Generators & Regulators: Description

Bosch and Motorola conventional 3-phase, self-rectifying type generators use 3 exciter diodes connected to stator windings. These diodes turn off generator indicator light and supply power to voltage regulator while engine is running. Bosch voltage regulators are transistorized and integral with generator. Some 5- and 7-series vehicles are equipped with a 150-amp water-cooled generator.

An unloader relay is used in the 5-series and 7-series vehicles. With ignition on and engine off, the relay receives battery voltage (B+) through fuse No. 28 and is grounded through terminal D+ of generator. The relay energizes and switches ground to some accessories. When engine is running and the generator begins to charge, battery positive voltage is also applied to terminal D+ to switch off relay.