Each area of technology has its own iconic device, looking at which you clearly understand what, where, where. A sail is the sea, yachts, ships. Propeller - aviation, airplanes, wheel - bicycle, car, etc. And we do not always reflect on the fact that once these now simple and understandable devices were the next, sometimes difficult, step in the formation of an entire branch of technology or engineering.
Such a story also has a well-known representative of electrical engineering - a transformer. Back in 1831, Faraday made history by the discovery of electromagnetic induction - the main principle of the transformer. Only 45 years later, the Russian scientist P. N. Yablochkov was granted a patent for the invention of a transformer. Two windings located on an open core confirmed the ability to transform, i.e. convert, change currents and voltages. The very first step-up transformer was manufactured. Modern transformers range in size from structures of several floors to tiny products of less than 1 cm, and their production is a leading industry in the electrical industry.
The technology uses a huge number of transformers for various purposes and each of them has its own specific name. For example, a step -up voltage transformer has widespread use in electric laboratories , which, with an output voltage of several kilovolts, has a supply voltage of 220 V.
So transformer - what is it? The classic definition is: a transformer is an electric machine that converts the current of an input power source into a secondary current with a different voltage. The transformer operates with AC voltage, as the induction effect is manifested only when the electromagnetic field changes . The transfer (transformation) of energy passes through the conversion of electrical energy in the windings first into a magnetic field, and then the transition back into electrical current energy, but already in the secondary winding. If the secondary winding exceeds the primary by the number of turns, then we have a step-up transformer, and if you connect the windings the other way around, then the transformer will be "vice versa" - step-down.
Suppose that you need to connect an electric consumer in a garage with a 36V electric network, for example, a battery charging unit with 220V power supply - this is a typical case in order to use a step-up transformer. The solution to this practical problem will be considered step by step.
1. Take the power of the charger from the passport - most likely it will be something around 100 watts. Understanding that you always need to have a margin for the future and taking into account the efficiency of the future transformer is approximately 0.9, we take the primary winding power of 150 watts.
2. Select the magnetic circuit. The easiest way to get an O-shaped magnetic core (from an old TV). Any one with a cross section no less than that follows from the relation: P1 = S * S / 1.44, where P1 and S is the power of the transformer in Watts and the core cross section in cm square, is suitable for us. The calculation gives the value S = 10.2 cm2.
3. The next step is the most important during the "construction" of the transformer - the number of turns per 1V is determined: N = 50 / S = 50 / 10.2 = 4.9 turns / V. Now it is very easy to calculate the number of turns (or, as they say, “winding data”), primary and secondary windings: W1 = 36 * N = 176 turns and W2 = 220 * 5 = 1078 turns.
4. Determine the currents of the windings. We assume that the power of each winding is approximately 150 watts. In this case, the operating currents of the windings are: J1 = 150/36 = 4.2A and J2 = 150/220 = 0.7A.
5. Now there is all the data for determining the diameters of the wires of the windings. So we will do: for the primary winding d1 = 0.8 * √J1 = 0.8 * 2.05 = 1.64 mm square. ;
similarly for the secondary winding d2 = 0.8 * √J2 = 0.8 * 0.84 = 0.67 mm sq.
For winding the windings, we select the diameters closest to the standard ones.
All! The calculation is over, but is it possible to make a step-up transformer with your own hands? As they say - there is nothing easier if you really need it. The real need is the main force driving self-made crafts, so then with pens, pens.
6. Make two frames for the selected magnetic circuit.
7. Half-wound primary windings are wound tightly over the frames and insulated with glass or varnish.
8. Next, lay on each frame half of the secondary winding and also cover them with varnish.
9. Assembling the magnetic circuit, tightening its parts with a clamp - the problem is not very complicated. When assembling the magnetic circuit, it is advisable to glue its halves with any composition using ferro-powder - this will eliminate the “buzz” of the device during operation.
That's all! Our homemade product, it is worth thinking, will work for a long time and in joy. And who would doubt it!