[TCML] High Power Static Gaps
bartb at classictesla.com
Sun Sep 7 15:10:20 MDT 2008
Greg, I like your gap. I made something more similar to Gary Lau's where
I used pvc around the lot up until the ends. The only pic of the gap I
really have is when the coil just happened to be sitting next to a large
flat coil frame I was taking a pic of (vacuum gap part of the little
coil on the left).
I like that you sweat the copper all the way around. This vacuum gap
performed fine, but the little coil could have been better. Something I
threw together for a buddy out of spare parts lying around.
G Hunter wrote:
> Years ago I built such a gap based on 1" copper pipe and fittings:
> I have not fired it up since 2005, when Katrina thoughtfully immersed it in dirty salt water. However, it worked fine before that, and still might.
> I have no scope data for it, no idea how well it quenched, no performance data relative to other styles of spark gap. I used it with three different tesla coil power supplies, and it held up fine: 1) two 9kv/60ma NSTs, 2) two MOTs driving voltage doublers, 3) and an 11kv pole transformer at up to 7200VA.
> Run times were as long as I wanted them to be--several minutes sometimes. I never had to shut down a coil due to overheating or power arcing. Clearly, the gap could remove heat faster than the arc could create it. The electrodes got only warm to the touch, even on runs over 1 minute. The gap faces got black and sooty-looking after a few minutes, but copper erosion was insignificant. I never had to replace the Cu reducers I was using.
> The gap was maintenance-free. At first I cleaned the electrodes frequently. Eventually, I got lazy and quit cleaning it. This had no visible impact on performance.
> On the plus side, the gap was easy to build, simple to adjust, maintenance-free, and capable of handling even pole-pig power levels without distress.
> On the minus side, it was bulky, very loud, and required it's own 15A AC outlet & extension cord.
> I never built a larger one, but I did build a smaller one based on 3/4" Cu pipe and fittings. It worked well on a 4"x18" coil driven by a pair of voltage-doubled MOTs. This little rig produced 42" streamers. Again, the noise level was obnoxious. Other than that, the little sucker gap was a winner.
> If I ever get my workshop set up, I plan to experiment further with the sucker-style gap and take some o-scope readings.
> P.S. Simple hyperbaric-type gap:
> An even simpler variant:
> --- On Sun, 9/7/08, Sfxneon at aol.com <Sfxneon at aol.com> wrote:
>> From: Sfxneon at aol.com <Sfxneon at aol.com>
>> Subject: [TCML] High Power Static Gaps
>> To: tesla at pupman.com
>> Date: Sunday, September 7, 2008, 12:05 AM
>> Hi All,
>> I'm curious about the spark lengths achieved by others
>> using a single static
>> vacuum aspirated gap, (I believe the one designed by Gary
>> Lau if memory
>> serves)? It uses a vacuum cleaner motor, PVC pipe and two
>> large copper tubing end
>> caps with holes in the middle for the electrodes.
>> What are the limiting factors with this type of gap? Can it
>> be scaled up for
>> higher power? It's a beautifully simple and elegant
>> design, without the need
>> for any close tolerance machine work like with rotaries,
>> and it's much safer
>> Tony Greer
>> **************Psssst...Have you heard the news? There's
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