[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: sparks running down secondary - why?
Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Esondrmn-at-aol-dot-com>
In a message dated 5/28/01 1:15:33 PM Pacific Daylight Time, tesla-at-pupman-dot-com
Last time I ran my coil, I got occasional loud snappy sparks running
down the length of the secondary, as well as occasional firing of my
safety gap. Wondering what causes the sparks down the secondary, and if
it's a problem?
The only change I made since my previous run (which was still
underperforming, but perhaps due to wind - not sure - this is my first
coil) was to hook my NST power supply (three 15/60's, two with internal
PFC) to a seperate 20 amp line. I could now run it without tripping the
breaker. I still plan on hooking it to a 30 amp 240 volt line, stepped
down by variac to 120 volt.
Oh, and the other change is a bigger topload. Originally, I had a
smaller toroid, and now have added a larger one on top. I can run with
just the larger.
My experience is that racing sparks on the secondary are almost always caused
by overcoupling, poor tuning or overpowering the coil. Did you re-tune with
the new larger toroid? Three 15 / 60 transformers should not over power a
6.5" diameter secondary. Maybe the old primary power set up was actually
current or voltage limiting the primary power to the transformers - and now
you are actually inputting more power. Coupling is tricky sometimes. At a
particular power level, the coupling might be just fine. Then you apply more
power and find that you need to back off (raise the secondary) the coupling
at this higher power level to prevent racing sparks.