instantly. It is characteristic that it is impossible to turn on the burner on which there are no dishes.

The efficiency of induction cookers reaches 90%. For comparison: for electric stoves it is about 55-65%, and for gas stoves - no more than 30-50%. But in fairness, it is worth noting that the operation of the described stoves requires special dishes.

Homemade induction oven

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

Induction furnace from high frequency generator

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

In addition to the generator, four high-power light bulbs and a heavy lamp for the ready-to-go indicator are required for assembly.

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

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

When manufacturing, it is necessary to remember some important points that affect the speed of metal boarding. This is:

power;
frequency;
eddy losses;
heat transfer rate;
hysteresis loss.

The device will be powered by a standard 220 V network, but with a pre-installed rectifier. If the furnace is intended for space heating, then it is recommended to use a nichrome spiral, and if for melting, then graphite brushes. Let's get acquainted with each of the structures in more detail.

Video - Welding inverter design

The essence of the design is as follows: a pair of graphite brushes is installed, and powdered granite is poured between them, after which a step-down transformer is connected. It is characteristic that when smelting, one can not be afraid of electric shock, since there is no need to use 220 V.

Assembly technology

Step 1. The base is assembled - a box of fireclay bricks measuring 10x10x18 cm, laid on a refractory tile.

Step 2. Boxing is finished with asbestos cardboard. After wetting with water, the material softens, which allows you to give it 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 is a transformer from a 0.63 kW welding machine. If the transformer is designed for 380 V, then it can be rewound, although many experienced electricians say that you can leave everything as it is.

Step 4. The transformer is wrapped with thin aluminum - so the structure will not get very hot during operation.

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

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

So, for the smelting of large volumes of metal, a furnace with nichrome wire is required. The principle of operation of the design is quite simple: an electric current is applied to a nichrome spiral, which heats up and melts the metal. There are a lot of different formulas on the Web for calculating the length of the wire, but they are all, in principle, the same.

Step 1. For the spiral, nichrome ø0.3 mm is used, about 11 m long.

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

Step 3. A small ceramic pipe ø1.6 cm and 15 cm long is used as a crucible. One end of the pipe is plugged with asbestos thread - so the molten metal will not flow out.

Step 4. After checking the performance and the spiral is laid around the pipe. At the same time, the same asbestos thread is placed between the turns - it will prevent a short circuit and limit the access of oxygen.

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

The advantages of such a design:

high productivity (up to 30 g per run);
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, downsides:

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

Note! You can not add metal to the stove if the previous portion is already melted there. Otherwise, all the material will scatter around the room, moreover, it may injure the eyes.

As a conclusion

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

Updated:

2016-08-14

The induction furnace is well known to those whose profession or hobby is connected with melting, metal processing. They are widely used in metallurgical enterprises. But at the same time, such stoves can be used for household needs. Let's say more, this equipment, with the right approach, is made by hand. However, first we will understand the principle of operation and design.

Every induction oven is based on induction heating. In simpler terms, heat is obtained due to electric current, which creates an electromagnetic field. In this case, do not confuse the concepts of induction stove and electric boiler. Although electricity is used in both cases, the devices are completely different from each other, a different circuit is used, etc.

Inductor - turns of wires into which an electrically conductive workpiece made of graphite is placed. Due to the power of the generator, different-frequency currents enter the inductor, which contributes to the creation of a powerful electromagnetic field. The field acts on the graphite billet, heating it. This makes it possible to obtain heat of high efficiency.

The heat generated by the induction furnace can be directed to various human needs and needs:

For melting various types of metal. These are powerful furnaces used in industry;
For surface hardening of metal. An indispensable thing for processing metal products;
For heat treatment of metal blanks;
For space heating and cooking.

Types of induction furnaces

Now that the principle of operation of the device is clear, let's figure out what an induction furnace can be.

