Over the years I have saved the Denso (Nippondenso) alternators on my 740s and 940s before the cars went to the crushers. I have several 80A Denso and 100A Denso alternators.
I removed the brush assembly in an 100A alt. yesterday and there was lots of corrosion which ended with broken screw tabs on the regulator where one tab of the brush assy. screw went. So, since the regulator is a voltage regulator, not a current regulator, I'm wondering if the 80A and 100A regulators are interchangeable. Physically, I think they are, but electrically? I have an 80A alt. with very little corrosion (salt state here) so I think the regulator screws should be easy to remove and I was thinking of putting that regulator in the 100A alt? Of course I could just use the 80A alt. but I'd like to keep that car, a 1994 940, as it was built 25 years ago.
It is interesting that the slip rings on the 100A are not in as good of condition as the 80A units I have seen.
Another question? To test the alternators, should it work to put the alt. in a vice and connect a battery + to the armature output (large stud), connect the battery + to a 12V bulb and the other side of the bulb to the field (sense) connection, and the battery - to the alt. case grd. connection. Then, spin up the alt. with a drill? Monitor the alt. voltage with a voltmeter across the battery. I tried this but don't think the drill spun the alt. up fast enough to get a higher voltage?
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Mine:3-940s running, 1-740, 2-940 parts, dtrs:4-940s running