Re: More on spark delay

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <FutureT-at-aol-dot-com>

In a message dated 4/23/02 4:06:43 PM Eastern Daylight Time, tesla-at-pupman-dot-com
writes:


>
> Very interesting about the single-shot length vs. repetitive; I don't know
> why
> that would (seem to) be.  



Ken,

I'm not sure what you're saying here.  Are you saying that you're
surprised that repetitive sparks are longer than single shot sparks?
If so, it's well known that sparks grow much longer as the bps
increases.  Some have found a near linear spark length with
bps at certain bps ranges in certain systems.  This happens
because the arc channels are re-ignited before cooling 
completely.  This happens for VTTC coils too, especially at
higher powers it seems. 

Your gap's behavior may have a bit to do with it

>
> although it possibly is the case that just 1 shot , from a disruptive coil,
> may
> not give much of a visible spark.  



Single shot sparks are visible, but may be very short and weak.

My ~5 ms duration yields quite a fat, bushy

>
> one--albeit relatively short.



That's the main problem with a long spark duration IMO.  The
power is "wasted" creating fat bushy sparks, unless that's your
goal.


>
> It seems to me that your "ringup to breakout", given identical gap and
> primary-charging behavior, is going to be the same from spark to
> spark--unless
> your repetition rate is fast enough so that the air's heating does not
> substantially dissipate between sparks.  When that heating remains, I'd think
> that your sparks would tend to congregate along the same path.  Perhaps you
> observe this?



This is standard for spark gap coils.  This is often called a
coalesce of the sparks; when the follow the same path, and
grow longer.  When the bps is too low, the sparks break out
at many spots on the toroid, and are short and weak.  this
is often called the gas burner effect.


>
> As to operating "on the edge of breakout", don't know quite what you mean... 
> If no breakout, no spark except, perhaps, for wispy "leaders".  Those leaders
> would not heat or displace air, appreciably, so likely they would not much
> affect any subsequent large sparks.



At the edge of breakout suggests just over the edge I would think,
such that the sparks do actually break out.

Cheers,
John


>
> Ken Herrick
>