Crucible furnace. The induction crucible furnace is used for melting metal. Such equipment has a characteristic difference from steel types of furnaces - there is no core, the scheme is non-standard.
Channel oven. This is a transformer that has a steel magnetic wire and a single-turn type secondary winding. This winding serves simultaneously as a load. Such a scheme for creating a furnace is not used as often as a crucible.
Vacuum oven. The metal melting process is carried out in a vacuum, which allows removing harmful impurities from the metal.
Household induction stove. Such an induction furnace is used for domestic needs. When working with them, an important rule should be observed - use dishes whose material absorbs an electromagnetic field.

The crucible furnace is of the greatest interest, therefore we will talk about it in more detail.

crucible furnace

This is the most common type of induction oven where everything is based on induction heating.

We have already noted that the design of the equipment provides for the absence of a core. Therefore, this is a product of the correct cylindrical shape, the material for the manufacture of which must necessarily be refractory. This is the crucible. It is placed in the cavity of the inductor and connected to an AC supply.

Among the main advantages of the crucible furnace are the following:

The principle of energy release is carried out during loading, therefore no intermediate heating element is required;
The process of operation of the crucible induction furnace makes it possible to obtain multicomponent alloys;
The uniqueness of the equipment is that it recreates a different type of atmosphere - oxidizing, reducing or neutral;
Pressure indicators can be adjusted;
Differ in high productivity of work. Even at medium frequencies;
Great for working with metals of various types and brands. To switch from working with one metal to another, you do not need to spend a lot of resources and time;
Ease of operation, ease of management and configuration;
Amenable to automation;
They do not have local overheating, equalize the temperature throughout the volume of the melting tank;
Eco-friendly. As a result of the operation of the crucible furnace, the atmosphere practically does not suffer;
The process of working on a crucible-type induction furnace is quite clean and hygienic.

But crucible furnaces have two drawbacks.

Sufficiently low temperature of the slags used for processing the melting mirror.
Not a particularly high indicator of lining resistance, which becomes especially noticeable with sudden temperature changes.

But the principle of operation, the quality of metal melting and the capabilities of a crucible induction furnace make us partially turn a blind eye to the shortcomings, since their advantages are significantly superior.

Lining

We touched on such a thing as lining. But what is it? Let's figure it out.

The lining is required to protect the skin, that is, the casing of the stove. The lining does not allow high temperatures to adversely affect the structure. But that's not all.

The lining significantly reduces heat losses, and therefore increases the efficiency of the device.

As practice shows, the most effective lining is made on the basis of silica modification - quartzite. In order for the lining to perform its tasks well, it is necessary to create three material condition zones:

intermediate;
Monolithic;
Buffer.

Only a three-layer lining allows you to maximize the protective functions of the induction furnace.

Several factors negatively affect the integrity of the lining:

Violation of recommendations and rules during the laying process, when the lining was created;
The use of low quality protective materials;
Conditions of increased load during the operation of induction equipment.

Do it yourself

Do you think a do-it-yourself induction oven is real? More than.

You need to start by understanding the circuit diagram of the device. We will give an example of the most elementary induction furnace. Having understood the principle and figured out which scheme is used here, you can try to create something more complex, suitable for domestic needs.

In the described manual for the manufacture of an induction furnace, we will take a not very powerful generator with low voltage transistors. It is enough to heat the iron. The resulting heating device is completely based on the work of Foucault currents.

For work you will need:

Wire for the inductor;
Light-emitting diode;
Ferrite rings with different diameters;
Scheme K174XA11. This chip is everywhere.

Now let's start assembling.

