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Re: Top Toroid



Hi Robert, all,
                A comment on your reply to Jim:

> >   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,
> 
> Congratulations for getting sparks out of the top this time. ; ) 
> I think the many simultaneous streamers is an indication that your ROC 
> is too small.  Good question.  I myself would like to see a good 
> reference to actual breakaway  voltage versus ROC but since nobody can
> actually put a hard number on the length of a streamer in air versus voltage 
> then I don't think this is really possible.  Too many variables are 
> involved.  I think there is another mechanism at work here as well.  
> I've seen the effect you describe on coils when they first start up, 
> but then as one dials in more power, one of those streamers will 
> mature and hog all the power, eliminating all the other little 
> imature starter streamers.  Could be you just don't have enough power 
> for your toroid.
> 
> rwstephens 

I also have seen that effect. A smooth firing primary makes a heck of 
a difference and does cause a nice fat streamer to come from what 
seems like a poor terminal. The one I'm using is about as ragged as 
you can get. I'm willing to bet I could do better with a larger 
terminal for the primary energy I'm running though.

Malcolm