If you're thinking of building this and adding it on to the cheap (non-hf start) TIG from Harbor Freight, don't. Unless you can figure a fool proof way to keep the high voltage and RF out of the Harbor Freight TIG, you'll toast it.
No sweat Mobius. For years I have had plans to make a fully programmable TIG square wave welder of around 200A, so I am quite interested in your post.Thanks for the reply.
It is not surprising because the coupling transformer and HF generator is a difficult area.Yep the coupling transformer is the part that's driving me crazy.
You may have the answer with the toroidial design, Im gonna see if I can locate a core to try it.
Yes, any frequency over about 100Khz would lead to high losses (with a solid core transformer), just like too lower frequency would.the winding in the primary of the coupling trans acts like an inductor (which Blocks?? HF signal) so that may be the problem.
Most probablyMY NST says:
Output 6365Vmrs 30ma Indoor type
So does that mean 6365 volts root mean square?? at 30ma?
It would be impossible for the frequency to be as high as 2161 megaHertz. Not sure what the label is saying there.7 2161MH...and if that means 2161 megahertz.
That would appear to be the best way forward as it seems to be a proven approach.I think the old auto ignition model on your hackaday link is what I need. Lower Freq and I also noticed the dimmer which I could use to keep it at a safe voltage.
Do you have a link to what you did there?I have an old lincoln buzz box trans, a set of diodes and a tig torch set up.
I forgot to mention that an air-cored coupling transformer would imply a high frequency signal in the MHz region,Most of the commercial welder manufacturers use what looks to be a simple air core coupling transformer.
I for one would be very interested in details of your design, DPI have done this with ferrite cores and it worked well, might have the data somewhere.
Hmm, that is interesting. I was imagining a much bigger gap, about, 25mm (1").I think the gap it would need to produce would be no greater than 1/4". The ones that I used back in the 80's, you touched the tungsten to the work, lifted it then hit the pedal and that kicked on the HF. In doing this I think you could get by with 1/8" or less.
Be good to hear how you get on.I'm going to mess with this project this week and I'll keep you guys posted.
That is what I thought too.Yep I just thought it was a super cool pic, and it came out of my TIG folder which almost certainly came from welding web where I was researching this. Weird but its actually beautiful.
I would be very interested as well. thanksI have done this with ferrite cores and it worked well, might have the data somewhere.
If my memory serves, that is how the arc looks when you pull the electrode farther than its "comfort zone". We used to play with them in high school and it would look just like that as you pulled it away just before the arc failed.I am surprised how unfocused the spark appears to be and would have expected a narrow column of ionized air. I once made a 20KV generator (not for welding) running with a 16 Khz 20KV peak to peak voltage at about 5ma. With a 10mm air gap the arc was quite well focused and started immediately with no messing.
Yes I have those basic tools and a small cash of misc parts from past projects. My electronic design experience is limited to knowing where to put relays in mechanical control circuits and being able to put the right resistor in line with LED lights, about here: https://www.amazon.com/Getting-Started-Electronics-Forrest-Mims/dp/0945053282Can I ask if you have any electronics building experience and do you have the basic tools- soldering iron etc.?
Ah. That makes senseIf my memory serves, that is how the arc looks when you pull the electrode farther than its "comfort zone". We used to play with them in high school and it would look just like that as you pulled it away just before the arc failed.
You have some experience and the tools- that's good.Yes I have those basic tools and a small cash of misc parts from past projects. My electronic design experience is limited to knowing where to put relays in mechanical control circuits and being able to put the right resistor in line with LED lights, about here: https://www.amazon.com/Getting-Started-Electronics-Forrest-Mims/dp/0945053282
In other words, ... I can usually build what I can find a schematic for.
The total capacitance needs to be around 470pF +100% -zero% and the working voltage needs to be 30KV or over. You can connect any number of capacitors in parallel to make up the total value. For example 5 of 100pF, 30KV capacitors would be OK, as would 330pF, 30KV and 180pF 30KV capacitors. I would think that the best source for extremely high voltage capacitors would be eBay.com.I can dig out everything besides that and the 500pf cap, Is there any substitution room on that?
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