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Re: [TCML] JavaTC Calc. Programm
Hello Fritz, All,
I hoped Bart would chime in, and explain how the static-gap is handled in
the Java TC model (what he did :-) ). If I'm not wrong, it seems to be a
reasonable linear model, to give a raw estimate of plausible gap performance
(a way I'd do it myself too). However I'm not shure, if it was possible,
taking in consideration (and to what degree) some of the really hard to
model effects, which nevertheless play an important role in the functioning
of a static gap in a TC. Three of those effects, interacting with each
other, are:
1.) Chaotic (within limits!) firing of a static gap in TC use: the
experimental BPS is almost never the one estimated with a design program,
'cause of the items following. Most of the time it will be higher in a well
performing TC. Simulation offers a better guess. The measurement of BPS was
an interesting topic on this list: search the archives for "BPS
measurement". Gary Lau has pioneered the view of the static gap for it's
chaotic behavior, by doing important Microsim/Pspice simulations.
2.) Partial (slight or strong!) (50/60Hz) resonant rise of charging the
primary cap, from the NST, even if the cap is LTR. This depends of cap uF
value, and leak-inductance behavior of the NST (see 3.)). The cap charging
peak voltage can easily be qite a bit higher than the NST nameplate HV
voltage, which represents 100% in Java TC. This is dangerous for the NST
life, but obviously gives better TC performance. I'm quite confident in
assuming most of the well performing NST/static gap TC's are charging the
cap higher than the 100% of the NST nameplate.
(see and digest Richie Burnett's site).
3.) Current-drawn-depending effects of the leak-inductance of the NST, as a
cause of saturation in the magnetic shunts --> which leads to so called
"ferroresonant" effects. If i.e. you have an LTR cap, the planned resonance
of the primary cap loading system will be _below_ 50Hz (you designed the cap
for 1.57 resonant). If now you begin to feed the primary system, and reach
the limit, where the NST shunts start saturating, which lowers the
leak-inductance, and approaches the primary cap-load tuning to the 50Hz
resonant value, you will experience a higher resonant voltage rise (2.)) and
power draw. More current is drawn... and the cat begins to bite it's tail,
till some balanced point is reached.
These effects are very hard to model in a design program, 'cause no
analytical formulae are available for it (with the exception of pt.2.) ).
Ferroresonace effects were disputed on the TCML, but no estimation of the
effects seem to be available. (Maybe David Mekers magnetics-simulator might
be a tool for estimation, in specific cases). My little UBTT-Twin 15/60 NST
draws about 1.6kVA from the line, instead of the 900VA calculated by
nameplate figures, which has to do with the above effects.
I recommend to read Gary Lau's investigation about chaotic static gap
firing:
http://www.laushaus.com/tesla/
http://www.laushaus.com/tesla/gapsim.htm
...please also read the last "late and important footnote", regarding NST
saturation effects, very carefully.
The wonderful site of Ritchie Burnett also is a "must" for the topic:
http://www.richieburnett.co.uk/tesla.shtml
...and specifically for the static-gap
http://www.richieburnett.co.uk/static.html
pay special attention to the graph:
http://www.richieburnett.co.uk/static8.gif
and it's description.
Hope, I was able to support you a little
Cheers,
Kurt
Fritz W. Egli wrote:
Dear Gentlemen,
I woud like to gain some more understanding conc. JavaTC
calculation-design programm.
Following 3 points in the file STATIC SPARC GAP OUTPUTS are of my
interest for a clear view:
XXXX (peak volts) = Charging Voltage
XX,X (%) = Percent Cp Charged When Gap Fires
XX (BPS) = Breaks Per Second
Can anyone please explain me the exact meanings of above terms
and the best target-figures (range) to be achieved in a good, sane TC
design -?
Please in short, simple terms, as my language is not English.
Thank you, kind regards,
Fritz W. Egli
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