portable power for MM140

admin

I have a MM140 I've been using around my home shop with no complaints.  Runs well, welds easy, plugs in to any of my shop outlets.   Today I borrowed my dad's old Honda EM3000 generator to haul out to repair/install some pipe fence.  Low and behold it wouldn't even begin to weld with that generator.Are there any special considerations for this welder powered from a generator.  I would have thought it would run it fine but apparently not.  Any advise on what size/type generator it would take to run it.  Thanks
Reply:Make sure the generator doesn't have the no-load low idle switch turned on.Also, I assume this is a "3KW" unit from the model number. Make sure this isn't 3KW peak power. If the continuous power is lower, you'll have a problem.3KW is already very small and if it's peak power, it's definitely small.
Reply:It is simple math. The voltages are matched, I assume, both 110vac? If so, then match wattage output from the genset (continuos) and wattage drawn from the welder, if the first is equal to or greater than the second, you're good to go! If not, don't bother, you need more than the generator can deliver. You may also use amp supply/draw to determine compatability, it works the same way as wattage, if you know how much the generator can deliver and you know how much the welder will draw, do the math. If they are matched evenly, the generator will be under FULL load, but it should function. Overworking a generator will at the very least, not work. You'll blow breakers or the engine won't even run, or worst case, something might be damaged.City of L.A. Structural; Manual & Semi-Automatic;"Surely there is a mine for silver, and a place where gold is refined. Iron is taken from the earth, and copper is smelted from ore."Job 28:1,2Lincoln, Miller, Victor & ISV BibleDanny
Reply:Don't forget to factor in transformer saturation.  It may peak 2-3 times what it normally draws during certain weld conditions and startup. If the welder's input current is below the genset's continuous output, all SHOULD be well. You may just be at the limit during peaks. This is the same as what you get from stationary power when using an undersized extension cord.Also, are you using an extension cord?
Reply:I would think your extension cord was the problem.  Try plugging directly into the generator.  The generator is supposed to maintain 2700watts continuously.
Reply:One more thing to throw into the mix.  The smaller the generator, and the closer you are to its maximum output, the "dirtier" the power.The MM140 is a variable-voltage unit with far moreelectronics in it than a tapped machine.  It may be more sensitive to the quality of the AC sinewave.My ancient MM130 is tapped and I ran it from many a small generator.  I've run my electronic MM Passport from a large generator, and I recently heard someone else say they had problems with it from a small one.Something to think about.
Reply:Thanks for the replies.   FYI, it is plugged directly into the 25 amp plug on the generator.  No extension cords.  I did look on line for the specs on that old generator (probably 20 plus gears and lots of miles on it).  It is rated for 2600 continuous watts.  I reckon that's just not enough oomph.   And I definetly don't want to ruin my little welder running it on something not up to task.I ought to hook my amp meter up to it and see what the generator really puttin out with the big load.  See how many amps I draw when I'm running off shop power.    My dad has been considering upgrading to an electric start generator.  He can't pull start that old Honda anymore.   So I'll explore going in half with him on a generator with electric start for him and big enough to run the welder for me.   I see some 5000 watt continuous power 6200 watt peak that I can swing half on I think.Shouldn't that be big enough?Thanks for all the input.
Reply:Note that if the generator is a 220-240V AC generator, typically only HALF of the rated power is available on the 110-120V outlets.So if the generator is a 2600W rated machine and is a 220-240V generator, then each leg on the 110-120V outlets will max out at 1300W.  Which is about 10A of current, which is not enough juice to do much with a 110-120V MIG (or other) welder.OK, so I did a quick look for the EM3000 generator, and it looks like that machine is a 120V only machine.  So all the rated power is supposed to be available on the 120V outlet(s).  The generator might be producing 'dirty' power when loaded up and the electronics on the MM140 might not like that.By the way, what do you mean by "Low and behold it wouldn't even begin to weld with that generator."  The generator cut out, the generator outlet breaker tripped, the welder shut off, the welder didn't even turn on, the arc was lousy when you tried to weld, what?
Reply:EXCELLENT point, MoonRise.  I forgot about that.  My FIL had a 3000W Coleman Powermate and it was a really nice little unit.  He got it so that he could run the 2000W A/C on his small RV.When I finally figured out why it wouldn't, we discovered the two 120V receptacles were indeed from a split-phase 240V generator, and, get this, it didn't even have a 240V receptacle.
