RE: All pain no gain

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

Original poster: "John H. Couture by way of Terry Fritz <twftesla-at-uswest-dot-net>" <couturejh-at-worldnet.att-dot-net>


Bart -

I ran the numbers for Nathan's coil in your Java program and came up with
the same outputs as the JHCTES program. It helped that I knew the answers
from the JHCTES program because your program is more complex. It is obvious
that the two programs are using the same calcs. One slight exception is in
the coil self capacitance calc. You are using a different Medhurst equation.
I adjusted the secondary terminal pf to allow for this slight difference.

One of the calcs thatI believe should be changed in your program is the one
for the sec wire insulation thickness. For Nathan's coil I enterred 1 mil
with zero for the spacing. This gave me the incorrect TPI and sec turns.
This was corrected when I entered an incorrect 2 mils. This also has a large
effect on the sec inductance.

You are having the problem I had with the JHCTES program over the more than
10 years of its existance. That is that coilers do not enter the correct
inputs that truly represent their coils. When they test their coils and find
something different they say the calcs don't work. The pri and the sec
capacitances are the biggest culprits. The capacitances of these two
parameters have a profound effect in tuning the TC system. This is why I
recommended that Nathan actually measure the pri capacitance.

The secondary capacitance is another matter. This is where Terry's E-Tesla6
program would be of help. However, this program like all programs suffers
from the fact that every time you add an input you increase the chance of
the user entering the wrong value. This is why the JHCTES Ver 3.2 program
uses only 8 inputs to determine if the system is in tune. This is the
absolute minimum required to find the critical tuning condition.

There is still a lot more to TC design. I hope that Nathan will not accept
the 15.52 pri turns I mentioned without verifying the actual sec TPI, pri
dimensions, etc, and entering these actual values in the TC programs. I was
not able to determine where Nathan strayed with the Java program to come up
with 25 pri turns.

John Couture

------------------------

-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Thursday, March 08, 2001 9:44 PM
To: tesla-at-pupman-dot-com
Subject: Re: All pain no gain


Original poster: "Barton B. Anderson by way of Terry Fritz
<twftesla-at-uswest-dot-net>" <tesla123-at-pacbell-dot-net>

Hi Nate,

I'm curious. Do you have a bit more dimensional info on your primary?
JavaTC, JHCTES, Ed Sonderman's
Spreadsheet, WinTesla, etc.. are all very close to one another. For the
most part, we all use the same calc's,
however, there are a few calcs we go about differently for different
reasons. I suspect there are dimensions
which are off one way or another due to the degree the tap point you
indicated is off. JavaTC shows about 18
turns if I use similar inputs to Johns. But, everyone is kind of guessing
at a few unknown dimensions. If the
program is that far off I'd like to find out why. Others have used it with
excellent results at first light.
Yours is the first case I've heard otherwise which is partially why I'm
interested in your input dimensions vs.
your actual measurements.

For TPI, simply count the turns in an inch and verify this at different
points (this isn't exact, but it's as
close as you'll get without counting the entire coil - as I once did). This
helps fine tune the secondary which
of course affects the resonant frequency and thus primary calcs. I would
also back up John about measuring the
cap and verifying all dimensions. They do make a difference regardless of
which program you use. I personally
like to use them all.

Keep us posted.

Take care,
Bart A.

Tesla list wrote:

> Original poster: "John H. Couture by way of Terry Fritz
<twftesla-at-uswest-dot-net>" <couturejh-at-worldnet.att-dot-net>
>
> Nathan -
>
> The JHCTES program indicates that your TC system is out of tune.
> Go to my web site at
>       http://home.att-dot-net/~couturejh
> go to the on line JHCTES Ver 3.2 program
> and enter Secondary parameters
>
> Rad      2.25
> Turns    1577
> TPI        83   1577/83 = 19 " lg
> Sec term   18
>
> Pri cap    .01
> Avg rad   9.00
> Width     5.00
> Gives    15.58 pri turns
>
> Measure the actual pri cap value (.01?) and enter.
> Verify the other pri and secondary parameter values and enter.
> Your coil will then be in tune.
> All you will then need is to make sure the NST is working properly. You
> should get a 16 inch streamer spark or a 9 inch controlled spark. A larger
> NST can be used with this coil.
>
> John Couture
>
> ----------------------------------
>
> -----Original Message-----
> From: Tesla list [mailto:tesla-at-pupman-dot-com]
> Sent: Thursday, March 08, 2001 6:55 AM
> To: tesla-at-pupman-dot-com
> Subject: Re: All pain no gain
>
> Original poster: "Nathan Morris by way of Terry Fritz
<twftesla-at-uswest-dot-net>"
> <themfam-at-home-dot-com>
>
> All,
> Thanks for all of the suggestions.  Here are the specs on my coil and more
> information on my attempted first light setup.
>
> I used the JavaScript Tesla Coil Designer
> For Classic Dual-Tuned Resonant Transformers
> JavaTC 7.04
> Copyright © 2000 by Barton B. Anderson
>
> My primary is 23 turns of insulated #10 AWG stranded.
> My secondary is #30 mag wire on a 19 x 4.5 PVC form.
> My torroid has an ID of 8 inches an OD of 16 inches and a chord of 4
inches.
> For the first light attempt I was running small a 7.5 kv 20 ma NST (no
> variac)
> My cap is two rows of four .02 uf 3kv caps.  The two rows of four are
> parralled for a total tank capacitance of .01 uf.
> My gap has 4 gaps that are quenched by a 120 VAC microwave blower.  Each
gap
> is individually adjustable.  Before energizing my primary I set the gap so
> that all 4 were sharing the duty.
> JavaScript Tesla Coil Designer suggests a primary tap at turn 25.  I got
> shorted on my wire from the hardware store so I was using the length of my
> primary.  I thought it might be close enough to get me started but to be
> quite honest I believe it is the main issue with my current setup.
> Oh yea, almost forgot, I was using the wall outlet for grounding my
> secondary.  While mowing the yard however, I did find 2 inches of a copper
> ground rod sticking up near my service entrance/breaker pannel.
>
> ----- Original Message -----
> From: Tesla list <tesla-at-pupman-dot-com>
> To: <tesla-at-pupman-dot-com>
> Sent: Wednesday, March 07, 2001 8:27 AM
> Subject: Re: All pain no gain
>
> > Original poster: "Bert Hickman by way of Terry Fritz
> <twftesla-at-uswest-dot-net>" <bert.hickman-at-aquila-dot-net>
> >
> > Nate,
> >
> > Did you use any design tools (WinTesla, JHCTES, etc.) to aid you in the
> > calculations/design of your coil? If you have a small coil (~500 VA or
> > less), you can get by with using the power line ground (although its
> > really not recommended). There are many reasons why you may not be
> > seeing breakout, but in order to figure out what to do more information
> > is needed about your system. Please provide the information below and we
> > should be able to suggest some fixes. The fact that your gap is firing
> > loudly is a good sign - it appears that your HV source and tank cap are
> > operational.
> >
> > Some possible reasons for failure to break out can include:
> > 1. Tank cap is too small (energy/bang too small)
> > 2. Toroid radius of curvature too large
> > 3. Coil is severely mistuned
> > 4. Secondary is internally shorting
> > 5. Coupling coefficient is too low
> > 6. Primary circuit miswired
> >
> >------------------  snip