Re: Primary construction

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

Original poster: Bart Anderson <classi6-at-classictesla-dot-com> 

Hi MCP,

2 turns sounds about right with a slight topload (maybe a point or your 
coiled wire?). Could you do us a favor and give more info as to the wire 
type used for the primary? We are still not clear on what your actually 
using. The topload would also be much needed data. This type of data seems 
to be very limited from coilers (full specs with center heights).

Both John C. and I truly enjoy crosschecking against the programs. We love 
doing it or we wouldn't. Your coil is pretty cool to run through the phases 
because of the extreme h/d ratio and small size. The 196 ft of wire is 
correct (the 394 may have been due to the JHCTES v3.4 radius limitation of 
0.5" as John explained). I personally won't recommend the toroid size 
unless I know your supply specs. With more top C will mean more primary 
turns. 1.2 MHz would indicate a linear current distribution (which would be 
wrong).

Fres will be higher, but only "you" can prove that with a measurement (John 
C. and myself always push for measurements when possible). If you don't 
have the equipment to measure then I certainly understand.

As far as calculating the small coil of wire your using as a topload, you 
might be hard pressed because it's difficult to model this as a topload 
when it is in situation with other components, except modeling something 
similar in shape, maybe a sphere. For example, I tried a sphere with 
dimensions of 2" x 2" at a center height of 12" (above coil). Fres dropped 
to 2.2 MHz and autotuned at 2.3 turns. Again, I have no idea of the topload 
used, but this might be a method to try. FANTC may be another option as one 
can be innovative in it's use. I may try that tomorrow if I get a chance.

Take care,
Bart


Tesla list wrote:

>Original poster: The MCP <ejkeever-at-comcast-dot-net>
>Thank you for the info. I've got a few quirks, however: When I use .75" dia
>(2.35" circumfrence) times 1000 turns, I compute 196 feet of wire, not 394...
>Something got doubled. But for some reason, we both got about 1.2 Mhz (The
>simple calculator I used probably doesn't account for self-capacitance)...
>???
>
>At any rate, I'm currently using 2 turns, varying from 2.5 to 3.5 inches high,
>and it's working about as well as it was previously (2.5" streamers -- 3"
>arcs). I'm beginning to wonder if something is wrong with the coil itself; Is
>the 27 Ohms (Measured DC) of resistance excessively high/low for a tesla coil
>like this? What about the large amount of self-capacitance caused by using
>such fine wire?
>
>Finally, how can I calculate the capacitance of the small coil of wire I
>mentioned that I currently use as a topload? Plus, is there a difference
>between the energy in the topload being stored as an electrostatic (toroid
>topload) vs electromagnetic (I presume the little coil stores energy as EM)
>field?
>
>On Wednesday 17 September 2003 03:52 pm, Tesla list wrote:
> > Original poster: "John H. Couture" <couturejh-at-mgte-dot-com>
> >
> >
> > MCP -
> >
> > The JHCTES Ver 3.42 TC computer program.
> >
> > Pri - 2.5" rad -3.5" hg
> >
> > Pri Cap - .006 uf
> >
> > Sec - .75" rad - 10.5" hg - 1000 turns - 95.24 TPI
> >        5.03 mh - 392 ft lg - 3.69 uh Cself
> >
> > Fres = 1167 Khz - no topload
> >         5.34 Pri turns - 3.1 uh
> >
> > Fres = 606 Khz - 10 pf topload
> >         10.28 Pri turns - 11.49 uh
> >
> > Streamer Spark = 10"
> >
> > For other parameters go to
> >
> >      www.mgte-dot-com
> >
> > Click TESLA, JHCTES, Go to bottom of Book page.
> >
> > John Couture
> >
> > -------------------------------------
> >
> >
> > -----Original Message-----
> > From: Tesla list [mailto:tesla-at-pupman-dot-com]
> > Sent: Tuesday, September 16, 2003 10:04 AM
> > To: tesla-at-pupman-dot-com
> > Subject: Primary construction
> >
> >
> > Original poster: The MCP <ejkeever-at-comcast-dot-net>
> >
> > My two new TDK caps arrived today, meaning that I now have 6nF/40Kv of tank
> > capacitor. However, this obviously throws the old setup completely out of
> > whack. I've been trying to get resonance again, but failed miserably.
> >
> > So, here are the specs:
> > Secondary: .75 inch dia, 10.5 inch wound, 1000 turns, 196 feet of 32 gauge
> > wire
> > Primary is helical, 5 inches in diameter, with 3.5 inches vertical to work
> > with
> > Tank caps are 3 X 40Kv/2nF TDK caps, X-fmr is 5000/20 NST.
> >
> > I've tried using JavaTC at classictesla-dot-com, but it's not working. After
> > giving up in it, I tried using 2, 3, 4, 6, 8, and 13 turns, none of them
> > that
> > much better than the other. I've got more 22 gauge wire than you want to
> > know
> > about and about 10 feet of .375 inch copper pipe to work with. HELP ME,
> > PLEASE!
> >
> > PS, JavaTC says the coil resonates at 750 Khz. Is it on crack?
>
>
>
>