Wrapping my head around duty cycles?

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Ok, so first, im new here. creating an account with a forum is usually a pretty good sign that ill be doing something for a LONG time, as im only registered on 2, with this being the second. now to the question..Im buying the newish Lincoln Electric Power Mig 210. ive already paid my money, but its on back order with lincoln so im waiting 4-6 weeks for the store to get it, then they ship it to me. so in the wait time, im constantly stalking it, reading downloadable manuals, watching reviews, etc. and in the process of this, the duty cycle has been mentioned a few times, but i cant find an answer to my question.Lincoln lists the duty cycle as follows:using the 120v cord, it is 100A/19.0V/40%using the 230V cord, it is 200A/24.0V/25%this, i understand. i run it at said amps/volts, and i can run it at that percentage of every 10 minutes, but heres where it gets shifty.. i want to be able to run it at closer to 80%. im in college for welding and my teacher told us that as we back off that amperage, the percentage goes up.what amperage would i need to drop it to in order to accomplish 80 or even 100%? i fully intend on only using the 230V power cord, and im only running it on scrap and coupons to prepare for the job world. i cant get enough. ill run the machines at school(miller and lincoln 350s) constantly for 8 hours and be sad when i have to leave and go home. but this is a smaller welder, and furthermore its paid for out of my personal pocket so i dont wanna destroy it. i just never want to have to stop other than to eat and sleep. so how low do i have to go? the most amps ive ever used at school is maybe 160 running 7018s so i dont think ill have to use that much at home. i currently make my harbor freight 70A work its *** off, but it can only handle 1/8" thick steel at most. im anticipating running 1/4-1/2" thick steel once this arrives, and again, i dont want to have to stop, or only stop as little as possible.i think that covers all the variables, so to summarize and save reading time,i want to get 80-100% duty cyclerunning on 1/4-1/2" thick mild steelusing the 230v power cordso the useable amperage/voltage would be approximately?Thanks for any/all input in advance. itll help this eager college student tremendously
Reply:it is what it is, you can't change it so why bother?when you get it you can test it out and report backmy wild *** guess is 90ampscall lincoln up they can probably tell you over the phone but even then it's just a guestimate, ambient temperature, downtime between welds, etc are all unpredictable.
Reply:Based on info in the owners manual, off a 230V input, it looks like the 100% duty cycle rating is going to be around 100amps for all three processes.ESAB Migmaster 250 Hobart Ironman 230Multimatic 215TWECO Fabricator 181i & 211iHH125EZ - nice little fluxcore only unitMaxstar 150 STH - very nice
Reply:Right from the manual:Basically a 3/32" 7018 would be 100% duty cycle.1/8" 7018 approx 40-80% duty cycle depending on amps, temp in your shop, etc.Last edited by MinnesotaDave; 03-01-2015 at 10:53 PM.Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:Try having someone run a stopwatch on your actual time from start of arc to stop. You'll be surprised at how little actual welding your doing. Duty cycle is calculated on actual time arc is running.                                MikeOl' Stonebreaker  "Experience is the name everyone gives to their mistakes"Hobart G-213 portableMiller 175 migMiller thunderbolt ac/dc stick Victor O/A setupMakita chop saw
Reply:The way our instructor explained it when we asked question about getting a machine, for example 40% duty cycle, are you going to weld more than a 4 minutes straight without a break in a period of 10 minutes. When using stick or flux you always have to take breaks to remove flux and with stick put another rod after you burnt one and also some positions like doing vertical it's better to take breaks between passes so your plate doesn't get too hot. Do you plan to use your 210 for hobby or out in the field?
Reply:What will you be building out of 1/2" steel plate?Hobart Beta-Mig 2511972 Miller AEAD-200LEMiller 250 TwinNorthern Ind. Hybrid 200Longevity Stick 140Longevity Migweld 200SThermal Arc Pak 3XR
Reply:Most major manufacturers duty cycle calculations are based off various tests done at or around 104°F too, so depending on the average temperatures you work and play in things might be slightly better."The things that will destroy America are prosperity at any price, peace at any price, safety first instead of duty first, the love of soft living and the get rich quick theory of life." -Theodore Roosevelt
Reply:With stick welding, about the highest you can ever go is about 70% but that means not chipping any slag and having another rod in your hand ready to go the second you finish the existing rod. I think you're really over thinking duty cycle. A 6" weld with a 1/8" rod takes about a minute. Then you stop, chip your slag and then put another rod in. This all lets the machine cool off for 15 seconds or so which adds to your welding time without exceeding the duty cycle.
