Alternator welder

[Iplayfarmer]

Right now it is straight DC...

I've been tempted to build one like you have so that I can have DC. My stick welder is purely AC, and I'm told that there are advantages to DC that I don't have with AC.

 

[alltoys]

I've been tempted to build one like you have so that I can have DC. My stick welder is purely AC, and I'm told that there are advantages to DC that I don't have with AC.

Nothing wrong with an AC machine only advantage to DC is being able to use a TIG and more rods available that will only work on DC. AC for home use is very efficient, rods such as 6011, 6013 work very good on AC and 7014 works the best on AC. 7018 will work on AC but it burns better on DC, although there is a purpose made 7018AC rod that works excellent on AC.

 

[bobodu]

Can't take the AC welder out in the field....or let the neighbor's do their own welding unless they want to run some new outlets. Plus,if I didn't build another welder...that engine would still be sitting on the shelf with the others.

Not a bad paint match!!!

 

[Kernopelli]

Curious how many amps it puts out ( approximately)? Obviously it works pretty well but curious if you can weld heavy material with it? Pretty cool idea, I currently have 3 motors sitting around waiting for a project....One is slated for a band saw mill and I already have 2 welders but maybe I'll need something portable in the future. Would a 5 hp engine produce enough umph for this type of set up?

 

[Aussiebushman]

Right now it is straight DC...

Great job - congratulations. I'm especially interested because I'm also working on a trolley-mounted DC welder so please excuse a few more questions you did not quite explain earlier. You mentioned a heap of Internet articles, but I have found a lot of conflicting arrangements and advice.

Your photos suggest that one welding lead is connected directly to the + terminal of the alternator and the other to the frame. If so, how did you rectify the 3 phase to DC? If you used external stud (power) diodes they are presumably mounted on a heat sink but I can't see them in the pictures?

The car battery is presumably used only to excite the alternator field. Did you use any resistors in that circuit?

A rough schematic would really help please to identify where the bits connect

Thanks and regards

Alan

 

[o2batsea]

If I walked into your garage and saw that thing, the first thing I'd ask is "how fast does it go?" assuming it to be some kind of vehicle. If I had to guess what it was, I think "welder" would be about number 27 on my list of wild stabs. Nice.

 

[2manyrocks]

If I walked into your garage and saw that thing, the first thing I'd ask is "how fast does it go?" assuming it to be some kind of vehicle. If I had to guess what it was, I think "welder" would be about number 27 on my list of wild stabs. Nice.

Put an old tractor seat on it. Post it somewhere else and ask people to guess what it is.

I was having the same question in the back of my mind about how big a welder you could make with a 5 hp lawn mower engine. It doesn't seem so radically different from the homebrew generator at this link: Building your own generator.

 

[bobodu]

From what I gather,at least as far as a marine charging system goes,it rakes roughly 1 horsepower for every 25 amps. I find this to be a very low assumption .
My SA3 had a ten horse Onan and it bogged down so bad that I found it hard to keep an arc lit at 130 amps. That was probably just me but it was bad enough to dampen my enthusiasm.
This alternator is an internal ground with internal diode pack. This has only one positive brush. I used the other empty brush holder and add a spring,brush and a ground wire,cutting the ground lead to the diode pack-insuring full power to the rotor.
This alternator uses big honking diodes not found on an alternator like a S101. They seem to use the alt. casing for a heat sink. Based solely on experience with my Tombstone,I'm gonna say it is pushing 130-140 amps. The only wires are
Battery positive to switch to rotor-Negative battery to ground
Rotor to ground
Positive lead to BAT. terminal
Negative lead to ground
I admit that I didn't put any resisters in line...plain forgot...but it works fine without them.
I'll try to find the link I used. But I caution again...this is a BIG alt....

 

[bobodu]

Here it is...I didn't need the relay because I don't have to protect any car electrics..
Again....not my alt.

On-Board Welder

I found a couple of links where they ran the leads from the battery....not a good idea in my book!!!

Found a picture of the alternator I used..they run $111 to $131 w/out the $27 core at Autozone...$40-50 at a junkyard.

This is a 87 Lincoln Continental 100 amp alt. I am either overclocking it or 100 amps is stronger on DC than AC...I couldn't light up a rod at 100 amps this way on my Tombstone!! Or I got a heavy duty one....never know at a junk yard.

 

[ddbtdd]

Hello and congrats on a great little project!
I have seen these alternator type welders on eBay.
While I am sure they work, I have always wondered how they are to weld with? Getting a good welding machine is half the battle.
I always loved those old torpedo type welders when they were running right. A good machine does half the work.
So how does it feel to weld with?