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Solid State Disruptive Coil Spark Gaps

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GimpyJoe

Mon May 22 2006, 02:37PM

Registered Member #316 Joined: Mon Mar 13 2006, 01:30PM
Location: Marietta, GA
Posts: 212

Nice! Do you think it could work reasonably well with just one IGBT section and run on mains with a voltage doubler or tripler? That would be great, a small lightweight coil with the simplicity of a SGTC and the portability of an SSTC.

williamn

Mon May 22 2006, 02:41PM

Registered Member #55 Joined: Thu Feb 09 2006, 04:56AM
Location:
Posts: 149

Very cool Terry! You have my attention, I started work on one of these coils this weekend.

HV Enthusiast

Mon May 22 2006, 03:08PM

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

Funky wrote ...

Nice! Do you think it could work reasonably well with just one IGBT section and run on mains with a voltage doubler or tripler? That would be great, a small lightweight coil with the simplicity of a SGTC and the portability of an SSTC.

Isn't that what an OLTC is???

Dr. Dark Current

Mon May 22 2006, 05:14PM

Registered Member #152 Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384

EastVoltResearch wrote ...

Isn't that what an OLTC is???

..but much simpler without any timers...?! Maybe another contribution to my "Super Simple Tesla Coil" ?

J.M.

Terry Fritz

Mon May 22 2006, 06:21PM

Registered Member #393 Joined: Tue Apr 18 2006, 12:30AM
Location:
Posts: 297

Nice! Do you think it could work reasonably well with just one IGBT section and run on mains with a voltage doubler or tripler? That would be great, a small lightweight coil with the simplicity of a SGTC and the portability of an SSTC.

That is actully how all this got started. I was trying to make a simple small coil with SIDACS (like my DF-DRSSTC trigger circuit) but they did not have the current drive ability. So I started looking for a way to get an IGBT to help them... The rest is history

I guess I can start thinking about that project again now that this is pretty much done

Unlike the OLTC, there are no timers, controls, or other brains... It really is just like a "spark gap" (but DC). One can fiddle with the SIDAC voltages to get it to fire at any voltage. One section could probably do say 1000, 1100, 1199.99 volts :o) Of course there are bigger higher voltage IGBTs too. Nothing is very critical and there are many things that could be adapeted or changed around. So far, an SISG system has never failed

I think over heating the IGBTs is the only obvious way and that is a bit hard to do.

Here is the latest news as of an hour ago. This pretty much finishes the project up here, be sure and see the nice movie!! I guess I forgot to "talk"

--------------------

Hi All,

It's been 24 days now and it is pretty much all finished

)

Without messing with coupling, tuning (probably real close), or any thing like that, I can fairly easily hit 24 inches at 117W - and 30 inches at 183W. The Freau number there is 2.22 in both cases. That number seems very "constant".

I was only able to go to 5 sections instead of six due to the limited safety area in my basement. With six sections, it should get to 263 watts for 36 inches. The whole mess could probably be more optimal, but my goal here was just to get "one" working

)

I made a movie here, with a good camera this time, of it doing 30 inch hits

(25 MB MPG movie file)

Got to the lower right and click "free". It makes you wait about 30 seconds to read the ads and click off the popups. Then type in the funny letters and download. I have been using

a lot so buy everything in the ads and donate to them

) It certainly solves the big file distribution problem!! It is a plain MPG file that even a modern DVD player should play if you burn it to disk...

The little heat sinks get to about body temperature for short runs which is just right according to the calculations. Bigger heat sinks and/or a fan would be good for extended operation.

The full data on everything is here (might take a while to DL since it is 'busy"

I still need to finish this up, but it is up to date as of last night. Let me know, off list, if there are any errors or something I should add or polish up. It was written in parts, very fast

But it is the best way to document stuff like this. A far cry from the OLTC :o)))

Nothing has blown up yet and everything seems perfectly happy. The only bug was the DC MOT charging which I had to whip up a high voltage blocking inductor for. But that was a mundane typical MOT coil issue.

You have to be careful to turn up the variac until is just starts to run smoothly (120 BPS) and no more. If you turn up the voltage too high, the BPS rate can go up dramatically and overheat the IGBTs. Higher BPS does not seem to increase spark length other than making them sound funny. Sort of "screetchy".

Thanks for everyone's help, input, and encouragement!!! Looks like we all have a new toy

)))

BTW - The dual MOT system has an extremely dangerous primary system!! Be very careful when working on them especially now that there are electronic circuits and stuff in there to fiddle with. Be ultra sure that the power is off before working on them. Be very careful of the output arcs since it is possible for a primary to secondary break over to present lethal currents on the secondary. Note too that the primary circuit can be almost at full power, but totally silent!

--------------------------

Cheers,

Terry

HV Enthusiast

Mon May 22 2006, 07:07PM

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

Looks good Terry. I think the next test is to make a true comparison between a spark gap coil and SISG coil ensuring identical break-rates.

Reaching

Mon May 22 2006, 08:45PM

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

hehe, exactly what i tried to build long ago with an scr and you did it with simple parts. incredible.
mhh, okay, i have many 600volt high pulsed current igbts, capacitors, a mot, coils etc, . have to make one

mhh, i searched but i didnt found anything called sidac in germany. a sidac is called diac in germany but no one sells them. now thats the question, can i use triacs as a sidac replacement? or can i use a transient voltage surpressor instead of the sidacs, something like this?

Self Defenestrate

Mon May 22 2006, 09:25PM

Registered Member #87 Joined: Thu Feb 09 2006, 01:36PM
Location: San Jose
Posts: 191

Finally a simple solid state option for my 1kv coil. No more "shrinking gap" effect with this. Cool.

Terry Fritz

Mon May 22 2006, 10:22PM

Registered Member #393 Joined: Tue Apr 18 2006, 12:30AM
Location:
Posts: 297

mhh, i searched but i didnt found anything called sidac in germany. a sidac is called diac in germany but no one sells them. now thats the question, can i use triacs as a sidac replacement? or can i use a transient voltage surpressor instead of the sidacs, something like this?

A TVS will not work since the SIDAC has to "stay on" "longer"... The "SIDAC" (no one knows, or will admit, to what SIDAC "really" stands for) has a data sheet here.

One may be able to wire up things like a DIAC to do the same function... I don't know...

Teccor makes them:

Here is probably far far more than anyone wnats to know about them (94 pages!)

)

A wiki -

Cheers,

Terry

HV Enthusiast

Mon May 22 2006, 10:58PM

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

Terry Fritz wrote ...

The "SIDAC" (no one knows, or will admit, to what SIDAC "really" stands for) has a data sheet here.

Cheers,

Terry

Thats an easy one. SIDAC simply stands for Silicon Diode for Alternating Current. Its a pretty old term.

Dan

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