The idea of heating metal with Foucault eddy currents excited by the electromagnetic field of a coil is by no means new. It has been successfully used in industrial applications for a long time. melting furnaces, blacksmith shops, household heating devices - stoves and electric boilers. The latter are quite expensive, so home craftsmen do not give up trying to make induction heater water with your own hands. Our task is to consider workable options homemade devices and figure out whether they can be used to heat a house.
About the principle of inductive heating
First, let's explain how electric induction heaters function. Alternating current, passing through the turns of the coil, forms an electromagnetic field around it. If you place a magnetic metal core inside the winding, it will become heated by eddy currents arising under the influence of the field. That's the whole principle.
Important condition. In order for the metal core to heat up, the coil must be powered by alternating current, changing the sign and vector of the field with high frequency. When you apply DC current to the winding, you get an ordinary electromagnet.
The heating element itself is called an inductor and is the main part of the installation. IN heating boilers he is steel pipe with coolant flowing inside, and in kitchen stoves– a flat coil, as close as possible to hob, as shown in the photo below.
The inductor coil heats the iron pipe, which transfers heat to the flowing water The second part of the induction heater is a circuit that increases the frequency of the current. The fact is that voltage with an industrial frequency of 50 Hz is of little use for the operation of such devices. If you connect the inductor directly to the network, it will begin to hum strongly and weakly warm up the core, together with the windings. In order to effectively convert electricity into heat and completely transfer it to the metal, the frequency must be increased to at least 10 kHz, which is what the electrical circuit does.
What are the real advantages of induction boilers over heating and electrode boilers:
- The part that heats the water is a simple piece of pipe that does not participate in electrochemical processes (as in electrode heat generators). Therefore, the service life of the inductor is limited only by the performance of the coil and can reach 10-20 years.
- For the same reason, the element is equally good friends with all types of coolants - water, antifreeze and even machine oil, there is no difference.
- The insides of the inductor are not covered with scale during operation.
Here the core is a utensil made of magnetic metal Homemade device options
There are a sufficient number of various designs created for various purposes. Take a small-sized induction heater made from a 250-500 W computer power supply. The model shown in the photo will be useful to a master in a garage or car service for melting rods made of aluminum, copper and brass.
But the design is not suitable for heating premises due to its low power. There are two on the Internet real options, whose tests and work were filmed:
- water heater from polypropylene pipe powered by a welding inverter or induction kitchen panel;
- steel boiler heated by the same hob.
Reference. There are others, completely homemade designs, where craftsmen assemble frequency converters from scratch. But this requires knowledge and skills in the field of radio engineering, so we will not consider them, but will simply give an example of such a circuit.
Now let's take a closer look at how to make induction heaters with your own hands, and most importantly, how they then function.
We make a heating element from a pipe
If you have been actively searching for information on this topic, you have probably come across this design, since the master posted its assembly on the popular YouTube video resource. After which many sites posted text versions of the manufacture of this inductor in the form step by step instructions. Briefly, the heater is made like this:
An important nuance. The length and cross-section of the wire for winding the coil should be determined from the standard inductor of the stove so that it matches the power of the field-effect transistors in the electrical circuit. If you take more wire, the heating power will drop; if you use less, the transistors will overheat and fail. How it looks visually, look at the video:
As you might guess, the role of the heating element here is played by metal brushes located in the alternating magnetic field of the coil. If you run the hob at maximum, while simultaneously passing running water through an improvised boiler, it can be heated by 15-20 °C, as tests of the unit have shown.
Since the power of the majority induction cookers lies within 2-2.5 kW, then using a heat generator you can heat the premises with total area no more than 25 m². There is a way to increase the heating by connecting an inductor to a welding machine, but this has its own difficulties:
- The inverter outputs D.C., but you need a variable. To connect an induction heater, you will have to disassemble the device and find the points on the diagram where the voltage has not yet been rectified.
- You need to take a wire of a larger cross-section and select the number of turns by calculation. As an option, copper wireØ1.5 mm in enamel insulation.
- It will be necessary to organize cooling of the element.
The author demonstrates checking the performance of an inductive water heater in his video presented below. Tests have shown that the unit requires improvement, but the final result, unfortunately, is unknown. It looks like the craftsman left the project unfinished.
