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Re: primary and secondary diameters


From: 	D.C. Cox[SMTP:DR.RESONANCE-at-next-wave-dot-net]
Sent: 	Wednesday, November 26, 1997 11:55 PM
To: 	Tesla List
Subject: 	Re: primary and secondary diameters

To: Chris

If you are building your first coil you might wish to reconsider some
parameters.  8 guage wire is quite large and is usually reserved for coils
operating at 8 kw or higher powers, ie, a pole transformer unit which is
quite dangerous to the first time builder.  If you are running a neon
transformer setup what kind of spark are you aiming for?  A nice 6" x 30"
sec coil closewound with #24 AWG polythermalize (200 degree C) magnet wire
will deliver a consistent 40-48 inch spark if equipped with a 20 x 5
toroid.  

A good "rule of thumb" is to place the lowest sec winding approx 1 1/4 to 1
1/2 inch above the top turn of the flat spiral primary coil.  The inner
primary turn should be approx 1 1/2 inch to 1 3/4 inch from the sec
coilform.  This will allow a correct coefficient of coupling on most coil
setups and good performance.  A good practice is to use some scrap 12 AWG
house wiring for the "test" primary and affix this to some scrap plywood as
well.  After you have your cap value and tried a number of different turns
you can replace the primary with some neater copper tubing or flat copper
strap (best if a large number of turns is required).  The plywood can be
laminated with Formica which makes a neat looking support.

Don't forget to elevate the primary/sec coil at least 12 inches above the
lower support so as to "decouple" the primary coil from the concrete floor
or table-top.  

Hope this information is of assistance.

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

----------
> From: Tesla List <tesla-at-pupman-dot-com>
> To: 'Tesla List' <tesla-at-poodle.pupman-dot-com>
> Subject: primary and secondary diameters
> Date: Tuesday, November 25, 1997 8:25 PM
> 
> 
> From: 	Christopher Stone[SMTP:stone-at-etak-dot-com]
> Sent: 	Tuesday, November 25, 1997 6:45 AM
> To: 	tesla-at-pupman-dot-com
> Subject: 	primary and secondary diameters
> 
> Hi all,
> 
> I am working on building my first coil and I have found information 
> that has stated that the primary should be twice the diameter of the 
> secondary and others state 3 times the diameter.  Which works best? 
> I was planning on using heavy guage wire #8 or so, how much difference 
> does it make between air wound and bundled?  
> 
> Thanks,
> 
> Chris
> 
>