oh man, you said 1/3, thats a small motor. i really cant see much you can do with that less HP. Alternators Can be monster machines depending on how you use them.. now if you want to take that small motor and spin an alternator it would be good to charge batteries with, IF the battery just needs a small charge, but if the battery needs to much charging it will pull that small motor down to much.
this is just what i think, i'm not even really sure that motor would even turn and alternator under any load.