Nikola Tesla is a legendary figure, and the meaning of some of his inventions is disputed to this day. We will not go into mysticism, but rather talk about how to make something spectacular according to Tesla's "recipes". This is a Tesla coil. Seeing her once, you will never forget this incredible and amazing sight!
General information
If we talk about the simplest such transformer (coil), then it consists of two coils that do not have a common core. There must be at least a dozen turns of thick wire on the primary winding. At least 1000 turns are already wound on the secondary. Please note that the Tesla coil has a transformation ratio that is 10-50 times greater than the ratio of the number of turns on the second winding to the first.
The output voltage of such a transformer can exceed several million volts. It is this circumstance that ensures the appearance of spectacular discharges, the length of which can reach several meters at once.
When the capabilities of the transformer were firstdemonstrated to the public?
In the town of Colorado Springs, a generator at a local power plant once completely burned out. The reason was that the current from it went to power the primary winding of the invention of Nikola Tesla. During this ingenious experiment, the scientist proved to the community for the first time that the existence of a standing electromagnetic wave is a reality. If your dream is a Tesla coil, the most difficult thing to do with your own hands is the primary winding.
Actually, making it yourself is not so difficult, but it is much more difficult to give the finished product a visually attractive look.
Simple transformer
First, you will have to find somewhere a source of high voltage, and at least 1.5 kV. However, it is best to immediately rely on 5 kV. Then we attach it all to a suitable capacitor. If its capacitance is too large, you can experiment a little with diode bridges. After that, you make the so-called spark gap, for the sake of the effect of which the entire Tesla coil is created.
Make it easy: take a couple of wires, and then twist them with electrical tape so that the bare ends look in one direction. We very carefully adjust the gap between them so that the breakdown is at a voltage slightly higher than that for the power source. Don't worry, since the current is AC, the peak voltage will always be slightly higher than stated. After that, the entire structure can be connected to the primary winding.
In this case, for the manufacture of the secondary, you can wind only 150-200 turns onany cardboard sleeve. If you do everything correctly, you will get a good discharge, as well as its noticeable branching. It is very important to ground the output from the second coil well.
This is how the simplest Tesla coil turned out. Anyone who has at least minimal knowledge in electrics can make it with their own hands.
Designing a more "serious" device
All this is good, but how does a transformer work, which is not ashamed to show even at some exhibition? It is quite possible to make a more powerful device, but this will require a lot more work. First, we warn you that in order to conduct such experiments, you must have very reliable wiring, otherwise trouble cannot be avoided! So what should be taken into account? Tesla coils, as we said, need really high voltage.
It must be at least 6 kV, otherwise you will not see beautiful discharges, and the settings will constantly go astray. In addition, the spark plug should only be made from solid pieces of copper, and for the sake of your own safety, they should be fixed as firmly as possible in one position. The power of the entire "household" should be at least 60 watts, but it is better to take 100 or more. If this value is lower, then you will definitely not get a really spectacular Tesla coil.
Very important! Both the capacitor and the primary winding must eventually form a specific oscillatory circuit entering into a state of resonance with the secondary winding.
Be aware that the winding may resonatein several different ranges at once. Experiments have shown that the frequency is 200, 400, 800 or 1200 kHz. As a rule, it all depends on the condition and location of the primary winding. If you do not have a frequency generator, then you will have to experiment with the capacitance of the capacitor, as well as change the number of turns on the winding.
Once again, we remind you that we are discussing a bifilar Tesla coil (with two coils). So the issue of winding should be taken seriously, because otherwise nothing sensible will come of the idea.
Some information about capacitors
The capacitor itself is better to take a not too outstanding capacity (so that it has time to accumulate a charge in time) or use a diode bridge designed to rectify alternating current. We note right away that the use of a bridge is more justified, since capacitors of almost any capacity can be used, but you will have to take a special resistor to discharge the structure. The current from him beats very (!) strongly.
Note that the Tesla coil on the transistor is not considered by us. After all, you simply will not find transistors with the desired characteristics.
Important
In general, we remind you once again: before assembling the Tesla coil, check the condition of all wiring in the house or apartment, take care of the availability of high-quality grounding! This may seem like a boring admonition, but such tension is not to be trifled with!
Be sure to very reliably isolate the windings from each other, because otherwise you will break throughguaranteed. On the secondary winding, it is desirable to make insulation between the layers of turns, since any more or less deep scratch on the wire will be decorated with a small but extremely dangerous discharge corona. Now get down to business!
Getting Started
As you can see, you don't need too many items to assemble. You just need to remember that for the device to work properly, you need to not only assemble it correctly, but also configure it correctly! However, first things first.
