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08-25-2013, 05:14 AM
 Sebacid Junior Member Join Date: Jul 2012 Posts: 18
Quote:
 Originally Posted by wayne.ct I have looked at this and done a bit of reading at the context and I don't really have a good feeling for where to start. I am thinking perhaps I should apply some of the functions and formulae that EPD has gathered and perhaps compute the size and other parameters of the necessary coils and capacitors? If someone would suggest some specific numbers and create an example of the calculations, that would seem like a helpful starting point. First, pick a typical AM frequency, such as that of your local 50 KVA AM station, and use that as an example. It seems we need to solve a simultaneous equation. There are two values for inductors and also two? values for capacitors. Then there is the actual circuit diagram. Again, I have a picture in my mind, but I'm not sure if it is right. If you want to post you sample data, my eyes are open. Thx. Attachment 13624
Hi Wayne,

All the information necessary to do this can be found in this forum under Eric's posts as T-Rex. See links in my previous reply. You just have to get your hands dirty and look for the information. That is a part of the challenge, to get people doing.

But here's some advice to get you started:

"The design of the Tesla Transformer starts with the secondary resonant coil. In its resonant mode it is a quadrapolar resonator. Two constants exist in the construction of this solenoidal resonator, one is that the height to length ratio must be 20%, the other is that the side by side spacing of the cylindrical conductor turns is 62% the diameter of the cylindrical conductor. The optimum number of turns is 20 on the secondary, with 2 on the primary. This gives the physical size of the coil for a given frequency. Increasing the number of turns reduces the size of the secondary coil in proportion to the increase in turns. Accordingly the conductor diameter also decreases as the copper is spread out over more windings. The ratio of secondary turns to primary turns must equal a constraint of 10 to 1. For a given number of turns the operating frequency becomes the sole independent variable in coil design.The primary coil is the same diameter as the secondary coil. The ratio of conductor width to coil diameter is 18%.

The sheet conductor is closely spiralled into two turns, for a secondary of twenty turns. For a conductor thickness as given by the maximum thickness vs frequency the volume of the primary metal must equal the volume of the secondary metal, based upon equal weights for primary and secondary metals. Brass can be 1.7 times thicker than copper, and bronze can be 2.8 times thicker than copper, for a given maximum thickness and frequency.The primary condenser should be made of the same amount of metal as the primary coil. Their weights should be about the same. The connecting leads must be short and the same width as the primary conductor. Large, multiplate air condensers are good, so are metal sheets and glass.The secondary capacitance is best a copper tubing ring around the outside of the H end of the coil. This ring must be open in one spot along its loop so as not to be a shorted turn. The end of the secondary wire connects to this capacity ring. Beer cans make the best elevated capacitors.The finished transformer must operate on a directly connected ground plane. A large plywood table with aluminum foil glued on to it, this covered with a plastic or glass sheet is the minimum required ground plane. Obviously the aluminum plane must be solidly earthed with special attention to minimizing ground lead inductance. In order to light a lamp a more broadcast station style of ground plane is required, but for testing purposes the metallized plywood “ten by” sheet is just fine. Good luck and good crystal set DX ing.

Hope this helps to get you started?

-Seb
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