Well, I would suggest before you do anything, try to get the coil in tune first. Looking at your coil specs, you have a long skinny coil (6:1 H/D) but your coil should still work ok as it is. Based on your data, the 12 turn primary requires a cap size around 40nF. So if you can hook up the 47nF (as you listed below) then you should be able to tune within 1 turn from where you are now. Make sure your secondary has a good RF ground and try again. I'm guessing this coil should hit 30" arcs when tuned. Some might calc longer arcs, but I don't think you will go much over 30" at this point until further improvements are made to other aspects of your coil.
Bart
Original Poster: "Kamil Kompa" <czlonek-at-polbox-dot-com>Hi!
I have made all parts of my tesla coil but I can't make it to work.
(Im goaing to make a DC powered unit).
Here is the description of all parts:1. The transformer is 150mA 13000V current limited.
2.I have a 20kV rectifier made from four diodes.
3.I have 90nF and 100nF capacitors so I can have 47,90,100,or 190nF tank
capacitance.(Both capacitors are rolled type polythene,oil filled. The
values are measured with a meter).
4.Spark gap is single air blown gap.
5.Primary is a flat spiral 12 turns.
6.Secondary is 100mm diameter , made from 0.7mm diameter wire on a PCV
pipe. It is 770 turns.
7.Toroid is 17pF
8.Grounding is cold water pipe (it's a metal pipe goaing straight to
ground.)I don't know why my coil is not working properly. Perhaps it's not tuned
properly. I tuned my coil by changing the tap point on the primary ,
and watching the spark lenght to the grounded rod.Unfortinately the
longest spark was only 20cm long. Also there were no sparksto the air.
I have got the 20cm spark when primary was 2,4 turns (close to 2,6
counted by WinTesla).What parts schould I change or what schould I do to make my coil
working.Thanks for all answers.
Kamil Kompa.
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