Reply:When I said it wouldn't work,  specifically it just wouldn't melt the metal.  Generator still ran, no circuit breakers popped or anything, wire just sparked, popped and left blobs on the steel.Today I took it back in the shop and hooked up my ammeter inline just to see what kind of amps it was drawing.  Had it on the same settings I was using to weld this 1/8 inch wall pipe.  It was welding it quite nicely on my shop power.  When I put the ammeter in, It drew up to 44 AMPS.   I was buy myself so didn't see the ammeter the whole time.  Just had it set to record the max amperage draw and that's what it was.  So in hindsight  DUH!   I need a much larger generator.  I'm looking at a Yamaha ef5200df.  I need electric start so my dad can use it (he can't handle a recoil start any longer).   Can't afford to just go buy a fancy unit.  The yamaha has 4500 continuous output and 5200 max.  That looks like it ought to cover my current requirement.   Good point on the only letting half of the output go to the 120V side if it is also running a 220V outlet.  I'll have to check into that.Thanks again for the insights
Reply:Well,  I'm finding more questions than answers looking for a generator.  The issue of how much power is available at a particular outlet is apparently a secret among many dealers and salesman.  I've found some high end that can send all the power to one outlet.  Others either can't do that, all power is split between all the outlets, or nobody seems to know.  I don't want to buy a big unit that is really a series of small output for each outlet!!
Reply:Your 44A current draw while welding was a current spike.  If it really was 44A, there is no way you could run that on a standard 15A 120V outlet, nor a 20A 120V outlet, nor even a schmancy 30A 120V outlet.The generator's current limit is a combination of the generator output -and- the circuit wiring from the generator part to the outlets.  The wiring limits include the wire itself, and the circuit breakers, and the outlets.Maybe the issue is a combination of power and how 'dirty' the power is.  For 'clean' power, check out some of the inverter generators.  Honda and Yamaha both make inverter generators.  Some benefits to the inverters are they are typically smaller, lighter, quieter, more fuel efficient, and produce clean to very clean power.  A drawback is that they are typically more expensive to buy, but once you add up some fuel costs they -could- be a better deal.Honda EU3000is might be able to run your welder.  Or you can get 2 EU3000is units and then get (or make) the special Honda "paralleling kit" which lets you rig two Honda EU Inverter generators together and double the power output.  The EU3000is looks like it is electric startYou can get 2 EU2000is units and the "paralleling kit" and get 4000w power output.  The EU2000i is recoil start only.Honda also makes an EU6500is.Or the Yamaha EF3000iSEB  might be worth a look, it has electric start and "boost" (uses power from the starting battery to give a 10 second boost to the power outputfrom 3000w to 3500w, enables the generator to have a little extra ooomph to start up the load).  The Yamahas include the 12V battery charging cables, Honda makes you buy them as an accessory.How about an electric-start, 526 lb (dry weight) twin cylinder diesel 6000W generator?    Yamaha EDL6500S.  It includes a toolkit.   But it's not an inverter unit.And someone mentioned to make sure that the no-load 'economy' idle switch wasn't on.  Definitely check that.Wire sparked, popped and left blobs instead of nicely melting the steel sounds like you may have had a bad work-clamp connection or were trying to weld over 'crud'.  Or maybe your old generator is producing dirty power and the electronics on the MM140 don't like it.  Or the no-load 'economy' idle was on.  Or the old generator isn't producing quite enough power for the welder.  Or you switched from solid wire to fluxcore and forgot to switch the polarity around.Check all the obvious things (good workclamp connection to the workpiece, no paint or grease, polarity, etc) and try the welder on a lower setting on some thinner steel practice pieces (try 16-18 ga sheet metal instead of 1/8 inch stuff).  If that works, then the generator doesn't have the needed capacity to produce enough and clean-enough power for thicker welding.Last edited by MoonRise; 07-27-2007 at 12:24 PM.
Reply:Thanks for all your input.  I have been confirming all the things you mentioned.  I'm convinced the old HOnda just doesn't have the muscle.   I did some more research with my ammeter and the 44 amp startup surge last less than a second.  As a matter of fact, you can't see it with the naked Eye.  You have to have the ammeter set up to record the highest amperage.Once the startup/surge passes, the welder settles down and draws a consistent 27 amps while welding 1/8 inch wall thickness pipe.That amount of current requirement is at the extreme top end of that old Honda generator and it just isn't doing it.   I plugged it into an RV trailer that has an Onan 3800 watt generator and it got the welder up to intermittently able to weld the 1/8" inch.  On smaller stuff it did fine with the 3800 watt onan generator.    My problem is I need to weld a bunch of that pipe up on a large fence project and I can't afford to hire out, or buy a bigger self contained welder to do this job.   My MM140 welds the pipe fine if it has enough power coming into it.So I can possibly justify buying a larger generator if I partner up with my Dad.  As I mentioned earlier It needs to be electric start for him.  I've been talking to lots of generator dealers the last 24 hours and am finding all the usual things.  Salesman who don't know a friggin thing.  Salesmen who want to sell me a 5000 dollar unit.  And salesmen who fess up that they just aren't quite sure.  I don't have any local dealer I can go and try one out.   Just got off the phone with Honda customer support asking them about their EM5000 generator.  Giving them the exact specs my welder was drawing the so-called expert was telling me I would have to plug it into the 120/240 twist lock outlet to get the max power from the generator.  I'm just barely a shade tree electrician but in my untrained enough eye,  a 4 prong 120/240V outlet on a generator is putting out 110V to one wire,  110V to the other wire, a neutral and a ground.  I don't know of a way to turn that into a standard 110V three prong plug that my welder would plug into.  That is getting into electricity above my pay grade.   Still trying to figure it out.  Don't want to buy something that won't work, don't want to burn up my welder, and can't afford to just go buy a 10 gigawat generator just to make sure I have the overkill.Unfortunetly I work for a living and work aint' that good right now.Thanks for all you help.
