Ray, attached is some information from a training manual published by Delco Remy. In particular, start at paragraph 4 where it describes how the alternator initially starts with battery voltage, and then paragraph 7 where if first confirms the connection, then describes how the diode trio takes over.
Due to this, if the indicator light bulb is burnt out, the alternator may not charge. The first step to trouble shoot this system is to always check that the bulb lights, key on, engine off. Many alternators have been replaced due to not first checking that the bulb lights first.
Tom
