Re: Official air breakdown voltage?

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Aaron Banerjee <spam_proof@xxxxxxxxxxxxxxxx>


I've seen anywhere from about 4Kv/cm for a point gap to 30Kv/cm for a
spherical gap.  Once you get the spark going, I'm not sure how far it
could be stretched -- I guess so long as you keep the "conductive" path,
you could concievably go quite a ways (depending on amperage I suppose).

If you're trying to calculate voltage from a spark, I'd suggest starting
so far away that you don't get a spark, and then moving in until you first
get breakdown.  Before doing this, of course, you will have taken
appropriate safety precautions.

I'm thinking that the length you get will be somewhat closer to the
"breakdown voltage" you'll see in a table.  Maybe that could be used to
estimate output voltage?

On Mon, 28 Nov 2005, Tesla list wrote:

> Original poster: "JT Bowles" <jasotb@xxxxxxxxxxx>
>
> Amperage determines how far an arc may be drawn. Cannot it be true
> that at 20KV, one inch may be stretched to 10 feet? (perhaps if the
> amperage is INCREDIBLY HIGH, millions of amps)
> Thank you mike- 20Kv is a common measurement
>
> >From: "Tesla list" <tesla@xxxxxxxxxx>
> >To: tesla@xxxxxxxxxx
> >Subject: Re: Official air breakdown voltage?
> >Date: Sun, 27 Nov 2005 19:32:23 -0700
> >
> >Original poster: "Mike" <mike.marcum@xxxxxxxxxxxx>
> >
> >Well, 60Hz  is weird and definitely not linear. Haven't seen a
> >breakdown table like DC,  but it's around 20kV for 1", 100kV for
> >10-12", and 11 feet for 500kV (from a lineman that works on 'em hot
> >and needs to know that distance). It's roughly following the rule of
> >thumb 5x the voltage=10x the distance with current controlling how
> >far it grows after that.
> >
> >Mike
> >----- Original Message ----- From: "Tesla list" <tesla@xxxxxxxxxx>
> >To: <tesla@xxxxxxxxxx>
> >Sent: Sunday, November 27, 2005 11:54 AM
> >Subject: Re: Official air breakdown voltage?
> >
> >
> >>Original poster: "JT Bowles" <jasotb@xxxxxxxxxxx>
> >>
> >>I say you are correct. Mostly. Voltage requirements for dielectric
> >>beakdown, in this case atmosphere, are linear, at slow-pulse DC
> > From what I have been reading lately, AC voltage requirements for the same
> >>dielectric are often much higher. Thus, we can conclude ac requires
> >>a much higher voltage to generate, say 1' arcs, than dc does.
> >>
> >>