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Re: Triggered Spark Gaps - Why?
At 10:42 PM 11/7/98 -0700, you wrote:
>Original Poster: Gavin Hubbard <ghub005-at-xtra.co.nz>
Why?
* Jitter-free, or greatly reduced
* Stable operating mode can prevent cap & transformer abusive transients
* Forced switching resonance with ballast & leakage inductance for more power
Also not mentioned is an Opening-switch type spark-gap. Take an inductor,
place a voltage across it for a period, and let current charge it up
according to V=L dI/dt.
Now open the switch quickly. Notice the large V generated by the "flyback"
effect. Usualy this will result in switch arcing.
But lets say you have a laser or electron beam activated switch. Lets take
the magnifier-type TC, and put the opening switch in series with the extra
coil and its cap. You fire a (relatively) low voltage pulse into the extra
coil letting a high current develop, then open the switch fast & let the
flyback excite the secondary.
You can do this with an opening switch (and maybe thyratron?), but not a
spark gap.
>I hope that the irony of using a non-controlled discharge to initiate a
regular discharge in the TC is not lost.
You also have to inject charge into a transistor, fet, or thyristor junction
too. How much is the gain? There is waste in tube & thyratron heaters, and
corona warming to improve switching speed. What will you pay for performance?
>However, at the end of the day I believe
>that a well designed and constructed tesla coil is worth two unrealisable
>projects in the spares box.
Very true. Chasing unrealistic idea's can give you a better understanding of
technology, providing you survive & don't burn all your parts in the process.
I plan on evaluating a dielectric-sparkover type switch. Simple design, with
common parts.
>P.P.S. To all of those who requested information on transformer design, I
>will use this weekend to start translating my notes into HTML.
There is a great transformer & inductor design demo program at
www.intusoft-dot-com. The help-file has some usefull equations too. I like the
thermal analysis, skin effect, leakage inductance and other factors I don't
consider with plain textbook equations. Anyone know how to get it to do
aircore inductors? I set the mu-eff to 1, and set Br, Bsat & B1 to
mega-gauss levels, but it doesn't quite work. And I need to turn IsSpice to
Pspice models.
Thanks.