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Re: Racing arc's casued by strike rail

Vivian,

You really don't want to run at higher power levels without a
strikerail. Replace it, and let's try some other things.

The easiest thing to try is raising the secondary somewhat versus the
primary. This will reduce the coupling a bit (reducing racing sparks)
while also increasing the distance from the toroid to the primary
strikerail. Then try raising the toroid relative to the secondary - this
may require that you retune the system a bit. The strikerail should be
the same diameter, or slightly larger, than the outermost primary turn
and about 1.5-2.5" above the outer turn.

BTW, using an inverse conical primary significantly reduces the distance
between the toroid and the strikerail, limiting ultimate coil
performance. Going to a flat primary will also make most of your current
problems go away. At higher power levels, it's sometimes necessary to
use a longer coilform and winding length so as to simply get more
clearance from the top of the coil to the bottom. 

Safe coilin' to you!

-- Bert --

Tesla List wrote:
> 
> Original Poster: "Vivian Watts" <V.C.Watts-at-btinternet-dot-com>
> 
> 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.