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Re: Solid state spark length record?
In a message dated 4/18/00 9:17:37 PM Pacific Daylight Time, tesla-at-pupman-dot-com
writes:
> Hi Gary, All,
>
> I would expect you have very interesting design, one that would be of great
> interest to us folks here. I have yet to try a solid state CW Tesla Coil,
> as Pulsed Tube coils are a bit easier to build. I think photos are in
> order! I think John Freau has produced some of the longest "pulsed" CW
> sparks (at least that I know of) at around 38" from several 833A tubes and
> 5-7KVA power. Even at only two pulses per second, the power must be great.
> But it is still a strong belief of mine that pulsing a very well designed
> (ie, impedance matched -spark to coil) CW coil, one may come close to a
> "Damped" wave design in spark efficiency (well close may be relative ;>)).
> David Trimmell
David, all,
In one experiment, I ran the pulsed coil using a DC supply and a
current limited transformer. This allowed for the use of some energy
storage in the filter capacitor, and provided for high peak powers from
a low steady input power. I obtained 17" sparks from a 135 watt NST
powered tube coil using this method. This is more "efficient" than many
spark gap TC's. The pulse rate was about 10 to 15 PPS, so the spark
looked reasonably steady. Higher pulse rates of course reduced the
spark length because the input voltage began to sag. I put efficiency
in quotes above because I am using a coiler's practical definition of
efficiency, not a true engineering definition.
A normal staccato or pulsed tube coil can achieve similar "efficiencies"
to the above, but the peak input power will be high (large transformer
needed). The DC filter cap storage method permits a small transformer
to power a large spark.
Cheers,
John Freau