Oscilloscope images of tig welders

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I would love to compare oscilloscope images from different tig welders. The only thing i found was a you tube video from this old Tony after i posted some images on tips and tricks forum. My goal is to take some of the magic out of the decision making when choosing a power source. Forget brand name, i want to see with my eyes what the power source is actually producing. There is alot of advertising about wave shape and the like but they never include the actual image.... just an idealistic image that looks perfect.So i will start this of with all i have right now, an everlast 250ex. I plan on upgrading to a miller dynasty dx, or a fronius magicwave 230i or htp invertig, in that order. So here  are the images taken so far.The image with with blue is the amperage. I had the machine set to about 35amps. The overshoot was 65 amps EN.the other thing i noticed is i can't get below 11 amps. These two facts are the main reason im upgrading. I don't think it matters for bigger material.Anyway, if anyone can add to the collection of images it could be a great resource!Sent from my SM-G930V using Tapatalk
Reply:Can you explain the traces for me please?I.e. "this blue line is volts, on straight DC" "this yellow line is volts, AC 100hz"That sort of thing. I'm assuming it's all voltage since you'd need some sort of current clamp and a converter to feed back to the scope...I can sort of guess, but I'm not entirely sure. e.g. the last two look like a pulsed DC, but I have no real idea.Last edited by Munkul; 10-07-2019 at 02:52 AM.
Reply:Originally Posted by MunkulCan you explain the traces for me please?I.e. "this blue line is volts, on straight DC" "this yellow line is volts, AC 100hz"That sort of thing. I'm assuming it's all voltage since you'd need some sort of current clamp and a converter to feed back to the scope...I can sort of guess, but I'm not entirely sure. e.g. the last two look like a pulsed DC, but I have no real idea.
Reply:Thanks for that. It's very helpful.So what settings correspond to which image? Like i said, I assume pics 3 and 4 are of a pulsed DC, but to be truly helpful you need to state exactly what it is we are looking at.i.e. some welders light give a rock-steady DC but an AC waveform all over the shop. Or at low amperages it's a bit rough. We don't know.So I propose if we have a thread like this, the following stats should be included for each image:- Machine brand and model, including voltage and 1phase/3phase- Waveform type (i.e. DC, Pulse DC, AC, Pulse AC, squarewave/sine/soft square etc)- frequency of AC or pulse- Set amps - peak and background if on pulseIt's interesting, because the small oscillations in voltage must be the feedback mechanisim within the inverter. I'm going to have to get a scope and see the outputs on my Lorch, and post em up too.
Reply:Originally Posted by MunkulThanks for that. It's very helpful.So what settings correspond to which image? Like i said, I assume pics 3 and 4 are of a pulsed DC, but to be truly helpful you need to state exactly what it is we are looking at.i.e. some welders light give a rock-steady DC but an AC waveform all over the shop. Or at low amperages it's a bit rough. We don't know.So I propose if we have a thread like this, the following stats should be included for each image:- Machine brand and model, including voltage and 1phase/3phase- Waveform type (i.e. DC, Pulse DC, AC, Pulse AC, squarewave/sine/soft square etc)- frequency of AC or pulse- Set amps - peak and background if on pulseIt's interesting, because the small oscillations in voltage must be the feedback mechanisim within the inverter. I'm going to have to get a scope and see the outputs on my Lorch, and post em up too.
Reply:I will redo the test and put all the info in one. It might take me a while,  I'm fighting a cold/ mild fever. Sent from my SM-G930V using Tapatalk
Reply:Recently using a AHP I found that the weld came out dull using higher ac frequency. For me the weld got much better when I dropped it down to around 70hz.12v battery, jumper cables, and a 6013.I only have a facebook page. https://www.facebook.com/pages/VPT/244788508917829
Reply:When you redo the test, can you set the trace so that the current vs volts have the exact starting point? I would expect the current would lag or have a phase shift from volts with a constant current welder. It's probly only a couple degrees but that's why the starting point for each trace needs to be close to exact. I don't have a battery powered scope so I don't dare try it because the short circuit current would fry a mains grounded scope.
Reply:Originally Posted by InsanerideWhen you redo the test, can you set the trace so that the current vs volts have the exact starting point? I would expect the current would lag or have a phase shift from volts with a constant current welder. It's probly only a couple degrees but that's why the starting point for each trace needs to be close to exact. I don't have a battery powered scope so I don't dare try it because the short circuit current would fry a mains grounded scope.
Reply:Originally Posted by VPTRecently using a AHP I found that the weld came out dull using higher ac frequency. For me the weld got much better when I dropped it down to around 70hz.
