DCEN vs DCEP

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An interesting question got asked in a thread yesterday, but it got shut down before it was really answered.Basically the question was, why is DCEN used with the non-consumable electrode processes like TIG or PAW, and DCEP is used with consumable electrode processes like Stick, MIG, and gas shielded Flux core?With DCEN and TIG, the electrons flow from the tungsten electrode to the base metal.  It is the impact of the electrons with the base metal, and transfer of kinetic energy, that is primarily responsible for heating and melting the base metal.Energy from the arc is also transfered to the work by conduction from the hot plasma gas, and this is why helium increases the heat to the work for all gas shielded processes, because its thermal conductivity is many times that of argon.With DCEN and TIG, it takes energy to force the electrons to leave the tungsten electrode, called work function, and the absorption of this energy by the electrons from the tungsten actually acts to cool the tungsten electrode.If the polarity of TIG is reversed to DCEP, the electrode is bombarded with the electron flow, it receives the primary heating, and as a result can only sustain a very low current before melting, as compared to DCEN.With DCEP and a consumable electrode process like Stick or MIG, the electron flow to the electrode puts the majority of heating into melting the stick or wire, this energy is then very efficiently transfered to melting the base metal as the molten droplets are propelled by electro-magnetic pinch effect to the impact the base metal.At this point I have not researched why self shielded flux cored wire is designed to run DCEN.  It must have something to do with the gas production from the cored wire, but why this is different from Stick, I don't know yet.
Reply:I haven't found anything answering that about the fcaw-s. I do know that from observation that unless you reverse it you really get a nasty mess with lots of splatter. On the correct polarity it appears to me to have considerable more dig than gmaw. Don't know why and haven't found very much info on it. So far all I have found is that the fluxes used affect how the arc acts. Most of the time too busy to do that type research and only here right now due to a small storm.The difference between art and craft is the quality of the workmanship. I am an artist.
Reply:Interesting.  And there there are some stick electrodes that are made to run negative rather than positive, while most can be run in either positive or negative, and some only in positive.  It doesn't make much sense.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:Plasma cutter uses DCEN.  I ASSume for the same reasons as TIG.DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:Here's another something to think about.   Most stick welding machines are constant-current, yet I have a constant-voltage machine (PowCon 300SM) that stick welds very smooth compared to my constant-current Thermal Arc 185 tig welder.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:I may be retarded here... but I thought the powcon machines were multiprocess  CC/CV?I like to party!
Reply:I left my GX271 on cv and fired up a stick and didn't like the result at all. I didn't mess with it as I had a time crunch and it is a new machine that I haven't really had time to get to know well. It does open roots with 6010 in pipe mode like nothing I have ever used. When I do get time I am going to play around just to see what it does or doesn't do. If I remember correctly my EX300's (same as XMT 304) operators manual says not to run sticks in cv mode.The difference between art and craft is the quality of the workmanship. I am an artist.
Reply:My PowCon has 3 settings: SMAW, GMAW-short arc, and GMAW-spray arc.   I'm not sure what the output is in each mode, but I set voltage in all modes and amperage comes as a result of the voltage I set and how I weld or what wire speed I use, as is normal for most MIG machines.  I assume that to be constant-voltage output, but I could be wrong.What is a GX271?MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:DECP can be used for GTAW aluminum with straight helium.  but that all i have to say haha
Reply:The GX271 is a Reddarc engine drive built for them by Lincoln. It's rated 275 amps at 100% duty cycle, but the Reddarc techs told me it is just a Ranger 305G in a stainless Ranger 10,000 case minus the volt and amp readouts. Has Smaw/Gtaw mode which is cc, pipe mode which is cc and blows a stringer in like nothing I have ever used, and a wire feed mode which is cv. It's just loafing running 5/32 7018. I would imagine your powcon switches to cc when you put it in smaw and cv in the wire modes. My EX300 (Reddarc for Miller XMT304) has more modes than I know what to do with. I don't really like single process machines and needed a power supply for a wire feeder, but I really like being able to move it around by myself and it sure doesn't take up much room for what it puts out. It switches from cc to cv depending on the mode selected. From everything I have read the powcon is supposed to be the Cadillac of inverters so I am sure it switches from cc to cv according to the mode selected.The difference between art and craft is the quality of the workmanship. I am an artist.
