How to make an induction heater with your own hands from a welding inverter. How to make an induction heater with your own hands? Induction heater 1000w

A simple induction heater consists powerful generator high frequency and low-resistance coil-circuit, which is the load of the generator.

The self-excited generator generates pulses based on the resonant frequency of the circuit. As a result, a powerful alternating electromagnetic field with a frequency of about 35 kHz appears in the coil.
If a core of conductive material is placed in the center of this coil, then electromagnetic induction will occur inside it. As a result of frequent changes, this induction will cause eddy currents in the core, which in turn will lead to the generation of heat. This is the classical principle of converting electromagnetic energy into thermal energy.
Induction heaters have been used for a very long time in many areas of production. With their help, you can do hardening, non-contact welding, and most importantly - spot heating, as well as melting materials.
I will show you a simple low voltage induction heater which has already become a classic.

We will simplify this circuit even more and we will not install the zener diodes “D1, D2”.
Items you will need:
1. 10 kOhm resistors - 2 pcs.
2. 470 Ohm resistors - 2 pcs.
3. Schottky diodes for 1 A - 2 pcs. (Others are possible, the main thing is for a current of 1 A and high-speed)
4. Field-effect transistors IRF3205 - 2 pcs. (you can take any other powerful ones)
5. Inductor "5 + 5" - 10 turns with a tap from the middle. The thicker the wire, the better. He wound on a wooden round stick, 3-4 centimeters in diameter.
6. Throttle - 25 turns on a ring from an old computer block.
7. Capacitor 0.47uF. It is better to gain capacity with several capacitors and for a voltage of at least 600 volts. At first I took it to 400, as a result of which it began to warm up, then I replaced it with a composite of two in series, but they don’t do that, they just didn’t have it at hand anymore.

Making a simple 12V induction heater

I assembled the entire circuit by surface mounting, separating the inductor from the entire circuit with a block. It is desirable to place the capacitor in the immediate vicinity of the coil terminals. Not like mine in this example in general. Transistors installed on radiators. Powered the entire installation from a 12 volt battery.

Works great. The blade of a clerical knife heats up to redness very quickly. I recommend everyone to repeat.
After replacing the capacitor, they no longer warmed up. The transistors and the inductor itself heat up if it is constantly running. For a short time - not critical almost.

To heat up to red or even melt a small metal object at home, it is not at all necessary to fire up the stove and transfer fuel - modern technologies allow for this to use high-frequency currents (HF). And the simplest (and most common) circuit for an induction heater of metals will be a multivibrator based on field-effect transistors. At least these modules are assembled from Chinese sites. Next, see 2 models that differ in power and, of course, in price.

ZVS50- an entry-level induction heating module, the module can be powered even from batteries with a voltage of up to 12 volts, that is, from both autonomous power supply, and from the network PSU. The price on www.banggood.com is about $8.

• Input voltage: 5-12V
• Board dimensions: 5.5 x 4 x 2 cm
• Coil size: length 2.8, diameter 2 cm

ZVS1000- a module for induction heating of metals by high frequency currents, with a power of up to 1000w. The average price is $35.

This induction heating unit uses a power supply direct current 12-48 V, maximum current 20 A, maximum power 1000 watts. Can be used to process small parts: hardening, annealing and other heat treatment. It can also be used with a crucible to melt gold, silver, copper, aluminum and other metals. Fast and uniform heating, which is very convenient for jewelers.

• Coil Inner Diameter: 40mm
• Coil Height: 50mm
• At 48 V no load current 5 A

The higher the voltage, the greater the heating current, and hence the power transmitted to the metal. The coil can accept inside 40 mm crucible. It is necessary to use the device with power supplies of the appropriate power and put a cooling cooler on the radiator.

The size of the object that is heated inside the induction coil cannot exceed 1/4 of the volume, otherwise overload and combustion of the circuit may occur. While this circuit can handle 30A temporarily - for long term operation the current should not exceed 20A for safe operation.

Induction heaters work on the principle of “getting current from magnetism”. In a special coil, a high-power alternating magnetic field is generated, which generates eddy electric currents in a closed conductor.

