From the emei;
"Alternator
5. The vehicle is fitted with an NSN 2920-66-095-0364 Generator, Engine Accessory, 100 A 28 V dc. For a detailed description of the alternator refer to EMEI Electrical P 412."
It needs to be excited, there are three terminals for it, positive, negative and a exciter feed which is fed by the 24v battery banks, switched via relay by the ignition
it also behaves like an alternator as it needs a few rev's to produce a decent current and voltage
I would love to be able to get a copy of EMEI Electrical P 412, if somebody knew of where to get it, that would be greatly appreciated