Transformers (MOTs) can be dismantled from any old microwave oven. This is almost a standard power transformer, but it has one important difference: its core almost always operates in saturation mode. Thus, a very compact and simple device may well deliver up to 1.5 kV. Unfortunately, they also have specific disadvantages.
So, the value of the no-load current is approximately three to four amperes, and the heating even in idle is very large. In an average microwave oven, the MOT produces about 2-2.3 kV, and the current strength is approximately 500-850 mA.
Characteristics of MOTs
Attention! With these transformers, the primary winding starts at the bottom, while the secondary winding is located at the top. This design provides better insulation for all windings. As a rule, on the "secondary" there is a filament winding from the magnetron (approximately 3.6 Volts). Between two layers of metal, an attentive craftsman may notice a couple of some kind of metal jumpers. These are magnetic shunts. Forwhat do they need?
The fact is that they close on themselves some part of the magnetic field that the primary winding creates. This is done to stabilize the field and the current itself on the second winding. If they are not there, then at the slightest short circuit, the entire load goes to the “primary”, and its resistance is very small. Thus, these small parts protect the transformer and you, as they prevent many unpleasant consequences. Oddly enough, is it still better to remove them? Why?
Remember that in a microwave oven, the problem of overheating of this important device is solved by installing powerful fans. If you have a transformer that does not have shunts, then its power and heat dissipation are much higher. For all imported microwave ovens, they are most often thoroughly filled with epoxy resin. So why should they be removed? The fact is that in this case, the "drawdown" of the current under load is significantly reduced, which is very important for our purposes. What about overheating? We recommend putting the ILO in transformer oil.
By the way, a flat Tesla coil generally does without a ferromagnetic core and a transformer, but needs an even higher voltage supply. Because of this, experiencing something like this at home is strongly discouraged.
Once again about safety
A small addition: the voltage on the secondary winding is such that an electric shock during its breakdown will lead to guaranteed death. Remember that the Tesla coil circuit assumes a current strength of 500-850 A. The maximum value of this value, which still leaves a chance forsurvival equals… 10 A. So don't forget the simplest precautions while working!
Where and how much to buy components?
Alas, there is some bad news: firstly, a decent ILO costs at least two thousand rubles. Secondly, it is almost impossible to find it on the shelves even in specialized stores. There is only hope for collapses and "flea markets" where you will have to run a lot in search of what you are looking for.
If possible, be sure to use the ILO from the old Soviet Elektronika microwave oven. It is not as compact as imported counterparts, but it also works in the mode of a conventional transformer. Its industrial designation is TV-11-3-220-50. It has a power of approximately 1.5 kW, produces about 2200 volts at the output, and the current strength is 800 mA. In short, the parameters are very decent even for our time. In addition, it has an additional 12V winding, ideal as a power source for a fan that will cool the Tesla spark.
What else should I use?
High-quality high-voltage ceramic capacitors of the K15U1, K15U2, TGK, KTK, K15-11, K15-14 series. Finding them is difficult, so it is better to have professional electricians as good friends. What about the high pass filter? You will need two coils that can reliably filter out high frequencies. Each of them must have at least 140 turns of high-quality copper wire (lacquered).
Some information about the spark plug
Iskrovikdesigned to excite oscillations in the circuit. If it is not in the circuit, then the power will go, but the resonance will not. In addition, the power supply begins to "punch" through the primary winding, which is almost guaranteed to lead to a short circuit! If the spark plug is not closed, the high voltage capacitors cannot be charged. As soon as it closes, oscillations begin in the circuit. It is to prevent some problems that they use a throttle. When the spark closes, the inductor prevents current leakage from the power supply, and only then, when the circuit is open, accelerated charging of the capacitors begins.
Device Feature
Finally, we will say a few more words about the Tesla transformer itself: for the primary winding, you are unlikely to be able to find a copper wire of the required diameter, so it is easier to use copper pipes from refrigeration equipment. The number of turns is from seven to nine. On the "secondary" you need to wind at least 400 (up to 800) turns. It is impossible to determine the exact amount, so experiments will have to be done. One output is connected to the TOR (lightning emitter), and the second is very (!) Reliably grounded.
What to make the emitter? Use an ordinary ventilation corrugation for this. Before you make a Tesla coil, the photo of which is here, be sure to think about how to design it more original. Below are some tips.
Finalizing…
Alas, but this spectacular device has no practical application to this day. someone showsexperiments in institutes, someone earns on this, arranging parks of “miracles of electricity”. In America, a very wonderful friend a couple of years ago completely built a Tesla coil … a Christmas tree!
To make her more beautiful, he applied various substances to the lightning emitter. Keep in mind: boric acid makes the tree green, manganese makes the tree blue, and lithium makes it crimson. Until now, there are disputes about the true purpose of the invention of a brilliant scientist, but today it is an ordinary attraction.
Here's how to make a Tesla Coil.
