Re: gap questions

            Re: gap questions
            Sat, 12 Apr 1997 21:01:48 -0700
            Bert Hickman <bert.hickman-at-aquila-dot-com>
            Stoneridge Engineering
            Tesla List <tesla-at-pupman-dot-com>

Tesla List wrote:
> Subject:
>         gap questions
>   Date:
>         Sun, 13 Apr 1997 14:16:07 -0500
>   From:
>         Mike Hammer <mhammer-at-misslink-dot-net>
>     To:
>         Tesla List <tesla-at-pupman-dot-com>
> Hello all,
> After seemingly finding the power limit of
> my RQ style gap made from rather small electrodes
> I decided to build a larger version and help with
> the quenching by pulling hi speed air through the teeth of the gap
> with a strong vacuum cleaner motor.
> The gap by itself works better than my old gap probably
> because of the larger electrodes but when I pull the air
> through with the vacuum motor things begin to act differently.
> I normally get about 34 inches of spark from a 16 X 4 toroid
> and running 12kv/90ma neon with my old gap. The new gap gets me
> up to 38 inches. When the vacuum motor is running I get shorter
> streamers but more of them. I was using a foil bump on the toroid
> to direct the discharge and was getting only a single streamer.
> Now I get 2 or 3 streamers even with a very pronounced foil bump.
> Also I get some splitting and sparks from the middle of the secondary
> that disappear when the vacuum motor is turned off.
> I feel the coil is processing more power with the vacuum gap
> but I need to know how to get back to a single streamer.
> Should I reduce the coupling a bit by raising the secondary?
> Is there something here that I'm missing?
> Any thoughts on this much appreciated.
> Mike Hammer
> mhammer-at-misslink-dot-net


Sounds like you're running into a couple of problems. The toroid
diameter (4") needs to be increased to 6" so that you can get more "hold
off" voltage before breakout. You may also need to reduce the coupling a
bit so that you aren't overvolting the coil. Once you can get the
hold-off voltage back up, you'll see single streamers again. I don't
remember the length/diameter of the secondary you're using in your
system or primary construction (inverse conical?). 

Good luck, and safe coilin' to you, Mike!

-- Bert --