New Coil

• To: tesla-at-pupman-dot-com
• Subject: New Coil
• From: Malcolm Watts <MALCOLM-at-directorate.wnp.ac.nz>
• Date: Tue, 29 Oct 1996 18:38:34 +1200

G'day all,
            I've just this day wound my new resonator (after a false 
start last week). It'll be a week or two before I characterize it as
several coats of varnish have to go on to hold the windings steady.
Winding length about 39"
Turns about 1000
Copper diameter = 0.9mm
Diameter = a little over 16"
Projected Fo without topload around 87kHz ( you can calculate Cs and 
Ls)

    The ribbed former turned out to be a bit too flexible and I had 
to buy a 1/8" or so thick sheet of LDPE to wrap around it. Welding 
the seam was an interesting exercise (all hot-melt). It was either 
that or get bogged down in a lot more plastic work. It may be 
possible to remove the central ribbed former from the coil if enough 
varnish is applied. That would be a nice touch but unnecessary. I will
be using this resonator for a number of different coil configurations
including : standard spark excited, CW MOSFET driven, an extra coil
and a special one that I'm keeping under wraps until it's done or I'm 
done.
     After varnishing and some initial tests, I will be constructing 
a compact general purpose primary system for driving down to 50kHz
(about 45pF topload for resonator). Main cost there is the copper pipe
but I am reducing that by use of mutual induction in the primary 
system. Max inductance will be around 200uH all turns in.
     I hope the results from CP will be reported before I do any 
serious firing as the caps will be used up to 20kV peak.

FYI,
Malcolm

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