If you are interested in making a welding machine or voltage regulator, then you need to know what toroidal transformers are. But the most important thing is how they work and what subtleties they have in manufacturing. In addition, such transformers, in view of their design, are able to give more power in comparison with those that are wound on an S-shaped core. Consequently, such devices are ideal for powering very powerful equipment - for example, low-frequency amplifiers.
So, before you start making a transformer, you need to study the match. First, you need to determine the type of wire used. Secondly, you need to calculate the number of turns (it follows that you will know how many meters of wire you need). Thirdly, it is necessary to choose the cross-section of the wire. The output current depends on this parameter, hence the power of the toroidal transformer.
It is also necessary to take into account that with a small number of turns in the primary winding, heating will occur. A similar situation arises even if the power of consumers connected to the secondary winding exceeds the value that the transformer can give. The consequence of overheating is a decrease in reliability. Moreover, the overheating can even lead to the ignition of the transformer.
What will be required for manufacturing
So, you're starting to make a transformer. You need to acquire tools and materials. Of course, you may even need a sewing needle or matches, but for sure such accessories are available to everyone. The most important thing is the iron from which the toroidal transformers are made. You need a lot of transformer steel, it should be in the form of a torus. Further, of course, the wire is in varnish insulation. Requires the presence of paint tape and glue type PVA. Also, to isolate the windings, a cloth-based insulating tape is needed. And a few pieces of wire to connect the ends of the windings. And the wire must be used in silicone or rubber insulation.
To get such an accessory, as it may seem, is very difficult. But in any house, shed, even at the reception points of metal today, you can find unsuitable voltage stabilizers. In the Soviet years, they were very popular, they were used together in black and white TVs, so as not to put kinescopes. You do not care if this stabilizer works or it's burnt out. The most important thing is the toroidal transformers used in it. They will be the basis of your design. But before that you need to get rid of the old winding, which is made of aluminum wire. And then - the preparation of the core. Please note that it has right angles. You do not need this, because you can damage the lacquer insulation when winding. Try to round the corners as much as possible by processing them with a file. Then, on top of the transformer steel, lay the fabric-based electrical tape. Only one layer is needed.
And now a little about how the calculation of the toroidal transformer is carried out. You can, of course, use simple programs, which are great. You can calculate with a ruler and a calculator. Of course, it will have an error, since many more factors that exist in nature are not taken into account. You should follow one rule when calculating - the power in the secondary coil should not be greater than the same value in the primary winding.
As for the process, like winding a toroidal transformer, it is very laborious. It is good, if it is possible to disassemble the magnetic circuit and, after winding, collect it together. But if there is no such possibility, then we can apply a kind of spindle. A certain amount of wire is wound on it. Then, passing this spindle through the torus, lay turns of windings. Time for this will take a lot, so if you are not sure of your abilities, better get a ready-made power supply.
It is best to describe the process using a specific example. The primary winding, as a rule, is powered by a 220 V alternating voltage network. Suppose you need two secondary windings, so that each produces 12 volts. And you also use a wire with a cross section of 0.6 mm in the primary winding. Consequently, the cross-sectional area will be approximately 0.23 square kilometers. mm. But this is not all calculations, toroidal transformers need a thorough adjustment of all parameters. And now again a bit of math - you need to divide 220 (B) by the sum of the voltages of the secondary circuits. In the end, you get a certain coefficient of 3.9. It means that the cross-section of the wire used in the secondary winding must be exactly 3.9 times greater than in the primary winding. To calculate the number of turns for the primary winding, you need to use a simple formula: multiply the coefficient "40" by the voltage (in the primary circuit it is 220 V), after which this product is divided into the cross-sectional area of the magnetic circuit. It should be noted that the efficiency and service life of the toroidal transformer depend on how accurately the toroidal transformer is calculated. Therefore, it is better to repeat each step of the calculation once more.