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Re: Isotropic secondary capacitance




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: Tesla List <tesla-at-pupman-dot-com>
> To: 'Tesla List' <tesla-at-poodle.pupman-dot-com>
> Subject: Re: Isotropic secondary capacitance
> Date: Sunday, September 07, 1997 11:51 PM
> 
> 
> 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
> 
> 
>