I bought an alternator today from partco, they done it by car reg plate and its the higher amp 70amp one for rs turbo. Anyway, i get it and find it has 3 connections on it for ring terminals to go onto, the 2 near each other, one bigger than the other which the 2 ring terminals of my wiring loom go to but then theres another one on the alternator. Does anybody know what this would be for, anyone come across the same problem? I wondered if its for a earth strap to go from to the inner wing or something.

cheers