Self-Study Program

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Alternator
Functional principle of the alternator regulator
The current output of the alternator depends on the excitation voltage, and hence the excitation current.
Transistor T connects the voltage applied to B+ to the excitation winding at a frequency of approximately
150 Hz. The resultant excitation current I
Exc
or I
Exc_eff
, from 0 A to max. 8 A, is directly proportional to
alternator current output.
Alternator characteristic
The diagram gives a qualitative overview of the relationship between speed and current output under full
alternator load, i.e. the characteristic curve gives the maximum possible current output for each speed.
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I
Exc_eff
I
Exc
U
Err
=U
Exc
I
Err
=I
Exc