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Functional description

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The alternator maintains the desired level of vehicle voltage. The alternator also supplies all electrical consumer units during driving. The controller regulates the output voltage of the electrically excited alternator with uncontrolled rectifier by applying the excitation current.

Fig 1: Identifying Alternator And Plug Connection
G09908593Courtesy of BMW OF NORTH AMERICA, INC.

Example

Index Explanation
1 Alternator
2 Regulator with rectifier diodes
3 2-pin plug-in connection (1 pin used)
4 Positive battery cable

For the alternator with serial data interface, the following functions are implemented in the engine control unit: