Re: surface breakdown was Re: 20 joules at 100 bps vs 4 joules at 500 bps

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Jim Lux <jimlux@xxxxxxxxxxxxx>

At 12:15 PM 8/4/2005, you wrote:
> Original poster: "Dmitry (father dest)" <dest@xxxxxxxxxxx>
>
> Tl> Original poster: Jim Lux <jimlux@xxxxxxxxxxxxx>
>
> Tl> At 07:25 AM 8/3/2005, you wrote:
> >>Original poster: Greg Leyh <lod@xxxxxxxxxxx>
> >>
> >>Based on experience, 5kV/inch seems to be a reasonable surface
> >>gradient to maintain on the outside of a secondary form.
>
> Tl> Is that for creeping discharges on the surface, or a "free air"
> Tl> distance from toroid to base?  Seems a bit low for the latter.
>
> "... average field required for breakdown is about 5kv/cm"
>
> isbn 5-89155-013-x
> Bazelyan and Raizer "spark discharge", page 18.
> it`s for "free air".

5kV/cm is about 12 kV/inch, roughly 2.5x what Greg had written, which 
is why I questioned Greg's number.

It's well known that clearance distances should be 3-4 times the 
uniform field gap for safety (which would be around 15-20 kV/inch), 
and that creeping discharges typically have a breakdown 1/3 that of 
free air in the same field.

The citation in B&R is on page 9 in my copy (different isbn) if 
anyone's looking for it. But that's in the context of a 1m long gap, 
with a 500kV breakdown voltage.


> -----
> I am skeptical about space aliens too, but space aliens have a greater
> probability of existence in my opinion than extra garage space...
> (c) Richard Quick  6-07-95 03:59