Reply:Jolly Roger, thanks for the explanation on the Reddarc machines.  Sounds like a good machine. Next time I have occasion to talk to the people down at Arc Products, I'll ask them if the PowCon goes to constant-current in stick mode.  It would make sense that it would.   Anyhow, it does make a very smooth arc in all modes.  I like welding with it.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:Originally Posted by DesertRider33Here's another something to think about.   Most stick welding machines are constant-current, yet I have a constant-voltage machine (PowCon 300SM) that stick welds very smooth compared to my constant-current Thermal Arc 185 tig welder.
Reply:Originally Posted by CaptainWillyI may be retarded here... but I thought the powcon machines were multiprocess  CC/CV?
Reply:Smithboy, I'll take from you that the PowCon 300SM is CV in mig mode and CC in stick mode, you seem to have more experience with them than I do.  I've only owned this one and only welded with one other that was the same model as mine and only used that one for mig spray.I haven't tried stick in the mig mode with it.   My PowCon has been having a problem in the mig mode for awhile now, it appears to be switching the contactor off and on by itself at a frequency, and that frequency increases as I set the voltage higher and decreases as I set it lower.  That is when I started using it for stick welding instead of mig and found out it works great as a stick welder.  It used to be a very smooth mig machine before the contactor problem arose.   I intend to get it fixed, some day, but right now I have no money to dump into it.  I'm thinking whatever circuit board controls the contactor has some problem.   It doesn't do anything unusual in stick mode except make some ticking noises, which appear to be normal for this machine.  It's always made all sorts of interesting ticks, squeals and whirrs.Thanks for the info!MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:I cannot for the life of me recall the name, but there is a company that rebuilds the boards for welding machines and I believe they sell direct. Cost runs at about half that of a new one. I looked at the powcon machines before I got the ex300, but 230 volt versions are hard to find used and very expensive. I couldn't even find a new one.The difference between art and craft is the quality of the workmanship. I am an artist.
Reply:The company you're thinking of is probly Arc Products, here in San Diego.  www.arcproducts.com.   They are the authorized PowCon service center here in southern California and they do offer circuit boards for various other machines as well.   I have taken my PowCon and a Cobramatic to them for other repair work in the past.  They are not inexpensive, but they know PowCons and nobody else seems to know that brand.  I have been avoiding taking mine back down to them cause I'm not certain it's worth dumping alot more money into fixing the mig function.   The charge is $125 to inspect the machine and make an estimate for the repair.   Last time I was down there I spent ~ $500 on work done to the PowCon.My PowCon runs on both single and 3 phase, as well as voltages from ~ 200 to 500, by linking inside the machine.  Max output is cut by 1/3 when used with single phase, according to the Arc Products tech who set up my machine for single phase 240v operation.  Without checking the machine data plate, if I remember right, max output for the 300SM is 375 amps on 240v, 3-ph.You probly couldn't find a new one cause PowCons have not been made for a number of years.   I see used ones on eBay and sometimes on Craig's List.   The one I got came from the company I use to work for.  They had 2 or 3 of them, with the pulsing units, and sold them for a smokin' $50 each!  I should have bought two....MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:The co. that repairs boards is Innovat, 800-626-1887.   innovatcorp.com       JohnSMAW,GMAW,FCAW,GTAW,SAW,PAC/PAW/OFCand Shielding Gases.  There all here. :
Reply:Thanks John.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:Originally Posted by DesertRider33My PowCon runs on both single and 3 phase, as well as voltages from ~ 200 to 500, by linking inside the machine.  Max output is cut by 1/3 when used with single phase, according to the Arc Products tech who set up my machine for single phase 240v operation.  Without checking the machine data plate, if I remember right, max output for the 300SM is 375 amps on 240v, 3-ph.You probly couldn't find a new one cause PowCons have not been made for a number of years.   I see used ones on eBay and sometimes on Craig's List.   The one I got came from the company I use to work for.  They had 2 or 3 of them, with the pulsing units, and sold them for a smokin' $50 each!  I should have bought two....
Reply:That's interesting, first I have heard of PowerCon.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:I could have that name wrong as it has been several months. It is the same guy who started Powcon and I thought that was what they called them, but not positive. If I find it I will put it up.The difference between art and craft is the quality of the workmanship. I am an artist.