SYSTEM / Electrical System Alternator Operation The alternator consists of field coil FC, stator coil SC and diode D. The regulator consists of tran- sistors T1 and T2, Zener diode ZD and resis- tances R1 and R2. Alternator terminal B is connected to base B of transistor T1 through the circuit [ B R RF (R) (R1) ] . When the battery relay is ON, the battery voltage is applied to base B of transistor T1 so that col- lector C is connected to emitter E. Therefore, field coil FC is grounded through transistor T1. At the beginning, no current is flowing through field coil FC. When the rotor starts rotating, al- ternate current is generated in stator coil SC by the rotor remanent magnetism.
When current flows through field coil FC, the ro- tor is further magnetized so that the generating voltage increases. Thereby, current flowing through field coil FC increases. Therefore, gen- erating voltage increases further and the batter- ies start charging. Alternator B R L Regulator Battery Relay RF (R) R 3 R 4 R 5 R 6 D ZD Battery SC B R 2 C E FC R 1 T 2 B D 1 C E (F) T 1 E (E) T157-04-02-008 T2-5-12