The closed conductor in induction cookers is metal utensils, which is heated by eddy electric currents. In general, the principle of operation of such devices is not complicated, and with little knowledge in physics and electrical engineering, it will not be difficult to assemble an induction heater with your own hands.

The following devices can be made independently:

1. Devices for heating in a heating boiler.
2. Mini ovens for melting metals.
3. Plates for cooking food.

Do-it-yourself induction cooker must be made in compliance with all norms and rules for the operation of these devices. If electromagnetic radiation dangerous for humans is emitted outside the case in the lateral directions, then it is strictly forbidden to use such a device.

In addition, a great difficulty in the design of the stove lies in the selection of material for the base of the hob, which must meet the following requirements:

1. Ideal for conducting electromagnetic radiation.
2. Not conductive.
3. Withstand high temperature stress.

In household induction hobs, expensive ceramics are used, in the manufacture of an induction cooker at home, find worthy alternative such material is quite difficult. Therefore, to begin with, you should design something simpler, for example, an induction furnace for hardening metals.

Manufacturing instructions

Blueprints

Picture 1. Wiring diagram induction heater
Figure 2. Device. Figure 3. Scheme of a simple induction heater

For the manufacture of the furnace will need the following materials and tools:

• solder;
• textolite board.
• mini drill.
• radioelements.
• thermal paste.
• chemical reagents for board etching.

Additional materials and their features:

1. To make a coil, which will emit an alternating magnetic field necessary for heating, it is necessary to prepare a piece of copper tube with a diameter of 8 mm and a length of 800 mm.
2. Powerful power transistors are the most expensive part of homemade induction plant. To mount the frequency generator circuit, it is necessary to prepare 2 such elements. For these purposes, transistors of brands are suitable: IRFP-150; IRFP-260; IRFP-460. In the manufacture of the circuit, 2 identical of the listed field-effect transistors are used.
3. For the manufacture of an oscillatory circuit you will need ceramic capacitors with a capacity of 0.1 mF and an operating voltage of 1600 V. In order for a high-power alternating current to form in the coil, 7 such capacitors are required.
4. When working such induction device , field-effect transistors will get very hot and if radiators from aluminum alloy, then after a few seconds of operation at maximum power, these elements will fail. Transistors should be placed on heat sinks through a thin layer of thermal paste, otherwise the efficiency of such cooling will be minimal.
5. Diodes, which are used in an induction heater, must be of ultra-fast action. The most suitable for this circuit, diodes: MUR-460; UV-4007; HER-307.
6. Resistors used in circuit 3: 10 kOhm with a power of 0.25 W - 2 pcs. and 440 ohm power - 2 watts. Zener diodes: 2 pcs. with an operating voltage of 15 V. The power of the zener diodes must be at least 2 watts. A choke for connecting to the power outputs of the coil is used with induction.
7. To power the entire device, you will need a power supply unit with a capacity of up to 500. W. and voltage 12 - 40 V. You can power this device from a car battery, but you will not be able to get the highest power readings at this voltage.

The very process of manufacturing an electronic generator and coil takes a little time and is carried out in the following sequence:

1. From a copper pipe a spiral with a diameter of 4 cm is made. To make a spiral, a copper tube should be wound onto a rod with flat surface 4 cm in diameter. The spiral should have 7 turns, which should not touch. Mounting rings are soldered to the 2 ends of the tube for connection to the radiators of the transistor.
2. The printed circuit board is made according to the scheme. If it is possible to supply polypropylene capacitors, then due to the fact that such elements have minimal losses and stable operation at large amplitudes of voltage fluctuations, the device will work much more stable. The capacitors in the circuit are installed in parallel, forming an oscillatory circuit with a copper coil.
3. Metal heating occurs inside the coil, after the circuit is connected to a power supply or battery. When heating the metal, it is necessary to ensure that there is no short circuit of the spring windings. If you touch the heated metal 2 turns of the coil at the same time, then the transistors fail instantly.