Reply:Two Honda EU3000is generators, one for you and one for Dad, plus one paralleling kit, and you then have 5600W (6000W surge) available on a 120V circuit.  That's 46+ amps.  The MSRP is ~$2k for each unit, plus the $240 for the parallelling kit.Or one Honda EU6500ISA (looks like Honda added another letter to the name).  The drawback there is the MSRP is ~$4k.  Yikes!Or rent or borrow a big(ger) generator, or an engine-drive welder/generator.
Reply:I've got an easier answer - just buy a 100' 10ga. extension cord, plug it in where you want and weld away. Unless you are out in a remote area, this will cover 90% of your field jobs...I hope. $30-50 and you're all set. John -  fabricator extraordinaire, car nut!-  bleeding Miller blue! http://www.weldfabzone.com
Reply:Originally Posted by MoonRise...paralleling kit, and you then have 5600W (6000W surge) available on a 120V circuit.  That's 46+ amps.  ...
Reply:One thought would be to seriously examine your long term needs as well as service duty requirements and then possibly think outside the honda box. Don't get me wrong, hondas are wonderfull units designed and built to provide enoumerous hours of trouble free, and quiet, run time for years on end. That's great, but for many of us just not within the budget and probably beyond our longevity needs or duty needs. There are many new models by major manufacturers out there all in the 4 kw, 5 kw and 6 kw or even up to the 7.5 kw range that are 1/3rd the cost of a honda. Check any of your big box stores.
Reply:Yes, I had to give up the Honda's.  Although I believe they probably are a top of the line generator product.  But look at the extract below (attachment) from the owners manual of the EM5000 generator.  I'm not an electrical engineer or even a liscensed electrician for that matter.  But a fair shade tree electrician.  And as I look at this information, it appears to me that the 5000 watt honda is really two 2500 watt generators in one box.   no matter where I would plug in my MM140 I can only get 18.8 watts of continous output.  Not enough to weld what I'm doing right now.   But if I get a Yamaha ef5200, or a briggs and stratton p6200, all the power is available at any single outlet.  Unless of course I'm all wrong (entirely possible). Attached Imagesem5000.pdf (36.9 KB, 16 views)
Reply:Many gen sets are that way. And it's not necessarily by brand but more model by model. You have to study side by side models very carefully. We're talking the non-industrial models so it's a word game between the manufacturer and consumer whether you are getting full labeled power or not. Always read very carefully and note any differences between what you see as receptacles and what the info package lists. Open up the users manual if you need to.
Reply:Parallel AC? It takes phase correction and voltage equalization to do this. I'd LOVE to see a "parallel" kit to phase 2 fuel-powered gensets that could cost under $6000! You have to keep both engines at the same RPM (frequency) and the outputs of both gensets' sine waves in phase AND at the same voltage or you will either: A) cut your output amperage back in half or B) go BOOM! (when the sine waves go out of phase) Also, while Hondas are nice generators, beware that when one of their internal regulators or the other 4 modules goes bad, you'll sink about $540.00 into it. If the engine fails, good luck getting internal engine parts. I just scrapped a 3 year old Honda (8KW) gas unit since the regulator is "obsolete" and unavailable. Steer clear of the Harbor Freight Chinese ripoffs of the Honda too. You can't even get a carb kit, muffler or starter for these POS gensets.If you have a generator dedicated to 120V, you can disconnect the two windings internally and rewire them 180 degrees apart in parallel to make your 120/240 unit into a 120-only unit with twice the amperage at 120V as it used to be rated. We do this commonly on mobile mounted power units where 240 is never used. We have also done this conversion for many gensets that are used for backup power for traffic lights at large intersections where the standard 120/240 unit didn't have enough nuts when at 120V.
