Do-it-yourself induction water heater working diagram. Induction heater: simple schemes for do-it-yourself implementation. Video - Welding inverter design

The modern and most economical device for heating water is an induction water heater. Unlike analogues, it is completely environmentally friendly, does not dry or burn out the air, and meets modern safety requirements. It can be used both as an instantaneous water heater and as a boiler for space heating. The device is usually bought in a store, we offer an alternative - self-production. In the latter case, the device may not have such an attractive appearance, but it will be much cheaper.

Pros and cons of induction devices for heating water

The device has a fairly simple design and does not require special documents allowing the use and installation. The induction water heater has a high degree of efficiency and optimum reliability for the user. When using it as a boiler for heating, you don’t even need to install a pump, since water flows through the pipes due to convection (when heated, the liquid practically turns into steam).

Also, the device has a number of advantages, which distinguishes it from other types of water heaters. So, induction heater:

In induction heaters, water becomes hot due to the pipe through which it flows, and the latter is heated due to the induction current created by the coil.

much cheaper than their counterparts, such a device can be easily assembled independently;
completely silent (although the coil vibrates during operation, this vibration is not noticeable to a person);
vibrates during operation, due to which dirt and scale do not stick to its walls, and therefore does not need to be cleaned;
has a heat generator that can be easily sealed due to the principle of operation: the coolant is inside the heating element and the energy is transferred to the heater through an electromagnetic field, no contacts are needed; therefore, sealing gum, seals and other elements that can quickly deteriorate or leak will not be needed;
there is simply nothing to break in the heat generator, since the water is heated by an ordinary pipe, which is unable to deteriorate or burn out, unlike a heating element;

Do not forget that the maintenance of an induction heater will be much cheaper than a boiler or gas boiler. The device has a minimum of parts that almost never fail.

Despite the huge number of advantages, the induction water heater has a number of disadvantages:

the first and most painful for the owners is the electricity bill; the device cannot be called economical, so you have to pay a decent amount of time for its use;
secondly, the device gets very hot and heats up not only itself, but also the surrounding space, so it is better not to touch the body of the heat generator during its operation;
third - the device has an extremely high efficiency and heat transfer, therefore, when using it be sure to install a temperature sensor, otherwise the system may explode.

Do-it-yourself induction water heater: diagram

The device is a transformer having two windings: primary and secondary. The first circuit converts electrical energy into eddy currents, thereby creating a directional induction field, which provides induction heating. On the secondary circuit, the converted energy is transferred to the coolant (in our case, it is water).

It is important to consider the type of material from which the winding is made. So, in household models, copper wire is most often used. Such material is well suited for heating water in boilers.

In addition to the transformer, the device has a generator and a pump (optional).

Scheme of a simple induction water heater. As you can see, the device has a fairly simple design and a small number of elements.

Units and parts of the heat generator

The device includes:

an alternator that increases the frequency of the current;
an inductor that transforms electricity into magnetic energy is a coil of copper wire;
heating element, most often its role is played by a metal pipe.

Thanks to this design, energy transfer is carried out almost without loss. The efficiency reaches 98%.

Principle of operation

The induction water heater consists of a generator, a coil and a core, the latter is heated by electromagnetic energy.

The device converts electrical energy into electromagnetic energy. The latter, in turn, acts on the core (pipe), which heats up and transfers thermal energy to the water. All these energies are converted by an inductor consisting of a coil and a core. The generator is used to increase the frequency of the current, since it is difficult to achieve high heating with a standard frequency of 50 Hz.

In factory models, the current frequency reaches 1 kHz.

Do-it-yourself flowing induction water heater

Before proceeding with the installation, you need to stock up on the necessary parts. So, the best option would be a welding high-frequency inverter, a smoothly changing current range. Such a device will cost the least. A more expensive option would be a three-phase transformer, which is the AC power source for the water heater inductor. In this case, it is worth using a coil of 50-90 turns, and as a material, take copper wire with a diameter of 3 or more millimeters.

As a core, you can use both a metal and a polymer pipe along with a wire (it is used as a heating element). In the latter case, the thickness of the walls should not be less than 3 mm in order to calmly withstand high temperatures.

To assemble the water heater, you will need: wire cutters, screwdrivers, a soldering iron and a welding machine if a metal pipe is used.

Installation of an induction water heater

Wrap the pipe with copper wire, making about 90 turns.

