Re: Solid state Secondary
From: RODERICK MAXWELL[SMTP:tank-at-mail.magnolia-dot-net]
Reply To: tank-at-mail.magnolia-dot-net
Sent: Sunday, January 04, 1998 9:58 PM
To: Tesla List
Subject: Re: Solid state Secondary
Tesla List wrote:
> From: Alan Sharp[SMTP:100624.504-at-compuserve-dot-com]
> Sent: Sunday, January 04, 1998 9:26 AM
> To: Tesla List
> Subject: Solid state Secondary
> -------------Forwarded Message-----------------
> From: Alan Sharp,
> To: INTERNET:tesla-at-pupman-dot-com, INTERNET:tesla-at-pupman-dot-com
> Date: 03/01/98 20:43
> RE: Solid state Secondary
> >I have finally finished coating my secondary for the solid state coil.
> >The coating is Bher build 50 super gloss. I used two coats to ensure
> >corona is suppressed. It is very high gloss, and seems to be very tough.
> > Coilform: a cylindrical ice chest shaped EXACTLY like a Pepsi can!
> >Made from HDPE.
> > Diameter: 12.54"
> > Length: 18"
> > Wire Gauge: #21
> > H/D: 1.44
> > The first 2.5"(at the bottom of the coil)is tapered down to 11". I
> >wonder how this will alter the operation of the secondary?
> Sounds great - should perform well. My secondary is wound
> on a polythene bucket - it does fine - no worry about the tapering.
> I've been going over Bylund's comments on secondaries.
> He shows that you get maximum inductance for a given length
> of wire when the hieght = 0.9 * the radius. This doesn't make
> for practical coils.
> I plotted indunctance against hieght/radius for different
> lengths of wire and different diameters. The graph was always
> the same shape. From the graph.
> Inductance = Max 100% when h/r = 0.9
> 90% when h/r = 2.2 (or 0.4)
> 80% when h/r = 3.6
> 70% when h/r = 5.4
> 60% when h/r = 8.1
> 50% when h/r = 12.5
> 40% when h/r = 20.5
> Your h/r gives 85% of theoretical maximum inductance which is fine.
> Bylund also gives the equation for output voltage
> Vout = Vin / R * sqrt(L / C)
> Thus like you I chose to maximise L and minimise R.
> But Bylund also comments that the losses in the coil
> are as nothing compared to Corona losses -
> My question is this could we do just as well winding
> 2000 turns of 32 guage wire onto a 4" drain pipe or
> whatever gives the same inductance.
> Have fun,
> Alan Sharp (UK)
From what I've read, resistance would be far to high. You would lose
most of your power as heat. It would probably be a couple hundred ohms
at least. My coil has a measured inductance of 52.4mh with a dc
resistance of 23.5ohms. By the way I'm not a mathematician! College
algebra was as far as I got!