Alternator as an emergency welder question
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  1. #1

    Alternator as an emergency welder question

    Anybody ever make or use an alternator welder like in this link-
    http://www.tongacharter.com/report-welder.htm

    I know it works for stick, but-

    My question is if it can be used as a mig or tig power source.

    Scott

  2. #2
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    Re: Alternator as an emergency welder question

    For mig you could add a pulled up field adjustable voltage regulator, so you could adjust it between 12-24v .
    Or add some zeners and a rotary switch to a regular regulator for a stepped type voltage setting.
    Adding an inductor to the output and capacitors would make it weld better.
    You would need a tank of shielding gas for mig.
    If there is much wind you will have to use flux core anyway.
    http://www.readywelder.com/

    Tig would add a whole new level of complexity, if you wanted HF and wave shaping and polarity biasing.

  3. #3
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    Re: Alternator as an emergency welder question

    here's a link to another forum where a guy made one, it is a pretty fascinating machine and some day when I have the time I plan to build one myself

    http://www.hotrodders.com/forum/my-d...der-77730.html

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    Re: Alternator as an emergency welder question

    Forget all the fancy contraptions

    I had to chase the cows out of the haygrazer one time, and the bunjee cord that I had holding the battery down in the pickup snapped, the poles lodged against the fender, and the pos cable welded itself to the fender

    Now I got a bunch of confused cows, tracks all over the field from the truck, and a small cloud of smoke coming from under the hood.

    I hit the brakes, the dog skids down onto the floor of the truck, and I'm running around the front to open the hood.

    An interesting afternoon
    "Any day above ground is a good day"

  5. #5
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    Re: Alternator as an emergency welder question

    and after all that, the stupid cows followed me back up to the house (me on foot) to get their cubes &*&^$^#@
    "Any day above ground is a good day"

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    Re: Alternator as an emergency welder question

    In the ``olden`` days prairie farmers would buy arc welding kits. It was post WW2 and there were lots of heavy DC aircraft generators around. They would hook it up to a spare engine or to a tractor power take-off. An inductor coil was added to smooth out the arc.
    The big problem with trying to run MIG is that you need a constant voltage power source rather than a constant current used for stick and TIG. For TIG you need a flat slope constant current that gives little change of amperage over long and short arc. For stick more change over long and short arc.

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    Re: Alternator as an emergency welder question

    There is a commercial solution which uses batteries, generally 24 volts, for MIG welding.

    http://readywelder.com/

    I have one, fits in an attache case. Most boats have two battery systems, so the boat already has the batteries. The average car has only one battery, so not enough voltage, but if you can get two cars, you have enough battery to weld.

    http://readywelder.com/

    Richard
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  8. #8
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    Re: Alternator as an emergency welder question

    I've come close... made a 14 volt 140 amp battery charger.
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    I used a $100 CS144 Delco Reme alternator from an auto bone yard.
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    I connected it via a $15 rubber coupled direct-drive to a $230 surplus gasoline engine of 6 hp (Briggs & Stratton Integ).
    Add 20 feet of dual #2 booster cables at sale price of $50.
    Add in about $15 of threaded steel rod and bolts.
    Add in about $40 worth of electric meters and switches
    (I got the thick aluminum and wood for free, plus I had free access to a lathe to machine the aluminum spacers and a bender to bend the aluminum plate.)
    My total cost = $450 before taxes

    Plus - three weekends of work <
    At full output, it's near the limit of 6 hp engine to drive it.
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    As the eyeball engineer url (http://www.hotrodders.com/forum/my-d...der-77730.html) stated, if you want to convert the CS144 to a welding voltage output of 22-24 volts, you have to replace internal diodes with an external diode pack and you have to replace the internal voltage regulator with an external (homemade) circuit to give you some control over the output voltage/current. That will likely cost at least another $50.

    Now, the modified CS144 alternator is going to be outputing twice the voltage (24 volts) at the same maximum current (140 amps). However, since the internal heating is current x current x resistance, and none of that has changed, the alternator will handle it. The problem is that you want to make almost twice the output power, changing from 12 volts @140 amps to 24 volts @ 140 amps. That means you need to change from a 6 hp engine to more like a 13 - 15 hp engine. Fortunatley, there are now some ~$300 chinese built 15 hp engines available.
    Still, at the end of the saga, you will spend ~$550 - almost the price of a new Lincoln 220 amp AC/ 140 amp DC tombstone arc welder or a 180 amp DC mig welder - and you might pick up either of those used for ~$250 each. So, you have to weigh the logic of this approach - unless you really need the portability.

    If you want portable DC welding on the cheap, check out the articles on this site about 'welding with car batteries' - two batteries with booster cables and an electrode holder can deliver DC arc welding at ~120 amps. If you want battery-powered MIG, the Ready Welder seems to have good reviews - again lots of postings on this web site.

