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Re: Scroungein' (fwd)



Hi Christopher,

> Original Poster: "christopher boden" <chrisboden-at-hotmail-dot-com>
>
> <big snips>
> I ordered a 60KV .001~.005 Cap from Maxwell. Does the value matter
> exactly? I figured that since people can pull this off with "Beer
> Bottles" I didn't have to have an exact value. I'm hopeing to be able
> to use these caps for both coils, can that be done? I'm also getting
> a BIG pulse cap (think 300 Lbs) for some other work, could that be
> usefull for this stuff as well?

The caps can be paralleled to increase capacitance if needed. Your voltage
rating will not change when they are paralleled. Depending on the value
and quantity of caps you purchased will determine how close you can get to
the "desired" capacitance. But regardless, it will work. You will need to
either increase or descrease the primary turns to match whatever total
capacitance you use. Something to keep in mind is the energy deliverable
from the cap value. The larger the value, the greater the energy and the
longer the charge time. The smaller the value, the less energy and the
shorter the charge time. If you use a 0.001uF instead of a 0.01uF, don't
expect a lot from the cap. Also, if you use a large cap value (i.e.,
0.05uF) you can expect a lot from the cap but you may need to increase
transformer current to charge the cap fast enough. I personally think you
will have no problem using the caps in parallel by just getting as close
as possible to your desired value, then simply set the correct number of
primary turns for a LpCp=LsCs match (Cs here is the total secondary
capacitance, toroid and all).

> We're trying a rather novel idea for the Toroid. A 20" Bicycle wheel
> with the standard aluminum ducting aroung the periphery (like a funky
> tire) It will balance well, be uniform, look sharp, and be easily
> mounted. The question is, will the damn thing work? I dunno, but it's
> worth a shot, and if it doesn't, it won't be an expensive mistake.

Sure it will work. The ducting size (top capacitance) will determine your
loaded resonant frequency and change the tune accordingly. Keep this in
mind anytime you increase/decrease/change the top capacitance. Retuning is
almost always a necessity.

Good luck with the caps,
Bart