Building a Portable Welder

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Hello everybody, just thought I'd share the project I'm starting on.  It's an engine driven portable welder, using a briggs and stratton 18 HP engine and a high output automotive alternator.  For the time being, it's just a 130 amp Lestek alternator, but I plan to upgrade it to something 200 amps or larger.  The field coil will actually be controlled by a delectable mode current and voltage sensing control board, allowing the unit to have true constant current and constant voltage for running arc and wire feed.Base frame is done... Initial mockup of engine and alternator
Reply:Awesome. What are you going to use to power the fields?
Reply:Originally Posted by anickodeHello everybody, just thought I'd share the project I'm starting on.  It's an engine driven portable welder, using a briggs and stratton 18 HP engine and a high output automotive alternator.  For the time being, it's just a 130 amp Lestek alternator, but I plan to upgrade it to something 200 amps or larger.  The field coil will actually be controlled by a delectable mode current and voltage sensing control board, allowing the unit to have true constant current and constant voltage for running arc and wire feed.Base frame is done... Initial mockup of engine and alternator
Reply:Originally Posted by Oldiron2Any chance you can still edit the post? --------------------------------------------1de·lec·ta·bleadj \di-ˈlek-tə-bəl\Definition of DELECTABLE1: highly pleasing : delightful
Reply:it looks like you're off to a good start. I look forward to watching your progress.I like these little diy machines
Reply:i use to have one on my old 4x4 made by pronto been thinking of building another good job and good luck with itLincoln Power Arc 4000 Thermal Arc Fabricator 252 iThermal arc 186Thermal Arc 26 tigTweeko 200 amp spool gunHobart AirForce 400WP-17V-12R
Reply:Please keep us posted.I want to add an auto altenator welder  to my 12hp wisconsin/generatorrig,and am wondering about the performance and electrical details.Miller a/c-d/c Thunderbolt XLMillermatic 180 Purox O/ASmith Littletorch O/AHobart Champion Elite
Reply:Stupid tiny little keyboard on my android.  I can never gat ALL the letters exactly right, and auto correct is no help either.As for the duty cycle, I'm really not certain.  I have done a lot of research into these things, and companies like Zena and PPW both claim 100% duty cycle.  Many guys who build them into trail rigs also find that they'll just go and go and go without significant overheating.  Part of the reason I want to go with a much larger alternator is so I don't have to push it as hard all the time, however with large case alternators, there doesn't really seem to be much issue with duty cycle.
Reply:I should also add that I am going to use a SPDT switch, a couple relays, and a solenoid that will allow me to switch the rig back and forth between 2 modes.1.  Welding mode - In this mode, the field winding is powered by the welding control board, and the welder's Positive output is fed to the welding positive output only.2  12v mode - the field coil is powered instead by the alternator's original voltage regulator, and a solenoid closes, connecting the alternator + to the battery + on the rig.  There will be an Anderson connector wired to the battery, giving me a high current 12v output for powering a large inverter, boosting car batteries, and serving as a backup 12v generator for solar/wind power systems.  In welding mode, the control board draws its power from the battery.  The engine has its own charging system, which should supply enough current to keep the battery from running down.  I plan to use a battery that's significantly oversized for the engine, just to have a nice reserve capacity for inverters and jump starting vehicles.
Reply:So you are going to try to have the voltage adjustable from about 15-21 volts ?I'm curious what that will do to the duty cycle.
Reply:CC voltage will vary just as it does in any CC machine. The board will limit OCV because an alternator will make 100+ volts if it's spinning fast enough with 12v to the field.CV welding will be variable from about 15 to 30 volts.
Reply:nice little project you have going, i started mine a couple days ago , i will post pics in a new thread. I have a large 6500 watt inverter in my truck for 110v , but with building and repairing gates at customers houses I needed a welder only so im building mine out of a generator frame.
Reply:I like this idea. check out mean green alternators, they make them up to 300 amps.
Reply:When I do upgrade the alternator, I'm planning to use something like an alternator for a fire engine or charter bus... something with loads of 12v lights and gadgetry.  I'm leaning towards a Leece Neville unit.
