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Re: Yesterday's GNATS meeting (fwd)





---------- Forwarded message ----------
Date: Tue, 28 Apr 1998 22:26:21 -0600 (MDT)
From: Chip Atkinson <chip-at-pupman-dot-com>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: Yesterday's GNATS meeting (fwd)

Ed,

The power system for the 9" coil is 220V, 40A breaker (tapped off the
electric stove wire) into a power cabinet.  The power cabinet has 2 28A
220V variacs ganged together.  I have one stove element in parallel with
an arc welder (your tip a while back).  The output then goes to a 14400V
10KVA pole pig.  

Chip

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
 Chip Atkinson 
 http://www.pupman-dot-com 
 --- If I can't fix it, I can fix it so it can't be fixed --
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

On Mon, 27 Apr 1998, Tesla List wrote:

> 
> 
> ---------- Forwarded message ----------
> Date: Mon, 27 Apr 1998 21:44:07 -0600 (MDT)
> From: Chip Atkinson <chip-at-pupman-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Yesterday's GNATS meeting
> 
> Greetings all,
> 
> Yesterday was another meeting of the Greater Niwot Area Tesla Society.
> Mike 
> Hollingsworth came over and we fired up my 9" coil for the first time.  
> 
> This coil has about 1000 turns of 22ga wire around a thickwall pvc pipe. 
> I believe that the coil form is 8" diameter pipe, but the o.d. is roughly
> 9".  We tried a couple toroids, different capacitor configurations,
> different power levels, different gap settings and the effects of
> different tunings.  We also had an oscilloscope running and watched the
> wave forms when the coil was in and out of tune.
> 
> We also discovered that there are some situations where you actually get 
> better performance when you let the smoke out.
> 
> Here are the details.  Mike came over and brought some goodies such as 
> large magnets and an old variac that I'll have to play with.  We decided 
> that we'd most like to play with the 9" coil that I had finished but 
> never gotten working.  I recently acquired three rolled caps and put 
> one of these into the circuit in parallel with the existing capacitor.
> The new capacitance total is roughly 0.04 uF (0.025 + 0.017).  The
> toroid is one that I had on my 4" coil, a 7x21 or so.  We got some
> pretty decent sparks.  However, the problem is that I have several
> space problems.  I have a garage door that I wish to keep alive, and a
> garage that's suitable for a good 4" coil.  Therefore, we had to keep
> the sparks pretty short and directed using a sharpened piece of wire
> on the toroid.
> 
> Next we decided to try a series gap in series with the rotary.  This
> didn't work too well, and we thought we'd try reducing the gap between
> the stationary and moving electrodes in the rotary so there wouldn't
> be too much total gap to bridge.  This didn't help too much either, so
> the stationary and moving electrodes in the rotary so there wouldn't
> be too much total gap to bridge.  This didn't help too much either, so
> we started backing out the series gaps until there were none at all.
> Now, with the reduced spacing of the rotary, the coil did much better
> than it had.  Out with the stationary for now.
> 
> The next idea to try was adding another capacitor to give a total of
> 0.06uF.  We didn't notice much if any improvement, but we did notice
> after a few seconds, that some smoke was starting to rise from
> somewhere and there was an orangish colored light coming from the
> rotary gap.  An immediate shutdown followed by an investigation
> revealed that the rotary gap was chock full of smoke (the rotary is
> totally enclosed in 1/2" lexan and 1" plexiglas).  After letting the
> smoke out of the enclosure and removing an end of the enclosure, the
> coil was back to its previous glory.
> 
> The other two things we tried were running the scope and a larger
> toroid.  The scope was interesting.  With the coil in tune, we could
> see the sort of dual hump damped wave profile.  When it was out of
> tune, there were between 4 and 6 humps and a much shallower angle of
> decreasing amplitude.  I took pictures and if they turn out, I'll send
> them to someone for scanning and subsequent posting.
> 
> The larger toroid probably had a beneficial effect, but I can't say
> for sure because it effectively decreased the distance between any
> grounded object and the coil.  I was basically running an RF jacobs
> ladder between a piece of grounded pipe and the toroid.
> 
> I guess the next thing is to put the coil outside and really throttle
> it up to see what it's capable of.  Next I'll start fiddling with it
> to see how I can increase the output.
> 
> Chip
> 
> 
> =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
>  Chip Atkinson 
>  http://www.pupman-dot-com 
>  --- If I can't fix it, I can fix it so it can't be fixed --
> =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
>