Alternator welder

[bobwills]

O ok that makes since, And that it about right voltage. Everywhere I read it is a internal voltage regulated so i guess i might be trying to take it apart sometime. First see if it works though. And yeah but im gonna put it on a gas motor so I can drive my welder where i need it and i have a portible one then. So im going with the mounting on a lawn mower.

[bobwills]

What about making one out of a generator. I have an old one laying around with a bad motor. Would there be a way to convert it or would it not even work

[blasphemy000]

No idea about the generator. But really before you go tearing it apart, take a battery charger and hook the positive and the ground to the 2 terminals inside the plug on the side of the alternator, spin it up with your motor and measure the voltage between the case and the terminal on the back. Report back with that voltage, that should tell us how it's regulated, some internally regulated ones if the fields are fed from an external source like you do when you weld with one then they will still work as there is no feedback current to the regulator.

[redbeard]

That one looks like an internal regulator. If memory serves, the way to tell on the old GMs is to look at the orientation of the plug terminals. If they are parallel with the shaft, it's external, if they are perpendicular, it's internal.

[I_Love_Plasma]

What about making one out of a generator. I have an old one laying around with a bad motor. Would there be a way to convert it or would it not even work

Oh a power generator, like 120vAC gas powered genset. I totally thought you were talking a "generator" like wind turbines have or really old tractors (starter/generator). What wattage does your genset have? you could step down the voltage with a transformer..120v is way to high, and i dont think it will draw down as much like the alt would.

[geezer]

Also does anyone have any knowledge of anything about what has to be done or really anything about them.

This is old technology, first ran into it in 1974 in BowIsland Alberta, a fellow there was adding an extra alternator to the local farm trucks. to make it work you need v belt pulleys on the alternators and a throttle control on the truck, a switch that stops the current from charging the battery and a volt meter to set your. voltage. Trying to use a serpintine belt on todays pickups would be a nightmare.

If you are thinking of converting a lawnmower over to this, you better have at least 13 to 15 hp to make it work.

Interesting project but not that easy.

[bobwills]

Yeah I need to do that. I got to get my volt meter to my dads and try it. Gonna be like a week before i can do anything but im sure its internal regulated. And the generator was just an idea. thought it might hold up a bit better but just an idea, And i dont have a clue the wattage. And ya got that right. Not easy at all

[blasphemy000]

That's a good bit of overkill on the gas engine's HP. For my 90A alternator I could spin it at full power with a 9HP Honda engine. The electric motor I'm using now is only 1.5HP and just barely slows down when striking an arc at full power. The main reason I switched over to using my air compressor motor instead of the gas engine is that it is much much quieter and I didn't need the portability, I only built my setup so I could learn to TIG weld before I dropped the money on a real welder. As far as building this thing though, you guys are making it WAY more complicated than it really is. I'm pretty sure this guy isn't mounting this to a car or truck, he's planning on running it with a dedicated gas engine so none of that switching circuitry is needed. I draw up a diagram in paint to show how to wire the thing. It really is as simple as I'm saying it is.

[Rivets]

Bobwills,

The picture of your alternator seems to indicate that's it's internally regulated. If so, you do'nt need to remove the regulator. Just bypass it.

See that little D shaped hole in the back of the casing just to the left of that 2 wire connector ? Have a look inside that hole, with a light if need be. You should see a small metal spade lug, just like the ones that your above-mentioned connector plugs into.

Those three lugs are part and parcel of the regulator and the one behind the D shaped hole is to test the alternator output. If you short it to ground, (the alternator case) with a screwdriver, you effectively bypass the regulator and maximum output is produced.

The alternator output would then be varied by the voltage applied to one of the other two lugs under the connector.

Cheers,
rivets

The diagram posted by Blasphemy000 above is correct.
So if you have an internal regulator and you disable/bypass it as above, and you hook everything up as per the diagram, it should work fine.

[bobwills]

Yeah. The motor im gonna put it on is a 11 hp. My idea is just make it to where I can drive the mower over where i need to weld. Engage the altornator. Be able to weld something and go on. And yeah im not gonna do anything more than i have to. The only hard hard part on it is if its internally regulated then Taking it apart and undoing the regulator.

[bobwills]

Ok rivets your just saying to ground out whats behind the hole and it will bipass it. Would you have to keep the screwdriver in there. Im confused?

