I have never heard of a "one wire alternator" which has more than one wire.
One wire alternators only have the 10 gauge wire held on by a nut on the back of it. This 10 gauge wire goes to the ammeter. This alternator is energized internally once a certain RPM is achieved.

1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission