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Re: Latest coil (with racing sparks)

In a message dated 99-09-06 05:24:28 EDT, you write:

<< Hi Alan. All,
 
> I don't yet have any answers to your racing sparks problem, but if misery
> loves company, perhaps I can offer you that.  I'm in the process of
> converting from my static gap to a sync RSG.  I had been getting nice 60"
> arcs from my 4 1/4" secondary, power by a 15/60 NST and a .02uF cap.  I
> upped my cap to .03uF so as not to over-volt it, and I too am now seeing the
> racing sparks (who coined that name anyway?), and also have a burnt spot at
> the base of the secondary to mend.  And I tried raising the secondary, still
> got the sparks.

Gary, Alan, all,

I think one way to stop the racing sparks is to build a tall secondary
coil.  Tall and large overall perhaps.  One of the few disadvantages of
120 bps operation, is the tendency to form racing sparks due to the
large bang size.  By runing at low bps, large bang....the TC is actually
behaving like a more powerful TC.  With high bps, small bang, none
of the bangs have enough power to form racing sparks, but overall
operation seems less efficient.  Racing sparks seem to depend only
on bang size for a given system and coupling.  It seems that 120bps
sync systems must be physically larger for a given power input and
spark length than a higher bps setup.  The toroid has to be bigger
too usually.

I don't know who coined the term "racing sparks".

You might have to raise the secondary even more.   I did a test
with a small TC last night.  With high break rate, small bang, I got
11" sparks, with tight coupling, and no racing sparks.  With low, 120
bps operation, I got 14" sparks, (had to use a larger toroid too), and
loosened the coupling a lot, but still got an occasional racing spark.
the secondary is too physically small at 3" x 12", for low bps operation.

Thin wire on the secondary might help by reducing the turn-to-turn
voltage. 

Cheers,
John Freau

 
> Right now I'm waiting for a HV probe that I ordered so I can scope my cap
> charging and phase, perhaps that will show up something.  I'll let you know
> if it does.
 
> Regards, Gary Lau
> Waltham, MA USA >>