Re: TC coil experements 7 years ago

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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.