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Re: secondary design?? RE: distributed capacitance measurem




From: 	Robert W. Stephens[SMTP:rwstephens-at-headwaters-dot-com]
Reply To: 	rwstephens-at-headwaters-dot-com
Sent: 	Sunday, September 07, 1997 4:03 PM
To: 	Tesla List
Subject: 	Re: secondary design?? RE: distributed capacitance measurem

> 
> From: 	William Noble[SMTP:William_B_Noble-at-classic.msn-dot-com]
> Sent: 	Sunday, September 07, 1997 7:44 AM
> To: 	Tesla List
> Subject: 	secondary design?? RE: distributed capacitance measurement? Isotropic?
> 
> the post below got me thinking - I know this is a dangerous thing, but sitting 
> here 15,000 miles from home, I can't go run an experiment.  Anyway, if it is a 
> good thing to have short secondaries (so more of the coil is in the field of 
> the primary), and if it is a good thing to minimize surface area, why not a pi 
> wound secondary - if a thick walled tube were used instead of thin, then it 
> could be groved - for example a grove of .1 inch wide and .25 inches deep (in 
> 1/2 inch thick tubing) could be made every 1/4 inch.  these groves would then 
> be filled with wire - with 24 gague or so, there would only be one or two 
> turns per layer, so maybe 25 to 50 turns per grove (not too much voltage build 
> up).  Once wound, the coil could be suitably coated to elimiate surface 
> conduction effects (ie no air exposure of the wire).
> 
> Any thoughts??? - this is like the idea someone else posted of threading the 
> secondary form, but you would get a higher number of turns per inch
> 
> -----Original Message-----
> From:	Tesla List 
> Sent:	Saturday, September 06, 1997 4:23 PM
> To:	'Tesla List'
> Subject:	Re: distributed capacitance measurement? Isotropic?
> [bill]  snip 
> Malcolm, I know you have done a fair amount of work with tight-wound
> and also with space-wound coils. Have you noticed anything odd about
> the total distributed capacitance of space-wound versus tight-wound
> Tesla secondaries? Is there any correlation between distributed
> capacitance and exposed wire surface? Or is it primarily an
> inter-turn phenomenon? What does that have to say about the relative
> merits of tight versus space windings? My own work has led me to
> believe that the exposed surface area of a coil is very important,
> especially in regard to the electrostatic phenomena that accompany
> Tesla coil operation. Probably much greater in its overall EFFECTS
> than the inter-turn capacitance. By the same token, the proximity of
> the inside of the coil windings and the coil FORM result in
> interactions that greatly affect the Q of a coil. The losses are
> probably capacitive in nature, in that energy is capacitively coupled
> to the material that makes up the form.
> 
> For what it's worth...
> Fr. Tom McGahee
> 
> 
> 
> [bill]  snip 
> 
Bill,

Your idea of cutting grooves in a secondary form and filling with wire is one I
have contemplated for the application of an L2 in a driver for a magnifier 
system.  Concentrating the L this way would allow for higher K 
factors which is what all of us who try our hands at maggy design 
attempt to do.  Your run a potential problem of overvolting the wire 
insulation itself within each of the little multi layer coils you 
have wound.  This technique also smells of hard work which means not 
many will attempt it.

Good idea though.

rwstephens