Nuances

1. When conducting experiments on heating and hardening metals, inside the induction coil the temperature can be significant and amounts to 100 degrees Celsius. This heating effect can be used to heat domestic water or to heat a house.
2. Scheme of the heater discussed above (Figure 3), at maximum load it is able to provide the radiation of magnetic energy inside the coil equal to 500 watts. Such power is not enough to heat a large volume of water, and the construction of a high power induction coil will require the manufacture of a circuit in which it will be necessary to use very expensive radio elements.
3. A budget solution for organizing induction heating of a liquid, is the use of several devices described above, arranged in series. In this case, the spirals must be on the same line and not have a common metal conductor.
4. Aspipe is used of stainless steel 20 mm in diameter. Several induction spirals are “strung” onto the pipe, so that the heat exchanger is in the middle of the spiral and does not come into contact with its turns. With the simultaneous inclusion of 4 such devices, the heating power will be about 2 kW, which is already enough for flow heating of the liquid with a small circulation of water, up to values ​​that allow the use this design in supply warm water small house.
5. If you connect such a heating element to a well-insulated tank, which will be located above the heater, the result will be a boiler system in which the heating of the liquid will be carried out inside the stainless pipe, the heated water will rise up, and a colder liquid will take its place.
6. If the area of ​​the house is significant, the number of induction coils can be increased up to 10 pieces.
7. The power of such a boiler can be easily adjusted by turning off or on the spirals. The more sections that are simultaneously turned on, the greater the power of the heating device operating in this way will be.
8. To power such a module, you need a powerful power supply. If there is an inverter welding machine direct current, then it is possible to make a voltage converter of the required power from it.
9. Due to the fact that the system operates on direct electric current, which does not exceed 40 V, the operation of such a device is relatively safe, the main thing is to provide a fuse box in the generator power circuit, which, in the event of a short circuit, will de-energize the system, thereby eliminating the possibility of a fire.
10. It is possible to organize “free” heating of the house in this way, subject to installation for powering induction devices batteries, which will be charged by solar and wind energy.
11. Batteries should be combined in sections of 2, connected in series. As a result, the supply voltage with such a connection will be at least 24 V., which will ensure the operation of the boiler at high power. In addition, series connection will reduce the current in the circuit and increase the battery life.

1. Exploitation homemade devices induction heating, does not always make it possible to exclude the spread of electromagnetic radiation harmful to humans, therefore the induction boiler should be installed in a non-residential area and shielded with galvanized steel.
2. Mandatory when working with electricity safety regulations must be followed and especially for networks alternating current voltage 220 V.
3. As an experiment can be made hob for cooking food according to the scheme indicated in the article, but it is not recommended to constantly operate this device due to imperfections self-manufacturing shielding this device, because of this, exposure to the human body of harmful electromagnetic radiation that can adversely affect health is possible.

Of the products provided for review, the choice fell on this induction heater. Why does he me..?

Vortex induction heater. A few words of theory.
“In the operation of an induction heater, the energy of an electromagnetic field is used, which the heated object absorbs and converts into heat. To generate a magnetic field, an inductor is used, that is, a multi-turn cylindrical coil. Passing through this inductor, the variable electricity creates an alternating magnetic field around the coil.
If a heated object is placed inside the inductor, it will be pierced by the flux of the magnetic induction vector, which is constantly changing in time. This gives rise to electric field, the lines of which are perpendicular to the direction of the magnetic flux and move in a vicious circle. Thanks to these eddy currents 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 consumed more efficiently, and the heating rate is noticeably increased.
“The inductor-blank system is a coreless transformer in which the inductor is the primary winding. The workpiece is, as it were, a secondary winding, short-circuited. The magnetic flux between the windings closes in air.
At high frequency, eddy currents are displaced by the eddy currents formed by them. magnetic field into thin surface layers of the workpiece (skin effect), as a result of which their density increases sharply, and the workpiece is heated. The underlying layers of the metal are heated due to thermal conductivity. It is not the current that is important, but the high current density. In the skin layer, the current density increases several times relative to the current density in the workpiece, while 86.4% of the heat from the total heat release is released in the skin layer. The depth of the skin layer depends on the radiation frequency: the higher the frequency, the thinner the skin layer. It also depends on the relative magnetic permeability of the workpiece material.
For example, at a frequency of 2 MHz, the skin depth for copper is about 0.25 mm, for iron ≈ 0.001 mm.
The inductor gets very hot during operation, as it absorbs its own radiation. In addition, it absorbs heat radiation from a hot workpiece. They make inductors from copper tubes cooled by water. Water is supplied by suction - this ensures safety in case of a burn or other depressurization of the inductor.
In our case, the inductor is not copper tube, and a piece of copper wire twisted into a spiral.
For myself, I personally outlined only one useful application such a misshapen heater. Warming up, and then, if possible, hardening of the sharpened tips of all kinds of screwdrivers, awls and pickers ...
Declared performance characteristics:
- Module power supply: 5-12V
- Dimensions: 5.5 x 4 x 2 cm (L*W*H)
- Coil size: length: 7.5cm, diameter: 2.8cm
- Inductor wire diameter:
Set:
- module: 1 pc.
- coil: 1pc.
We don't know anything more about him yet. Well, let's check what it is capable of and whether it meets my expectations ...
The module arrived like this.




