Re: Fritz vs TCBOR -- initial results in...

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

Original poster: Bart Anderson <classi6-at-classictesla-dot-com> 

Hi Ed,

I expect you've probably looked at this gap in some detail. Can you share 
any other details about it? I've been meaning to build something similar. I 
have about 100 square brass sheets (1.5" x 1.5" x .01") which are perfectly 
precut. I'm not sure where I picked these up at, but when I saw them, I 
immediately thought of the old quench gaps. I'm sort of curious on gap 
spacing. What I've imagined is building 1000V sections where sections could 
be series'd for higher breakdown potentials. I'm sort of curious on the 
size of the inner hole (I would think a small hole would be sufficient and 
beneficial to quickly evacuate the breakdown cavity quickly). I think for 
mechanical ease and electrical adjustment, series'd sections would be the 
way to go on something like this.

Thanks,
Bart

Tesla list wrote:

>Original poster: Ed Phillips <evp-at-pacbell-dot-net>
>Tesla list wrote:
> >
> > Original poster: "Gerry Reynolds" <gerryreynolds-at-earthlink-dot-net>
> >
> > Hi Brett,
> >
> > I for one have enjoyed this tread and appreciate your experiments.  Any
> > experiments however less than ideal can be useful, even if only to improve
> > ones insight to planning the next set of experiments.
> >
> > I have a Fritz (sorta) style gap employing 12 pipes and 11 gaps and I'm
> > pretty happy with it.  I seem to get 1st notch quenching with streamer
> > loading but no power arcing.  I have no way of knowing if it is optimized
> > but between your experiments and comments on another thread about losses in
> > static gaps, I'm beginning to think that there are two factors affected by
> > the number of gaps used to build a spark gap.
> >
> > 1.  The power loss in a spark gap seems to be a function of the number of
> > gaps.  ie, the more gaps, the greater the loss (for a given current).  This
> > would be due to the voltage drop across the extra electode/air interfaces.
> > The more gaps, the more interfaces.  The voltage drop across the arc itself
> > (air only) would be a function of the length of the arc.
> >
> > 2.  The ability of the spark gap to quench seems to also be a function of
> > the number of gaps.  ie, the more gaps, the easier it is to quench.
>The
> > power loss is distributed over more electodes and thus easier to cool.  Ion
> > generation is distributed and maybe easier to evacuate.
> >
> > If the above is correct, then #1 jwould say to reduce the number of gaps
> > while #2 would say to increase the number of gaps.  Maybe the optimum 
> design
> > is to increase the number of gaps only until desired quenching is obtained.
> >
> > Comments welcomed.
> >
> > Gerry R
>
>     I have an old (ca 1918) AMRAD quenched gap which has about 20 separate
>gaps, each totally enclosed and with circular plane electrodes about 1"
>in diameter.  Individual plates are separated with a fiber insulating
>washer and the whole stack is kept under compression with a jack screw.
>Originally used in spark transmitters of course.  Works just fine on a
>small TC running off a 9 kV, 60 ma transformer.  Almost no sound from
>the gap itself, and a nice "hissing" sound from the streamers because of
>a rather high spark rate, not measured.  In the last 85 years the fiber
>insulators have been compressed enough that the breakdown voltage for
>the assembly is only about 7 kV, resulting in the high spark rate with
>the 0.009 ufd primary capacitor I'm using.
>
>     The design and function of such gaps is well known and discussed in the
>literature of the times, so I won't go into it here.  Note that the
>spark is NOT in air.  After the assembly has run for a while all of the
>oxygen in each of the little sealed cavities is exhaused and further
>running causes the sparking faces to be a nice clean pink color.  The
>objective of the quenching is, of course, to cause the spark to
>extinguish when BOTH current through it and voltage across it go to zero
>simultaneously, as at a "notch".  As a matter of interest one of the
>features of the quenched gaps which was often mentioned is that they
>could be operated at lower voltages than the open-air gaps such as
>SRG's.
>
>Ed
>
>
>
>