Well, I'm pretty sure the alternator has it's own internal regulator. Which means that there should be no relay or anything in the circuit. (Some of the older alternators do have external regulators, but you wouldn't want to use one of those.) Not sure what the scraping sound would be, but you should have at least 14 volts at the battery with the engine running if the alternator is working.
You should probably just pull the alternator and take it to an auto parts place and let them check it.
61 II 109" Pickup (Restomod, 350 small block, TR4050)
66 IIA 88" Station Wagon (sold)
66 IIA 109" Pickup (Restomod, 5MGE, R380)
67 IIA 109" NADA Wagon (sold)
88, 2.5TD 110 RHD non-hicap pickup
-I used to know everything there was to know about Land Rovers; then I joined the RN Bulletin Board.