Someone had put a Bosch regulator on a 30 tractor I purchased years ago. Somehow it got moisture in it and became badly corroded. I just purchased a new regulator identical to the one that was on it. I don't remember how to polarize it. The generator has one wire coming through the housing and one post with a wire on it. I don't remember which one is the field and which one is the armature. Looking for advice.