Re: safety gaps at high power

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

Original poster: "Phillip Heslin by way of Terry Fritz <twftesla-at-uswest-dot-net>" <pheslin-at-home-dot-com>

David,

  I have seen pictures of safety gaps on high voltage equipment that
look like small Jacobs ladders. I believe these are called horn gaps.
The difference is that a Jacobs ladder is designed with a shallow angle
so that the arc will travel a long time for a nice display and a horn
gap has a very wide angle so that the arc will extinguish quickly. I
don't know if these are still used on any modern equipment, perhaps
there is a better alternative these days.

              Hope this helps,

              Phil Heslin



  
Tesla list wrote:
> 
> Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>"
<Tesla729-at-cs-dot-com>
> 
> Hi all,
> I've got a quick question for y'all. I have a safety gap that I installed
> on my 10 kVA pole pig. The problem that I have with this SG is that
> when it is set to where it does occasionally fire, it immediately power
> arcs, when it fires, due to the heavy current, and will only extenguish
> when I turn the power control variac way down. If I set it where it dosen't
> fire at all, then I am defeating the purpose of having it in the first place.
> I was wondering if any of you other "pig" coilers had noticed this pro-
> blem. I remeber reading an article by Richard Hull in one of the TCBA
> volumes, and he stated that he didn't even use safety gaps at power
> levels over 5 kVA due to this problem. BTW, my pig is externally bal-
> lasted with an arc welder. Comments anyone?
> 
> David Rieben