[blasphemy000]

Wiring Diagram:


Before you go ripping into that thing, I would seriously wire it up like the above picture and check the output voltage. If it is internally regulated, since it has two field terminals it might require external voltage feedback for the regulator to work. If it is wired up as the picture above there is no feedback voltage going to the regulator. If it has an internal feedback you shouldn't get that much voltage from the output terminal to the case when it is wired like the picture above. With mine wired as above and 12v going into the field, I'm getting around 100v between the output terminal and the case. That will be a very quick and easy way to tell if you're going to need to defeat the regulator or not. Another thing I would do is find out for sure how much amperage that thing puts out before you go putting a lot of work into it. If need be just go to the junk yard and pick up a 90A Chrysler alternator from a mid 90s Caravan with the 3.0L engine(that's what mine is from) or figure out what kind of Ford vehicle their 130A externally regulated alternator came from then you'd really have some power to play with.

[bobwills]

yeah im definatly gonna hook it up first. See what she will do. If i had to guess from what it was out it will be about a 50 amp. Because it was out of a 70s truck. So it didnt have a whole lot of power consumption. And o i see what you mean. Without it hooked to a battery where the positive goes it might not activate the regulater. And I would really like to do that. Be really nice having that extra power.

[Rivets]

Ok rivets your just saying to ground out whats behind the hole and it will bipass it. Would you have to keep the screwdriver in there. Im confused?

Hi Bobwills,

The "screwdriver in the hole" is a quick and dirty way to bypass the regulator and determine if the alternator is producing full output.

To permanently disable the regulator, I would slightly enlarge the D hole so as to make it round, then I would tap it.

Screw in a bolt so that the bolt tip contacts that lug on the regulator and you're done.

Also, put a nut on the bolt and tighten it against the alternator case to lock everything in place.

Cheers,
rivets

[bobwills]

Yeah that might work pretty good. Wonder if it would be easyier to take it apart and unhook it though cause that seems a lot more complicated

[DaveO]

A couple questions:
>>To permanently disable the regulator, I would slightly enlarge the D hole so as to make it round
When you enlarge this hole, presumably with a drill, do you run the risk of metal turnings from the drilling process getting into the regulator and shorting things out?

Does the end-product welder require a cooling fan? Blasphemy, did you incorporate a cooling mechanism in your welder?

[blasphemy000]

My alternator had a big fan on the front of it to start with, the little pressed metal one behind the pully, but its outside of the case.

That's not my alternator, but the fan is the same. Just for reference though my motor spins the alternator the opposite way it would normally spin on a car so instead of it sucking the air trough the alternator and blowing it out the front its sucking it in the front and blowing through the alternator. None of this was on purpose though as I didn't even realize it was spinning backwards till like a week after I built it. Most car alternators don't care which way they spin since they generate 3-phase AC internally anyways. As for the cooling, I'm really not sure which way works better as I never had any problems with it overheating. Like I said, at full power the case gets very hot to the touch but it's never gotten hot enough for the current to drop off so I don't think I'm over working the diodes inside. After I'm done welding with it I cut the power to the field and let it spin for a few minutes to cool down. It just seemed like a good thing to do.

[Rivets]

Bobwills,

My last post above has a significant OOPS, so you can't hook up as per Blasphemy's schematic, because I forgot about the diode trio.

Unfortunately, you'll have to open up the cases and dive in.
See schematic below. (The 12 Volt Doctor's Alternator Book - Edgar J. Beyn - Spa Creek Inc.)

Remove the diode trio, and while you're at it solder a lead to the test lug and route it outside the case where you can easily ground it. Then you don't need a threaded hole.

Also, the + charger lead goes to lug #1 and the - charger lead goes to the casing and NOT to lug #2.

You can also remove the regulator, but then you'll have to connect leads to the slip rings and bring them outside the case.


There is an even neater way.

If you keep the diode trio, and hook up the rheostat between the test lug and the case, then you need the battery charger (or a battery for that matter) for only 1 or 2 seconds after start up.

Cheers,
rivets

[Rivets]

[QUOTE=DaveO;15396]A couple questions:
>>To permanently disable the regulator, I would slightly enlarge the D hole so as to make it round
When you enlarge this hole, presumably with a drill, do you run the risk of metal turnings from the drilling process getting into the regulator and shorting things out?
QUOTE]

DaveO,

It could be an issue, but my thinking was to use a drill bit in a threading tap chuck and enlarging the hole by hand and blasting with compressed air.

No longer relevant since the cases have to be opened. Easier and neater to route grounding wire outside the case - see post above.

Cheers,
rivets

[bobwills]

Im still a bit confused. So whats a diode trio and what does it do that you would have to remove it sometimes. And ok so your saying to open it up and just put a wire grounding out the regulator. Is that really all you all are saying to do. Sorry i dont understand too much. Not the best on some of these types of things. But hey ya gotta learn somehow.