Reply:Finally made some more progress.  It's turning out about how I had hoped.  She ain't gonna be pretty, but I say function above form.Got a fuel tank sorted.  I'm using a 5 gallon harbor freight air tank.  I've flipped it upside down, and I'm going to install a fuel bowl in the old air port.  The fill neck will just be half a 2" NPT nipple welded in, with a screw-on cap.  I made mounting feet out of some scrap 1.5" angle, and welded on with 3/32" 7018 @ 80 amps (all my poor little harbor freight inverter can muster)I got the upper frame partially tacked together... It's just 1.5" 11ga square tube.  This shows how the fuel tank will sit.  There will be another vertical member behind the fuel tank to match the height of the verticals at the end, so the fuel tank sits in a "notch" in the cabinet.View from engine end...The battery will be housed inside the cabinet near the top, along with an inverter.   The top of the cabinet will be hinged to provide access to the battery for maintenance.All welding related components will be in the bottom.  I had all the dimensions drawn out on paper... but now that I'm putting it all together, it seems a lot bigger than I imagined it.  I'd better hurry up and find a bigger alternator.  I feel pretty silly having such a big machine that only does 130 amps.Last edited by anickode; 04-18-2012 at 10:36 PM.
Reply:Looking good, I havent had mine together long enough to see how long the gas tank will last, but I figure 1.5 gallons should do 3 to 4 hours. And  If i am welding for 3 to 4 hours I would need a break anyways. Mine is up and running and I have been using it. but Im still working on a few little things like shrouds and quick connects for the leads. You could add a second alternator and bring your 130 amps up to 260. I wanted mine to stay somewhat small and portable as i will need to be able to lift it up into the back of my truck to take to a jobsite. Big would be nice around my acreage because the one i have tends to be top heavy when i pull it around from my garage to the truck. Keep up the good work ,
Reply:Interesting... I'll keep watching.Miller Performance AD Helmet - Camo Edition Soon to have: Jackson HSL 100 - Forest Digi CamoMiller Thunderbolt AC/DC((Currently at welding school))
Reply:I was thinking about dual alternators... However I'd want a matching pair.  I'm keeping an eye out for good deals though.More progress today... got the gas tank mostly done.  It needs a little soft wheel work around the fill neck.Also the frame is pretty much finished.
Reply:Originally Posted by Oldiron2Any chance you can still edit the post? --------------------------------------------1de·lec·ta·bleadj \di-ˈlek-tə-bəl\Definition of DELECTABLE1: highly pleasing : delightful 2: delicious — de·lec·ta·bil·i·ty \-ˌlek-tə-ˈbi-lə-tē\ noun— de·lec·ta·bly \-blē\ adverbSee delectable defined for English-language learners »See delectable defined for kids »Examples of DELECTABLE   1. The meals he prepares are always delectable.   2. one of the most delectable men she's ever metOrigin of DELECTABLEMiddle English, from Middle French, from Latin delectabilis, from delectare to delight — more at delightFirst Known Use: 15th centuryRelated to DELECTABLESynonyms: agreeable, blessed (also blest), congenial, darling, pleasant, delicious, delightful, delightsome, dreamy, dulcet, enjoyable, felicitous, good, grateful, gratifying, heavenly, jolly, luscious, nice, palatable, pleasing, pleasurable, pretty, satisfying, savory (also savoury), sweet, tasty, welcome  ----------------------------------------------------------- I was just talking to a friend who still has some of the old 30's era starter/generators which used to be modified for the same purpose; plans were featured in lots of magazines after WWII. I know it's possible to increase the voltage of those alternators considerably, but how does one double the current without rewinding them, unless the duty cycle is very short?
Reply:The thing that bothers me is the small size of the alternator, about 1/5th the size of a usual 4,000 watt 117 volt generator or 1/10th the size of a a more typical 8,000 watt generator/welder.   Yeah, I know it's 3-phase and all that but... it just seems to me you don't get something for nothing... big engine driving dinky alternator - looks somewhat questionable to me. Guess we just have to wait and see.anickode, I wish you luck with this. Rick V 1 Airco Heliwelder 3A/DDR3 CTC 70/90 amp Stick/Tig Inverters in Parallel1 Lincoln MIG PAK 151 Oxy-Acet
Reply:The engine is oversized by double for this alternator.  Yes, they are physically smaller.  The main enemy is heat.  A welder generator is large in part to keep things cooler.  Alternators must be small to fit under the hood of a car, so every alternator has its SAE amp rating, and a 200 degree F rating.  Proper ventilation is crucial for weldernators because of the small case size.  I plan to make a boot that fits around the back side of the alternator with a 12v fan to boost air through the case.
Reply:this is awesome... subscribed
Reply:Another quick thought regarding size of the generator...Welder generators generally have separate windings for the welder and generator portions of the machine.  2 sets of windings = more space required.