Sizes slightly larger matchbox excluding throttles.
Scarf width - 37 mm.
The length of the scarf is 55 mm.
The height from the bottom of the conders to the top of the throttles is 45 mm.


Coil dimensions and diameter.
Coil length - 35 mm.
Diameter - 22 mm.
Wire diameter - 2 mm.
Coil length with leads -70 mm.
The weight of the assembly is 114 grams.


The scarf has inscriptions with the recommended supply voltage, its polarity on the connector.


WITH reverse side handkerchiefs have a connector for connecting the coil.


Conder below.


Solder the module.
The scarf itself is very well made. Bottom silk-screened, the image of scorpions. Probably some kind of brand name of the manufacturer printed circuit boards. The inscriptions on the transistors are filed off. :0)


We draw a diagram.
The scheme turned out to be the most common on the Internet. Although the marking of transistors was erased on this board and it was not possible to decipher the marking of zener diodes, it is easy to find a similar circuit on the Internet by googling. Although it is possible that the details are somewhat different, but it does not matter. It is easy to find an analogue for a replacement in case of a malfunction.


used capacitors.


Now we assemble everything, fasten the coil and apply power. The blue LED lights up.


Currents at idle.


currents under load. As a "load" I used a trihedral needle file.


The frequency of the generator at idle is 214 kHz, under load it drops to 210 kHz.


A small video of heating the tip of a triangular needle file.

The induction heater works, but eats a lot at idle.
The transistors soldered on the board heat up pretty decently, the board does not dissipate heat well. If you modify the scarf, put more powerful transistors and put them on radiators, you can get quite a heater. What I will do in the near future.
Would I recommend to buy? Probably yes, but not as a working finished product, but rather as a trial version with the possibility of a small finish. Well, if the money is too much. :0)

The product was provided for writing a review by the store. The review is published in accordance with clause 18 of the Site Rules.

I plan to buy +37 Add to favorites Liked the review +55 +103

Hi all. Today we will consider a popular thing - an induction heater straight from China, more precisely from a banggood store.

The Chinese produce such boards with various modifications, for every taste.

My sample is not one of the most budgetary budget ones, there is an inductor in the kit, now get it copper pipe the desired diameter is quite difficult, so if you take such a board, it is better to immediately with an inductor.

So, this is a popular ZVS driver circuit, on the basis of which you can build anything, from simple converters to induction heaters, I intend to test this sample in detail, unleash its potential, and make all possible measurements, so we will not limit ourselves to one article.

The board and the inductor itself are included, the heater circuit is now in front of you.

The declared power is 1 kilowatt, the input voltage is from 12 to 36 Volts at a maximum current of 20 Amperes, here the Chinese refute themselves, because even at the maximum voltage and current the power consumption will be no more than 720 watts, but knowing this circuit, I will say that it can be powered and from a higher voltage, up to 60 volts and consume currents of more than 20 amperes, so that when it comes to power consumption, it can exceed 1000 watts, but the Chinese are silent about the useful power, taking into account the efficiency of the circuit. In real useful power about 200-250 watts when powered from a 36V source.

The printed circuit board is double-sided, made perfectly, but the Chinese were a little too lazy to clean up the flux residues, the manufacturer additionally tinned the power tracks, in general, there are no complaints, you can now see the dimensions of the board on your screens. (Later, when 36 Volts were supplied, after some time one of the power tracks simply burned out, I had to reinforce it with a stranded copper wire and tin everything additionally)

The circuit has forced cooling in the form of a cooler, it is located directly above the transistors and is powered by a separate step-down regulator based on the XL2596 chip. The stabilizer board is glued to the cooler with snot (hot).

