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Re: Ruminations on Gap geometry

Subject:  Re: Ruminations on Gap geometry
  Date:   Fri, 2 May 1997 10:33:46 -0400 (EDT)
  From:   DavidF4797-at-aol-dot-com
    To:   tesla-at-pupman-dot-com


Greetings all

Reflecting on the post a while ago about the difficulty in getting a RQ
gap
to fire initially, it has occurred to me that the same thing has
happened
with my smaller table top systems verses as the larger (higher power)
ones I
have built.  Reviewing my experience with a number of gap configurations
that
I have tried while experimenting it seems to me that the Richard Quick
style
gap (several coper tubes/gaps in parallell) seems to work great for
medium
medium - somewhat higher powered - coils (15KV-at-60/120ma).  On small
coils
(6kv-at-20/40ma), however, it seems that the long copper tubes in the RQ
style
gap cause a certain "reluctance" in first fireing that is not as
apparent as
when smaller (say1/4in) tungsten rod is used end to end (for the same
number
and spacing of gaps).  This, I suspect, has something to do with the
larger
surface area of the smoth copper pipe creating more of an inhibition to
initial breakdown of the air between the cylinders.  The chart below,
posted
a few days ago implies this issue.  Is this phenomenon due to  Inter
electrode "E" fields perhaps?  Radius of curvature, etc? And might this
have
sometning to say for general recommendations for gap styles in higher
verses
lower powered systems?  Any thoughts on the matter?

-----------
Chart showing the gap voltage for needle points, and spherical
electrodes of
2.5, 5, 10, and 25 cm.  of possible interest here, :


KV    2.5cm  5cm  needle
----------------------------------------------------------------------
5       0.13    0.15    0.42cm length of spark gap
10      0.27    0.29    0.85cm
20      0.58    0.60    1.75
30      0.95    0.94    2.69
50      2.000   1.71    5.20
100               4.77    15.5
300                          54.7
------------------------

As regards the "DR. Who" post...

> ....... if  DR.WHO continues to get his/it's/their posts accepted on this
List 
>  then I might start using this equally blatantly stupid title).
  rwstephens

While it is true that the name "DR. Resonance" seems a mite standoffish
and
unnecessarily grandiose, I for one, appreciate reading the Dr.'s posts
as
they are often knowledegeable and well considered.  What someone choses
to
call themselves on this list (no matter how strange it may seem to some
of
us) should, as far as I am concearned, not be an issue.

It is the exchange of ideas and information that is paramount.


-DavidF-