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Re: RF chokes & bypass caps.

tesla-at-grendel.objinc-dot-com On Wed, 20 Mar 1996 13:31:20 +0700, you
wrote:

Robert,
>
>I thought you and the group might like to know that I have had 
>excellent results with multi-section, universal wound air core chokes 
>and I do not employ bypass capacitors with them, just a safety gap
>across the output of the 15 KV neon transformer.  Since air lacks the 
>permittivity of iron or ferrous derrivative cores, many more turns are 
>required.  I've had good success with 240mH chokes and 320mH.
>Yes that's three hundred and twenty millihenries! 
You are a better coiler than I. You'll need that 20 miles:)
[snip]
> I'm experimenting now with winding my own air core chokes
>to solve an acquisition problem and have just made a pair of 142mH
>chokes (4-sections, 0.5 inches thick, 0.5 inch air spacing,  scramble wound
>between 3.75 inch diameter plexyglass (acrylic) washers on a hollow 
>1 inch phenolic tube using #22 AWG aluminum enamel covered magnet wire.
>(I got a great price on a 20 mile roll!).  I haven't had a chance to 
>test these yet but I'll post the results when I do.
>

Try 2,5K ohms at 100W in series with 2-4mH. You will lose only a few
10s of watts and it sure beats winding miles of wire. And no oil
needed! only 2 layers of electrical tape ove a $1.49 toroid.

>It has been my experience that bypass capacitors like 500pF 20KV 
>mica doorknobs can quickly overheat a small portion of the secondary 
>of a 23mA, 10KV furnace transformer due to a series resonant/localized 
>overvoltage condition at 60Hz within the potted secondary and short out
>the transformer.
>
>Happy coiling, R.W.S.
>
>
I did blow a 15KV -at- 60ma neon with just the RFI choke and bypass cap.
I'm getting longer sparks and only an occasional fireing of my safety
gap with the 2.5Ks in inline.

	jim