Alternator & Regulator - BOSCH: Description

NOTE: Some Volvos may have a Nippon Denso alternator. Testing information on these alternators is not available from the manufacturer.

Bosch alternators are a conventional 3-phase, self-rectifying type. Bosch 55-amp through 75-amp alternators have 3 positive and 3 negative diodes connected to stator windings to rectify current. Bosch 80-amp and 90-amp alternators have 14 diodes. All alternators use 3 exciter diodes connected to stator windings. These diodes turn off the alternator indicator light and supply power to voltage regulator while engine is running. Voltage regulator is transistorized.