There are 2 power transistors, these are powerful field devices IRFP260 (200V 50A), and the circuit is a push-pull oscillator.

Powerful 470 ohm resistors were used to limit the gate current of the keys, they look like two-watt, but the dimensions are slightly larger than standard two-watt resistors, so that resistors of 3 or 4 watts are possible.

Resistors are at the same time limiters for zener diodes, which do not allow the formation of increased voltage on the gate of the keys, stabilizing at the level of 12 volts, it can be seen seat for a linear stabilizer at 12 or 15 volts, since the zener diodes in some versions are replaced by a linear regulator.

An inductor with a bank of capacitors form a parallel oscillatory circuit, the parameters of these components set the operating frequency of the circuit as a whole, since this is a resonant converter.

The battery consists of 6 and specialized capacitors, the capacity of each is 0.33 microfarads, the total capacitance is about 2 microfarads.

Such capacitors are designed to operate in high-frequency circuits and are used in particular in induction heaters, so that this perfect option for such a scheme.

The board has brass stands for mounting the cooler and the inductor, a rather convenient solution.

There are two chokes, power is supplied through them, both chokes are identical, wound on rings made of powdered iron. The number of turns is 30, the wire diameter is 1 mm, the inductance is 74 μH.

The inductor or circuit is a copper pipe with a diameter of 5 mm, the inner diameter of the inductor is 42 mm, the number of turns is almost 8, the turns can be stretched or compressed, the main thing is not to close.

Power is supplied to the terminal block, which is located in a secluded place under the cooler.

The same terminal block is also available in front, a circuit can be connected to it. Such a terminal block is convenient in the case of using copper wire circuits.

The polarity is signed on the power terminals, there will be no connection problems.

I think everything is clear with the board, let's move on to the tests. I want to say right away that I will fully load the inductor in one of the following articles, since water cooling is needed for maximum overclocking, and, unfortunately, I do not have an appropriate water pump.

So first of all let's check the current idle move from a 12 volt source.

As you can see, the circuit consumes about 2 Amperes, I will say that for this particular circuit, such consumption is the norm.

From a source of 24 volts, consumption increased to 4 A, which was to be expected.

And finally, from a source of 36 volts, the circuit consumes almost 5.5A at idle.

The working frequency is about 90KHz,

This is the shape of the pulses on the gate of one of the keys.

We observe a pure sine wave on the inductor, pay attention to the amplitude swing, which many times exceeds the supply voltage.

For tests, 3 completely new 12-volt batteries were bought from an uninterruptible power supply, connected in series to get 36 volts.
In a couple of seconds, you can heat a thin tin like blades from stationery knives, etc.

Now you see the consumption of the circuit in the case of heating a tin sleeve from a 18650 battery, the battery voltage dipped to 26 Volts.

Without a fan, everything heats up - keys, chokes, capacitors and gate resistors, the circuit heats up especially critically even without load, so it is in the form of a pipe, and if you are going to use the heater for some purpose, be sure to let in water cooling, otherwise the circuit will literally become red hot. I also highly recommend strengthening the power buses on the board, the Chinese have tinned them, but they heat up terribly.

Readers may have a completely normal question - will such an inductor heat other metals besides iron, I will say that it heats, but so weakly that it is almost imperceptible. I tried aluminum, brass, copper, tin, the heating is barely felt, but despite this, it will be possible to melt some metals with such an inductor if the crucible is installed in iron pipe, A better pipe into the crucible, the iron will heat up and the heat will be transferred to the metal to be melted.

In any case, you need to remember that the circuit is amateur and is not suitable for serious purposes due to the lack of a PWM control circuit, current control, temperature, protection and other components that are contained in expensive, professional heaters, but professional models can cost several hundred thousand rubles , and our scarf costs only some 36 evergreen dollars.

In the case of operation, I advise you to put a 40 Ampere power fuse so as not to burn the keys if something happens, and this is easy to do if you accidentally close the circuit turns at high supply voltages, or reverse the power polarity.
That's all for today, subscribe to our group so as not to miss updates.

Product can be bought

Video review