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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,
>--
>
>
>