How to assemble an induction boiler
In this case, there is no need to disassemble the cheap Chinese stove. The point is to weld a boiler tank according to its dimensions, following step-by-step instructions:
- Take steel profile pipe 20 x 40 mm with a wall thickness of 2 mm and cut blanks from it to the width of the panel.
- Weld the tubes together lengthwise, joining the smaller sides.
- Weld iron caps hermetically at the top and bottom to the ends. Make holes in them and install threaded pipes.
- Attach 2 corners to one side by welding so that they form a shelf for the induction stove.
- Paint the unit with heat-resistant spray enamel. The assembly process is shown in more detail in the video.
Final assembly and commissioning consists of mounting the boiler on the wall and inserting it into the heating system. The hob is inserted into the socket from the corners on the rear wall of the tank and connected to the mains. All that remains is to turn on the heating of the inductor.
Here you are faced with the same problem that occurred with the previous model. Undoubtedly, induction heating will work, but its power of 2.5 kW is enough to heat a couple small rooms when it's cold outside. In autumn and spring, when the temperature has not dropped below zero, a homemade boiler can heat an area of 35-40 m². How to properly connect it to the system, see the next video:
We deliberately presented options for induction water heaters of simple design, so that anyone could make such a unit on their own. But the question remains: is it necessary to engage in this business and spend own time. There are a number of objective considerations in this regard:
- Users who do not understand electrical and radio engineering are unlikely to be able to increase the heating power above 2.5 kW. To do this, you will have to assemble a frequency converter circuit.
- The efficiency of the inductor is no higher than that of other electric boilers. But assembling a heater with heating elements is much easier.
- If you don’t have an induction panel lying around at home, you will need to buy it for about 80 USD. e. This is how much cheap Chinese products cost in online stores. Ready-made ones are sold for the same money electrode boilers power up to 10 kW.
- Electric stoves are equipped with automatic safety switches household appliance after 1 or 2 hours of work. This causes inconvenience during operation.
- If, for various reasons, the coolant leaks out of a homemade heat generator, then the heating will not stop. This is fraught with fire.
Of course, you can do without expensive purchases, thoroughly understand the design and make an induction heater from scratch. But you won’t be able to do everything for free, because you will need to purchase components for the circuit. Please note that the bonuses from such a heating unit are small, so it is not advisable to seriously undertake its manufacture for the purpose of heating a private home.
Many people are attracted to electric heating the fact that it works autonomously and does not need to be constantly looked after. Negative side of such heating boilers is the cost and technical requirements.
In some places they simply cannot be used. But many owners are not afraid of this, and they believe that it is the ease of operation that covers all the shortcomings.
Especially when new types with inductive coils, rather than heating elements, appeared on the sales markets. They With instantaneous speed warm up and economically heat the building, according to the owners of the units. New type boilers are called induction.
The new type of heaters is easy to use. They are considered safe, in comparison with gas heaters, there is no soot and soot, which cannot be said about devices with solid fuel. And the most important advantage is that there is no need to prepare solid fuel(coal, firewood,).
And as soon as induction heaters appeared, there were immediately craftsmen who, in order to save money, were trying to create such an installation with their own hands.
In this article we will help you design a heating device yourself.
A device where metal and similar products are heated without contact is called an induction heater. The operation is controlled by an alternating induction field acting on the metal, and the currents inside generate heat.
High frequency currents affect the product in addition to insulation, which is why the design is unusual compared to other types of heating.
Today's induction heaters contain semiconductor frequency reducers. This type of heating is widely used in the heat treatment of surfaces made of steel and various compounds and alloys.
The compactness of equipment is used in innovative technologies, while there is a huge economic effect. A variety of models help implement flexible and automated combinations, including all-round transistor frequency reducers and connection blocks when an induction system is preferred.
Description
Heater device A typical heating element includes the following components:
- A heating element in the form of a rod or metal tube.
- Inductor- This is a copper wire that frames the coil in turns. During operation, it acts as a generator.
- Generator alternating current. Separate design, where the standard current is converted into a high frequency value.
On practice, induction units recently used. Theoretical studies are much ahead. This can be explained by one obstacle - obtaining high frequency magnetic fields. The fact is that using low-frequency settings is considered ineffective. As soon as they appeared with high frequency, the problem was resolved.
HDTV generators have passed their evolutionary period; from lamp, to modern models, running on the basis of IGBT. Now they are more efficient, lighter in weight and smaller in size. Their frequency limitation is 100 kHz due to dynamic losses of transistors.
