The next thing you have to consider about the small case welders is,
They are all NEGATIVE ground.
If you attach a welding lead to their cases, and welding OFF the vehicle, you are fine.
If you try to weld on your OWN vehicle,
The entire vehicle is 'Ground', So you have to use a POSITIVE electrode to do any welding on your own vehicle.
When you crank up that DC output case to ground welder,
You are risking every electrical device in the vehicle.
Batteries HATE pulsing DC and won't tolerate AC at all,
And fuel injection computers/digital ignition boxes/digital radios don't stand a chance unless you unhook them before you weld on your own vehicle.
You can minimize the damage by having a dedicated ground clamp very close to your welding spot,
But stuff like a CDI ignition module is going to let the Magic Smoke out somewhere between 16 and 18 volts,
And you CAN NOT disconnect the ignition on a vehicle with an engine driven welder, no ignition, no engine, no welder.
This little tid bit came to me when I watched a guy burn up an ignition module, replace it with his trail spare, and do it again in the space of about 30 minutes.
Amperage is dependent on the heat you are trying to generate at the welding electrode, the small the electrode (Large stick vs, small wire) uses less amperage,
But you still need between 18 & 24 volts DC to sustain that arc.
You can use a large line diode to keep polarity reversals in the 'Ground' that services everything on the vehicle from happening (AC WELDING, DC IS ALREADY RECTIFIED)
But the voltage pulsing as the arc strikes and breaks,
And the large amperage is still a problem.
One bad 'Ground' between where you are welding and the alternator case, and you get a crappy weld, if it welds at all, and/or you get metal overheating at the bad ground point,
Throw in some rust, some undercoating or a hand full of leaves around the 'Bad Ground' site, and you have a fire when that bad "Ground" point heats up from 50 to 150 Amps DC, and you have a fire instead of just blistering paint or burning the body out around a bolt that wasn't tight.
So a dedicated 'Ground' wire from the case to the weld site is ALWAYS mandatory in my book.
I don't do 'Sheet Metal' work on the trail.
Body damage can wait until I get home.
I can 'Spot Weld' tin by putting the ground clamp behind what I'm working on and applying the other polarity to the metal on the other side,
Crude, but effective. And if I'm doing that in the field, it's good enough until I get home to a MIG welder and I don't have to pack the spool gun and all that goes with it around all the time.
I still build these things for the farm service trucks for the family farm,
Which is were the pictures of the one above came from.
We've tried the small case, several makers, several different conversions,
But nothing lives like the Leece-Neville and is as useful as the Leece-Neville.
The truck has seen some pretty damaged farm equipment in the field before,
But it has the under hood room for the big case Leece-Neville,
And it's got storage for the MIG and all it's crap, TIG and all the crap that goes with it,
And of course, stick welding stuff.
Tractors, plows, cultivators, planters, wind mills, water pumps, you name it, if it's on a farm, we've had to fix it at one time or another...
And the Leece-Neville has held up to all that welding without complaints.
The reason this one showed back up here is the brushes on the slip rings FINALLY wore out after about 8 or 10 years.
I didn't bother to rebuild it, at $100 for a reman and about $5 for the conversion, I just started with a fresh Reman with a warranty.
The best part about these Leece-Neville alternators is, with a little wiring and a couple of switches, the go from charging the vehicle to welder with the flip of a switch,
You will have that regulator laying there doing nothing,
So it's pretty easy to install it in the control box for the welder,
Hook the welding leads to the battery if the primary alternator goes out, and use the Leece-Neville for it's primary task, charging the batteries...
Once you hot wire the rotor in those small case alternators, good luck with getting them back without buying a manufactured unit that someone has figured out how to hot wire the regulator so it can be switched back and forth,
Then you still have to deal with the welding leads switching back and forth...
Like I posted in the beginning of this thread, you can take the 'Insulator Sleeve' off the Delco Screw, but from that point on, it's a WELDER,
If you do what I did, use an 'Eye' ring terminal on both sides,
Control that ground, you can switch back and forth until the regulator gives up from abuse...
IF YOU BUILD THIS WELDING GENERATOR FOR ANYONE ELSE...
You will have to watch out,
They WILL put an electric motor or gas engine on it and use it as a shop welder!
I kept catching my cousin using a big old 220 volt compressor motor to power up the Leece-Neville!
And that's just not it's intended purpose,
First, he was driving it WAY TOO FAST, kept having bearing failures and rectifier failures...
Second, the large AC 220 volt motor was consuming more energy than an actual shop welder would,
Third, they would leave it cranking and cranked up when they weren't welding... WAY TOO MUCH HIGH OUTPUT RUN TIME!
Hard on everything... This isn't an Industrial unit with 'Standby' capabilities...
When I'm out in the Jeep,
In day to day operations, I find two batteries have more uses than two alternators, so I go with dual batteries and weld off them.
I've gone back to welding off the batteries because they are there, I weld so infrequently on the trail, and I don't run into anything out there a 'Rod' won't handle...
Two batteries will give you about 10 minutes of burn time with smaller diameter rods before they need a rest and recharge,
Larger batteries would do more.
I don't carry dedicated welding leads anymore, I've gone to using 4 Ga. welding cable as my 'Jumper' cables, and those double as my welding leads.
Since the engine IS NOT running, and the batteries are NOT plugged into the Jeep when I'm welding,
No issues with toasting anything important (Usually just the hair on my knuckles!
With high amperage 'Quick Connects' I can have the batteries unhooked and plugged back in for welding in about 30 seconds,
And I can be geared up for welding in under 2 minutes without rushing.
Raise hood, unplug the batteries, plug in the welding yoke/jumper cables,
Throw a welding rod in the stinger, gloves, eye protection, and I'm off to the races.
If you need more than 10 minutes of actual burn time on the rods,
Then recharge the batteries for about 20 minutes and go after it again...