    Richard, I don't want to discourage you - as building gear is very rewarding. Just weigh up all the ways and means. Apparently quick and easy looking projects have a way of eating up more money and time (especially time) than you would ever dream - as I am certain many members of this forum can confirm.

    Best of Luck to you!

    Rick V

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    Re: Alternator as an emergency welder question

    This might be of some interest...

    http://www.diy-welder.com/index.shtml

    Lots of info and he sells the control boards for a DIY unit.

  10. #10

    Re: Alternator as an emergency welder question

    Rick- That is AWESOME!

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    Re: Alternator as an emergency welder question

    Quote Originally Posted by farmersamm View Post
    Forget all the fancy contraptions

    I had to chase the cows out of the haygrazer one time, and the bunjee cord that I had holding the battery down in the pickup snapped, the poles lodged against the fender, and the pos cable welded itself to the fender

    Now I got a bunch of confused cows, tracks all over the field from the truck, and a small cloud of smoke coming from under the hood.

    I hit the brakes, the dog skids down onto the floor of the truck, and I'm running around the front to open the hood.

    An interesting afternoon
    LMAO! Thats funny Sorry about the pos cable.

  12. #12
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    Re: Alternator as an emergency welder question

    This guy built a nice unit

    [ame]http://www.youtube.com/watch?v=ojiSR0vFkSQ[/ame]

    The video doesn't show much other than the unit and some nice welds..

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    Re: Alternator as an emergency welder question

    The video doesn't show much other than the unit and some nice welds.. Mudbugone
    Yeah, that's the truth. I guess we have to go on faith - the video doesn't actually show him welding with that machine.
    e.g. Maybe he used DC Tombstone to weld with while the video showed us a door in the garage for a minute

    Given the small size of an alternator and a typical 15 hp engine, his welder is Big - about 2 times the size I would have expected. On the other hand, who knows, maybe he has a 20-22 hp engine under the hood?

    I noticed that Lincoln has a new line of portable engine-driven welders/AC generators that deliver 145-185 amps DC welding and 4,200 - 5,200 110 volts AC. Those commercial units are similar in size to his.


    Rick V

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    Re: Alternator as an emergency welder question

    In the last couple of years, we have witnessed a major increase in the number of small (<10,000 watts) engine driven DC welder/AC generator combo units in the marketplace.

    Most are for stick but the Miller Renegade is a wire-feed welder. The imported 'stick' units are less than $1000 for 160 amps DC welding and 3600 watts AC generator.

    When you first look at the home-built welder articles, you think, hey with a $100 used alternator, I can build a DC welder way cheaper than the commerical units! This might have beeen true say 5 years ago when there were few small engine-driven welders available - and those few were AC only. Today, you have Lincoln, Miller and offshore units that have filled that gap. As I showed in the home-build of my earlier post, the basic, finished home-built alternator welder is likely to cost $600 - and it won't function as an AC generator.

    You have to ask yourself, is all my labor worth the extra $400 it would cost to simply buy an imported unit at $1,000 or maybe a used Lincoln or Miller? When I built 7 years ago - yeah, maybe. Today ?

    Rick V
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    Re: Alternator as an emergency welder question

    Quote Originally Posted by Rick V View Post
    As the eyeball engineer url (http://www.hotrodders.com/forum/my-d...der-77730.html) stated, if you want to convert the CS144 to a welding voltage output of 22-24 volts, you have to replace internal diodes with an external diode pack and you have to replace the internal voltage regulator with an external (homemade) circuit to give you some control over the output voltage/current. That will likely cost at least another $50.

    Rick V
    I built a DC stick welder using this style setup a few years ago. It was a used 6HP reclaimed for free and a 70 amp Delco 12SI alternator. The pulleys cost about $15 and the frame was made of discarded bed rail. It was a fun project. The best it could do was about 3/32" rod on 1/8" plate if prepped properly.

    Recently, I picked up a Bosch IR 160 amp alternator. It has the avalanche diodes like the CS144, AD230, AD244. Therefore, it can't do arc welding with a high OC voltage. I plan on converting the setup to fluxcore. This would require 15-28 volts. From all that I read the avalanche diodes go up to 35-40 volts so I don't see the diodes being a problem. Yes, the regulator will need to be replaced or adjusted. I planned on taking the B+ input of the regulator and adding a variable voltage divider. The alternator output will also feed the wire feed assembly.

    EDIT: I forgot to mention that I planned on replacing the current single pulley in the 6HP engine with a double groove pulley so that I can run a smog pump off a GM V8 to push air into the carb. I need to figure out the carb fuel mods before this setup is put into action. The purpose is to get the required 9+ hp.
    Last edited by weld; 01-26-2010 at 05:49 PM.

