Re: S.s.t.c. "booster" proposal

["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 4/1/02 2:17:50 PM Eastern Standard Time, tesla-at-pupman-dot-com
writes:


>
> As to John's comments on pulse-burst rate and duration:  He's quite right as
> to
> my ~5 ms pulse-burst duration brightening the spark but not increasing the
> length (substantially).  But I don't think that decreasing that duration and
> at
> the same time increasing the burst-rate does much for the spark length. As
> I've
> mentioned before, initially I went to some trouble to devise a circuit that
> would detect when the spark broke out and end the excitation 50 us or so
> after
> that--thinking that I would thereby avoid wasting input power.  That scheme
> worked fine but the sparks ended up looking very pallid indeed.  When I
> extended the duration I got much more impressive sparks but the length didn't
> change a whole lot.



Ken,

I think my suggestion about the pulse time/pulse rate was too
simplistic.  Still I think that if the pulse duration was reduced
some, for example to 1mS instead of 5mS, this may permit the
pulse rate to be doubled to 32PPS, and may give some spark
length benefit.  Maybe only a 10 - 20% benefit.  If not, then a
higher peak pulse power is
probably needed.  I suspect that peak pulse power is the key
for long sparks.  Although your sparks break out from the
toroid, this is no reason why they should be longer than they
are.  A spark gap TC spark can also break out of the same toroid
as yours, and give the same spark lengths as you're obtaining, 
if the peak power is "too low".

If you can increase the peak power, this will tend to brighten
and lengthen the spark, so it will permit the spark duration to 
be reduced, to keep the total power input reasonable.  I suspect
that if you can make the peak input power 4 times higher, you'll 
double your spark length, and maintain adequate brightness, even
with a shorter pulse duration.  


>
> The only way to
> increase the voltage drop across "spark", in a given coil assembly, and
> thereby
> to increase its length, is to increase the driving voltage at the "other
> end". 
> That's the reason that spark-gap coils do better in that regard than s.s. or
> tube coils.  Or most of the reason, in case my notion as to the air's thermal
> inertia has any merit at all.



Yes, for a given coil setup, I agree.
I think the peak power is very important.  Of course voltage and
power are related considering the system impedance.  I like to
think of the power as being important, because if you use a lower
input voltage, then a stronger input current is needed to keep
the power constant.  Either higher voltage, or higher current will
work as long as the power is kept constant, but they'll be more
losses possibly with the high current method, unless conductors
are robust.  Unfortunately as the current is increased, the point
is reached where one is using only one turn on the primary.
There is no doubt that higher input voltage is a "good thing".

>
> One might well ask, of course, "Why, then, bother with s.s. or tube drive at
> all?  Just be conventional."  That would be a good question and were it to be
> asked, I would work on an answer.



Certainly the SS and tube methods offers variety and
challenge.  If everyone was always conventional, they'd be no
progress.

Cheers,
John


>
> Ken Herrick
>
>