Voltage Regulator Q's

[swampdigger]

Hey guys... anyone know what the early 80s externally regulated units will put out for a max field voltage? Will they go the full 12V if need be, or are they capped at a lower voltage?

I just mounted a second alternator to be used as a welder, and I'd like to add a second regulator which I can trick into holdings specific voltages between say 20 and 120 volts. Lower for welding and stuff, and 120 for running grinders, lights, etc..

The plan:

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So if you have the pot set to feed the full output of the battery terminal into the regulator, it will make the alternator put out 13.8V as it normally would.

If you start turning it down the regulator only sees a fraction of the actual alternator output. It could be jamming out 120V from the alt, but because it sees 13.8V coming out of the potentiometer, it's happy, and holds that field voltage.




At least in theory, anyway......

 

[wwwabbit]

Take a look here: http://members.shaw.ca/milton/weld/weldunater.htm at the prep work that was done to the alt. This was done by a friend of mine a few years ago who works in an auto/marine electronics. The thing to remember is that the regulator only limits the voltage. If you open the field up to get it to produce full voltage, you will have to set your RPM at the point you are getting 120v from the alt. Adjusting a what the regulator sees will only limit the voltage. Unless you do a pully change you will find that getting 120v out of it will be at a higher RPM then you want to leave your motor running at for any lenth of time with no real load on it.

To weld with, ya, it will work well as you don't need to spin it to get the high voltages.
For 120v though, get an inverter, then you can use it for everything.

 

[swampdigger]

I was thinking if I revved it to the point where it was making say 140 volts, then I could regulate it and keep it at a nice even 120 as the load changed.

Went to the boneyard looking for a Ford althernator, walked out with a GM 120A. Got it mounted up above the power steering pump and played for a bit.

There's no way I'm getting that thing to put out 120V, unless I can get the field above 12V without burning it up, or rev it A LOT faster. Will experiment later..

As far as welding goes, my readings on the 'net had me expecting the GM rectifier to cook above 30V--which it did. The IDI was probably just under 2000 rpm when that happened. A smaller pulley would definitely be nice. Never got the voltage to weld very good, so I can't really comment just yet. Glad I took the time to mount the rectifier externally, it should be swapped out rather quick.

Need some real welding stuff now. The Chineese made "Western Rough" brand $4 welding googles at picked up at the dollar store just won't cut it. And a pair of vicegrips wrapped in duct tape doesn't make a very good stinger.

 

[Compu Doc]

The only way to make 120V from a 12V source would be a stepup transformer. My Cadillac ambulance has an alternator that has 3 posts coming out of the top that goes to a 120V plug that has a transformer behind it. The other way is to use an inverter.

As for the alternator, there was a company called Linc-Arc that made alternators that also would weld. I have one of those that I will probably be using under the hood to replace my secondary alternator. It loooks like the old style GM alternators and has an outpiut of 165 amps. It also has 2 wires coming out of it that would go to the welding part.

Tried looking for one on Ebay to show you but there is no listings for any.

 

[swampdigger]

Comp, that's a neat idea using a transformer. Might give it a shot tomorrow. I think I have a 1200W 120V->435V transformer kicking around in the shop, come to think of it.

There are a few commercial solutions out there, but I'm trying to do it on the cheap (and because it's fun? I think?). If I wasn't so cheap, I'd probably just shell out for a 1000W inverter. Even though I think I've come close to that amount buying the alternator, belt, etc...

All this trouble to be able to run a grinder in the woods. Need to hack off some body sheetmetal that's making it hard for me to pull the transfercase out of a rolled parts truck my buddy picked up.

 

[riotwarrior]

I know this is a tad pricey for ya but from what I have heard they kick **** as welders.

http://www.premierpowerwelder.com/index2.html

This is what I eventually hope to have installed, though it will likely take me a couple years because other things tend to take precedence over this kind of decadence for a trail rig.

This is apparently a kool rig too http://www.premierpowerwelder.com/readyweld/readyweld.html something I have thought about as well.

 

[Compu Doc]

With the prices of those alternators that you provided a link for maybe I will sell the Linc Arc I have. Should be able to get half of those prices for it.

 

[riotwarrior]

With the prices of those alternators that you provided a link for maybe I will sell the Linc Arc I have. Should be able to get half of those prices for it.

What is a Linc Arc?

Ya those units are a sweet setup, that alternator and welder setup used in conjunction with that wirefeed would be the most awesome trail repair rig.

 

[Compu Doc]

A Linc Arc alternator is the same type as the link provided above except I think Linc Arc was out before the other company.

As for what I have I only have the alternator and not the rest of the setup to weld which should not be to hard to obtain. The cool thing about this alternator is it can be a primary or secondary alternator. Its not just for welding but will also run all the electrical system and charge the batteries in a vehicle.

 

[swampdigger]

New rectifier, and I finally got to burn some rods today. I'm unsure of the amps it's putting out, but it was performing slightly better than the 70A buzz boz welder I have for comparison. Maybe pushing 80A or so.

I hooked a transformer up to it and got 150V. Unfortunately, it could provide little current. I think the frequncies are all wrong.

Also wondering if I could disconnect my stock alternator from the charging system, and run the two in parallel for 65A + 120A of welding goodness. If they're not both pushing the same voltage, will it only draw from the one pushing more volts?

Need to figure out a way to spin it faster. I can't getting the pulley on the alternator much smaller, so I'll have to make the crank pulley bigger, or come up with an idler system to provide the speed increase.

 

[riotwarrior]

Need to figure out a way to spin it faster. I can't getting the pulley on the alternator much smaller, so I'll have to make the crank pulley bigger, or come up with an idler system to provide the speed increase.

How about driving a auxiliary pulley (a large one) then from that one you can drive the alternator and spin it to oblivion? kinda like how watch gears work?

Or you could always hand crank it

 

[swampdigger]

Yeah! That's what I'm thinking, riot. My buddy just picked up a lathe, and it should be ready to go in a few days. Might try my hand at making a pulley like you describe.

I'll get some pics when I make a bit more progress.