Reply:Some inverters like high freq, some like lower. That's my experience, anyway.My old ESAB liked 120hz, no other frequency kept the tungsten in as good a shape. Just a little peculiarity.My Lorch doesn't care about the frequency as far as tungsten goes, but it wets out the puddle much nicer at lower frequency say 60hz, as well as a lot stiffer and directional at 200hz.Inverters are weird about balance, as well. The ESAB liked 65% EN, the Lorch likes 75%. I think it's individual to the hardware design for each manufacturer.
Reply:Originally Posted by MunkulSome inverters like high freq, some like lower. That's my experience, anyway.My old ESAB liked 120hz, no other frequency kept the tungsten in as good a shape. Just a little peculiarity.My Lorch doesn't care about the frequency as far as tungsten goes, but it wets out the puddle much nicer at lower frequency say 60hz, as well as a lot stiffer and directional at 200hz.Inverters are weird about balance, as well. The ESAB liked 65% EN, the Lorch likes 75%. I think it's individual to the hardware design for each manufacturer.
Reply:What year was your EX250 made. The reason I ask is they went from analog to all digital I believe 2016 or 2017 on the EX250.  I am going from memory so those dates might not be correct.  I know the one I got is the all digital one .  When I purchased it they still had some of the older version left but I wanted the newer version . So far it has bean able to do anything I have needed to do with it.  I will say I do not like its for stick welding but I did not buy it for stick welding.  I do need to stick weld some with it so I wish it worked better for that.Last edited by thegary; 10-08-2019 at 10:28 AM.
Reply:Originally Posted by SimclardyNot quite sure what your asking. The trace is on the voltage and the current (blue) is locked in actual time. Any lag or lead you see is real. I did not shift them (i did shift them vertical for clarity)    I am not sure what to expect on a welder but with a capacitive load the current leads voltage and on inductive loads voltage leads. Resistive loads would be in phase with each other.      Yes, connecting a scope to a welder with high frequency start is dangerous. The rigol probe im using gives me the protection i need. Sent from my SM-G930V using Tapatalk
Reply:Originally Posted by SimclardyI would love to compare oscilloscope images from different tig welders. ... i want to see with my eyes what the power source is actually producing. There is alot of advertising about wave shape and the like but they never include the actual image.... just an idealistic image that looks perfect..
Reply:Originally Posted by MCTigThis is a very interesting project to pursue, but if you want to know what is actually being produced you need to use an analog oscilloscope.  Digital oscilloscopes are great for certain tasks, their multi-color outputs can make work easier, and they certainly make capturing the waveforms easier as well, but because of filtering what they display on their screens typically can be a lot better than what the actual signals look like when those signals are noisy. A digital oscilloscope's bandwidth specification tells you you the sampling rate of its A/D converter, it does not tell you how that signal is subsequently processed prior to being displayed.  This isn't a hypothetical issue.  I have four digital oscilloscopes, but when I need to see transients or noise on a signal I use an analog oscilloscope.  Using a digital oscilloscope for your project defeats the purpose because the oscilloscope  produces "an idealistic image that looks perfect" even when the input signal isn't.
Reply:Originally Posted by InsanerideWhat you said, voltage leads in an inductor, current leads in a capacitor.  I would expect a noticeable current lag in a transformer machine. Maybe there's no lag in an inverter that's why I ask if the horizontal was synced between channels. I would still expect a lag in an inverter.
Reply:Originally Posted by thegaryWhat year was your EX250 made. The reason I ask is they went from analog to all digital I believe 2016 or 2017 on the EX250.  I am going from memory so those dates might not be correct.  I know the one I got is the all digital one .  When I purchased it they still had some of the older version left but I wanted the newer version . So far it has bean able to do anything I have needed to do with it.  I will say I do not like its for stick welding but I did not buy it for stick welding.  I do need to stick weld some with it so I wish it worked better for that.
Reply:Originally Posted by SimclardyAm i missing something?
Reply:Originally Posted by MCTigThis is a much more specialized topic than appropriate here.  But, as an example, your Rigol displays all signals at the same intensity, whereas an analog oscilloscope displays transients at an intensity appropriate for the time they occupy on each cycle.  That is, if a glitch appears roughly only once every 10 sweeps, it would be 10x dimmer on an analog oscilloscope and hence would be a much more accurate representation of the true output.  I have two Rigol oscilloscopes and they're great for many things.  But, if I wanted to achieve the goals you stated for your project, I definitely would use my Tektronix 2465B.
Reply:Ok the first photo is just my warm up pad, with the torch fixed with a very small gap. Second photo shows peak high frequency voltage around 2700 volts. Third photo shows my machines minimum amp setting. You can see EN is still up at about 17amps. The rms is 13amps. The arc is very unstable. I used a 3/32" tungsten 2% lanthonated. A thinner tip would be better. Let's just say it's not fun welding small stuff with this machine. CheersSandySent from my SM-G930V using Tapatalk
Reply:Originally Posted by Simclardy  To be certain I called rigol and explained my experiment and they agreed that everything should work fine. Of course they might be biased but they are a reputable company.
