Re: SRSG gap spacing?

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

Original poster: "Barton B. Anderson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <tesla123-at-pacbell-dot-net>

Hi Dave,

The reason I maintain a relatively narrow gap is to maintain a constant
bang size - bottom line.
When the gap is narrow, the timing between alignment sets the firing time
and I control the
voltage and current at the panel. If I want more, I turn a knob. If the arc
voltage is set for
an arc distance of say 1/4", the gap will fire 1/4" before the electrodes
align (this distance
varies with the voltage I throw at it). The arc may quench while the
electrodes are still moving
"into" alignment. Increasing the width simply allows the gap to come closer
to alignment before
the gap fires (the distance is still the same). The higher the voltage, the
wider this gap can
be before misfires become a problem.

When you misfire, the cap charges to a higher voltage for the next
alignment and you'll have a
larger bang size - and assumed better performance. If the cap is highly
derated in your design,
then it may not be a big problem (up to a point) and you may not even
notice the misfires until
they become a large number. Once you get the gap width to the edge, it only
takes a little more
width to cause a much higher number of misfires identified by the gap
firing eratically. Since
you've been setting gap distances, you must have run into this once or
twice. Of course, if you
make big movements in setting the gap width, you can go from firing
consistently to not firing
at all pretty fast.

As far as arc dwell time, the arc will stop conducting when the energy is
no longer there to
maintain the arc.

The only advantage I can see to setting the gap to a wider distance would
be to prevent refiring
of the gap. In otherwords, if the gap fires before alignment and is nearing
alignment as it
nears it's quench point, it may quench then reignite (maybe a few times)
because of the narrow
gap distance - which is a waste. That's the only advantage I can ponder for
a larger gap width.
I think a narrow setting has the advantage of ensuring a constant firing
voltage and bang size.
I don't see anything wrong with a wider gap width as long as the gap fires
consistently. But
that's my view and it's only one.

Take care,
Bart

Tesla list wrote:

> Original poster: "Dave Leddon by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<leddon-at-attbi-dot-com>
>
> What is the rational behind maintaining a narrow gap spacing on a SRSG?
> I've seen this recommendation so often in this list that it begins to take
> on the dimension of dogma.  On my coil, as the electrodes wear down and the
> gap spacing approaches 1/8 inch, the performance actually seems to improve.
>  In theory a wider gap should reduce the arc dwell time.  So what are the
> advantages?
>
> Dave