Re: Safety Gap Question

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

Original poster: "Malcolm Watts by way of Terry Fritz <twftesla-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>

Hi Peter:

On 3 Oct 2001, at 16:57, Tesla list wrote:

> Original poster: "Peter Lawrence by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <Peter.Lawrence-at-Sun-dot-com>
> 
> Dave,
>      I too have pondered this question. Here are some of my observations,
> which are based on using a static main gap so they may not be relevant for
> your SRSG situation...
> 
> 1) safety gap next to NST (therefore power resistors between primary cap and 
> safety gap) results in "weak" spark in safety gap when it does fire, leading
> me to wonder if it is really bleeding off much energy from the primary cap
> and if it is really protecting against resonant rise in the primary or not.

Resonant rise in the TC primary is not an issue. Peak voltage across 
this component occurs when the gap first fires. The idea of 
protection is to stop an excessive voltage reaching the transformer 
secondary terminals.

Malcolm
 
> 2) safety gap next to CAP (therefore power resistors between safety gap and
> NST) results in "explosive" safety gap firing. For sure this prevents any
> resonant rise in the primary, but I wonder about the abuse to the primary cap
> due to the virtually unimpeded very high current pulse.
> 
> I'm personally sticking with (2), until someone can show by direct electrical
> measurements that (1) does eliminate resonant rise in the primary (and can
> show by EE what the resistance of the power R should be. And I try to keep
> my main spark gap adjusted so that the safety gap fires only occassionally.
> 
> Peter Lawrence.
> 
> 
> 
> 
> >Original poster: "Dave Kyle by way of Terry Fritz <twftesla-at-qwest-dot-net>" 
> <dave-at-kyleusa-dot-com>
> >
> >Last weekend I completed construction of the neon transformer protection
> >module. It consists of two 1K 100 watt resisters and 4 small doorknob caps
> >wired in the usual RC configuration and a safety gap. I elected not to
> >include the MOV devices at this time. My question is should the safety gap
> >be on the neon side or the primary side of the resistors? I have seen it
> >shown both ways and I am curious what the arguments are for ether case. I
> >will be using a SRSG with a three x 15KV-at-30ma neon farm if that has any
> >baring on the answer.
> >
> >Dave
> >
> >
> >
> >=========================================
> >Dave Kyle
> >Austin, TX USA
> >Email: dave-at-kyleusa-dot-com
> >
> >
> 
> 
> 
>