RE: [TCML] Spark gap for first TC

["Lau, Gary" <Gary.Lau@xxxxxx>]

Hi Jim,

I must admit that I'm also unclear about the finer points of constructing such a 3-log gap.

I understand the basic premise - that adjusting the top/middle pipe adjusts the two intervening gaps, but I can't imagine an easy way to build this - how to suspend the middle pipe such that the moving it stays parallel to the lower pipes in both vertical and horizontal axes.  For simple, low-powered gaps, I've always just had two parallel pipes side by side on a piece of G10, with screws/bolts and slotted holes in the G10 to the pipes.  At least the pipes remain parallel in the vertical plane as I slide one of the pipes.  Is there a photo you can cite?

Thanks, Gary Lau
MA, USA

> -----Original Message-----
> From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On
> Behalf Of jimlux
> Sent: Sunday, February 21, 2010 10:57 AM
> To: Tesla Coil Mailing List
> Subject: Re: [TCML] Spark gap for first TC
> 
> John Byström wrote:
> >
> >  jimlux wrote:
> >> Almost anything will "work".
> >> I like a gap made of three pieces of 3/4" or 1" diameter copper pipe
> >> about 2" long arranged with the long axes parallel.  So you effectively
> >> have 2 long skinny gaps in series.  You have a small fan blow air
> >> through the pipes (along the axis of the pipe.  If you arrange them in a
> >> sort of squashed triangle, you can permanently mount the two end ones,
> >> and adjustments only need to move the middle one.
> >>
> >> The other easy gap that works fairly well is a couple of copper pipe
> >> caps facing each other, with a shop vac blowing between them.
> >>
> >> You could even do the two bolts thing, but I've found that the bolt is
> >> so small  (even if you use carriage bolts and the gap is the head of the
> >> bolt) the spark always goes from exactly the same spot on the electrode
> >> and you get a hotspot.  Once you get that glowing hot spot, the gap
> >> characteristics change (it breaks down more easily), and the output of
> >> your coil drops.
> >
> > The first gap you mention, when I use the long side of the copper
> > tubes facing each other, how do you mean it would be (like a squashed
> > triangle)?
> >
> > I'm probably going to start with the "two bolt thing" because of the
> > time limit. If I have time left, I'll try another spark gap, like the one
> > you mentioned or the classic RQSG (I believe it's called)
> >
> >
> 
> 
> Imagine stacking three logs in a triangle.
>   O
> O O
> 
> If you put the lower two tubes, say, 3/4" inch apart (actual gap, not
> center to center), then the upper tube can be used to adjust the gap
> width (you actually have two gaps in series).
> 
> The small fan blows down the length of the tube (both inside and
> outside) so the cooling is really effective.
> 
> YOu can also turn this on end and have the axes of the tubes vertical,
> which opens up some alternate mounting techniques.
> 
> 
> The RQ gap is similar.. but not so easily adjustable.  If you want to
> get into multiple gaps, then one of the "laid out flat" multiple gaps is
> probably better.  They're a whole row of tubes parallel to each other
> with a small fixed gap between tubes.  The gap is adjusted by chosing
> "how many gaps".

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