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Re. Semi-Rotten Spark Length
Hi Reinhard:
"Semi-Rotten"? I think you're being a bit hard on yourself and your coil ;-)
I'm sure many would be quite happy with 57" sparks!
But I know what you mean, too much is never enough!
I don't recall what kind of gap you were using, but is it possible that
as you increase your power supply current, the gap quench degenerates?
Regards, Gary Lau
Waltham, MA USA
>Original Poster: "Reinhard Walter Buchner" <rw.buchner-at-verbund-dot-net>=20
>
>Hi All,
>
>I=B4ve got a problem. Maybe someone has some ideas.
>First of all, here is my complete coil data:
snip...
>Spark length data from start of project till now:
>-----------------------------------------------------------
>
>1.) 15nF MMC & 562VA unmodified NST. This got me around 30" sparks
>2.) 25nF MMC & 562VA unmodified NST. This got me around 41" sparks
>
>3.) 31nF MMC & 900VA unmodified NST (I just turned the shunt out for 120m=
>A).
>This got me around 50" sparks.
>
>Up to then I was really happy with my coil and it=B4s performance, but
>let=B4s look at (being the latest setup) case #:
>
>4.) 67nF MMC & 1257VA modified NST
>(I shortend the shunt for 170mA output current).
>This setup only gets me around 57" sparks. Only once did I get a 63" spar=
>k.
>
>NOTE: Spark length is measured "point to point". I do NOT "straighten out=
>"
>the spark. Doing so, would give me longer spark lengths, but the way I
>measure the length is more realistic, I think.
>
>Now, why the **!-at-##-at- is my spark output in case number 4 so rotten?? I
>almost doubled the input Joules compared to setup number 3. I increased
>the xformer current by a factor of 1.4. I would have expected to get at
>least around 65-70" continuous sparks, but no go. The only thing I could
>finally get the coil to do, was to break out a single streamer in case #4=
snip...