To begin with, we will assemble a master oscillator for our induction type heater.
You need a circuit (K174XA11), which is pre-tuned to the frequency limits of 40-80 kHz.
Set the duty cycle to 50%. For the equipment being created, these are optimal indicators.
Transformer TP1 is wound on a small ferrite ring with a diameter of about 2 centimeters.
For winding, wires with a diameter of 4 millimeters are used. The winding should be 30 turns.
The TP2 transformer is wound on a ferrite ring of a larger diameter - 5 centimeters. On the primary winding, 22 turns of wires with a diameter of 1 millimeter are required.
For the secondary winding, 2-3 turns are required from a similar wire, only folded four times.
The inductor is made of wire 3 mm thick. The diameter of the resulting inductor is 11 millimeters. The number of turns is exactly 6.
To adjust the resonance, use a conventional LED connected through a 1k resistor.
If, after turning on, the generator did not start working, try to swap the outputs of the windings on the transistor bases.
Be sure to apply voltage gradually at first start-up in 10 V increments.
At the same time as increasing the voltage, monitor the condition of the transistors so that the circuit can withstand the load. If you put it together correctly, the transistors will only get slightly warm, they shouldn't be hot.

Experts note that when choosing between an induction stove and an electric analogue, preference should be given to the first option. But this is a personal matter for everyone. So decide.

An induction furnace may well be used to organize the melting of metal. Its principle of operation was laid down in the distant 19th century through discoveries in physics. Its essence is that heat is generated from electricity, which creates an alternating magnetic field. Thus, electrical energy is formed from electromagnetic energy, and thermal energy is formed from it.

If we classify induction furnaces according to the scale of use, then two types can be distinguished: industrial and domestic. However, there is also such a conditional division:

1. Channel. By design, they are similar to transformers. The inductor in this design is around the metal. An induction furnace of this type is filled with molten metal at the first start, a metal template can be used. After the process is completed, the raw material is partially drained to leave a part for the next heat.

A variety of induction furnaces - channel

2. Crucible. A common option in metallurgical production, used for processing and smelting metals of all kinds (steel, aluminum, magnesium, copper, precious, non-ferrous metals, etc.). The induction crucible furnace is also used in other industries, for example, in jewelry. In such devices there is no core. An important advantage of crucible devices is their ease of execution. The crucible is immersed in the inductor for subsequent heating of the metal. Such a container can be made of graphite, ceramics, steel and other materials.

A variety of induction furnaces - channel

Modern models of crucible induction furnaces

3. Vacuum. An effective tool for removing various impurities from the melt.

A variety of induction furnaces - vacuum

This division, of course, applies to industrial induction furnaces. As for household devices, they are divided into the following types:

For cooking food. An important characteristic of such stoves is the economical consumption of electricity. In addition, they are characterized by a high level of security.
For heating. Small heating devices are used in schemes of autonomous heating systems.

According to the organization of the process, there can be different actions:

continuous;
semi-continuous;
periodic.

Crucible devices

Induction furnaces without a core are called crucible. The basis of their scheme is a melting crucible. It is made of refractory material, installed in the cavity of the inductor. A metal element is loaded into the crucible, through which electromagnetic energy passes.

Melting Crucible Industrial Type Induction Furnace

Advantages of crucible furnaces:

intermediate heating elements are not used;
any atmosphere can be created in the crucible furnace: from neutral to oxidizing;
high efficiency provided by power;
low air pollution;
convenience and ease of maintenance;
provides a quick transition from one metal to another.

Among the shortcomings, one can single out the low temperature of the slags.

Work of industrial crucible induction furnace

According to the design of the crucible, there are such schemes of crucible furnaces:

with refrigeration;
with graphite;
with metal;
with ceramic crucible.

The difference between homemade and factory devices

Many are interested in whether induction can be made. After all, this is a rather complicated device. However, a fairly simple principle of operation allows you to implement the task yourself. Experienced specialists can create a device with their own hands literally from improvised materials, guided by simple diagrams. To work, you will need certain knowledge and skills. Schemes can be used ready-made.

