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Racing arc's casued by strike rail
Hi All,
Some may recall I'm the one who destroyed his Neon by using a Sync
Rotary and too big Safety Gaps. Subsequently with more powerful Neons had
Safety Gaps firing due to multiple charging caused by to small cap. Well
I've increased my cap (only about 1.5 reso charging value Terry but couldn't
afford any more poly :-( ) This caused resonance freq from 240Khz down to
166Khz so bigger toroid. Being chicken I decided just to run the coil from
one 5Kv 120ma Neon. I achieved 30" with a breakout point and targeting an
earth rod. However taking the breakout point off caused racing arcs on the
secondary from about 1/3 up to 2/3 up. This was cured (suppressed) by
removing my earthed strike rail.
First the Data
One or Two 5Kv 120ma Neons
Toroid Smooth 25.5" by 6"
Secondary 6" by 25" about 840 turns 22 A.W.G. Starts 1.5" above primary
bottom turn.
Primary, 11 turns tapped at 6.5 about 30 Degrees inverse cone
Primary Cap, dry flat plate 52nf
Safety Gaps 2 1/4" to ground one 1/2" across Sync Rotary.
Resonance measured as 166Khz
Coupling measured as 1.5
So how far up the secondary height can/should a strike rail be mounted and
at what diameter. Should it be that of the outer primary turn or say the
Torroid diameter or larger. Mine is 6.5" above secondary bottom turn at 24"
diameter.
With my Primary tapped at 6.5 could the remaining outer turns be acting like
an auto-transformer doubling the voltage field?
My safety gaps are rounded, is the spacing OK for this shape (Yes I'm
paranoid about blowing my Neons).
Finally just to say the ability to phase the rotary in real time shows how
fine the tune point is and when I connected the Two Neons the phase angle
was considerably different for max arc, min drawn current. However I
couldn't run the two at full input without safety gaps firing.
Thanks for all the advice so far.
Regards
Viv Watts UK.