Welding Machine Polarity Check Without Trial and Error

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Just throwing this question out for opinions:Say you're up in the pipe rack a long ways from your machine and all you have is 2 lead ends with no way of knowing which is which without doing a trace back or trying them out and 50/50 chance of screwing up your tungsten point.Is there some device like a multimeter or such that would tell you which is pos and which is neg?
Reply:Interesting question. I know one guy who solved this issue by making each lead different. The "hot" side was always female on the machine side, and male on the stinger side. The "ground" was always male on the machine side, female on the work side. The only change he had to make was to change out the QD's on the machine and ground clamp. His machine allowed him to change the polarity at the machine.I guess if you were constantly swapping between tig and stick it might be an issue, but I'm betting if you set the stinger up one way and the tig torch the other and worked an adapter out for the ground you could make this work..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Sure, any  common DC  voltmeter will indicate polarity.When the meter's +/- leads are connected with correct polarity the meter will indicate power source voltage. With  leads reversed  the meter would indicate an error, or negative voltage. Although it wouldn't be a good idea to subject most meters to high frequency - not that it's an issue here.Good LuckLast edited by denrep; 01-29-2013 at 07:32 AM.
Reply:Originally Posted by denrepSure, any  common DC  voltmeter will indicate polarity.When the meter's +/- leads are connected with correct polarity the meter will indicate power source voltage. With  leads reversed  the meter would indicate an error, or negative voltage. Although it wouldn't be a good idea to subject most meters to high frequency - not that it's an issue here.Good Luck
Reply:Touch the leads to your tongue? The one that you feel should be the hot one.
Reply:if you have a 24v light bulb it should burn when conected to something grounded (scafolding ,pipes, structure) and the + lead ...don't shoot if I'm wrong --------------------------------------------------------------www.becmotors.nlyup, I quit welding.. joined welder anonymous
Reply:Just color code your leads with tape and you won't need to guess
Reply:delete
Reply:Originally Posted by welds4dJust color code your leads with tape and you won't need to guess
Reply:Originally Posted by Donoharmif you have a 24v light bulb it should burn when conected to something grounded (scafolding ,pipes, structure) and the + lead ...don't shoot if I'm wrong
Reply:http://www.homedepot.com/p/t/2034891...specificationsOr just a small multimeter?NickESAB CaddyTig 2200iPowermax 45MM140 (Sold)
Reply:Originally Posted by Snuffyhttp://www.homedepot.com/p/t/2034891...specificationsOr just a small multimeter?
Reply:TimyTig, I think you can make a simple polarity checker with a ball point pen, resistor and LED plus 6 " of wire. The LED will only work in REVERSE POLARITY as it is a diode. Im thinking of using a 1K OHM resistor. Mybee less. Stay tuned as you and DENREP gave me the idea. I can make one up in about 15 minutes when I get motivated enuf.
Reply:you know, I started this thread after work and I already had more than a few beers in me...it's a nice idea, but wouldn't you  have to have a pretty big resistor to go between pos and neg and not burn up with 75 amps or so on it?I asked the electrician foreman about it, and he claims a meter would work, but I haven't got around to trying it yet.
Reply:Originally Posted by TimmyTIGwouldn't you  have to have a pretty big resistor to go between pos and neg and not burn up with 75 amps or so on it?
Reply:OK, papaharley,  I believe those Miller 8 banks at work are 30 volts max, so that shouldn't be a problem.
Reply:Originally Posted by TimmyTIGOK, papaharley,  I believe those Miller 8 banks at work are 30 volts max, so that shouldn't be a problem.
Reply:And to follow that up, power is P=I*V, so once you know the voltage and LED current, this will give you the wattage.- Tim
Reply:Made this up this afternoon.15 min thinking, 15 min doing  and burning up the trial, and 15 min making the proto plus 15 min doing it over.  1 hour total and material that is at least 30 years old xcept the rub a dub holder part (only 5 years).  They could probably make it in Chinna for 2 cents.The LED only works in REVERSE POLARITY unless your leads are backwardsRED goes  to stinger then touch the YELLOW to work. If it lights, its DCEP. If it dont light, then try the reverse and if it lights then;  its STRAIGHT POLARITY.The bottom right in the last two pics shows on/off  at about 10 amps on the welder (Invertec 250S).  I havnt tried at 150 amps yet but?Its hard to tell in the pics but:In the third pic; YELLOW isnt touching work.In the fourth pic; YELLOW is touching work.I used two matching resistors in parralel (1 watter's I think) under the shrink tubing in first pic. Attached ImagesLast edited by Insaneride; 01-31-2013 at 09:26 PM.Reason: polarity checker
Reply:i usually run the leads separate and can remember. but i put a peice of duct tape on the ground side always to remember.Miller ab/p 330Hobart champ 16Miller 140Lincoln Power Mig 255Lincoln SA-250
Reply:HOT DAMN!!!!! I gotta make me one of those, I coulda used it last night.Crank the heat up to about 100 and see what happens, Mr. Insaneride.you need to patent that and start selling them!what happens if you plug it in backwards, it just doesn't light up?Last edited by TimmyTIG; 02-01-2013 at 05:44 AM.