The structure of the mass production induction furnace

Advantages

Considering induction furnaces, it is impossible not to note their advantages. And they are:

Provides instant heating.
A focus of energy is created.
There is no fumes.
You can change the capacitance, frequency over a wide range.
It can be used not only for direct heating, but also as a source for a water circuit.
The coolant can be any liquid compositions: water, oil, antifreeze and others.
More economical than standard electric heaters.
They have high reliability.
A do-it-yourself induction furnace made can be used for private purposes and for heating and for creating jewelry.
For organizing home heating, a separate room is not required, since the stove can be installed in any room, it works silently.
It can be used as the main heat source or participate in a combined circuit with other devices.
Simplicity and reliability of a design guarantee absence of need for service.
Devices meet the requirements of fire safety, do not emit harmful substances.

Features of the plates

Not only stoves, but also stoves can be induction. Today, the home appliance market is widely represented by various options for execution. And they successfully break the idea of electric stoves as pancakes or spirals that are red-hot.

Induction hob in the house

An important feature of such stoves is the need to use special dishes, since traditional options are not suitable in most cases. We need ferrimagnetic alloy products. The dishes pass through a magnetic field, which, as a result of physical reactions, is converted into thermal energy used to heat food, water, etc. At the same time, the device itself does not heat up! And when the pot or pan is removed from the stove, the heating stops (the core opens).

As a result, there are several significant advantages of induction cookers:

The efficiency of such devices is high - 90%. This is a very good indicator when compared with other options for heating food. For example, for electric, this parameter is less, for gas - even less.
Provides high precision contact with the heated surface. It is enough to close 70% of the working surface so that the device independently determines the heating area and begins to operate.
Cooking on such stoves is accelerated. This is a positive thing, but when you first meet, you need to take this fact into account so that the food does not burn. Food, water will heat up instantly.
Manufacturers deliberately equip such equipment with additional functions in order to expand their application.
If food, water or something else that accompanies cooking gets on such a work surface, nothing burns, there is no smell.
The plate does not heat up, looks attractive. It can be supplied both free-standing and built-in.
No special care conditions required. You can use a sponge and detergent.
Operational safety is at a height, however, it is recommended that the panels be placed on the countertop, but not washing, dishwashers, refrigerators and other appliances.

Note: However, it must be remembered that when an induction furnace is operating, a person has to be near it, which means that eddy currents act on him, which can have undesirable consequences. And, of course, special utensils will be required to work with the equipment, as already mentioned.

Design

The classic induction furnace has the following composition:

frame;
inductor;
generator;
chamber (if the device is used for melting) or heating element (if the device is used for heating).

Power from the generator launches currents into the inductor, which creates a source of eddy currents - an electromagnetic field. It is absorbed by the metal, as a result of which it heats up, melts (depending on the need).

Heating system

Note: To organize an induction furnace with your own hands, budget options for welding inverters are often used in the circuit. And here it is necessary to take into account the energy consumption of such equipment, so a cable with a cross section of 4–6 mm 2 is required to supply voltage.

Such systems are controlled automatically and are closed. Additionally, a pump is needed to circulate the coolant. A pressure gauge and a device must also be provided that will ensure the effective exit of air from the system.

The following distances are regulated:

from walls, other objects - more than 30 cm;
from the floor, ceiling - 1 m.

Generator

Inductors in domestic conditions can work from converters of different frequencies or from generators. On an industrial scale, special installations are used. If you create an induction furnace with your own hands, you must use high-frequency generators. In this case, the equipment should give a fairly soft current spectrum. The recommended frequency is 27.12 MHz.

Inductor

You can use different modifications of the inductor. The central element is a metal or graphite product. A conductor is wound around it. Nichrome spiral and graphite brushes are heated to high temperatures.

Scheme of organizing heating using an induction boiler

For the manufacture of the inductor, it is best to use a spiral, its inner diameter can be 80–150 mm. PEV 0.8 can serve as a material for creation. The number of turns with a diameter of 10 mm can be 8–10, the distance between which is 5–7 mm.

Cooling

In order for the induction furnace to work more efficiently, the creation of cooling is required. This is a necessary condition not only for industrial, but also for household devices. If a home-made device is created with low power, and besides, short periods of time will be used, then it is quite possible to do without cooling in the circuit.

