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  1. #181
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    so does anyone have a working schematic they could share please, i have the polish one that does ac/dc but i cant make heads nor tails of it.



  2. #182
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    Kaign80: there are some open designs, as the one Raban offers and others in this thread. You can look at this one also, TIG_Welder_Project. I think that you won't be able to build a HF AC (for aluminum) welder at a lower cost... you will probably spend less money on the final components, but you'll work a lot, and spend a lot in experiments and tools!
    You might build a DC TIG on the cheap if you take an AC stick welder, add a rectifier and a torch + argon tube + argon pressure & flow regulator (argon tubes work at very high pressure). That is what we did in my home, and it works! Our welder didn´t have an efficient current regulation so it was tricky, but we sorted it out.
    Some people even make the transformer out of microwave oven transformers (MOT), and regulate them with huge dimmers.

    Josue: We bought a DC TIG welder after that last experiment, so i haven´t worked on that circuit anymore... we use the welder for work so it was worth the cost!

    I first tried putting the car ign. coil in parallel with the old welder output, and made the most expensive experiment so far; Doing that, i applied HV "kicks" of about 6-30KV to the welder's rectifier bridge, and luckily only burned one diode...
    In your case, the capacitor might dampen the HV and save your bridge (also, it may not), but at the same time it will dampen the HV output. It might work, but it's a risky gamble. Furthermore, if you pierce the capacitor's isolation, it might short the welder, boil and explode, as electrolytic capacitors have liquid inside.

    An auto ignition coil fed with a dimmed 120V 60HZ will deliver bursts of HV AC; it´s a HV transformer fed with "pieces" of 60Hz AC current. The output will be a sort of 60Hz + perhaps some noise; It, by itself, is not capable of generating much HF. If I've understood well, the spark gaps + capacitors + HF transformer winding make a HF HV resonant circuit which do the work. The auto coil is like a hammer, and the rest is kind of a bell. The HF transformer is air cored or ferrite cored, both of wich transmit HF rather well but 60Hz pretty bad, and can be made with few turns on the secondary, so that you can use heavy gauge wire without trouble; that way you can induce HV in series with the welder//supressors, not burn the welder nor the arc starter, and still create a spark between electrodes.

    You need about 1-3KV to make a spark through 1mm of fresh air, so i think the improvement in your welder's start is due to the capacitor giving lots of power by itself during the electrode touch, in a kind of explosion; i'm not sure how that would work on TIG.
    If you want less power during weld, you might try putting a smaller capacitor, or 2 of them in series. You can also add a huge dimmer to control the welder, but it depends on how your welder is built.

    bye!



  3. #183
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    gfioro!!!!
    You might build a DC TIG on the cheap if you take an AC stick welder, add a rectifier and a torch + argon tube + argon pressure & flow regulator (argon tubes work at very high pressure). That is what we did in my home, and it works!

    That is exactly what I did....I added rectifiers and an inductor to my AC Stick welder and the difference to start the arc was evident....I haven´t bought the torch, the hose, the regulator etc. but this is going to work for sure.
    Right now I am not using the capacitor (400V 180mf electrolytic cap) because the inductor is giving me a really nice weld bead...I did use the capacitor immediately after adding the bridge rectifier and started the arc just by touching the metal work but the weld bead was a mess....I must say that I usually weld material between 1/16 and 1/8 of an inch and I felt that the weld bead was as I said before too hot so when I built my inductor I did it with 14 gauge wire because I wanted some resistance....my inductor was wounded in a UPS transformer...is not a large inductor but works really good (I least for what I weld)

    I first tried putting the car ign. coil in parallel with the old welder output, and made the most expensive experiment so far; Doing that, i applied HV "kicks" of about 6-30KV to the welder's rectifier bridge, and luckily only burned one diode...
    In your case, the capacitor might dampen the HV and save your bridge (also, it may not), but at the same time it will dampen the HV output. It might work, but it's a risky gamble.


    Thanks for sharing the above info so I can take my precautions or totally forget the idea.

