Re: Beating a Dead Horse - Neons

To: tesla-at-pupman-dot-com
Subject: Re: Beating a Dead Horse - Neons
From: David Trimmell <dwt-at-efn-dot-org>
Date: Mon, 04 Nov 1996 18:18:54 +0000
You wrote:

> I think I'm more confused now than I ever was about protecting my
> neon transformers. It's a big deal to me because I only have 5 left
> and don't want to fry them. I've seen a certain person in Fort Worth
> go through many of them (30 over the course of two years), sometimes 2-3 at a time ;-)
> I'm sure I didn't understand all the Spice simulations, but I'm
> more interested in what people have actually done anyways. I'd hate to
> fry a neon based on theory, I simply can't afford the loss (i.e. no
> money). So heres the deal:
> If you have ever run a Tesla Coil with neons then please tell me
> exactly what you used to protect it, with as much detail as
> possible. Saying,"two chokes and one bypass cap", doesn't help much.
> Here's my setup, which got two neons fried:
> 
> I had a safety gap which fired intermitently to ground (a bolt
> attached to each leg of the neon output with a center bolt to ground,
>   ----   |  ----   ). After that came a 3 inch toroid choke on each
> leg with about 10 inches of 18 gauge wire on each. (not enough I'm told). For a safety cap I
> had 5 small doorknob caps which screwed together and were attached across the
> neon outputs (series). Each one says,"2500 MMFD - 5KVAC" (I'm really not sure what
> MMFD means. I'm used to mfd and pf. Don't laugh, my major is psychology not
> electronics ;-)
> 
> So there you have it. A recipe for burning up a neon! Anyone have a
> better recipe?

I have been running a resonator off of a 15 kV-at-120mA neon with many
hours of run time (~3-5 hours total run time) using the following setup;
My RF filter is setup in the following maner: (Per legg) off of the HV
leed is connected a 1.5 Kohm 50 Watt resitor (to dampen the resonance
that may occure between the secondary of the neon and the filter Cap), a
total of 1.5 nanoFarad doornobs to RF ground and finnaly two chokes for
a total of ~3.5 mH (calculated). Now this setup has worked well for me
although a bit lossy with the resisters. I get about 48-55 inch
streamers off of a 4.5 inch coil with a heavily loaded terminal.
Exeriment yourself, but the more inductance the better and the
resistance seams to make the difference for me. Yes, I have lost many
neons too. Look for the 120 mA neon as they are a bit stronger. I have
done away with the safety gap, but that is a matter of opinion. By the
way MMFD is the same as Pico Farad (micro micro farad). Hope this helps.

David Trimmell <dwt-at-efn-dot-org>