Re: General Questions

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

Original poster: "davep by way of Terry Fritz <twftesla-at-uswest-dot-net>" <davep-at-quik-dot-com>

Tesla list wrote:
 
> Interesting...  I know epoxies like to work around the ~20Kv area but I
> have never heard of problems at the ~200kV area...  I would be interested
> to hear more on this...?  Even plate glass will blow right through at
> ~200kV.

	Depends on the thickness....
	and the quality.

> Only oil is a real good insulator at really high voltages.

	And air.  And porcelain.  And epoxy.  And water.  and SF6...
	And vacuum.

	(yes: Water.  As I've mentioned, near here (powering this
	post in part) is a +/- 500kvdc (DC) converter.  For cooling
	AND insulation of the switch stacks:
	Very Pure Water....)

	Now getting That Pure water for 'home' use is tricky.  As is
	SF6 and air and hard vacuum.

> Epoxy will fail from over voltage but melting and any "odd"
> problems with epoxy at these super high voltages would be new to me.

	'air' is tricky (as has been noted by others):
	Generally:
		Increasing pressure increases dielectric withstand.
		Decreasing first decreases, then as Serious vacuum
		is reached, the withstand goes up again...

	best
	dwp