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The factory I work in has several Tig welders. Based on the operation, the amps are as low as 10 Amps or as high as 150 Amps.If I wanted to check the calibration (i.e. knob or display setting for accuracy and precision), what equipment would I need? Is there equipment I could buy just for checking calibration of tig welders?Thank you,BennyB
Reply:Benny,The best way to do it is with a calibrated voltage source. This device puts out a known voltage to the meter on your welder, and you compare the reading on the voltage source to the reading on your meter.Yes, I know I said voltage source and you asked for amperage. The amps meter on most welders is a voltmeter, it takes the current and drops it across a resistor bank to produce a voltage proportional to the amperage, and displays a number for the amperage.You could buy the required equipment, I just use a local calibration shop, they come in once a year and validate the calibration. And they check it across the entire range of operation and give me actual readings vs. input reading across the whole scale, so that I'll know if there has to be a correction factor at one end of the scale or the other. Takes a few minutes a machine, and I'm not out the several thousand dollars for the NIST calibrated source (which you have to send out and have calibrated every 6 months)Hope that helps,KBI r 2 a perfessional
Reply:Several companies also sell load banks which will show both voltage and amperage output. We used a Miller in the shop with no issues. I'm not sure just how precise you need to be in your measurements, as I believe the load banks are calibrated to +/- 3% on average.
Reply:You can use a clamp on amp meter and have one person hold an arc while you read the amp meter on the ground cable (or the electrode lead, does not mater). This is what I have done. -Dan
Reply:Standard amp clamp is designed for typical electrical installations for ac in the 60 hz area, won't give proper readings with DC or HF AC.Just in case that is what you are trying to measure.
Reply:I would contact the power supply manufacturer to see if they have a published calibration procedure. One of our suppliers actually sells a load resistor that is used for calibration. It is as simple as measuring the voltage drop across the resistor with a fluke digital volt meter. We just give the published procedure to our calibration/maintenance dept and they do it based upon when the calibration stickers expire.
Reply:Simple - Just use a clamp on inductive DC meter.I have done it.just clamp the meter on the wire between the welder and the box when you are welding.It will show how much current is being drawn,Last edited by Donald Branscom; 07-21-2008 at 03:25 PM.AWS certified welding inspectorAWS certified welder
Reply:These are all great suggestions, just remember, if you are going through a customer audit, or an ISO audit, or, God forbid, a Nadcap audit, the calibration of the machines must be to a known, calibrated standard traceable to NIST. No traceability, immediate audit failure, even if you are following the manufacturer's published technique.You know how it goesQ. Who calibrated the welder?A. Our maintenance department?Q. Using what instrument?A. This chingus right here!Q. (Wait for it......) Who calibrated the chingus?If you're just going for you own information, then, yeah, any of these other methods will work.I r 2 a perfessional
Reply:NADCAP ?NIST ?What do those stand for?What industry or trade?Thanks.AWS certified welding inspectorAWS certified welder
Reply:I use a hall effect inductive clamp on amp meter. It tells me which welders are right and which ones are wrong. So far only one is wrong ant that is an older Lincoln V250-S.David Real world weldin. When I grow up I want to be a tig weldor.
Reply:Don,NIST - The National Institute for Standards and Technology. They own the standards for just about anything that can be measured. Want to know if your voltmeter is really reading 24.47 volts? They own the standard to which all calibrated sources must eventually be measured. If you buy a voltmeter with a calibration certificate, the manufacturer measured it against their in-house standard. Twice a year, they check their in-house standard against the NIST standard to make sure it is correct.Nadcap, Used to be the National Aerospace and Defence Contractors Accreditation Program, now it's just Nadcap. It's an organization sponsored by the defense and aerospace primes (Boeing, Honeywell, Raytheon, ) to validate that companies providing special processes (welding, heat treating, chemical processing, non-destructive testing), meet the minimum requirements of all the aerospace primes, so that, with one accreditation, you could do work for any of them. Typical audit lasts 3-5 days of them crawling in your socks and out your ears. But if you can pass it, you represent world class.I r 2 a perfessional
Reply:ISO does not require calibration of equipment. You may have it written into your procedures, and therefore ISO will require it... but if you leave it out of your procedures and manual, or state that it is not considered necessary, you shouldn't have problems with an ISO audit.
Reply:Engloid,I respectfully beg to differ. Once upon a time, ISO's rules were so loose that, if you proceduralized it, you could verify a .001 micrometer with a yardstick. It was all about "say what you do, and do what you say". I know, I got away with it in 1993. Not so anymore. Check the sections of ISO regarding "Continual Improvement" (read that to say, "You're gonna keep paying every 6 months for the recert") and you'll find that ISO now requires realistic improvement of measurement standards. ISO found all the holes we were slipping through, and they don't let them anymore. Remember, an ISO finding is a "judgement" on the behalf of the auditor.I r 2 a perfessional
Reply:Sorry Benny. Never used the displays. Just turn the knob to set max and foot pedal away.
Reply:Originally Posted by GSteveSorry Benny. Never used the displays. Just turn the knob to set max and foot pedal away.
Reply:I would not use a clamp on meter to calibrate in the 10 amp range. We have a few weld procedures near 10 amps, and a few tenths of an amp will make or break our procedures. I don't even think a clamp on would have the scale to read fractions of an amp. As for volt meters and load resistors, we use NIST calibrated volt meters when using the manufactures published procedures. I think that is how they do it at the factory. Our new orbital weld systems come in with a signed certified calibration sheet with a log of measurements across the whole range of the power settings.
Reply:Keep in mind that clamp on ammeters can be made more accurate for low currents, by winding the cable through them.Just one loop, with two passes through the clamp, will double the reading.
Reply:The answer to your question is yes there is equipment to check out your machine.But I get to use Martha, Maggie, Betty Sue, Barbra Ann(my favorite), Sue Ann, and Dorthy named affectionately not. None of these machines are calibrated. I stick with them all. Some have meters and some don't. Now you tell me how I know what setting to use. And no I can't see the meters with my hood down Tigging on fuel tanks to truck frames. If I ever ran into an iso I reckon I would test weld a bit to check out the amps. But If you must hold me to a certain number of amps I hope you realize poor fitters are my worst nightmare. Or just get yourself another robot.
Reply:Why use the whole thing when a tip toe is what you need? Ok so how many passes does it take to weld 3/4 in steel together, just generally speaking?Last edited by GSteve; 07-29-2008 at 12:50 AM.
Reply:3 said the wise old owl.Miller Thunderbolt 225Millermatic 130 XPLincoln HD 100 Forney C-5bt Arc welderPlasma Cutter Gianteach Cut40ACent Machinery Bandsaw Cent Machinery 16Speed Drill PressChicago Electric 130amp tig/90 ArcHobart 190 Mig spoolgun ready
Reply:It only takes two licks to to get to the center of a tootsie roll pop. Good thing steel is not like tootsie roll pop. |
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发表于 2021-8-31 23:56:58