Roger,
Nice work. It's not clear to me exactly how you applied the extra energy from the
capacitor and series choke to the tube plate... how the SCR was arranged circuit-wise to feed in
this energy? Do you have a schematic available or a more thorough description
of the circuit?
Thanks,
John
-----Original Message-----
From: Roger Smith<rwsmith@xxxxxxxxxxxxxx>
To: Tesla Coil Mailing List<tesla@xxxxxxxxxx>
Sent: Fri, Sep 2, 2011 7:30 am
Subject: [TCML] Capacitive Discharge Pulse Mode with my VTTC
The holy grail for many people who build tube coils is to get those
nice sword like sparks and there are several people on this mailing
list who have found some creative ways of getting them by pulsing the
plate voltage in just the right way to get the best spark growth . I
have recently been experimenting with a rather low tech way of doing it
with my 3cx10000a3 tube coil. I use a SCR in the cathode circuit to
start the pulse like you would do running in staccato mode and I charge
up a big capacitor capacitor in the plate circuit and I have a big iron
core choke between the capacitor and the plate of the tube. When the
capacitor is charged the SCR is triggered and the capacitor discharges
though the choke and drives the tube coil for some fraction of a second.
Currently my capacitance is 7uf and the choke is 6 Henrys and I'm
charging the capacitor to about 20,000 volts. The sparks I'm getting
are much more sword like than what I get in other modes and they are up
to 50" long ( longer than what I get running staccato mode). Here
is a link to a video .... http://www.youtube.com/watch?v=KxIEz_Q_hmo
Also, here is a link to a time exposure of the coil running in pulse
mode... http://www.flickr.com/photos/29248051@N02/6104333777/in/photostream
Roger
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