Re: Jonathon's 6" Coil (fwd)

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---------- Forwarded message ----------
Date: Sat, 30 Jun 2007 23:33:47 -0700
From: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: Jonathon's 6" Coil (fwd)

Hi Dave,

>As for the spark gaps being discussed, my gaps are silver plated copper
>electrodes with hemispheres mounted in the middle of a flat disc.  These
>were taken from military surplus electrical contacts.  Do you think the
>hemisphere center and flat disc background have advantages over pure spheres
>or pure flat discs
>  
>
I don't see an advantage to the geometry described. The gap spacing is 
affected just as planar vs hemispheres would be. In all cases, thermal 
dissipation is what to be careful of. If power is low enough, these type 
of electrodes may be fine, but as power increases, they will get hot 
which will increase gap losses and lower the voltage at the gap required 
to arc the gap.

The reason I used spherical gap equations has to do with multi-segment 
pipe gaps that are common in a static gap. Even that changes things as 
more pipes are used. Those gaps however have the ability to be cooled 
quickly as they use thin wall pipe (like copper tubing) where the 
surface area is large (inner and outer surfaces) and air is ideal to 
handle the cooling task.

Take care,
Bart