Reply:Also, the Generac brand with a Briggs engine works fine. My shop backup generator is a Generac 6500W w/electric start that I bought at Home Depot through our local municipality. It cost me $459.00. It runs all of my shop lighting, compressor, MIG, plasma, office baseboard heat, parking lot lights, water cooler, 10 gallon water heater and the computers with no problem. If you have a municipal connection (either fire department, police department or such) your local HD may hook you up with a killer price the next time you have a long duration power failure in your area.It runs almost 6 hours under load on a full tank, it will pull start on the 2nd or 3rd pull and it's super quiet after adding a Toyota Tercal muffler to it!Don't look away from domestic units. The Briggs engine IS a dinosaur, but it runs just fine and I can get any part for it for years to come and for little money. The Gillette generator that they use is simple with only a capacitor and two diodes for exitation and regulation, it doesn't have all of the technical-masturbation inside like the Honda.
Reply:Arrrgh!  I had this long reply almost all the way typed out and I hit the wrong button on the keyboard and lost it all.Take 2.Two Honda EU3000is generators running with the Parallel Kit are rated at 5600W (5.6 kVA) coming out of one L5-30R receptacle (page 23 in the manual).The Honda EU3000is, EU2000i, and EU1000i Inverter generators are 120V-only units and produce all their rated power on the 120V outlets.  They don't produce 240V AC and split the two hot legs between two 120V circuits.The reasons I mention the Honda Inverter generators are:- they produce clean AC power;- part of how they produce that clean AC power is becasue they are inverter machines, which leads to;- they are typically much more fuel efficient than 'dinosaur' generators, especially at partial load because they can throttle down the engine and still meet the power demand (an EU3000is at 1/4 partial load or 700w is listed as a run-time of 20+ hours from 3.4 gallons of gas and 7.1 hours at full rated load of 2800w);- they are LOTS quieter than a typical big-box generator (49-59 dB for the EU3000is versuss 80+ dB for a typical big-box generator).The Honda EU6500is Inverter generator has a switch on the control panel to change from 120/240V operation to a 120V only mode and make full rated power available on the L5-30R receptacle, which should run the OP's MM140 just fine.The Honda EM5000is Inverter generator has a similar 120V-only switch and L5-30R receptacle, which the wiring diagram shows as protected by a 30A circuit breaker.  That should feed the OP's MM140 fine.Check http://www.wisesales.com/ or http://www.mayberrys.com/gentran/parallel.htm for info/pics on the Honda EU Paralleling Kits.  Both vendors have good reps from other web postings AFAIK.
Reply:These kits will work only on those generators. Why not use a real generator to start with?As for inverter generators: TECHNICAL MASTURBATION!!!!!!!!You take 5 simple parts that use to make AC power and now have 20X the parts to do the same thing. They are like switching power supplies. They are lightweight and more efficiant and they don't last. Come see me in 10 years with your inverter generator and tell me how many times it broke.Why use two very expensive units with a jipper parallel kit (which by the way, I can guarantee do not properly align the sine waves properly) when you can just get a generator without electronics and inverters that has a real copper winding that is heavy and can dissipate heat unlike the solid state units. Why is it that Hoover Dam or any other large scale generation doesn't use inverters? The only advantage of the inverter setup is when you have a varying rotational input speed such as wind power.
Reply:Varying rotational input speed with the inverters and their ability to still produce clean AC power under that partial input and output condition and the efficiency under those conditions is a very good benefit to the inverter generators.Large scale generation in the mega-watt range is a whole nuther beast and operating realm than a little 5-10 hp generator.Big and heavy copper-n-iron is sometimes good.  But I think trying to run his MM140 on an old-style machine is going to take a machine in the realm of an 8000+ watt rated (not peak, but continous rating) 120/240V generator, specifically because those machines are 120/240V machines (only half the rated power is available on each of two 120V circuits because of the 120V coming from opposite legs of the 240V output).  And it will need the internal circuits and wiring to support a 120V 30A output circuit.  The OP's test with an Onan 120V 3800W RV generator not quite having enough power to run the MM140 on 1/8 inch work says he needs a little more, and then multiply it times 2 because of the whole 120/240V generator operation.It will typically be louder and bigger and heavier and drink way more gas than the high-end (yeah, darn expensive!) Inverter generators.Somewhere up above I mentioned to just beg, borrow, or rent a bigger capable generator to do the fence job.
Reply:well,  I learned and relearned alot of things about basic electricity trying to figure this all out.  Calls to Miller and Generac (briggs and stratton) and Honda all confirmed my worst fears.  I needed a darn big generator to power the 110 welder.  If I had a 220 welder I could have gotten by with a much smaller generator.  Anyway,  I went in with my dad and bought a 8000 watt Briggs and Stratton with a Generac engine (home depot version).  It managed to get the welder going when I built a plug to use the 120/240 outlet (which is the only one that will give you the max generator power).  So now I am able to finish my long way from the shop welding tasks.  Thanks for all the help and insight.It managed to get the welder going when I built a plug to use the 120/240 outlet (which is the only one that will give you the max generator power). So now I am able to finish my long way from the shop welding tasks.