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Re: TC coil experements 7 years ago



Original poster: "resonance" <resonance@xxxxxxxxxxxx>




3.1459 is the best, however, top to pri flashovers can easily occur. We use 4.5:1 ratio for most all of our coils with 1,000 turns. I've also tried experiments with 800.900,.... up to 1,600, and 1,000 seems to work the best. The resistance seems to start crimping performance above 1,000 to 1,400 range. For great current and hot sparks use 1,000 turns for most all designs, NST or pole xmfr units.

For a great running coil, some standard design data:

h/d ratio of 4.5:1.

Example, with an 8 inch dia coilform, then 4.5 x 8 = 36 inch winding length.

Divide this 36 inch length by 1,000 turns to get the wire OD, in this example, OD = .036 inches (36 mils).

Consulting a standard double build enamel (150 degree C.) wire chart and you will find #19 AWG is .0359, the closet value to .036, so let's use this size wire to wind. This gives 36 inches / .0359 = 1,003 total turns. Always use the double build insulation as this provides max protection against flashovers especially if your coil should happen to have a few dust spots on it.

Top it with a toroid that is approx 3 to 4 times the dia. of the sec coil form. In this case, let's use 3 x 8 inch OD coilform = 24 inch major dia. toroid. 24 x 6 inch is a standard size that would work very well.

Max potential across an inductor is E = -L x dI/dt inductance x rate change of current.

Inductance is r^2 x n^2 / (9r + 10L) (in this equation, L is length of coil winding)

Inductance goes up as the square of the radius of the coilform and potential goes up directly as the inductance, so going to larger coilfroms is always a definite advantage.

Keep L large as possible by using the largest radius coilform your plans can accomodate. Keeping the inductance large and using large dia coilforms will also keep your sec discharge current up and form high temp sparks to provide longer plasma spark channels.

Then, using Bart's excellent JAVATC program to enter all the data, experiment with cap values and # pri turns, etc. Within an hour you will have a super coil design that will work great without major headaches and hassles.

Usually, increasing capacitance in JAVATC until you end up with approx 5-6 turns on the pri for pole xmfrs and around 9-10 turns on the pri for NSTs gives excellent performance.

These techniques work on nearly every coil design from a small or medium size NST, to PTs and pole xmfrs as well.





Original poster: gary350@xxxxxxxxxxxxx
Vanderbelt University did some research on Tesla Coils. The best length to diameter ratio is 3 to 1 according to them. Research shows 3/1 is better than 4/1 and that is better than 5/1. If you are going for absolute maximum output try 3/1 ratio.