Transformator Tesla Na Ne555

Tesla did not want to create music but rather transmit electricity wirelessly - and to some extent he did! There are rumours that he turned on 100 light bulbs 26 miles away using Tesla Coils! However, there isn't enough evidence to support this claim, but it would be an awesome idea! Essentially, a Tesla Coil is a high voltage, step up transformer.

You may wish to skip this first section if your not interested in the theory. Originally the secondary winding was wound conventionally around the primary coil on the middle leg. The all important cross-sectional area of this centre leg, where all the cores meet, was 8 square inches. I say important, because larger cores are better at dissipating heat among other things. The amount of flux created depends on things like: core size and material, input voltage and the primary inductance, etc. As you ultimately want a high turns ratio, you will want the minimum number of primary turns, that will not saturate the core. Transformer design is actually quite complex, and the usual simplified textbook explanation can lead you to wrongly think it's easy to design one.

Aware of this from my own teenage college years, I took the easy path and used the existing primary specifications. If you also choose this path, don't stray too far from the original specifications, as manufacturers tend to design the primary to be as close to saturation as possible from the outset, without it actually occurring. If though you need a completely new primary, there are several standard formulas for calculating both the core size needed, and the number of turns, but these all depend on you knowing the magnetic permeability of the core material, and also assume that the coefficient of coupling is close to one (1).

An approximation can be found by taking the square root of the expected power and multiply that figure by 0.14. Meaning my intended 5800 watt DIY transformer, should have had a core size of sq root(5800) * 0.14 = 10.66 sq inches, in reality it had 8 sq inches.

A transformer for electronics or particularly audio use, has to be built to a high standard. But a homemade transformers for tesla use, only really needs to fulfill two requirements: a high output voltage, and the ability to supply as much current as possible.

So assuming you are using a proper laminated core, and not an old pipe packed with welding rods, an acceptable formula that I found that will give a starting point, is to measure the cross sectional core size in sq inches. This measurement we will then call 'A', the input voltage will be 'E', and 'K' will equal 6.5 for a 60Hz system or 7.507 for 50HZ. Number of primary turns = (K * E) / A. Using this figure on my core I got a figure of 222 turns needed to create sufficient flux. The number of secondary turns is worked out like this: 222 turns / 240 volts = 0.925 volts per turn on the primary. Assuming a coefficient of '1', a secondary of 10,000 turns will develop 10,000 * 0.925 volts = 9,250 volts. So firstly wind the 222 primary turns and connect it to the mains to check that your unloaded primary current, the so called energising current, is not too high.