Re: rotary gap: disc with holes?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>

Hi Wells,

I tried this with plastic and the arc just chopped the fins right off.  I
think the plasma is like 10,000 degrees!!  I have always wanted to try it
with alumina or some high temp ceramic that might have a small chance
against the super hot arc.  Water cooling should work too if one could
figure it out.

Also note that the arc last only about 150uS.  In that time, a rotor at
3600 RPM will move only 3.24 degrees.  If you want to try to stop the first
notch, you have to turn the gap on and then off in only say 50uS or only 1
degree of movement.

Trying to turn a 20000 volt 1000 amp arc on and then off in 50uS
mecanically is almost impossible.  DC Cox has a gap that can do it (even
can quench on peaks!) but the losses in the sixteen high speed gaps eat up
the potential advantage.

I think super perfect quenching low loss gaps are going to be left to the
future solid state gaps.

Cheers,

	Terry



At 12:17 PM 7/6/2002 -0700, you wrote:
>hello, 
>
>has anyone tried building a rotary gap with holes in the disc instead
>of electrodes? I was thinking about it, and it seems that the biggest
>problem would be the wear on the disc by the arc, but an arc it seems
>would wear an insulator less than a conductor, because electrons would
>not actually be entering / exiting the material. The post about phenolic
>discs for grinders got me thinking, with their nice evenly spaced holes,
>etc. 
>
>has anyone tried this type of gap? I.m cobbling together a small one
>now, with plexi, no less, to study if the arc heats the material, etc.
>I'll post results. 
>
>-- 
>Wells Campbell
>wellscampbell-at-onebox-dot-com - email
>(415) 430-2169 x3756 - voicemail/fax
>
> 
>