RE: JF efficiency theory (again)

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "sundog by way of Terry Fritz <twftesla-at-uswest-dot-net>" <sundog-at-timeship-dot-net>

Hi All, Ed

 Nothing magic about it.  John is trying to reduce gap losses by increasing
the inductance of the primary, which reduces the surge current and RMS
current respectively.

  Wether or not I agree with it, I dunno.  If you're striving to get every
last bit of performance out of a given input power, it probably can't hurt
to use a higher-inductance secondary and primary.

 In my case (the LTR pig), gap losses don't even concern me, it's
controlling the RMS current that is important.  The driver will have close
to 1000 turns on it, and the extra coil will have 1000+ turns (1200 or
something like that, I can't remember what I figured)  because I need the
inductance.  But with high # of turns comes higher resistive losses.  Larger
wire counteracts that, but I got a nagging feeling the losses will stay
around linear as you scale the size of the coil up (IE. 1600 turns of 32 ga
would be just as lossy/resistive as 1600 turns of 16ga on a porportionally
larger form).  I may (and probably am) wrong, but I'm an MIS, not an EE :)

  Now, what I will admit is a downside to this approach is size.  Especially
for higher power levels.   A large primary is exactly that, large.  15 turns
of 1/4 tubing spaced 1/4" with an 11" center diameter is a big spiral. Ppl
have gotten excellent results from a few hundred turns to several thousand
(Marc M. 3k turn coil), so I guess it's more a matter of personal
preference.

  Hope it helps!
													Shad


-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Tuesday, February 20, 2001 1:08 AM
To: tesla-at-pupman-dot-com
Subject: Re: JF efficiency theory (again)


Original poster: "Ed Phillips by way of Terry Fritz <twftesla-at-uswest-dot-net>"
<evp-at-pacbell-dot-net>

Tesla list wrote:
>
> Original poster: "Mike Novak by way of Terry Fritz <twftesla-at-uswest-dot-net>"
<acmnovak-at-msn-dot-com>
>
>  First off, If you haven't done so already, read through
> http://hometown.aol-dot-com/FutureT/page5.html
>
> I was wondering why some coilers get such good results when completely
> disregaurding such details. For instance, Ross Overstreet's coil:
> 6"x24" wound with #22 for a total of ~880 turns, a primary of approx 7-8
> turns (from the photo) and ~2.2kVA input along with a static gap. He gets
> 6-7 ft sparks which is just about right from 1.7(sqrt(input power)).
> However, he's only using half the reccommended number of turns on both the
> primary AND secondary. Is it possible that it is not the NUMBER of turns,
> that maybe it's simply proportionate on some level?

	What is supposed to be magic about 1600 turns?  As long as the primary
and secondary are in tune, the inductance only affects the resonant
frequency for any given secondary geometry and primary capacitor.

Ed