Operating principle and scope
The generator increases the frequency of the current and transfers its energy to the coil. The inductor converts high-frequency current into an alternating electromagnetic field. Electromagnetic waves change at high frequencies.
Heating occurs due to the heating of eddy currents, which are provoked by alternating eddy vectors of the electric magnetic field. Energy is transmitted with almost no losses with high efficiency and enough energy to heat the coolant and even more.
The battery energy is transferred to the coolant, which is located inside the pipe. The coolant, in turn, is the coolant of the heating element. Due to this, the service life increases.
Industry is the most active consumer of induction heaters, since many designs involve high heat treatment. Their use increases the strength of the product.
High-power devices are installed in high-frequency forges.
Forging and pressing companies, using such units, increase labor productivity and reduce wear of dies, and reduce metal consumption. Installations with through heating can cover a certain number of workpieces at once.
When surface hardening parts, the use of such heating makes it possible to increase wear resistance several times and obtain a significant economic effect.
Common areas of application for devices are soldering, melting, heating before deformation, and high-frequency hardening. But there are also zones where single-crystal semiconductor materials are produced, epitaxial films are grown, materials are foamed into electrical components. field, high-frequency welding of shells and pipes.
Advantages and disadvantages
Pros:
- High heating quality.
- High precision control and flexibility.
- Reliability. Can work autonomously, having automation.
- Warms any liquid.
- The efficiency of the device is 90%.
- Long service life(up to 30 years old).
- Easy to install.
- The heater does not collect scale.
- Due to automation, energy savings.
Minuses:
- High cost of models with automation.
- Dependence on electricity supply.
- Some models are noisy.
How to do it yourself?
Electrical diagram induction heater Let's say you decide to make an induction heater yourself, for this we prepare a pipe, pour small pieces of steel wire (9 cm in length) into it.
The pipe can be plastic or metal, most importantly, with thick walls. Then, it is closed with special adapters on all sides.
Next, we wind up to 100 turns of copper wire onto it and place it along the central part of the tube. The result is an inductor. We connect the output part of the inverter to this winding. We resort to as an assistant.
The pipe acts as a heater.
We prepare the generator and assemble the entire structure.
Required materials and tools:
- wire from of stainless steel or wire rod (diameter 7 mm);
- water;
- enameled copper wire;
- metal mesh with small holes;
- adapters;
- thick-walled plastic pipe;
Step by step guide:
- Mode wire into pieces, 50 mm long.
- We prepare the shell for the heater. We use a thick-walled pipe (diameter 50 mm).
- We cover the bottom and top of the body with a mesh.
- Preparing the induction coil. Copper wire We wind 90 turns on the body and place them in the center of the shell.
- Cut out part of the pipe from the pipeline and install an induction boiler.
- We connect the coil to the inverter and fill the boiler with water.
- We ground the resulting structure.
- We check the system in operation. It cannot be used without water, as the plastic pipe may melt.
From a welding inverter
The simplest budget option is the manufacture of an induction heater using a welding inverter:
- To do this, take a polymer pipe, its walls should be thick. We install 2 valves at the ends and connect the wiring.
- We pour pieces into the pipe(diameter 5 mm) metal wire and mount the top valve.
- Next, we make 90 turns around the pipe with copper wire, we get an inductor. The heating element is a pipe, and we use a welding machine as a generator.
- The device must be in AC mode with high frequency.
- Connecting the copper wire to the poles welding machine and check the work.
Working as an inductor, a magnetic field will be emitted, while eddy currents will heat the chopped wire, which will lead to boiling of water in polymer pipe
.
- Open areas of the structure should be insulated for safety reasons.
- The use of an induction heater is recommended only in closed systems heating, where a pump is installed to circulate the coolant.
- The structure with an induction heater is placed 800 mm from the ceiling, 300 mm from furniture and walls.
- Installing a pressure gauge will protect your structure.
- It is advisable to equip the heating device automatic system management.
- The heater should be connected to the electrical network using special adapters.
Electric heating devices are extremely convenient to use. They are much safer than any gas equipment, do not produce soot and soot, unlike units operating on liquid or solid fuel; finally, they do not require the preparation of firewood, etc. Main disadvantage electric heaters - high price electricity. In search of savings, some craftsmen decided to make an induction heater with their own hands. They received excellent equipment that requires much less expense to operate.