Reply:If you plug it in backwards STRAIGHT POLARITY it wont turn on. The LED is a diode and only works one way.  As far as cranking up to 100 amps, stay tunedI didnt have a pen cap for it but with a cap and a hole drilled in the top, it would be much easier to see in daylight and easy to carry in your shirt pocket.  I will dig up a cap and show what I mean when I find an xpendable cap.If it doesnt blow at 100 amps, I can give it to you.   Ive made these before to drain capacitors that were charged to about 280 VDC.
Reply:Originally Posted by TimmyTIGCrank the heat up to about 100 and see what happens, Mr. Insaneride.
Reply:The Amps setting shouldn't make much difference.  It's more the open circuit or working voltage."USMCPOP" First-born son: KIA  Iraq 1/26/05Syncrowave 250 w/ Coolmate 3Dialarc 250, Idealarc 250SP-175 +Firepower TIG 160S (gave the TA 161 STL to the son)Lincwelder AC180C (1952)Victor & Smith O/A torchesMiller spot welder
Reply:Why not keep a spare tungsten that needs to be re ground anyway and arc it to something on or near the work that won't matter?Edit: I know you said without trial and error, but it wouldn't ruin a ready tungsten.Lincoln AC/DC 225/125 and WP17. 75A AC is for pipe thawing!HH 140 - new addtion 9/2012.I didn't agree, but hoped for Hope and Change.I got change for myself and my family: for the worse.This is the reality of: Barackalypse Now. Again.I tried 100 amps and it works the same as 15amps.I thought the SOFT START would make it blow since theres a  boost of electricity but no problem.TimmyTig, if you want it, PM me. If you want to make it yourself, I used two 10K ohm resistors in parallel. The LED drops 1.5 volts in forward bias. I like to put the resitors an the cathode side but it dosnt matter.
Reply:pm sent
Reply:pm sent again, that thing is great!
Reply:Where you might run into problems is with a high OCV welder.  You could scale the resistor for that but it might be very dim on lower OCV welders."USMCPOP" First-born son: KIA  Iraq 1/26/05Syncrowave 250 w/ Coolmate 3Dialarc 250, Idealarc 250SP-175 +Firepower TIG 160S (gave the TA 161 STL to the son)Lincwelder AC180C (1952)Victor & Smith O/A torchesMiller spot welder
Reply:Glad it works for you TimmyTig.Thanks 7A749, its really simple, now if I really wanted to impress you guys, I would have Tig,d the Led and resistors together instead of solderIve made these for discharging capacitors that were charged to about 280 Volts. As Oldendum said, the resistors could be scaled for a higher voltage.I started with a 10K pot/LED connected in DCEP and decreased until I heard a sizzle then stopped and measured the pot. So it seems 5K ohms(two 10k in parallel)is about what you need for 28V DC welder. I beleive I have a CV welder. Lincoln Invertec. I wonder what would happen with a CC welder?
Reply:Originally Posted by Insaneride... I wonder what would happen with a CC welder?
Reply:Originally Posted by OldendumWell, you do list your location as Sparks, NV.  If you scale your resistor so that you don't exceed the maximum LED current at about 90 volts, you should be OK.  It may not be very bright at 50 volts.
Reply:That's not necessary, you keep that money, I can use it like this, it's fine.
Reply:Pick 1 lead and put a turn or 2 on each end of white electrical tape. I mark positive usually.Miller thunderbolt 250Decastar 135ERecovering tool-o-holic ESAB OAI have been interested or involved in Electrical, Fire Alarm, Auto, Marine, Welding, Electronics ETC to name a just a few. So YES you can own too many tools.
Reply:Originally Posted by dumb as a stumpPick 1 lead and put a turn or 2 on each end of white electrical tape. I mark positive usually.