Fwd: [TCML] Spark gap for first TC

[otmaskin5@xxxxxxx]

I don't believe I got any replys on this question.  Anyone care to comment on the merits of a 2 parallel pipe spark gap vs. other single blown or sucker gaps for a 15/50 or 15/120 NST driven coil?  Thanks, Dennis Hopkinton MA





-----Original Message-----
From: otmaskin5@xxxxxxx
To: tesla@xxxxxxxxxx
Sent: Mon, Feb 22, 2010 9:41 am
Subject: Re: [TCML] Spark gap for first TC


Gary, is the two parallel pipe spark gap you describe as good as other single 
ap configurations, assuming you can deliver ample air flow.  I hear a lot about 
ingle gaps having lower losses & therefore higher efficiency than 
ulti-segmented gaps.  The two parall pipe set-up would be a single gap & seems 
uch easier to build than other single gaps I've read about.  I'd appreciate 
our or anyone elses thoughts on this.  Thanks, Dennis Hopkinton MA


----Original Message-----
rom: Lau, Gary <Gary.Lau@xxxxxx>
o: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
ent: Sun, Feb 21, 2010 9:56 pm
ubject: RE: [TCML] Spark gap for first TC

i Jim,
 must admit that I'm also unclear about the finer points of constructing such a 
-log gap.
 understand the basic premise - that adjusting the top/middle pipe adjusts the 
o intervening gaps, but I can't imagine an easy way to build this - how to 
spend the middle pipe such that the moving it stays parallel to the lower 
pes in both vertical and horizontal axes.  For simple, low-powered gaps, I've 
ways just had two parallel pipes side by side on a piece of G10, with 
rews/bolts and slotted holes in the G10 to the pipes.  At least the pipes 
main parallel in the vertical plane as I slide one of the pipes.  Is there a 
oto you can cite?
hanks, Gary Lau
, 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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