This function cannot be implemented by a home master, since scale on copper causes the furnace to stop working, which means that the inductor will need to be replaced.

Organization of heating with an induction boiler

In industrial conditions, either air is used in combination with water, or only water cooling. The air method alone is not used as the fan can disrupt the process resulting in lower efficiency.

Security

If there is an induction oven nearby, the biggest danger is thermal burns. In addition, the fire hazard of the device must be taken into account. Devices must not be moved while they are in operation. And you need to be especially careful about safety conditions if the induction furnace is used in residential buildings.

Creation of a heating system based on an induction boiler

It should be understood that such devices provide heating of the entire surrounding space, including devices, metal objects, human tissues, etc. If a person has implanted pacemakers, this must be taken into account when using the furnace.

We create

Induction furnaces are very often made by craftsmen who are engaged in the manufacture of metal products. For these purposes, power from a transformer or mains power can be used. Also, such devices can be used for space heating.

Making an induction boiler with your own hands

To assemble the oven with your own hands, you can use a high-frequency generator. The frequency of its oscillations, as mentioned, can be 27.12 MHz. The circuit includes 4 tetrads, as well as a lamp necessary to signal the possibility of starting operation.

The condenser handle in such a device is outside. Before assembling such a furnace, it is necessary to take into account the factors affecting the melting rate:

generator power;
frequency;
eddy losses;
heat transfer rate.

It is necessary to use high power llamas - up to 4 pieces. For power supply, a 220 V network with a rectifier is used. If induction furnaces are used for heating, then a nichrome spiral is used, for melting - graphite brushes.

It must be remembered that at the first start, you should not immediately apply the maximum voltage, this should be done gradually, adding 12 V each. At the same time, you need to watch the transistors, which can only be warm, but in no case hot.

Results

As you can see, induction furnaces are a useful device that has found wide application in everyday life and industry. In the first case, the distribution of these devices is largely ensured by the possibility of creating them yourself. This allows the owner to save money and get an efficient device that can be used either for melting metal or for space heating.

Many people believe that the process of smelting metal requires huge facilities, practically factories with a large number of employees. But there is still such a profession as a jeweler and metals such as gold, silver, platinum and others used to make delicate and exquisite jewelry, some of which are rightfully considered real works of art. A jewelry workshop is an enterprise that does not tolerate excessive scale. And the melting process in them is simply necessary. Therefore, an induction furnace for melting metal is necessary here. It is not large, and very efficient, and easy to handle.

The principle of operation of an induction furnace is a wonderful example of how an undesirable phenomenon is used with increased efficiency. The so-called Foucault eddy currents, which usually interfere with any kind of electrical engineering, are only aimed at a positive result here.

In order for the metal structure to begin to heat up and then melt, it must be placed under these same Foucault currents, and they are formed in an induction coil, which, by and large, is a furnace.

Simply put, everyone knows that during operation, any electrical appliance starts to heat up. The metal melting induction furnace takes full advantage of this otherwise undesirable effect.

Advantages over other types of melting furnaces

Induction furnaces are not the only invention used to melt metals. There are also famous open-hearth, blast furnaces and other types. However, the furnace we are considering has a number of undeniable advantages over all the others.

Induction ovens can be quite compact, and their placement will not cause any difficulties.
High melting speed. If other metal melting furnaces require several hours just to heat up, induction copes with this several times faster.
The efficiency is only slightly less than 100%.
According to the purity of the melt, the induction furnace confidently takes the first place. In other devices, the workpiece prepared for the melt is in direct contact with the heating element, which often leads to contamination. Foucault currents heat the workpiece from the inside, affecting the molecular structure of the metal, and no side elements get into it.

The latter advantage is essential in jewelry, where the frequency of the material enhances its value and uniqueness.

Furnace placement

Compact induction furnace, depending on the size, it can be floor and desktop. Whichever option you choose, there are a few basic rules for choosing where to put it.

