Re: lightning arrestor for safety gap

To: tesla-at-pupman-dot-com
Subject: Re: lightning arrestor for safety gap
From: "rwall" <rwall-at-ix-dot-netcom-dot-com> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)
Date: Wed, 24 May 2000 21:10:11 -0600
Approved: twftesla-at-uswest-dot-net
Delivered-To: fixup-tesla-at-pupman-dot-com-at-fixme

5/24/00

Yes, I've used and still use them on high voltage/power systems.

I've been told that they contain literally thousands upon thousands of tiny
individual free to randomly move PN junctions.  They are calculated to
conduct at predetermined voltages.  As such, I don't think there is a
"quench" problem as with a spark gap.  I have never broken one apart so I
have never analyzed one internally.  Maybe someone on the list who is more
familiar with them may care to comment. They tolerate lightning strikes so
the must be super tough.  They come in various voltages and power
dissipations which are usually stamped on their ceramic side.

RWW

----- Original Message -----
From: Tesla List <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Wednesday, May 24, 2000 7:32 PM
Subject: lightning arrestor for safety gap


> Original Poster: Tesla729-at-cs-dot-com
>
> Hi all,
>
> I was wondering if anybody had tried using a lightning arrestor (the kind
> your local electric utility co. uses on primary lines to protect their
pole
> transformers from lightning surges) as a safety spark gap for a pole pig?
> I have one rated at 12 KV that a picked up at the last Teslathon in VA,
> and I decided to hook it up to my pig. So far, so good! It seems to me
> that this should be a good idea, since these things are designed to pro-
> tect the pole xfmrs from overvoltage surges by allowing the  momentary
> overvoltage to short out to ground. Isn't that what a safety gap does?
>
> Also, I've read that Richard Hull doesn't even use safety gaps with pole
> pig powered systems over 5kVA. At these power levels, the safety gap
> may not want to quinch, oncethe ionized path has been established.
>
> I would welcome any comments from other members out there.
>
>                                                                  Thanks,
>                                                             David
>
>