Reply:I believe he's looking at a mig welder.  It's easier to approach the duty cycle with wire feed.  Still the temperature of what you are welding will require you to take a break every now and then.
Reply:The 210 is a stick, tig and mig machine
Reply:I don't think I have ever had a welder shut down because of duty cycle? It's usually that I have to stop for some reason or another because of repositioning, etc. Based on what you are wanting to do maybe you should think about upgrading now and see if they will give you credit on the 210 since you have not received it. This way you can weld without any worries, I have never heard of anyone complaining their welder has too much power, it's usually the other way around and if you get into welding 1/2 steel all day then you will wish you had a 250 machine.ESAB Rebels 215 and 235, ESAB HELIARC 281i, ESAB ET 301i, Hypertherm 85 and 45XP, Thermal Arc 185, TD 60i, HTP PRO PULSE 300
Reply:Originally Posted by Ti TruckerThe 210 is a stick, tig and mig machine
Reply:Originally Posted by JawslandsharkI don't think I have ever had a welder shut down because of duty cycle?
Reply:Originally Posted by kotdadabong...i want to be able to run it at closer to 80% [duty cycle].
Reply:To sum up the welder you bought aint big enough.As for welding non stop,you cant do it.You have high hopes but your plan wont fly.She can look up longer than you can look down.
Reply:wow thanks guys for all the help. and to MinnesotaDave, im going to have to re-search the manual for it to find that chart, so i can print that out in case they dont already have it under the flap. but a huge thanks to all of you. i never really thought about the time for chipping and brushing on stick and flux, or rather i guess i never thought it took that much time out of my 10 minutes. this is awesome news. also im not really building anything, im just running beads on scrap i get to take home from school to get more practice. to get a job at my girlfriends dad's company i have to pass 3g tests in mig, flux, and stick and theyre pretty harsh on grading those tests so i need to get perfect. nothing can me there except hood time so im prepared to spend alot of that. and from what the majority of you guys said, ill be able to get plenty of that with this one.also another big thanks to MikeGyver, that formula will surely come in real handy in the future
Reply:Originally Posted by farmer37To sum up the welder you bought aint big enough.As for welding non stop,you cant do it.You have high hopes but your plan wont fly.She can look up longer than you can look down.
Reply:Being in school and learning, you shluldn't come close to the duty cycle. You will and should spend more time cleaning and prepping. Duty cycle isn't an issue unless you are hitting the thermo switch. Even before then machines start to act silly.So try it out and I unless it shuts down I wouldn't worry. Also as said all these tests are done at 104* so if the temp in your room is 70* expect a higher duty cycle than what's stated. I took that small little 130en Clarke and welded wide I open back and forth. It took 11 straight minutes of trigger time to hit the limit on that small guy. 11 straight minutes is a LOT of on time. So I wouldn't worry.Torchmate 2x2 CNC with Flashcut CNC controlsHypertherm Powermax45 Esab ET220i Razorweld 195 MigRazorweld 200ac/dc TigTormach 770, Tormach xstechRazorweld, Vipercut/Vipermig, SSC Foot Pedal Dealer
Reply:Originally Posted by MikeGyverFormula for estimating output at a given duty cycle:Ia=I*((T/Ta)^(1/2))Ia= amps at required duty cycle (solve for this)I= known rating ampsT= known rating duty cycleTa= required duty cycleYour 100% duty cycle rated output is 110 amps so....Ia=110*((100/80)^(1/2))so you're about120amps @ 80% dutyIf you want to estimate amperage at a lower duty cycle use the other known rating for more accurate results (200amps @ 25% duty)Ia=200*((25/40)^(1/2))so around 148amps @ 40%formula source: AWS Welding Handbook 9th Edition – Welding Processes Part 1 Volume 2
Reply:ya typo, good catch.Welding/Fab Pics: www.UtahWeld.com
Reply:Just for S&G's, and because I'm snowed in today.............To understand the ramifications of duty cycle, just run a rod.  It puts out more heat in the first half of the weld, and starts to put out less heat at the end of the weld.  As the electrode heats up while welding, it has more resistance, and carries less current.  The same occurs inside the machine, inside the cables, clamps, etc.  This is duty cycle.Duty cycle is related to useable welding power, not machine shutdown.  Hardly anybody ever gets this right."Any day above ground is a good day"http://www.farmersamm.com/
Reply:Running beads on scrap isn't all there is to preparing for 3G tests. Once you get the basic beads down, you need to concentrate on making sound welds by having all the variables down. If you are practicing all these fundamentals to the 3G process you will never hit duty cycle!
