re: srsg behaviour

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

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


>Hello all,
>I have just completed and run a 300 bps srsg on my coil and have noted the
>following points.
>Coil specs - 4 pack MOT supply- 0.047uf tank cap- secondary is 4"x24"-
>toroid is 4"x22" on top of a smaller 4"x16"
>1) Streamers are about the same length (55") as with my single static gap
>but with the static gap they are much thicker and brighter.


Claude,

Maybe the srsg is not truly firing at 300 bps.  Sometimes one of
the electrode presentation times is at a time when the voltage is
too low, and the gap does not fire.  The gap may still be firing
at 200 bps, or even possibly 100 bps.  In contrast, when you
used the static gap, the true break rate may have been higher,
explaining the thicker sparks.

>2) A lot more multiple streamers with the srsg and they look thinner and
>weaker.


This is often an indication of a lower breakrate.  Lower breakrates demand
the use of a larger toroid generally.

>3) Tried a 200 bps srsg before this and did not notice any great difference
>in performance between this and 300 bps.


This is evidence the gap is still firing at 200 bps.

I have no idea where in the cycle

>the gap is firing, I just adjust the phase angle for best performance.
>4) Static gap is much louder.


The wider gaps of a static gap tends to have higher losses and
produces more noise.

>5) Have to use ballast with the static gap otherwise it powerarcs however
>with the srsg I don't have to use any ballast. Actually the best performance
>is without a ballast and the line current with the srsg is much lower than
>with the static gap.


MOT's have some built in ballasting, which is often enough with
a srsg.  It may be that you need to use a different value of capacitor
for best results with the srsg.

>6) I've noticed that when I increase the variac to almost full power the
>saftey gaps fire severly and then I have to switch of and start another run.
>I widened the saftey gaps a little and this helped a bit but it gets to a
>point where they fire continously and the srsg does not fire at all. I
>prefer not to open the saftey gaps further as I might risk overvolting the
>tank cap.


The high voltage may be a sign of a too-small cap value, but can be
a sign of missed firings.  Are you srsg electrode spacings quite
narrow?  They should be, otherwise many problems can occur.
Often, they must almost touch.

I can still increase the power input if it was'nt for this

>problem. What could cause this and is this normal with a srsg.
>7) At the moment I still prefer the look of the sparks with the single
>static gap even though quenching is a problem. It seems to be a balance
>between the right balast for a given size tank cap.


Tank cap value is very important.

Cheers,
John


>Anyway, that's what I've noticed.
>I think the srsg has improved the quenching problem but I was hoping that it
>would also result in longer streamers. Maybe I am missing something.
>
>Best wishes for the season
>Claude.
>