Re: [TCML] High Power Static Gaps

[Quarkster <quarkster@xxxxxxx>]

Bart -
 
I'm not sure that I agree that the performance "will be the same".
 
Certainly, you can increase the width of the non-pressurized gap so the breakdown voltage is the same as a pressurized gap. However, one of the largest benefits of of a correctly-designed "pressurized" gap is the extremely high air velocity through the gap. Quenching should be measurably better than a simple ventilated TCBOR gap, or even a vacuum gap where the maximum pressure differential across the gap can never exceed 14.7 PSI. However, I don't have comparative data at this point .....
 
Regards,
Herr Zapp

--- On Sun, 9/7/08, bartb <bartb@xxxxxxxxxxxxxxxx> wrote:

From: bartb <bartb@xxxxxxxxxxxxxxxx>
Subject: Re: [TCML] High Power Static Gaps
To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
Date: Sunday, September 7, 2008, 4:46 PM

The static gap DC Cox has been discussing this last year in various 
postings is just this. It's a simple pressure gap. Nothing special other 
than the pressure is changed via forced air. A pressure gap changes the 
air pressure. This increases the breakdown voltage for a given distance 
and electrode geometry.

With "all things equal", I don't realize longer sparks. All
things are 
not equal. To equalize the gaps (pressure versus not), increase the gap 
distance on the non-pressurized gap to equal the breakdown of the 
pressurized gap. At that point, they will perform the same (and harder 
on transformers because of the higher breakdown voltage).

Regards,
Bart

futuret@xxxxxxx wrote:
> Another (at least theoretical) advantage of using pressure for
> the gap is that the gap spark length is shorter in higher pressure air
> than in lower pressure air for a given voltage.  Short sparks have
> lower losses so a stronger spark output streamer length should
> result.  I'm not sure how much difference it makes in the
> real world.  I think Gary Lau used this approach when he
> switched from his vacuum gap to his vortex gap.  It's interesting
> to note that whereas Gary obtained around 63" sparks from his
> vacuum and vortex static gaps, he obtained around 80" or 90"
> sparks using a sync rotary spark gap, using the same NST power supply
> transformer.
>
> I don't think all that much work and research has been done in
> this area (high powered air blast quenching for Tesla coils), so it's 
> worth
> more experimentation.
>
> An useful approach might be to add an electronic trigger electrode
> for stable 120 bps operation.  This adds complexity, but not of
> the mechanical machining type.
>
> John
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