There are many options for assembling the device. We suggest trying to assemble the device according to the following scheme:

Prepare the workplace, materials and tools.
Fix a small piece of polymer pipe (remember that the minimum wall thickness should be 3 mm).
Trim the ends of the core to leave 10 cm of spare wire for the taps.
Mount a corner on the lower outlet. In the future, the return from the heating should be connected here (if the heater is used as a boiler).
Lay the chopped wire tightly around the pipe. It is necessary to make at least 90 turns.
Install a tee on the top pipe through which hot water will exit.
Mount the protective circuit of the device. It can be made from both polymer and metal.
Connect copper wire to the water heater terminals, then fill the core with water.
Check the functionality of the inductor.

Recommendations. It is better to install ball valves on all outlets for convenience and ease of dismantling the water heater in the event of a breakdown. But it is not necessary to fill the pipe with metal pieces, since this does not give the desired effect. Do not forget to leave a window in the housing for access to the control panel of the welding machine.

Induction water heaters for heating

Heating circuit, where an induction boiler serves as a coolant heater.

Such a device has proven itself not only as an instantaneous water heater, but also as a boiler for heating. True, in this case, the welding machine as a generator is no longer suitable, you have to use a transformer with two windings. The latter transforms the eddy currents that occur on the primary winding into an electromagnetic field that is created on the secondary circuit.

In the heating system, the coolant can be not only water, but also oil or antifreeze. That is, any liquid that can conduct electricity.

The boiler from the induction water heater must be equipped with two pipes for hot and cold water. Cold water will flow from the bottom, it must be mounted on the inlet section of the line, and a branch pipe must be placed on top, which will supply hot water to the heating system. As a result, the circulation of water is carried out naturally under the influence of convection without a pump.

What you need to know about security

Do not forget that we are dealing with a source of increased danger - an electric heater, so when assembling and using it, you must follow some rules:

Be sure to use a separate electrical line to connect the induction boiler, and also equip it with a safety group.

If water circulates naturally in the boiler, then be sure to equip it with a temperature sensor so that the device turns off automatically when overheated.
Do not plug a homemade water heater into a power outlet; it is better to run a separate line for this with an increased cable cross section.
All exposed wires must be insulated to protect people from electric shock or burns.
Never turn on the inductor if the pipe is not filled with water. Otherwise, the pipe will melt, and the device will close, or it may even catch fire.
The device must be mounted at a height of 80 cm from the floor, but so that about 30 cm remains to the ceiling. Also, you should not install it in a residential area, since the electromagnetic field has a bad effect on people's health.
Don't forget to ground the inductor.
Be sure to connect the device through the machine so that in the event of an accident, the latter will turn off the power from the water heater.
A safety valve must be installed in the pipeline system, which will automatically reduce the pressure in the system.

Conclusion

The induction water heater has a high efficiency, can act as a boiler for the heating system, self-assembly and installation is also allowed, and its use is in no way regulated by the law of the Russian Federation. But still, before using it, it is worth weighing the pros and cons. Despite its high efficiency, the device consumes a large amount of energy, is considered unsafe (especially home-made) and has a bad effect on human health. Therefore, we recommend mounting the inductor in a private house or in the country.

The tip of a conventional resistive soldering iron is heated by an electric current that flows through a nichrome spiral wound around the rod capsule. Disadvantages of this process: low efficiency, local heating, and as a result, high power consumption.

Ceramic soldering irons are more advanced, but they are afraid of sudden temperature changes. An induction soldering station works on a completely different principle. The tip heats up quickly, and the heating adjustment is as simple as possible.

The main difference between an induction soldering iron and a conventional soldering iron is the heating element, or rather, its complete absence. The heating of the tool occurs due to the occurrence of eddy induction currents under the action of an alternating magnetic field.

The design of the induction soldering iron provides a coil into which the tip of the device is inserted.

When current is applied to the coil, a magnetic field is generated in it. It acts on, where induction currents are formed, heating the rod itself.

In this case, the soldering iron tip heats up evenly, because the induction current acts on it along its entire length. The service life of such a tool increases, and its efficiency increases.

Initially, induction soldering stations with a frequency of 470 kHz were produced, but today there are models in which a voltage of 13 MHz and higher is supplied. Warming up takes place in just a second.

Heating control

The core of an induction soldering iron is made of copper (not a magnetic material), and the back of it is coated with a ferromagnetic material (an alloy of iron and nickel). The front part serves as a sting, the core itself is called a cartridge.

The heating of the copper tip is adjusted as follows:

when an alternating voltage is applied, and hence the field, Foucault currents are generated in the coating, which heat up the material;
heat is transferred to copper;
as soon as the temperature of the coating reaches the Curie point, the magnetic properties disappear and the heating stops;
in the process of working with an induction soldering iron, the copper tip gives off heat to the part and cools down, the ferromagnetic coating also cools down;
as soon as the coating cools down, the magnetic properties return, and heating resumes instantly.

We can say that there is an automatic temperature control, and with high accuracy.

