Re: Tesla Coil Blunderbusses

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

Original poster: "Malcolm Watts by way of Terry Fritz <twftesla-at-uswest-dot-net>" <m.j.watts-at-massey.ac.nz>

Just following on from my last post:

Actually, there is an energy thing buried in here: if the gap does 
quench early, it leaves more energy available for output sparks 
rather than the gap wasting it on each successive transfer.
    Also, this mechanism, if correct, is probably in use in dozens of 
systems already. It seems to be common practice to run the primary at 
a lower frequency than the secondary. Many have attributed this to 
tuning for streamer loading but I am becoming increasingly suspicious 
of this idea. Reason: discharges in a system with a large ROC topload 
don't actually issue until the secondary has fully or nearly fully 
rung up which leaves the primary out of the picture during the 
initial discharge at least. It might also assist gap quench in 
systems which until now have attributed earlier quench to superior 
construction techniques and complex gap configurations. I wonder.

Just thought I'd round things out. The ideas remain to be proven or 
shown to be utter rot.

Malcolm


On 10 Apr 01, at 18:18, Tesla list wrote:

> Original poster: "Malcolm Watts by way of Terry Fritz
> <twftesla-at-uswest-dot-net>" <m.j.watts-at-massey.ac.nz>
> 
> Hi all,
>         This morning after doing a bit of thinking about this result,
> I had an idea which I would like to put to the list for scrutiny and 
> testing. I was spurred by Dr Cadd raising the subject and also John's
> reply below:
> 
> On 10 Apr 01, at 12:25, Tesla list wrote:
> 
> > Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>"
> > <FutureT-at-aol-dot-com>
> > 
> > In a message dated 4/9/01 8:54:54 PM Eastern Daylight Time,
> > tesla-at-pupman-dot-com writes:
> > 
> > > >I have seen exactly that effect. I started with a smoothly
> > > >running
> > >  >coil, then tuned the primary down to enhance the lower sideband
> > >  >response. Operation went from smooth to erratic but the sparks
> > >  >increased considerably in length (about 20% from memory).
> > >  >
> > >  >Regards,
> > >  >malcolm
> > 
> > Malcolm, all,
> > 
> > Thanks to all who have responded.  It turns out I was aware of
> > this effect, but wasn't thinking.  I wonder why the operation became
> > erratic at the new tune point?  
> > 
> > John Freau
> 
> There are two "mysteries" to be explained here - the longer sparks and
> the erratic gap operation. Here is a possible answer to both. It can
> be put to the test by capturing "before and after" waveforms on the
> storage scope - I plead lack of time and sleep to do it right now but
> I certainly will in the course of time, especially if no-one else
> takes up the challenge.
> 
>       Here goes: we know that Ep was the same in both cases so we can
> reasonably assume that in both cases, Es was roughly the same. Hence,
> spark length cannot be explained by differences in energy.
>      Suppose the tuning difference results in the secondary being
> unable to backload to the primary as effectively as it would if the
> tuning of the circuits was identical. Two things would result: energy
> would be bottled up in the secondary for longer and this amounts to an
> earlier gap quench by proxy. We know that the shorted gap at firing
> time assists the power supply in storing energy in its leakage/ballast
> inductance and there is a time dependence in there. Admittedly the
> time difference is short but it may be significant (e.g. a quench
> after 1 beat instead of 3). So a marginally set gap might have
> difficulty refiring due to less resonant rise in the power supply due
> to stored energy. And the secondary rings for longer without an
> interbeat period of quietness in between.
>       Does this make any sense? This might be a useful hint at a way
> of increasing gap quench effectiveness no matter what method is
> currently employed in a system. And it may be less lossy than forcing
> a jet of air to blow the primary spark our as well. I think this
> should be tested. I hate unknowns.
> 
> Regards,
> malcolm
> 
> 
> 
> 
>