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    Re: Alternator as an emergency welder question

    Quote Originally Posted by weld View Post

    EDIT: I forgot to mention that I planned on replacing the current single pulley in the 6HP engine with a double groove pulley so that I can run a smog pump off a GM V8 to push air into the carb. I need to figure out the carb fuel mods before this setup is put into action. The purpose is to get the required 9+ hp.

    Without going into too much technical detail, hooking the output of your air pump to the inlet of the carb will not work. Carburetors work on the venturi principle. Any positive pressure on the inlet will prevent the venturi from creating the necessary vacuum at the main jet needed to draw the fuel from the float chamber. The only way around this is to pressurize the entire carburetor with the pump, thereby creating a neutral pressure differential between the carb throat and all the fuel circuits, including the float chamber. I've actually seen this done on an older Toyota Corolla with a turbo charger, and it worked. The entire carb was in a sealed aluminum enclosure with the turbo feeding it. Of course your fuel pump has to be outputting more pressure than your blower!

    Typical carbureted turbo / supercharger applications place the turbo / supercharger between the carb and the engine intake. Pressurization takes place after the fuel and air are mixed.
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    Re: Alternator as an emergency welder question

    Recently, I picked up a Bosch IR 160 amp alternator.... This would require 15-28 volts... The purpose is to get the required 9+ hp. - weld
    With most 60 cycle AC generations, the output watts are tied pretty solidly to the horsepower (hp) of the engine. (1 hp = ~750 watts)
    Examples of typical generators
    electric output watts.....Input horse power (watts)
    3,800...............................6.5 (4,875 w)
    5,500..............................11 (8,250 w)
    7,500..............................15 (11,250 w)
    10,000 ...........................22 (16,500)

    I looked at that and said OK, figure out the electrical output in kilowatts and double it to get the needed driving engine horsepower.
    e.g. 5.5 kilowatts output needs 5.5 x 2 = 11 hp engine
    So I looked at my CS144 alternator and said, for battery charging it outputs about 15 volts x 140 amps = 2100 watts. That means it needs an drving engine of 2.1 x 2 = 4.2 hp or so I thought!

    I bought a 4 hp engine and it was just tearing itself apart trying to drive the alternator.
    I had to buy a 6 hp engine and that can just to an adequate job at 140 amps alternator output.
    Why? Why wasn't 4 hp enough?
    It is because the alternator is really putting out more power? i.e. not single phase AC but 3-phase DC?

    That's why I said that if you convert an alternator to a welder, raising the output voltage from say15 volts to more like 27, you are going to need 27/15 =1.8 times more engine. e.g. 6 hp x 1.8 = 10.8 or 11 hp.

    So 'weld' if you are going to use the full output of the Bosch 160 amp alternator, you may need more than 9 hp. You might want to aim for 13 hp to be on the safe side.

    Rick V

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    Re: Alternator as an emergency welder question

    Quote Originally Posted by bratkid63 View Post
    Without going into too much technical detail, hooking the output of your air pump to the inlet of the carb will not work. Carburetors work on the venturi principle. Any positive pressure on the inlet will prevent the venturi from creating the necessary vacuum at the main jet needed to draw the fuel from the float chamber. The only way around this is to pressurize the entire carburetor with the pump, thereby creating a neutral pressure differential between the carb throat and all the fuel circuits, including the float chamber. I've actually seen this done on an older Toyota Corolla with a turbo charger, and it worked. The entire carb was in a sealed aluminum enclosure with the turbo feeding it. Of course your fuel pump has to be outputting more pressure than your blower!

    Typical carbureted turbo / supercharger applications place the turbo / supercharger between the carb and the engine intake. Pressurization takes place after the fuel and air are mixed.
    Pitot tube. I fab turbo setups.

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    Re: Alternator as an emergency welder question

    Quote Originally Posted by Rick V View Post
    With most 60 cycle AC generations, the output watts are tied pretty solidly to the horsepower (hp) of the engine. (1 hp = ~750 watts)
    Examples of typical generators
    electric output watts.....Input horse power (watts)
    3,800...............................6.5 (4,875 w)
    5,500..............................11 (8,250 w)
    7,500..............................15 (11,250 w)
    10,000 ...........................22 (16,500)

    I looked at that and said OK, figure out the electrical output in kilowatts and double it to get the needed driving engine horsepower.
    e.g. 5.5 kilowatts output needs 5.5 x 2 = 11 hp engine
    So I looked at my CS144 alternator and said, for battery charging it outputs about 15 volts x 140 amps = 2100 watts. That means it needs an drving engine of 2.1 x 2 = 4.2 hp or so I thought!

    I bought a 4 hp engine and it was just tearing itself apart trying to drive the alternator.
    I had to buy a 6 hp engine and that can just to an adequate job at 140 amps alternator output.
    Why? Why wasn't 4 hp enough?
    It is because the alternator is really putting out more power? i.e. not single phase AC but 3-phase DC?