Despite the ease of handling the oven, it is still an electrical appliance that requires safety measures. And the first thing to consider during installation is the availability of the correct power source corresponding to the model of the device.
The ability to carry out high-quality grounding.
Provision of installation with water supply.
Table ovens require a stable base.
But most importantly, nothing should interfere with work. Even if the melt is not too large in terms of volume and mass, its temperature is more than 1000 degrees and accidentally splashing it out of the mold means inflicting very severe injury either on oneself or on what is nearby.

There is nothing to say about the fact that there should not be any combustible and, even more so, explosive materials near a working induction furnace. But a fire shield within walking distance is absolutely necessary.

Types of induction furnaces

Two types of induction furnaces are widely used: channel and crucible. They differ only in the way they work. In all other respects, including advantages, such melting furnaces are very similar. Let's consider each option separately:

Channel oven. The main advantage of this type is a continuous cycle. You can load a new portion of raw materials and unload already molten metal directly during heating. The only difficulty may arise at startup. The channel through which the liquid metal will be removed from the furnace must be filled.
Crucible furnace. Unlike the first option, each portion of the metal will have to be loaded separately. This is the point. The raw material is placed in a heat-resistant crucible and placed inside the inductor. After the metal melts, it is drained from the crucible and only then the next portion is loaded. Such a furnace is ideal for small workshops where large masses of molten raw materials are not required.

The main advantage of both options is the speed of production. However, the crucible furnace wins here too. In addition, it is quite possible to make it yourself at home.

A home-made induction furnace does not contain any difficulties so that an ordinary person who is at least a little familiar with electrical engineering cannot assemble it. It has only three main blocks:

Generator.
Inductor.
Crucible.

The inductor is a copper winding that you can make yourself. You will have to look for the crucible either in the appropriate stores, or get it in other ways. And as a generator can be used: a welding inverter, a personally assembled transistor or lamp circuit.

Induction furnace on a welding inverter

The simplest and most widely used option. Efforts will have to be expended only on the construction of the inductor. A copper thin-walled tube 8-10 cm in diameter is taken and bent according to the desired pattern. The turns should be located at a distance of 5-8 mm, and their number depends on the characteristics and diameter of the inverter. The inductor is fixed in a textolite or graphite case, and a crucible is placed inside the installation.

transistor induction furnace

In this case, you will have to work not only with your hands, but also with your head. And run around the shops in search of the necessary spare parts. After all, you will need transistors of different capacities, a couple of diodes, resistors, film capacitors, two copper wires of different thicknesses and a couple of rings from chokes.

Before assembly, it must be borne in mind that the resulting circuit will become very hot during operation. Therefore, fairly large heatsinks must be used.
Capacitors are collected in parallel in a battery.
Copper wire with a diameter of 1.2 mm is wound on the throttle rings. Depending on the power, the turns should be from 7 to 15.
On a cylindrical object, suitable in diameter to the size of the crucible, 7-8 turns of copper wire with a diameter of 2 mm are wound. The ends of the wire are left long enough for connection.
According to a special scheme, everything is mounted on the board.
The power source can be a 12-volt battery.
If necessary, you can make a textolite or graphite case.
The power of the device is regulated by increasing or decreasing the turns of the inductor winding.

It is not easy to assemble such a device on your own. And you can take on this work only when there is confidence in the correctness of your actions.

Lamp induction oven

Unlike a transistor one, a lamp furnace will turn out to be much more powerful, which means that you will have to be more careful with both it and the circuit.

4 ray lamps connected in parallel will generate high frequency currents.
Copper wire is bent into a spiral. The distance between the turns is 5 mm or more. The turns themselves are 8-16 cm in diameter. The inductor must be of such a size that the crucible can easily fit inside.
The inductor is placed in a housing made of a non-conductive material (textolite, graphite).
You can put a neon indicator lamp on the case.
You can also include a tuning capacitor in the circuit.