    If I've understood well, the spark gaps + capacitors + HF transformer winding make a HF HV resonant circuit which do the work. The auto coil is like a hammer, and the rest is kind of a bell. The HF transformer is air cored or ferrite cored, both of wich transmit HF rather well but 60Hz pretty bad, and can be made with few turns on the secondary, so that you can use heavy gauge wire without trouble; that way you can induce HV in series with the welder//supressors, not burn the welder nor the arc starter, and still create a spark between electrodes.

    What a nice explanation!!!!!!! Thank you again!!!

    You can also add a huge dimmer to control the welder, but it depends on how your welder is built.

    My welder is 120/220 V (can work either way)55/250 Amps. The transformer is variable...it has a piece of metal (I think in english is called shunt)that goes in and out of the transformer via a knob that is rotated.
    How many amps or how may watts should be the dimmer?
    As I have read and understood the dimmer must be connected before the primary....is that right?

    Sos de Argentina?

    Thank you very much gfioro!!!!



  4. #184
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    Jaja si, soy de Argentina. Vos de Guatemala? Eso dice el usuario :P

    By "argon tube" i meant the high pressure vessel, the tank, which in our case works at 140 bar of pressure. Argon regulators often deliver 5 bar, and some can be setted to lower pressures. If you don´t have it, consider it can be expensive.

    Adding a dimmer is something electrically "incorrect" but works; I´ve seen commercial welders with them. A dimmer for a welder should be designed for inductive loads. And yes, dimmers work better at the primary, because of the lower currents.
    If you make or buy a dimmer, remember that their cases, heatsinks and even perhaps knobs can be connected directly or somehow to the mains (TRIAC and SCR heat dissipation tabs are often connected to a terminal), so electrocution risk is high.
    *** BE VERY CAREFUL! *** , don't take risks and don't use it if you don't fully understand it. Ask the seller for the dimmer's instalation procedure or standar housing, also.

    Here's a homemade design: Homebuilt arc welder · Dan's Workshop Blog

    Selecting voltage capability of a dimmer or its components is not so hard: If your mains is 220V, that is it's RMS value, kind of a power equivalent to DC voltage. If you want to select a SCR/TRIAC, it´s datasheet will probably specificate peak voltage; sine wave AC has a peak voltage of 1.41 ( = sqrt(2)) the mains RMS voltage: 220Vrms * 1.41 = 311Vpk, so any 400Vpk component should work okay.... at least from what i know.

    The current capability of the dimmer needed to control a welder is a bit hard to estimate, at least for me. First of all, you should look at the plate of the welder and try to figure out peak primary current, "I1max" probably.
    If that is impossible, you can measure the current with a clamp inductive amp meter, and try every possible use (vary power, weld with a long arc, a short arc, and stick the electrodes in short circuit). As a last resource, you can calculate power output of your welder, calculate amps needed at the primary, and apply a generous safety coefficient. Stick welders usually deliver around 20V at medium amperages, TIGs are around 14V @ 30A. Be warned that welder are highly inductive loads, so their power factor is poor and draw extra current that flows but -due to not being in phase with voltage- does not deliver active power; that means that a welder delivering 2200W@220V will need 10 amps of "active" current and some more (some times a lot more) of "reactive" current... if the welder data plate specificates power factor or Cos(phi), you can calculate the reactive current.

    Safety considerations and design of the circuit can be found in many websites.. google it. Again, be careful -even if you just buy it- and don't use it until you fully understand it. Take into account the heat dissipation requirements of the dimmer, they dissipate about P = 1.5 Volts * I ... if i'm right.

    If the result goes up many amps, it can be too expensive, so you might consider using a smaller but detachable dimmer, only when requiring low power, and protect it with a fuse or thermomagnetic switch (it might not be enough, but it's something). I´ve seen a commercial welder with a rather small triac.

    bye!



  5. #185
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    Si soy de Guatemala!!!! Saludos!!!
    As is said in your country "Sos un monstruo vos" thank you very very much for everything!
    Have a nice day!!



  6. #186
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    Here is the whole plan for free.

    Access point



  7. #187
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    Default Here is the pdf file

    Here is the pdf file for free.


    Quote Originally Posted by gfioro View Post
    Jaja si, soy de Argentina. Vos de Guatemala? Eso dice el usuario :P

    By "argon tube" i meant the high pressure vessel, the tank, which in our case works at 140 bar of pressure. Argon regulators often deliver 5 bar, and some can be setted to lower pressures. If you don´t have it, consider it can be expensive.

    Adding a dimmer is something electrically "incorrect" but works; I´ve seen commercial welders with them. A dimmer for a welder should be designed for inductive loads. And yes, dimmers work better at the primary, because of the lower currents.
    If you make or buy a dimmer, remember that their cases, heatsinks and even perhaps knobs can be connected directly or somehow to the mains (TRIAC and SCR heat dissipation tabs are often connected to a terminal), so electrocution risk is high.
    *** BE VERY CAREFUL! *** , don't take risks and don't use it if you don't fully understand it. Ask the seller for the dimmer's instalation procedure or standar housing, also.

    Here's a homemade design: Homebuilt arc welder · Dan's Workshop Blog

    Selecting voltage capability of a dimmer or its components is not so hard: If your mains is 220V, that is it's RMS value, kind of a power equivalent to DC voltage. If you want to select a SCR/TRIAC, it´s datasheet will probably specificate peak voltage; sine wave AC has a peak voltage of 1.41 ( = sqrt(2)) the mains RMS voltage: 220Vrms * 1.41 = 311Vpk, so any 400Vpk component should work okay.... at least from what i know.

    The current capability of the dimmer needed to control a welder is a bit hard to estimate, at least for me. First of all, you should look at the plate of the welder and try to figure out peak primary current, "I1max" probably.
    If that is impossible, you can measure the current with a clamp inductive amp meter, and try every possible use (vary power, weld with a long arc, a short arc, and stick the electrodes in short circuit). As a last resource, you can calculate power output of your welder, calculate amps needed at the primary, and apply a generous safety coefficient. Stick welders usually deliver around 20V at medium amperages, TIGs are around 14V @ 30A. Be warned that welder are highly inductive loads, so their power factor is poor and draw extra current that flows but -due to not being in phase with voltage- does not deliver active power; that means that a welder delivering 2200W@220V will need 10 amps of "active" current and some more (some times a lot more) of "reactive" current... if the welder data plate specificates power factor or Cos(phi), you can calculate the reactive current.

    Safety considerations and design of the circuit can be found in many websites.. google it. Again, be careful -even if you just buy it- and don't use it until you fully understand it. Take into account the heat dissipation requirements of the dimmer, they dissipate about P = 1.5 Volts * I ... if i'm right.

    If the result goes up many amps, it can be too expensive, so you might consider using a smaller but detachable dimmer, only when requiring low power, and protect it with a fuse or thermomagnetic switch (it might not be enough, but it's something). I´ve seen a commercial welder with a rather small triac.

    bye!




  8. #188
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    Default Here is the pdf file

    Here is the pdf file for free.
    Access point


    Quote Originally Posted by gfioro View Post
    Jaja si, soy de Argentina. Vos de Guatemala? Eso dice el usuario :P

    By "argon tube" i meant the high pressure vessel, the tank, which in our case works at 140 bar of pressure. Argon regulators often deliver 5 bar, and some can be setted to lower pressures. If you don´t have it, consider it can be expensive.

    Adding a dimmer is something electrically "incorrect" but works; I´ve seen commercial welders with them. A dimmer for a welder should be designed for inductive loads. And yes, dimmers work better at the primary, because of the lower currents.
    If you make or buy a dimmer, remember that their cases, heatsinks and even perhaps knobs can be connected directly or somehow to the mains (TRIAC and SCR heat dissipation tabs are often connected to a terminal), so electrocution risk is high.
    *** BE VERY CAREFUL! *** , don't take risks and don't use it if you don't fully understand it. Ask the seller for the dimmer's instalation procedure or standar housing, also.