Working principle of induction heating
An induction heater uses energy to operate electromagnetic field, which the heated object absorbs and converts into heat. To generate a magnetic field, an inductor is used, i.e. a multi-turn cylindrical coil. Passing through this inductor, the variable electricity creates an alternating magnetic field around the coil.
A homemade inverter heater allows you to heat quickly and to a very high high temperatures. With the help of such devices you can not only heat water, but even melt various metals
If a heated object is placed inside or near the inductor, it will be penetrated by the flux of the magnetic induction vector, which constantly changes over time. In this case, there arises electric field, the lines of which are perpendicular to the direction magnetic flux and move in a vicious circle. Thanks to these vortex flows Electric Energy transforms into heat and the object heats up.
Thus, the electrical energy of the inductor is transferred to the object without the use of contacts, as happens in resistance furnaces. As a result thermal energy is consumed more efficiently, and the heating rate increases noticeably. This principle is widely used in the field of metal processing: melting, forging, soldering, surfacing, etc. With no less success, a vortex induction heater can be used to heat water.
Induction heat generator in a heating system
To organize heating of a private house using an induction heater, the easiest way is to use a transformer, which consists of a primary and secondary short-circuited winding. Eddy currents in such a device arise in the internal component and direct the resulting electromagnetic field to the secondary circuit, which simultaneously serves as a housing and a heating element for the coolant.
Please note that not only water, but also antifreeze, oil and any other conductive media can act as a coolant during induction heating. At the same time, the degree of purification of the coolant of great importance does not have.
The inverter heater is compact in size, operates silently and can be installed in almost any suitable place, meeting safety requirements
Equipped with two pipes. The lower pipe, through which the cold coolant will flow, must be installed at the inlet section of the pipeline, and at the top, a pipe is installed that transfers the hot coolant to the supply section of the pipeline. When the coolant in the boiler heats up, hydrostatic pressure arises and enters the heating network.
There are a number of advantages to using an induction heater that should be mentioned:
- the coolant constantly circulates in the system, which prevents the possibility of overheating;
- the induction system vibrates, as a result, scale and other sediments are not deposited on the walls of the equipment;
- lack of traditional heating elements allows you to operate the boiler at high intensity without fear of frequent breakdowns;
- absence detachable connections eliminates leaks;
- the operation of the induction boiler is not accompanied by noise, so it can be installed in almost any suitable room;
- During induction heating, no hazardous fuel decomposition products are released.
Safety, quiet operation, the ability to use a suitable coolant and the durability of the equipment have attracted many homeowners. Some of them are thinking about the possibility of making a homemade induction heater.
How to make an induction heater yourself?
Making such a heater yourself is not very difficult task, which even a novice master can handle. To get started, you should stock up on:
- piece plastic pipe with thick walls, which will become the heater body;
- steel wire with a diameter of no more than 7 mm;
- adapters for connecting the heater body to heating system Houses;
- metal mesh, which will hold pieces of steel wire inside the housing;
- copper wire to create an induction coil;
- high frequency inverter.
First you need to prepare the steel wire. To do this, simply cut it into pieces about 5 cm long. The bottom of a piece of plastic pipe is covered with a metal mesh, pieces of wire are poured inside, and the top of the body is also covered with a metal mesh. The housing must be completely filled with pieces of wire. In this case, wire made not only from stainless steel, but also from other metals may be acceptable.
Then you should make an induction coil. A prepared plastic case is used as a base, onto which 90 turns of copper wire are carefully wound.
After the coil is ready, the housing is connected to the heating system of the house using adapters. After this, the coil is connected to the network through a high-frequency inverter. It is considered quite advisable to make an induction heater from a welding inverter, since this is the simplest and most cost-effective option.
Most often, when making homemade vortex induction heaters, they use inexpensive models welding inverters, because they are convenient and fully meet the requirements
It should be noted that you should not test the device if no coolant is supplied to it, otherwise the plastic case may melt very quickly.
An interesting version of an induction heater made from a hob is presented in the video:
To increase the safety of the structure, it is recommended to insulate the exposed areas of the copper coil.
The induction heating system should be placed at a distance of at least 30 cm from walls and furniture and at least 80 cm from the ceiling or floor.
To make the operation of the device safer, it is recommended to equip it with a pressure gauge, as well as a system automatic control and devices for removing air trapped in the system.
