Is there a reason that you need to know about that particular alternator?
Also
I'm thinking this plus
- what car?
- What year?
- What electrical modifications?
- Which type of voltage regulator?
What does it matter? Corroded, "looks like a core." Maybe already been rebuilt once. The one FIELD TERMINAL is either broken off or modified to be GROUNDED
That was originally a "square back" AKA somewhere around 73 and later. It has/ had isolated field (two field terminals, incorrectly called "dual field") and one is broken or modified.
So the question "what regulator" are you running is somewhat important, because if you replace that with a similar --later model-- and--isolated field unit--and if-- you have the older 69/ earlier regulator, you will have to ground one field terminal to get it to work