The manufacture of both circuits requires the possession of some knowledge, which can be obtained, but it is better if a real specialist does this.

Cooling

This question is probably the most difficult of all those that are put before a person who decides to independently assemble a melting apparatus based on the induction principle. The fact is that it is not recommended to put the fan directly near the oven. The metal and electrical parts of the cooling unit may adversely affect the operation of the stove. A fan located far away may not provide the necessary cooling, which will lead to overheating.

The second option is to carry out water cooling. However, it is not only difficult to perform it at home qualitatively and correctly, but it is also not financially profitable. In this case, it is worth considering: would it not be more economical to purchase an industrial version of an induction furnace, produced at the factory, in compliance with all the necessary technologies?

Safety precautions when smelting metal in an induction furnace

There is no need to expand on this topic, since almost everyone knows the basic safety regulations. It is necessary to dwell only on those issues that are unique to this type of equipment.

Let's start with personal safety. When working with an induction furnace, it should be well understood that the temperatures here are very high, and this is a risk of burns. Also, the device is electrical and requires increased attention.
If you bought a finished oven, you should pay attention to the radius of influence of the electromagnetic field. Otherwise, watches, phones, camcorders and other electronic gadgets may start to fail or even break down.
Work clothes should be selected with non-metallic fasteners. Their presence, on the contrary, will affect the operation of the furnace.
Particular attention in this respect should be given to the lamp oven. All elements with high voltage must be hidden in the case.

Of course, such equipment is unlikely to come in handy in a city apartment, but radio amateurs who are constantly engaged in tinning and jewelry craftsmen cannot do without an induction furnace. For them, this thing is very useful, one might say irreplaceable, and how it helps in their work, it is better to ask them themselves.

Before we talk about how to assemble a homemade induction heater, you need to find out what it is and how it works.

History of induction heaters

In the period from 1822 to 1831, the famous English scientist Faraday conducted a series of experiments, the purpose of which was to achieve the conversion of magnetism into electrical energy. He spent a lot of time in his laboratory. Until one day, in 1831, Michael Faraday finally got his way. The scientist finally managed to get an electric current in the primary winding from a wire that was wound on an iron core. This is how electromagnetic induction was discovered.

Power of induction

This discovery began to be used in industry, in transformers, various motors and generators.

However, this discovery really became popular and necessary only after 70 years. During the rise and development of the metallurgical industry, new, modern methods of melting metals were required in the conditions of metallurgical production. By the way, the first foundry, which used a vortex induction heater, was launched in 1927. The plant was located in the small English town of Sheffield.

And in the tail and in the mane

In the 80s, the principle of induction was already being applied in full. Engineers were able to create heaters that worked on the same principle of induction as a metallurgical furnace for melting metals. Such devices heated the workshops of factories. A little later, household appliances began to be produced. And some craftsmen did not buy them, but assembled induction heaters with their own hands.

Operating principle

If you disassemble an induction type boiler, then there you will find a core, electrical and thermal insulation, then a body. The difference between this heater and those used in industry is the toroidal winding with copper conductors. It is located between two pipes welded together. These pipes are made of ferromagnetic steel. The wall of such a pipe is more than 10 mm. As a result of this design, the heater has a much lower weight, higher efficiency, as well as small dimensions. A pipe with a winding works here as a core. And the other serves directly to heat the coolant.

The induction current, which is generated by a high-frequency magnetic field from the external winding to the pipe, heats the coolant. This process causes the walls to vibrate. Due to this, scale is not deposited on them.

Heating occurs due to the fact that the core is heated during operation. Its temperature rises due to eddy currents. The latter are formed due to the magnetic field, which, in turn, is generated by high voltage currents. This is how an induction water heater and many modern boilers work.

DIY induction power

Heating appliances that use electricity as energy are as convenient and comfortable to use as possible. They are much safer than gas powered equipment. In addition, in this case there is neither soot nor soot.