    That's why I said that if you convert an alternator to a welder, raising the output voltage from say15 volts to more like 27, you are going to need 27/15 =1.8 times more engine. e.g. 6 hp x 1.8 = 10.8 or 11 hp.

    So 'weld' if you are going to use the full output of the Bosch 160 amp alternator, you may need more than 9 hp. You might want to aim for 13 hp to be on the safe side.

    Rick V
    I agree. The 9HP will not support the 160 amps. The 750 watts / hp doesn't really hold with a 4 cycle engine. The alternator is only about 60% efficient. The alternator power VI relationship is constant. That is, as V is increased then I drops. So I don't expect the 160 at weld voltage unless I increase the field voltage beyond the stock 14.8 volts.
    This alternator also has more than three windings. I need to remove the rectifier and see how all six of the winding stubs are connected.

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    Re: Alternator as an emergency welder question

    I looked at the rectifier assembly and regulator/brush holder on the Bosch 160 amp alternator. I think I will end up blowing the avalanche diodes because the OC voltage will be about 35 volts. I have some diodes to replace the assembly. The problem is the regulator / brush holder. The brushes are integrated into the regulator. I will have to destroy the regulator to figure out how to connect to them. I really don't want to destroy a 50,000 mile alternator I got for $50. I think I will put it on my chevy replacing the current 70 amp Delco 12SI unit.

    I am going to get a Delco AD244 145 amp and use that for the welder. I can get and aftermarket drop in rectifier w/o avalanche diodes. The brushes are easily accessible so that I can make a jumper wire setup so that it can be a battery charger at 14.xx volts, a stick welder at 80+ volts, TIG welder at 17 volts, and wire feed at 24 volts. Overall, it is a simple modification. I really think the AD244 is the way to go so I ordered one with about 75K miles on it.

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    Re: Alternator as an emergency welder question

    I can make a jumper wire setup so that it can be a battery charger at 14.xx volts, a stick welder at 80+ volts, TIG welder at 17 volts, and wire feed at 24 volts. - Weld
    This should be very interesting!
    Actually, you only need about 24 - 32 volts to stick weld at 120 - 220 amps.

    Best of luck with that project... that may be quite something.
    Rick V

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    Re: Alternator as an emergency welder question

    The only bad part is I am actually going to have some money into this thing that started out as a free-stuff-and-will-it-work project. The AD244 was $50, the 6-70A non-avalanche rectifier is $50, an upgraded 240 amp stator is $75 (if I go that route). The other thing is spinning that kind of power will require a multi-belt system. I know that max. I can get is a 2 v-belt pulley for the engine. Using the stock alternator 6 rib would be nice.

    I just need to watch for feature creep. Just doing the AD224 at 145 amps is $100. Going to the 240 amp stator is $75. Then the motor is too small.......another $300-500. Oh yeah, I forgot to mention I just missed out on a 18HP briggs for $100 in the classified ADs.
    The Harbor Freight 151 wire feed assembly & torch setup is around $40. I might just pull the stuff off the Campbell Hausfeld 70-80 amp fluxcore box someone pulled out of the metal dumpster and gave to me non-working.

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    Re: Alternator as an emergency welder question

    You might consider using a chain drive for the alternator, less slippage and lower bearing load.

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    Re: Alternator as an emergency welder question

    Rick V,
    Did you use a Lovejoy coupler (jaw type w/ rubber in the middle)? If so, how did you mount the cast steel jaw coupler on the alternator?

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    Re: Alternator as an emergency welder question

    Did you use a Lovejoy coupler (jaw type w/ rubber in the middle)? If so, how did you mount the cast steel jaw coupler on the alternator? - Weld
    Ha - is that what you call it - LoveJoy Coupler?
    Yes, I think it had three steel jaws per coupler side and a rubber spider between.

    A very perceptive question about the mounting the jaw coupler on the alternator shaft!
    How the 'H' did I do that...? A few years back!
    I do remember the alternator shaft was smaller in diameter than the engine shaft....
    If I recall correctly, I think the inner bore of the coupler I used on the alternator was different, smaller in diameter - a good fit for the alternator shaft. I do remember using three (or four) 1 inch diameter cut off disks sandwiched mounted in in a dremel tool (miniature electric grinder) to cut/grind out a keyway channel in the alternator shaft. Worked real slick! I then slipped the coupler over and put in the key to lock the shaft/couple together. I also recall a couple of allen key studs through the coupler sides to the shaft. BUT... I think I had partly counter-bored the inside of the alternator coupler so that I could screw (& loctite) the retaining nut back onto the alternator shalf - and the top of the nut was then flush with the inside of the coupler. I may have had to grind down the thickness of the nut; I can't remember.

    I hope that helps
    Rick V

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