Reply:Originally Posted by farmersammDuty cycle is related to useable welding power, not machine shutdown.  Hardly anybody ever gets this right.
Reply:Originally Posted by farmersammJust for S&G's, and because I'm snowed in today.............To understand the ramifications of duty cycle, just run a rod.  It puts out more heat in the first half of the weld, and starts to put out less heat at the end of the weld.  As the electrode heats up while welding, it has more resistance, and carries less current.  The same occurs inside the machine, inside the cables, clamps, etc.  This is duty cycle.Duty cycle is related to usable welding power, not machine shutdown.  Hardly anybody ever gets this right.Duty cycle is just the amount of time you can weld before the machine is damaged from overheating. Can it be exceeded, yes for short periods on most machines. Not all machines have thermal cut outs. I was walking by a Lincoln DC600 running sub-arc to go to the rod oven when I saw sparks coming out of the machine. I was going to go over and shut it off when all of sudden it sounded like a stick of dynamite went off and it was pitch black! Blew the main circuit breaker for the whole shop and this was a big vessel shop. It was at 11pm and we got about an hour and half break while they called the maintenance guy in to find the problem.
Reply:Welding/Fab Pics: www.UtahWeld.com
Reply:There have been good explanations of what the duty cycle is.Thermal cut-offs are not the same as duty cycle, but are built into machines to protect the machine from over zealous weldors, who would continually operate the machine past the recommended limit.I had a smaller 220 Lincoln MIG machine which, when I first got it, had lacquer on the windings that was a beautiful honey color. After violating the duty cycle a few times, the lacquer looked more like a rich Mocha-CaramelIt still ran fine, but after I discovered that, I started paying closer attention to how I was using it. If you pay attention, you can tell when the arc starts degrading.I can't imagine it being an issue with the machine the OP will be using, for the purpose he intends to use it.Last edited by geezerbill; 03-03-2015 at 09:27 AM.Hobart Beta-Mig 2511972 Miller AEAD-200LEMiller 250 TwinNorthern Ind. Hybrid 200Longevity Stick 140Longevity Migweld 200SThermal Arc Pak 3XR
Reply:It would be great if these machines came with an internal temp gauge - so us newbies could back off before any damage occurs.  Maybe this has been covered - but is the duty cycle truly based on a 10 minute cycle?   Or is that what everyone uses as an example for simplicity?Hobart 210 MVP
Reply:Originally Posted by sea bassIt would be great if these machines came with an internal temp gauge - so us newbies could back off before any damage occurs.  Maybe this has been covered - but is the duty cycle truly based on a 10 minute cycle?   Or is that what everyone uses as an example for simplicity?
Reply:Weld a ticket.  While letting it cool, set up the next ticket.  Then go back and chip/brush the first ticket. Examine your first ticket and see if you can do better on the next one.  Should give you plenty of cooling time unless you are running full out on long beads.Sold a very clean Clarke 130EN to a newbie.  A couple days later he called and it wasn't working right.  Turns out he set it up and proceeded to weld like nobody's business.  Welded continuously for a looong time, then just shut off the machine.  Burned up the diodes.Last edited by Oldendum; 03-03-2015 at 11:27 AM."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:Whenever I do some what I consider heavy welding w/ my 175 for an extended period when finished I let it run for 5 or so minutes to let things cool down before shutting it off.                                         MikeOl' Stonebreaker  "Experience is the name everyone gives to their mistakes"Hobart G-213 portableMiller 175 migMiller thunderbolt ac/dc stick Victor O/A setupMakita chop saw
Reply:Originally Posted by sea bassIt would be great if these machines came with an internal temp gauge - so us newbies could back off before any damage occurs.
Reply:Just weld with it!  If you start tripping the overtemp, then back off a little.  Hitting the overtemp once or twice isn't going to hurt the longevity of the machine.  If you're hitting it a dozen times a day, then you're pushing the machine too hard and you need something bigger.100amps at 100%.  My dynasty 200 has the same rating.  I've run 1/8" 7018 all I wanted and never hit the overtemp.  Doing normal work, you typically won't get the duty cycle that high.Dynasty200DX w/coolmate1MM210MM VintageESAB miniarc161ltsLincoln AC225Victor O/A, Smith AW1ACutmaster 81IR 2475N7.5FPRage3Jancy USA1019" SBAEAD-200LE
Reply:Originally Posted by geezerbillThere have been good explanations of what the duty cycle is.Thermal cut-offs are not the same as duty cycle, but are built into machines to protect the machine from over zealous weldors, who would continually operate the machine past the recommended limit.