The maximum heating of an induction soldering iron depends on the properties of the magnetic alloy and the core. Such control is called smart heat.

You can change the temperature for specific soldering conditions by installing a temperature sensor that is connected to the station control unit, or by changing the cartridges (core with a tip) that are inserted into the handle of the induction soldering iron.

The first option is cheaper than the second, so not only professionals use it today. But the second method is more accurate and reliable.

DIY assembly

The question of whether it is possible to make an induction soldering iron with your own hands is mainly theoretical. From a practical point of view, this is unjustified even from a purely price position.

It's just that any Chinese soldering station will cost the same as a do-it-yourself one. And the conversation about a home-made design will mainly concern the control unit. Why buy an induction soldering iron?

As for the direct manufacture of the tool itself, it can be made from improvised materials. True, such an induction soldering iron will be low-power.

You will need a 5-10 ohm resistor, copper wire and a ferrite bead to make the coil, as well as wires to supply electric current.

First of all, the resistance of the resistor is checked with a multimeter. Then, on one side, remove the cover. Now you need steel wire.

For example, you can use a paperclip for this. It is unfolded, and one end is tinned. The resistor is wrapped around the second end in the place of the removed cover.

Next, you need a piece of textolite, which is also tinned on both sides. Its size is selected so that it enters freely into the future coil body. Now the textolite plate is soldered to the wire from the paper clip and the wire from the resistor.

Next, the coil is assembled - a copper wire is wound onto the bead, to the ends of which wires with a plug are attached. A tinned textolite plate is inserted into the prepared coil. All connections are soldered.

It remains only to wrap electrical tape around the coil, insert a thick copper wire into the open resistor, and the coil itself into the prepared housing. For example, it can be an aluminum tube.

Please note that the copper wire must enter the resistor with an interference fit so that the tip of the induction soldering iron does not move in its body.

And the last - winding the entire body of the device with insulating tape. Here is such a simple assembly scheme for a homemade induction soldering iron. Of course, they cannot solder large workpieces, but for a small microcircuit it is just right.

Instrument features

Among the features of induction soldering irons, it should be noted a thin replaceable cartridge, on which the heating temperature of the tip largely depends.

It is a thin tube, which, in combination with the light body of the device, makes it possible to sit for a long time during the soldering process.

The hand does not get tired, which means that the accuracy of the tip and solder supply does not change, there are no smudges of excess material, and the speed of operations increases. There is no complex electronic circuit, the degree of heating is automatically regulated.

By all measures, the induction soldering iron is more advanced than traditional soldering tools. Although it is not yet widespread enough, such a design can be attributed to a new generation of technology.

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, the assembly will require four high-power light bulbs and a heavy lamp for the ready-to-work indicator.

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. It:

power;
frequency;
eddy losses;
heat transfer intensity;
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 heating a room, 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 frank, the described design (like everything available on the Internet) is not quite a furnace, but a Kukhtetsky laboratory inverter. It is simply impossible to assemble a full-fledged induction structure at home.

Recently, there was a need to create a small do-it-yourself induction heater. Wandering around the Internet, I found several schemes for induction heaters. Many schemes did not suit because of the rather complicated strapping, some did not work, but there were also working options.

A few days ago I came to the conclusion that an induction heater can be made from an electronic transformer at minimal cost.

The principle of induction heating is to act on the metal with Foucault currents. Such a heater is actively used in various fields of science and technology. In theory, Foucault currents are indifferent to the types and properties of metals, so the inductor can heat up or melt absolutely any metal.

An electronic transformer is a switching power supply on the basis of which our heater is built. This is a simple half-bridge inverter built around two powerful MJE13007 series bipolar transistors that overheat terribly during operation, so they need a very good heat sink.

To start with the electronic transformer, you need to unsolder the main transformer. We will make a kind of inductor based on a ferrite cup. To do this, we take a cup of 2000 NM (the size of the cup is not particularly important, but a larger one is desirable). On the frame we wind 100 turns with a wire of 0.5 mm, remove the varnish from the ends of the wires and tin. Then we solder the ends of the wires to the place of the standard pulse transformer - everything is ready!

It turned out to be a fairly powerful home-made induction heater (efficiency no more than 65%), on the basis of which even a small induction stove can be assembled. If you take a piece of metal and bring this metal closer to the center of the coil, then after a few seconds the metal will heat up. Such a heater can melt wires with a diameter of 1.5 mm - I managed to do this in just 20 seconds, but at the same time, the high-voltage ET transistors got so hot that they could fry eggs on them!

During operation, there may be a need for additional cooling for heat sinks, since experience has shown that the heat sink simply does not have time to remove heat from the transistors.

