As 5-90 notes, the 91-up models using the Mitsu. alternator have the regulator in the ECU, and we'd better hope those things are good, because that is indeed a very expensive bit of integration! Because an alternator doesn't require current regulation, the voltage regulator is required only to control voltage, and that is the same whatever the alternator's current output, which explains why you can upgrade alternators without worrying about the regulator. The regulator switches current to the field, controlling its magnetism, which controls the voltage induced in the stationary windings. In order for this to work, unfortunately, the field cannot have significant residual magnetism (you couldn't regulate it then) and this means that there must always be an outside source of current to "excite" the field or it won't start generating. I don't know about special applications, but I've never run across an automotive alternator that was self-exciting. Whatever the connections and regulation, you'll need at least a smidgen of current in the battery to get it going.