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New Type of SGTC?

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LAN_403

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Thu Oct 05 2006, 10:31AM

Registered Member #76 Joined: Thu Feb 09 2006, 10:04AM
Location: Hemer, Germany
Posts: 458

hello, i made a few thoughts about sgtcs and i had a idea. why not combine a marx generator and a sgtc?
i thought about rectifying a 6kV 120mA transformer to charge a 2 stage marx bank up to 8kV . each stage consists of 5x wima mkp10 0,22 1600v, to get a capacitance of 44nF.. when the marx stage is charged the first spark gap triggers and both stages are in series for 22nF 16kV. what would happen if you connect a primary coil of an sgtc to the marx generator.when the primary is in resonance with the 22nF 16kV cap matching the resonant frequency of the secondary coil, very long bright sparks could be possible, okay only pulsed with 1-2bps or less but is it worth the effort? 22nF 16kV are 2,8 Joule bang energy and you can add more and more stages to get more voltage and energy... just a thought but would it work?

vasil

Thu Oct 05 2006, 11:55AM

Registered Member #229 Joined: Tue Feb 21 2006, 07:33PM
Location: Romania
Posts: 506

Greg Hunter did it.

http://hot-streamer.com/greg/marx.htm

I thought to this as a simple way to rise the voltage in a double MOT SGTC....never done though...

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Thu Oct 05 2006, 04:03PM

Registered Member #76 Joined: Thu Feb 09 2006, 10:04AM
Location: Hemer, Germany
Posts: 458

mhh, nice, are there any pics of the setup or pictures of the discharges? my thought was to rectify the output of the hv transformer to charge a big amount of caps and stages to get a very high voltage pulse,that should give plenty of power for a short time without having a huuge hv transformer..

but its a good idea to use the maximum capacitance the transformer can charge in a halfwave to charge the marx stages,..

and ahhm, what would happen if you use more marx stages to get say 50kV and not only 12 kv or so. a 50kv transformer is hard to get and i think nobody used one in a sgtc before with such a high voltage. so what would happen if you discharge a 50kv 20nF cap into a teslacoil circuit at resonance?

Marko

Thu Oct 05 2006, 05:06PM

Registered Member #89 Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145

Problem is, that when using marx you again need to make a gap that will quench well at low voltages.

Rotary gap may help as well as turning marx inductors into charging reactors, etc.

HV Enthusiast

Thu Oct 05 2006, 05:18PM

Registered Member #15 Joined: Thu Feb 02 2006, 01:11PM
Location:
Posts: 3068

Keep in mind that the long discharges from a Tesla coil are the result of continually arcing (at high frequency >60Hz for example) through previously ionized spark channels.

If you run the system this way, you just aren't going to take advantage of this action. Also, voltage is not the only parameter in creating big arcs with a Tesla coil. Current is another one, and with a marx you just won't get the large energy transfer unless you use very big caps.

I personally don't see any advantage to this.

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Thu Oct 05 2006, 05:45PM

Registered Member #76 Joined: Thu Feb 09 2006, 10:04AM
Location: Hemer, Germany
Posts: 458

yeah i know, but whats about a drsstc in one shot mode, it does exactly the same,a long arc with the same lenght as you would usually get. so why not using a great amount of caps to get a high bang energy. the pulse would be really short i know but several yS are enough to build up a spark and let the secondary ring a few times like in a drsstc. i see no real advantage here for myself but why always so theoretical, lets try it out and see what happens.and a well build marx generator with good caps can have a high current rating, you get a short high voltage high current pulse for around 100ys or so, that can ring up a secondary coil with 100khz 10 times, more than enough to ionize the air and build up a spark.
the only problem i see is the resistance of the spark gaps, this will reduce the maximum current flow

J. Aaron Holmes

Thu Oct 05 2006, 07:10PM

Registered Member #477 Joined: Tue Jun 20 2006, 11:51PM
Location: Seattle, WA
Posts: 546

One of the (related) thoughts I had a little while ago was to use Terry's SISG as the basis for an "off-line" Marx generator, operating at voltages below where a SG-based Marx could operate. Such a thing might be the basis for an OLTC.

To avoid major timing issues, the total output of the SISG-based Marx would probably have to be less than or equal to the voltage of any single IGBT. Thus a three-stage SISG Marx based on 1200V IGBTs ought to be able to easily take in 300V and output 900V, becoming a voltage tripler.

Regards,
Aaron, N7OE

HV Enthusiast

Thu Oct 05 2006, 08:12PM

Registered Member #15 Joined: Thu Feb 02 2006, 01:11PM
Location:
Posts: 3068

wrote ...

yeah i know, but whats about a drsstc in one shot mode, it does exactly the same,a long arc with the same lenght as you would usually get.

Not really. Single-shots are almost always shorter than continuous operation.

teravolt

Fri Oct 06 2006, 04:42AM

Registered Member #195 Joined: Fri Feb 17 2006, 08:27PM
Location: Berkeley, ca.
Posts: 1111

an idea I had would be to make a PFN with a thyratron or scr. if the PFN has a pulse width equal to 1/2 cycle of the primary resonsnce the tesla should ring like bell. a thyratron or SCR should be able to do 1khz.

Electroholic

Fri Oct 06 2006, 11:54AM

Registered Member #191 Joined: Fri Feb 17 2006, 02:01AM
Location: Esbjerg Denmark
Posts: 720

Thyratron eh?

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