Recently the need arose to create a small induction heater with your own hands. Wandering around the Internet, I found several diagrams of induction heaters. Many schemes were not satisfactory due to the rather complex wiring, 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 the effect of Foucault currents on metal. Such a heater is actively used in the most different areas science and technology. In theory, Foucault currents are indifferent to the types and properties of metals, so the inductor can heat or melt absolutely any metal.
Electronic transformer - pulse block power supply, on the basis of which our heater is built. This is a simple half-bridge inverter built on two powerful bipolar transistors of the MJE13007 series, which overheat terribly during operation, so they need a very good heat sink.
First, you need to remove the main transformer from the electronic transformer. We will make a kind of inductor based on a ferrite cup. To do this, take a 2000NM cup (the size of the cup is not particularly important, but preferably larger). We wind 100 turns of 0.5 mm wire on the frame, remove them from the ends of the wires varnish coating and we'll screw it up. Then we solder the ends of the wires in place of the standard pulse transformer - everything is ready!
The result is a fairly powerful homemade induction heater (efficiency no more than 65%), on the basis of which you can even assemble a small induction stove. 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. With such a heater you can melt wires with a diameter of 1.5 mm - I succeeded in just 20 seconds, but at the same time the high-voltage ET transistors got so hot that you could fry eggs on them!
During operation, there may be a need for additional cooling for the heat sinks, since experience has shown that the heat sink simply does not have time to remove heat from the transistors.
The basic operation of such an inverter is quite simple. The induction heater circuit itself is convenient in that it does not require any configuration(over complex schemes Often there is a need to adjust the circuit to the resonance frequency, accurately calculate the number of turns and diameter of the circuit wire, as well as count the circuit capacitor, but here all this is not present and the circuit works immediately).
The mains voltage (220 Volts) is first rectified by a diode rectifier, then supplied to the circuit. The frequency is set by a DB3 dinistor (diac). The circuit itself does not have any protection, only a limiting resistor at the power input, which supposedly should work as a mains fuse, but when the slightest problem Transistors fly out first. The reliability of the induction heater circuit can be increased by replacing the diodes in the rectifier with more powerful ones, adding network filter to the input of the circuit and replacing the power transistors with more powerful ones, say, MJE13009.
In general, I do not recommend turning on such a heater for for a long time, if there is no active cooling, otherwise you will be forced to change transistors every 5 minutes.
Scheme of a 500 Watt induction heater that you can make yourself! There are many similar schemes on the Internet, but interest in them is disappearing, since mostly they either do not work or work but not as expected. This scheme induction heater is fully working, tested, and most importantly, not complicated, I think you will appreciate it!
Components and coil:
The working coil contains 5 turns; it was used for winding copper tube about 1 cm in diameter, but it can be smaller. This diameter was not chosen by chance; water is supplied through the tube to cool the coil and transistors.
The transistors were installed with IRFP150 since IRFP250 was not at hand. Film capacitors are 0.27 uF 160 volts, but you can put 0.33 uF and higher if you can’t find the first ones. Please note that the circuit can be powered with a voltage of up to 60 volts, but in this case, it is recommended to install capacitors at a voltage of 250 volts. If the circuit is powered by a voltage of up to 30 volts, then 150 will be enough!
You can install any zener diodes at 12-15 volts from 1 Watt, for example 1N5349 and the like. Diodes can be used UF4007 and the like. Resistors 470 Ohm from 2 Watts.
A few pictures:
Instead of radiators, copper plates were used, which are soldered directly to the tube, since this design uses water cooling. In my opinion, this is the most effective cooling, because the transistors heat up well and no amount of fans or super radiators will save them from overheating!
The cooling plates on the board are located in such a way that the coil tube passes through them. The plates and tube need to be soldered together, for this I used gas burner and a large soldering iron for soldering car radiators.
The capacitors are located on two-sided PCB, the board is also soldered directly to the coil tube for better cooling.
The chokes are wound on ferrite rings, I personally took them from a computer power supply, the wire was used in copper insulation.
Induction heating The atelier turned out to be quite powerful, it melts brass and aluminum very easily, it also melts iron parts, but a little slower. Since I used IRFP150 transistors, according to the parameters, the circuit can be powered with a voltage of up to 30 volts, so the power is limited only by this factor. So I still recommend using IRFP250.
That's all! Below I will leave a video of the induction heater in operation and a list of parts that can be bought on AliExpress at a very low price!
Buy parts on Aliexpress:
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