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Re: acmi and mandk sources anyone?



Original poster: "Peter Lawrence by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Peter.Lawrence-at-Sun-dot-com>

Paul,
     thanks for the reply. I might get more than the usual time to send on
this hobby over the holidays (last xmas I spent the whole week(!) in my shop
building the forms for these coils), so here goes.

I could not find acmi because there is no "directory" at
	http://www.abelian.demon.co.uk/
and I was looking in "tssp" and there are no links over to "acmi" and I
did not think to look...

I'ld like to have the _sources_ to MANDK since I only run Linux at home and
SPARC/Solaris at work and cannot execute a windoz exe file. But if ACMI is 
more accurate I'll stick with that, being a programmer I'm used to difficult
user interfaces :-)

I've built four coils with the same overall dimensions

common overall dimensions:

	primary ID  5.5"	primary initial height 0.25"
	primary OD 11.5"	primary final height   0.75" (very shallow cone)
	
	secondary D 3.5"	secondary initial height  0.75"
				secondary final height   11.75"

	toroid 2"x8" - center of toroid height 13" (1/4" between top of coil
	and bottom of toroid).

For E-Tesla-6 I add 30" to all the heights, and use Terry's example room size.
It gives me an "effective" total secondary capacitance of 10.4-pF in all cases.
	
I always "tap" my primary on the inner rather than the outer turns to further
reduce coupling.

I'm running with 9.6-nF primary cap, and a 9kV-30mA NST, and a static (WC) gap.
I keep my safety gap at 0.180" (IIRC) which is about right for 9kV * sqrt(2),
and open my main gap until the safety only fires occasionally. Thats when
I start getting racing sparks...


All my primaries are 50% space wound, all secondaries are close wound with
single thickness PU-varnish magnet wire. I have not coated any of these
secondaries with any additional varnish (easier to rewind that way. Though
a coating might(?) cure the racing sparks, it makes the forms unreusable...)


	primary				secondary            (calc-meas mH)
	
1)   6 turns #2 wire, 2-tpi	495 turns #24 wire, 45 tpi   (5.97-6.18)

2)   9 turns #6 wire, 3 tpi	759 turns #28 wire, 69 tpi   (14.03-14.4)

3)  15 turns #10 wire, 5 tpi	1287 turns #32 wire, 117 tpi (39.8-?)

4)  24 turns #14 wire, 8 tpi	1993 turns #36 wire, 181 tpi (96.6-105.2)

You probably need to know where I tap the primary to get accurate K values
since K is a function of geometry, I'll have to get those over the weekend.

I don't have a measured-mH for the #32 coil because it burned up a while
back from racing sparks, and I have not rewound it yet, and my #36 coil
is close to burning up so I don't run it much now.

These coils all give about 12" streamers on 9kv-30ma power (they all have
very different looking sparks though, and the #36 coil is my favorite).

The reason I'ld like to see coupling/overtones explored as a possible cause
of racing sparks is that Ed (?) puts 15kV into a very similar coil and gets
twice as long sparks with out getting racing sparks like I do.

I have one other primary IIRC it is #10 wire with 14.5"-OD so I can do some
more experiments with smaller K when I get my #32 secondary re-wound.

thanks, and I'll try to get the tap points over the weekend...
Peter Lawrence.


>
>
>Original poster: "Paul Nicholson by way of Terry Fritz <twftesla-at-qwest-dot-net>" 
<paul-at-abelian.demon.co.uk>
>
>Peter Lawrence wrote:
> 
>> Can anyone point out where ACMI sources are now,
>> 
>> And if MANDK sources...
>
>MANDK is available in
> http://hot-streamer-dot-com/TeslaCoils/Programs/MANDKV31.ZIP
>with documentation in 
> http://hot-streamer-dot-com/TeslaCoils/Programs/MANDKV31.PDF 
>
>ACMI is harder to use,
> http://www.abelian.demon.co.uk/acmi/
>
>> I'm getting too many racing sparks with my current 3.5"x11"
>> secondaries and 5.5-11.5" spiral primaries which have a
>> computed K of around 1/7 (.1428) so
>
>I'd like to do some arithmetic on this.  Can you send me more
>details of your setup:
>
>primary inner diameter: 5.5"
>        outer diameter: 11.5"
>   total primary turns:  ?? turns
> primary tapping point:  ?? turns
>        primary height:  ??"  above/below secondary base.
>
>secondary winding length: 11"
>                diameter: 3.5"
>    secondary wire gauge:  ?? awg
>         secondary turns:  ??     
>
>        primary tank cap:  ?? nF
>
>toroid:  inner and outer diameters, and height above the
>         secondary?
>
>firing voltage at which
>       racing arcs occur:  ?? kV
>
>If you can measure any of these:  secondary inductance, Fres,
> primary inductance; it would be useful.
>
>Oddly enough, you wrote to the list about this exactly a year
>ago, to the day!  Then, you wrote:
>
>> I seem to have had the most racing sparks in the middle of my
>> secondary, not at the bottom. I had thought this was because a
>> high K caused resonances at harmonics above the fundamental F of
>> the secondary...
>> Are harmonic resonances real, could this explain any racing
>> sparks, are they really related to K?
>
>Prescient thoughts.  Overtone resonances are real - they can be
>measured easily enough.  It looks like they increase with the
>coupling, but I'm not sure how they relate to K.  It may be more
>to do with how evenly the coupling is distributed along the coil.
>Do overtones hasten the onset of racing arcs - I'd like to find out.
>If you can supply some numbers, I'll work out what your secondary is
>doing with its voltage gradient.
>
>> Peter Lawrence, Linux-vale, CA.
>                  ^^^^^^^^^^
>Nice address!
>
>Cheers,
>--
>Paul Nicholson,
>--
>
>
>