Anthony,
Sorry for the late reply.
The alternator is a regular 90 amp chrysler. It got it from a junk yard and it said Dodge Caravan but it works for my 92 Dakota 5.2 and it looks like the jeep 4.0 alternators of that year.
The key is to use an externally regulated alternator.
There are plenty of web sites that show you how to do a GM or Ford alternator but none I found for this type of alternator.
Assuming you have the same alternator, there are three terminals on the back, one is a big one that is the positive out to the battery, this terminal is connected to the stinger (i.e. rod holder), the other two smaller terminals control the voltage generated by the alterntor (dont ask me how exactly - windings, stator ???? I dont know). One (it does not matter which one) should be attached to ground, the other should be attached to a switched 12 VDC (Pos side of the battery). The case of the alternator can be attached to the ground clamp using any of the mounting bolts.
You can test if the field voltage is working by turning the alternator by hand without Pos 12VDC, it should spin easily. When you hook up the 12 VDC to one small terminal and the other to ground it should be harder to spin the alternator. If you have a multi meter, hook it up to the battery output post and to the case, and spin the alternator with 12VDC on the field terminals, you should see some voltage.
The external regulator varies the field voltage to make the alternator put out 14 VDC to charge the battery, no more no less. The alternaotr can supply 120+olts DC if it was spun fast enough and given full field voltage. What we do is apply 12 VDC and that maxes out what the alternator can do.
The mounting bracket I made and mounted to the alterntor mounting bolts and to a power steering mounting bolt.
You'll have to fabricate one yourself.
I made up welding cable from 50 ft of #4 welding cable and I used quick connects (400amp ones for a winch). The rod holder was a set of jumper cables and a vice grip pliers if you remember.
Once you get it mounted and spinning, you can check the voltage output between the pos out to the battery (+ terminal) and the alternator case (ground) while the engine is at idle. It should be about 20-30 VDC. I had to play with the RPM settings to find the right RPM for welding. My setup runs at 1700 RPM and I get 38-40 VDC. At 2400 RPM I get 110 VDC enough to run a HF 4.5 inch grinder. (I just wired a short piece of extension cord to the welder cables).
You might want to try 1900-2000 RPM for thicker rod.
The only concern I have is I've been told the difference between the alternators setup for the OBW like Mobiweld and the like is the bridge diodes are extra beefy to handle to extra current generated by the alternator. I dont know how long my alternator will last but I can always get another at a junk yard for cheap.
Good luck with this. Here are some picts.
