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Alternator & Regulator: Description

Bosch alternators are conventional 3-phase, self-rectifying type alternators. Bosch 55 through 75 amp alternators use 6 diodes (3 positive and 3 negative) connected to stator windings to rectify current. Bosch 80 and 90 amp alternators use 14 diodes, instead of 6.

All alternators use 3 exciter diodes connected to stator windings. These diodes turn off the alternator indicator light and supply power to the voltage regulator while the engine is running. Bosch regulators are transistorized solid state and integral with alternator.

Fig 1: Cutaway View of Bosch Alternator
G29365
ALTERNATOR APPLICATION

Model Volts/Amps (1) Manufacturer's Part No.
Coupe & 4000S 4-Cylinder
Without A/C 14/65 049 903 017A
With A/C 14/90 049 903 027
Coupe & 4000S 5-Cylinder
Without A/C 14/65 034 903 015C
With A/C 14/90 034 903 015D
4000CS Quattro 14/90 034 903 015D
5000CS Turbo & 5000S 14/90 034 903 015D
(1) Bosch alternator part numbers are preceded by the numbers 0 120.