Reply:Originally Posted by MCTigIf Rigol made both analog and digital oscilloscopes asking them for technical information to help choose between the two types might have been reasonable.  But, they only make digital oscilloscopes so of course they said digital was fine.The issue isn't refresh rate, memory depth, bandwidth, etc.  Yes, the repetition rate of the pulses is low so your digital oscilloscope has no trouble displaying the big features.  But, does a given welder provide clean pulses, or could there be noisy, intermittent transients on those pulses that affect the arc but that your digital oscilloscope effectively filters out and doesn't display?  Again, your stated purpose is to see "what the power source is actually producing."  With a digital oscilloscope you're seeing a sanitized version of what the power source is actually producing so you won't see certain kinds of possibly-relevant features that you would see if they were there had you been using an analog oscilloscope.
Reply:Originally Posted by SimclardyIm curious what your background is? How did you come to own 4 scopes?
Reply:Originally Posted by MCTigI've used oscilloscopes in my profession for over 40 years but my interest in them in recent years is more for studying obscure types of automotive electronics.  .Originally Posted by SimclardyDo you follow scanner danner?
Reply:Originally Posted by MCTigI wasn't aware of him but quickly found him on youtube.  I checked one video at random that looked like it would be about automotive electronics and found him pulling plug wires off the coils on a running engine to check for spark.  That's a great way to ruin a coil since if the HV can't get to the plug a weak point in the internal insulation will feel the full brunt of the max. voltage the coil generates.  If it arcs through and a carbon track develops an otherwise-good coil has been unnecessarily turned into toast. Even if it doesn't kill the coil immediately it further weakens the weak insulation, seeding the path to a premature death.So, how should he have tested the coils?  A battery-powered digital oscilloscope with an inductive probe around the wires would have been the way to do it, taking almost no more time to test the coils properly than pulling the plug wires.  Plus, the oscilloscope gives useful diagnostic information in addition to just spark/no spark.  There may be good stuff in his other videos but I won't be spending the time to watch them to find out.
Reply:Originally Posted by SimclardyNot sure which video you watched, but that does not sound right. When he does pull plugs he will hold an incandescent tester to give the spark a safe path. He is an instructor at rosdale tech and is all about proper diagnosis.
Reply:Originally Posted by MCTigHe has a lot videos and I just picked one at random so I can't tell you which one it was.  But, he definitely didn't give the spark any alternative but to try to escape through the insulation of the coil.  I didn't realize he was an instructor.  That makes what he did even worse.
Reply:I just ordered a new open box dynasty 210dx. I can't wait to post images from my scope!Sent from my SM-G930V using Tapatalk
Reply:This is the dynasty 210dx.200hz75% balance30ampsAdvanced waveBlue line is amps Yellow voltsSent from my SM-G930V using Tapatalk
Reply:This is the dynasty 210dx.200hz75% balance30ampsSoft waveBlue line is amps Yellow voltsSent from my SM-G930V using Tapatalk
Reply:This is the dynasty 210dx.200hz75% balance30ampsSine waveBlue line is amps Yellow voltsSent from my SM-G930V using Tapatalk
Reply:This is the dynasty 210dx.200hz75% balance30ampsTriangle waveBlue line is amps Yellow voltsSent from my SM-G930V using Tapatalk
Reply:So my observations:1. The cleaning action (positive side) is not effected by the wave selection2. The amperage does not overshoot as bad as the everlast3. The reaction time of the scr or igbt, whatever miller uses is almost twice as fast as the everlast and appears to be much more stable or consistent (compared photo below to everlast image to see the frequency of oscillations)4. The beads i stacked are the first out of the box. Too excited to clean. Mostly 75 balance, a couple with 80% balance.I thought it was smoother than the everlast. I have not pushed the low amperage limits yet and that is where i expect the biggest difference. 5. The stick welding was noticeably smooth compared to what i have been using. Conclusion: i like to buy quality tools but i don't like paying for a name brand.If the name brand happens to delivers a better product in an ethical way i consider the extra cost worth it. I see the R&D that miller has published on the web along with lincoln and i notice. Every time i call miller with technical questions i get a very knowledgeable tech within minutes, i notice. I have used some of Miller's products and i notice a difference. I purchased the wireless foot pedal for $700 and thought about the expansion card for $500 and damn it miller i notice. LolI will just add that i don't trust bean counters and i have seen many good companies erode their quality and ethics for profitability. Miller is not immune from temptation, so i hope they never become just a "name"Cheers and happy new year!Sent from my SM-G930V using Tapatalk