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Re: Pancake Primary (fwd)





---------- Forwarded message ----------
Date: Sat, 14 Feb 1998 22:52:51 -0700
From: "D.C. Cox" <DR.RESONANCE-at-next-wave-dot-net>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: Pancake Primary (fwd)

to: Steve

Wood, especially oak, will work if you dry it near a heat souce for a few
days to reduce the moisture content.  Cut your slots and then coat it with
polyurethane to seal it against moisture present in the air.  If your
budget allows an even better material is white delrin which is available
through any large plastics supplier.  Have then cut you eight rectangular
blocks approx 3/4 in wide x 1 in high x the length required to hold the
number of turns you need.  Slots are cut approx 1/2 - 3/4 in deep.  With
copper strap a good rule of thumb is to allow 1/2 in total spacing between
turns per revolution in a flat Archemedian spiral.  With the white delrin
you won't have to dry it like wood.  You can fasten each piece to your
upper sub-base assembly with 1/4-20NC white nylon screws.  Each block is
drilled (shallow --- 3 threads) and tapped 1/4-20 NC  to accept the nylon
machine screws.

DR.RESONANCE-at-next-wave-dot-net

----------
> From: Tesla List <tesla-at-pupman-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Pancake Primary (fwd)
> Date: Saturday, February 14, 1998 5:16 PM
> 
> 
> 
> ---------- Forwarded message ----------
> Date: Sat, 14 Feb 1998 18:31:05 -0500 (EST)
> From: SBJohnston-at-aol-dot-com
> To: tesla-at-pupman-dot-com
> Subject: Pancake Primary
> 
> 
> Many folks have recommended a flat pancake-style primary coil instead of
my
> current vertical air solenoid coil.  
> I remembered I have a big roll of new 1" copper strap that could be used
to
> make a nice flat primary, so I guess I should give it a try.  
> 
> I wonder how to mount such a coil (Hmmm... maybe an "X" of wooden 1"x1"
> strips with slots cut partway thru?) and how far apart to space the
turns?
> 
> Also... Can anyone help me out with the equation for calculating the
> inductance of a flat spiral coil of this sort?  Thanks!
> 
> Steve Johnston
> 
> sbjohnston-at-aol-dot-com
>