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Re: Isotropic secondary capacitance


From: 	Malcolm Watts[SMTP:MALCOLM-at-directorate.wnp.ac.nz]
Sent: 	Wednesday, September 10, 1997 12:54 AM
To: 	tesla-at-pupman-dot-com
Subject: 	Re: Isotropic secondary capacitance

Hi Jim,
       _All_ coils I have wound and connected up as grounded 
resonators have obeyed this formula to within a few percent.
    For a more technical treatment of this, I can do no better than 
refer you to Dr Rzeszotarski who is somewhat more adept in the 
mathematics than I.

Malcolm

> From:   bmack[SMTP:bmack-at-frontiernet-dot-net]
> Sent:   Monday, September 08, 1997 8:31 PM
> To:     Tesla List
> Subject:    Re: Isotropic secondary capacitance
> 
> Thanks malcolm!
> Have you confirmed this formula with a few coils yet?
> 
> Jim M

> > 
> > 
> > From:     Malcolm Watts[SMTP:MALCOLM-at-directorate.wnp.ac.nz]
> > Sent:     Sunday, September 07, 1997 5:05 PM
> > To:   tesla-at-pupman-dot-com
> > Subject:  Re: Isotropic secondary capacitance
> > 
> > Hello Jim,
> > 
> > > From:   bmack[SMTP:bmack-at-frontiernet-dot-net]
> > > Sent:   Saturday, September 06, 1997 10:07 PM
> > > To:     tesla list
> > > Subject:    Isotropic secondary capacitance
> > > 
> > > Fr Tom,
> > > 
> > > A very astute observation on the nature of distibuted 
> > > capacitance animal!  That surface area capacitance could
> > > calculated(?) using the "free air capacitance" equation for
> > > the coil area and the standard  "plate equation" with curvature
> > > of the wire considered, to find the inter winding capacitance.
> > > Am I on track here?
> > > 
> > > Now, are these two entities in parallel or series with respect to 
> > > each other? Maybe a little of both? Ouch!
> > > 
> > > When I run very low power tests to tweek the systems, placing ones
> > > hand near the coil body has as much effect on the resonance as getting
> > > near the top cap. This in my opinion clear evidence of isotropic
> activity.
> > > 
> > > With a little help from our friends, there might even be a way to
> reliably
> > > predict the distributed capacitance mathematically! 
> > 
> > There is indeed!! You'll be pleased to know that after a three month 
> > search while researching a TC article for a magazine, I found it. It 
> > is Medhurst's formula:
> > 
> > C = HD pF  where D is coil diameter in cm and H is a factor that 
> > follows the law:
> >                  h/d = 2     H = 0.51
> >                  h/d = 5     H = 0.81
> > Interpolation is linear for this h/d range. H bottoms out at 0.46 for
> > an h/d = 1 (which as fate would have it was the final form Tesla's 
> > extra coil took :)  The tabulated values for H remove the complex 
> > mathematics from the formula.
> > 
> > Malcolm
> > 
> > 
> > 
> 
> 
> 
>