The basis of the operation of such an inverter is quite simple. The induction heater circuit itself is convenient in that it does not require any configuration.(in more complex circuits, it often becomes necessary to adjust the circuit to the resonance frequency, accurately calculate the number of turns and the diameter of the circuit wire, as well as count the circuit capacitor, but here all this is not there and the circuit works immediately).

The mains voltage (220 Volts) is first rectified by a diode rectifier, then fed to the circuit. The frequency is set by the dinistor (diac) of the DB3 brand. The circuit itself has no protections, only a limiting resistor at the power input, which supposedly should work as a mains fuse, but at the slightest problem, transistors fly out first. The reliability of the induction heater circuit can be improved by replacing the diodes in the rectifier with more powerful ones, adding a network filter to the input of the circuit and replacing the power transistors with more powerful ones, say MJE13009.

In general, I do not advise turning on such a heater for a long time if there is no active cooling, otherwise you will be forced to change transistors every 5 minutes.

Induction heating boilers are devices that have a very high efficiency. They can significantly reduce energy costs compared to traditional appliances equipped with heating elements.

Industrial production models are not cheap. However, any home master who owns a simple set of tools can make an induction heater with his own hands. To help him, we offer a detailed description of the principle of operation and assembly of an effective heater.

Induction heating is not possible without the use of three main elements:

inductor;
generator;
heating element.

An inductor is a coil, usually made of copper wire, that generates a magnetic field. An alternator is used to produce a high frequency stream from a standard 50 Hz household power stream.

A metal object is used as a heating element, capable of absorbing thermal energy under the influence of a magnetic field. If you connect these elements correctly, you can get a high-performance device that is perfect for heating liquid coolant and.

With the help of a generator, an electric current with the necessary characteristics is supplied to the inductor, i.e. on a copper coil. When passing through it, the flow of charged particles forms a magnetic field.

The principle of operation of induction heaters is based on the occurrence of electric currents inside conductors that appear under the influence of magnetic fields.

The peculiarity of the field is that it has the ability to change the direction of electromagnetic waves at high frequencies. If any metal object is placed in this field, it will begin to heat up without direct contact with the inductor under the influence of the created eddy currents.

The high-frequency electric current flowing from the inverter to the induction coil creates a magnetic field with a constantly changing vector of magnetic waves. The metal placed in this field heats up quickly

The lack of contact makes it possible to make energy losses during the transition from one type to another negligible, which explains the increased efficiency of induction boilers.

To heat water for the heating circuit, it is enough to ensure its contact with a metal heater. Often, a metal pipe is used as a heating element, through which a stream of water is simply passed. Water simultaneously cools the heater, which significantly increases its service life.

The electromagnet of an induction device is obtained by winding a wire around a core of a ferromagnet. The resulting induction coil heats up and transfers heat to the heated body or to the coolant flowing nearby through the heat exchanger

Advantages and disadvantages of the device

The “pluses” of the vortex induction heater are numerous. This is a simple circuit for self-production, increased reliability, high efficiency, relatively low energy costs, long service life, low probability of breakdowns, etc.

The performance of the device can be significant; units of this type are successfully used in the metallurgical industry. In terms of the rate of heating of the coolant, devices of this type confidently compete with traditional electric boilers, the water temperature in the system quickly reaches the required level.

During the operation of the induction boiler, the heater vibrates slightly. This vibration shakes off limescale and other possible contaminants from the walls of the metal pipe, so such a device rarely needs to be cleaned. Of course, the heating system must be protected from these contaminants with a mechanical filter.

The induction coil heats the metal (pipe or pieces of wire) placed inside it using high frequency eddy currents, contact is not necessary

Constant contact with water also minimizes the likelihood of heater burnout, which is a fairly common problem for traditional boilers with heating elements. Despite the vibration, the boiler operates exceptionally quietly; additional noise insulation at the installation site of the device is not required.

Induction boilers are also good because they almost never leak, if only the installation of the system is done correctly. This is a very valuable quality for, as it eliminates or significantly reduces the likelihood of dangerous situations.

The absence of leaks is due to the non-contact method of transferring thermal energy to the heater. The coolant using the technology described above can be heated almost to a vapor state.

This provides sufficient thermal convection to stimulate efficient movement of the coolant through the pipes. In most cases, the heating system will not have to be equipped with a circulation pump, although it all depends on the features and layout of a particular heating system.

Conclusions and useful video on the topic

Roller #1. An overview of the principles of induction heating:

Roller #2. An interesting option for manufacturing an induction heater:

To install an induction heater, you do not need to obtain permission from regulatory authorities, industrial models of such devices are quite safe, they are suitable for both a private house and an ordinary apartment. But owners of homemade units should not forget about safety.

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