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Re: Top Toroid

Tesla List wrote:
> 
> Subscriber: jim.fosse-at-bdt-dot-com Fri Jan 31 23:11:00 1997
> Date: Sat, 01 Feb 1997 03:21:50 GMT
> From: Jim Fosse <jim.fosse-at-bdt-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Re: Top Toroid
> 
> >Subscriber: rhull-at-richmond.infi-dot-net Thu Jan 30 22:56:39 1997
> >Date: Thu, 30 Jan 1997 18:27:28 -0500 (EST)
> >From: richard hull <rhull-at-richmond.infi-dot-net>
> >To: tesla-at-pupman-dot-com
> >Subject: Re: Top Toroid
> >
> 
> >I trust these are calculated values!!!  I can almost tell due to the fact
> >they are all in error from real world, honest to God, measured values.  A
> >true, relative isolated toroid is usually about 25-30% lower in capacity
> >than the calcs say it is.  My 12X3 spun unit is 7.8pf and my 5X20 is 15.1
> >pf.  put them on a coil and they can appear to be even more than calculated!
> >It's a crap shoot!  The thrust is that the math isn't even close for  any
> >form of critical engineering purposes. Especially on small toroids.
> >
> All,
>         Does any one have voltage holdoff vs radius of curvature
> values or formulas for toroids? Or suggestions for ROC vs power level?
> 
> I'm asking because I've bought my TC back on line and I only getting
> 2' air discharges from the toroid. WHAT you say! Only 2' discharges?
> Yes but, there are about a dozen at once. I'm using a 15kV 60ma
> transformer, 16nF primary cap, 120uH inverted cone primary, 8" by 20"
> #22 secondary and a 27" by 3" toroid. The resonant frequency
> (instrument measurement) is 133kHz.
> 
> Any suggestions for a toroid major and minor diameters for this?
> 
>         Regards,
> 
>         jim

Jim,

Use a toroid diameter of at least 2/3 to 1X the diameter of your coil.
An 8" coil, driven fairly agressively, should support a 6" ROC toroid.
If you err on the large side, you can still always force it to break out
by using one or more small foil duct-tape "bumps" to disrupt the e-field
and instigate corona (where you want it - :^)). It sounds like your
system is prematurely breaking out and could use a bigger ROC toroid.

If you can get to the point where the toroid just starts breaking out
after 1-3 seconds of operation (i.e., after you've built up a local ion
cloud around the toroid), you've hit the right size! Unfortunately, I
find that day-day variations in humidity may cause better/worse
performance when you're right at the egde. 

Safe coilin' to you, Jim!

-- Bert H. --