One of the disadvantages of such a heater is the high consumption of electricity. In order to somehow save money, craftsmen learned how to assemble induction heaters with their own hands. The result is an excellent device that requires much less electrical energy to operate.

Manufacturing process

To make such a device yourself, you do not need to have serious knowledge in electrical engineering, and anyone can handle the assembly of the structure.

To do this, we need a piece of thick-walled plastic pipe. It will work as the body of our unit. Next, you need a steel wire with a diameter of not more than 7 mm. Also, if you need to connect the heater to the heating in the house or apartment, it is advisable to purchase adapters. You also need a metal mesh that should hold the steel wire inside the case. Naturally, copper wire is needed to create an inductor. Also, almost everyone in the garage has a high-frequency inverter. Well, in the private sector, such equipment can be found without difficulty. Surprisingly, you can make induction heaters with your own hands from improvised means at no special cost.

First you need to carry out preparatory work for the wire. We cut it into pieces 5-6 cm long. The bottom of the part of the pipe must be closed with a net, and pieces of cut wire should be poured inside. From above, the pipe must also be closed with a net. It is necessary to pour so much wire to fill the pipe from top to bottom.

When the part is ready, you need to install it in the heating system. Then you can connect the coil to electricity through the inverter. It is believed that an induction heater from an inverter is a very simple and most budgetary device.

Do not test the apparatus if there is no water or antifreeze supply. You just melt the pipe. Before starting this system, it is advisable to make a ground for the inverter.

Modern heater

This is the second option. It involves the use of products of modern electronic devices. Such an induction heater, the diagram of which is presented below, does not need to be adjusted.

This circuit implies the principle of series resonance and can develop decent power. If you use more powerful diodes and larger capacitors, you can increase the performance of the unit to a serious level.

Assembling the vortex induction heater

In order to assemble this device, you need a choke. It can be found if you open the power supply of a regular computer. Next, you need to wind a wire made of ferromagnetic steel, copper wire 1.5 mm. Depending on the required parameters, it may take from 10 to 30 turns. Then you need to pick up field effect transistors. They are selected based on the maximum open junction resistance. As for the diodes, they need to be taken under a reverse voltage of at least 500 V, while the current will be somewhere around 3-4 A. You will also need zener diodes rated for 15-18 V. And their power should be about 2-3 Tue Resistors - up to 0.5 W.

Next, you need to assemble the circuit and make a coil. This is the basis on which the entire VIN induction heater is based. The coil will consist of 6-7 turns of 1.5 mm copper wire. Then the part must be included in the circuit and connected to electricity.

The device is able to heat the bolts to yellow. The circuit is extremely simple, however, the system generates a lot of heat in operation, so it is better to install radiators on transistors.

More complex design

In order to assemble this unit, you need to be able to work with welding, and a three-phase transformer is also useful. The design is presented in the form of two pipes that must be welded into each other. At the same time, they will play the role of a core and a heater. The winding is wound on the body. Thus, you can significantly increase productivity while achieving small overall dimensions and low weight.

To perform the supply and removal of the coolant, it is necessary to weld two pipes into the device body.

It is recommended that in order to eliminate possible heat losses as much as possible, as well as to protect yourself from possible current leaks, make insulation for the boiler. It will eliminate the occurrence of excessive noise, especially during intensive work.

It is desirable to use such systems in closed heating circuits in which there is a forced circulation of the coolant. It is allowed to use such units for plastic pipelines. The boiler must be installed in such a way that the distance between it and walls and other electrical appliances is at least 30 cm. It is also desirable to keep a distance of 80 cm from the floor and ceiling. It is also recommended to install a security system behind the outlet pipe. For this, a pressure gauge, an air release device, as well as a blast valve are suitable.

This is how easy and inexpensive you can assemble induction heaters with your own hands. This equipment may well serve you for many years and heat your home.

So, we found out how an induction heater is made with our own hands. The assembly scheme is not very complicated, so you can handle it in a matter of hours.

Categories

Popular