Alternator & Regulator - BOSCH: Description

Bosch alternators are conventional 3-phase, self-rectifying type alternators. The 900 Series use either Bosch 70 or 80 amp alternators. The 9000 Series use Bosch 80 amp alternator. An internal regulator is used on the Bosch 70 amp alternator. An external regulator is used with the Bosch 80 amp alternator. These alternators are internally ventilated and have a 12-pole rotor.

The Bosch 70 amp alternator has 6 silicon diodes while the Bosch 80 amp alternator has 14 silicon diodes. An exciter diode is connected to each of the 3 stator windings. These diodes turn off the alternator indicator light and supply power to the voltage regulator while the engine is running. The voltage regulator limits the voltage to a maximum of approximately 14 volts.