Reply:Don't trust your machine to a thermal cut off. Not all machines have it. I could strongly smell a Dialarc 250 burning up when a guy was burning 1/4" Jet rod welding shells of a large tank together. We told him and his response was he was almost done. I think the machine was done quite a bit before that. Generators don't have thermal cut off. Gouging has been known to burn up machines and/or make them weld differently. I think a lot times people think they are a lot faster than they actually are. If you could run 50% duty cycle in a production shop, you'd be doing good.
Reply:Weld away dont worry about it we run 900 amps on a Lincoln DC 1000 all day long burn 250 lbs wire 4 spools.
Reply:yea i learned that part too out of personal experience. it was freezing outside, so in my "shop"(outside storage closet) it was pretty close to freezing if not at that temperature too and i could run my little harbor freight for longer than i could physically take the cold, including the heat i was receiving from the act of welding and hovering over hot metal which was about 4 hours. once you take the slag removal into consideration and the amount of rods i burned, id say i ran my 20% machine at more like 60-70%. ambient temperature definitely plays a big role in that. i wasnt aware you could add heat sinks to it though, perhaps that could be my next project once i get my 210 in, make a heat sink to increase the capabilities of my harbor freightFrom hundreds of hours under the hood, I will push for thousands. I will push until I achieve the greatness i seek. Shoot for the moon and at least land amongst the stars.
Reply:There's no way you were at 60-70% duty cycle. Sorry, but that's wishful thinking.
Reply:Originally Posted by sea bassIt would be great if these machines came with an internal temp gauge - so us newbies could back off before any damage occurs.  Maybe this has been covered - but is the duty cycle truly based on a 10 minute cycle?   Or is that what everyone uses as an example for simplicity?
Reply:The big iron core once its hot takes a long time to cool down! This is were the 10 minute Duty Cycle probably originated, to keep the wire from over heating you need to keep the core temperature down to a reasonable level.
Reply:Originally Posted by Welder DaveThere's no way you were at 60-70% duty cycle. Sorry, but that's wishful thinking.
Reply:I understand better than you do. Your own words confirm it."you really underestimate the amount of rods i can burn once i get started. i dont walk down the street to get a new one each time i burn a rod. i keep a full 5lb box with me on the table and light up, weld, end, drop the stub, chip, brush, reload, and go again"What the heck man, you're going to get everybody fired! In order to be respected in this industry you have to realize that you need that walk down the street after every rod. Didn't want to spill the beans but someone had to. Duty cycle has nothing to do with the machine. When they talk about welder duty cycle, they aren't talking about the machine, they're talking about the person doing the welding. You spend more than 2 minutes crouched over welding, you get all cramped up and need to walk it off for the next rod. Squeeze every last bead in? Are you welding or applying silicone. Every time you  "end, drop the stub, chip, brush, reload", what do you think the machine is doing?  It certainly isn't welding, it's cooling off for 10 seconds or so while you're doing all this stuff after you finished the previous rod. As I said before, about the highest duty cycle a person could achieve with stick welding is 70%. That would be running bigger rods that take longer to burn and not chipping any slag, just one after the other. I doubt you're even at 40%.
Reply:You could weld basically non stop, it only takes 5 seconds to clip a new rod and continue welding. No chipping between rods or anything if you're not stacking welds.Nobody does this in the real world 8hrs a day though obviously.Welding/Fab Pics: www.UtahWeld.com
Reply:Experts on the subject say it's extremely hard to go over 70% when stick welding.
Reply:Girlfriend or Teacher stops him?I'm thinking as far as this thread has gone, he is a punk azz kid who thinks he is a hot shot pipeliner BUT will probably burn out in a year!
Reply:yea it has gone too far. i asked my question, and it was answered when whoever it was posted the graph that i missed in the manual. i appreciate the help, lets not get to bashing. as for squeezing in every last bead, i was referring to the time i have to do it, not literally squeezing anything.. as for you drujinin, i dont think im a hot shot. i just have the determination to put in the work it takes to become one. but anyways, ill be sure to message you next year just to watch you eat your words. thatll be well worth it(the thought to remember you said that). again super thanks to those who actually answered the question instead of trying to start **** on the internet. i know its hard for some old people to not start or get that involved in arguments on the net, but for those who didnt, thanks.From hundreds of hours under the hood, I will push for thousands. I will push until I achieve the greatness i seek. Shoot for the moon and at least land amongst the stars.