    Here's a homemade design: Homebuilt arc welder · Dan's Workshop Blog

    Selecting voltage capability of a dimmer or its components is not so hard: If your mains is 220V, that is it's RMS value, kind of a power equivalent to DC voltage. If you want to select a SCR/TRIAC, it´s datasheet will probably specificate peak voltage; sine wave AC has a peak voltage of 1.41 ( = sqrt(2)) the mains RMS voltage: 220Vrms * 1.41 = 311Vpk, so any 400Vpk component should work okay.... at least from what i know.

    The current capability of the dimmer needed to control a welder is a bit hard to estimate, at least for me. First of all, you should look at the plate of the welder and try to figure out peak primary current, "I1max" probably.
    If that is impossible, you can measure the current with a clamp inductive amp meter, and try every possible use (vary power, weld with a long arc, a short arc, and stick the electrodes in short circuit). As a last resource, you can calculate power output of your welder, calculate amps needed at the primary, and apply a generous safety coefficient. Stick welders usually deliver around 20V at medium amperages, TIGs are around 14V @ 30A. Be warned that welder are highly inductive loads, so their power factor is poor and draw extra current that flows but -due to not being in phase with voltage- does not deliver active power; that means that a welder delivering 2200W@220V will need 10 amps of "active" current and some more (some times a lot more) of "reactive" current... if the welder data plate specificates power factor or Cos(phi), you can calculate the reactive current.

    Safety considerations and design of the circuit can be found in many websites.. google it. Again, be careful -even if you just buy it- and don't use it until you fully understand it. Take into account the heat dissipation requirements of the dimmer, they dissipate about P = 1.5 Volts * I ... if i'm right.

    If the result goes up many amps, it can be too expensive, so you might consider using a smaller but detachable dimmer, only when requiring low power, and protect it with a fuse or thermomagnetic switch (it might not be enough, but it's something). I´ve seen a commercial welder with a rather small triac.

    bye!




  9. #189
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    I was reading through your forum and I thought you guys might be interested in my project. I bought a defective Chinese TIG welder on E-bay and repaired it. I bought it because it had an inverter in the front end. I had hoped that I could just bring out the A/C output from the inverter and do thin aluminum welding.

    I originally lifted the center taps on all 4 secondaries on the 2 output transformers. (They use 2 output transformers in parallel). I checked the phases of the secondaries and tied all 4 in parallel. The biggest problem I faced was converting all the control items from the original DC output to work the same as it was now seeing in A/C. I solved that problem by simply rectifying the A/C for the control inputs. When done I had perfect PWM control and could vary the intensity of a large flood lamp load from almost out to so bright I thought I might blow the bulb. The spark starter worked great and I thought I had successfully pulled it off.

    I set up my gas and tried to weld on a scrap piece of thin aluminum. I barely got enough current to carry an arc. I then hooked up (5) 1 ohm wire wound resistors in series so I could read the voltage drop at full short to see how many amps I was getting. At full PWM setting I was developing 12 amps RMS. I couldn’t pull a sick prostitute off a pot with that kind of amperage. With a huge amount of labor I then put my welder all back to the original DC TIG to see if it was still working. I accidentally bumped my TIG torch to the plate I was using to make a dead short on the line for testing and it blew a hole in the plate. Plenty of amps back. I measured it and got as much at full low as I got from full high using the A/C.

    I then experimented thinking maybe I was loosing some thing in the transformer windings. I tried one secondary with the others just swinging in the breeze. I lost about ten percent of what I got with all four in parallel. Then I put each transformer secondary and its sister in parallel and put the two doubles in series for higher output voltage. I still ended up to low for welding.

    I then gave up this approach and decided to pulse the secondary DC to give me the A/C I needed. I have engineered a pretty good looking system with one major obvious problem I haven’t come up with a fix for yet. The pulsing MOSFETS carrying the high current are expensive and I don’t want to fry a bunch of them. They will be hit by the very high voltage and frequency of the spark starter. I don’t know how to handle that yet.

    Any ideas?

    I don't get to much time to get back to forums. If you would like to discuss my project or see my latest proposed diagram e-mail me directly.

    Toolmanx@peoplepc.com



  10. #190
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    Default Re: My Homemade TIG welder

    anybody have plans about to build tig welder ?
    Regards.



  11. #191
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    Default Re: My Homemade TIG welder

    cool idea!



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