Re: Lightning Arrestors (was Geek Pig)

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

Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>" <Tesla729-at-cs-dot-com>

Hi all,

I just wanted to clarify an earlier post that I submitted regarding
the breakdown voltage of a 12 kV rated lightning arrestor. I had
stated that it seemed to break down around 15 to 17 kV. Actu-
ally, it seems to be at this voltage range that it will STOP con-
ducting once it's pushed beyond its breakdown level. The INITIAL
breakdown voltage seems to be even a bit higher than this, pro-
bably in the 20 to 22 kV range, but once it does actually start 
conducting, then the voltage has to be brought down to around
15 kV or so before it completely stops conducting, if this makes
sense. Keep in mind that I am pretty much guestimating these
figures, since I don't have a HV probe. However, it isn't difficult to
tell that it takes MORE initial voltage to cause the first breakdown,
but once the conduction is initiated, it has to drop down to a lower
value than the initial breakdown voltage for it to return to normal 
operation (i.e. completely cease conduction). 

I carried out this "red neck hi-pot test" with an old x-ray transformer
power supply thru a variac, so I did have a general idea of the volt-
age levels involved, but certainly not a precise knowledge of it.

Sparkin' in Memphis,
David Rieben