Alternator Functional Diagram

Alternator Functional Diagram DC Current Applied to the Rotor

Alternator Functional Diagram 3-Φ AC Output from the Stator DC Current Applied to the Rotor

Alternator Functional Diagram 3-Φ AC Output from the Stator DC Current Applied to the Rotor Six Output Diodes Two per Phase Full-Wave Rectifier

Alternator Functional Diagram 3-Φ AC Output from the Stator DC Current Applied to the Rotor Six Output Diodes Two per Phase Full-Wave Rectifier Three Diodes One per Phase Sample Battery Voltage

Alternator Functional Diagram 2 Inputs Regulator Controls the Amount of Field Current applied to the Rotor

Regulator Inputs Control Voltage Input Field Current Supply Controls current through the Rotor Field Current Supply One input from the alternator via the Diode Trio Second input from the battery via the warning lamp

Regulator Action If the battery voltage drops, more current applied to the rotor, increasing the magnetic field strength, increasing the alternator voltage output. If the battery voltage increases, less field current applied to the rotor, reducing the alternator voltage output.

Field Current Supply Two Sources Turn ignition ON, Alternator via the diode trio Battery via the warning lamp Turn ignition ON, Source of field current is the battery via the ignition switch and the warning lamp

Field Current Supply (continued) After engine starts, Alternator is up to speed, output of diode trio is fed back to the regulator and serves as the source of the field current. Alternator is now self-sustaining

Alternator Circuitry

Warning Lamp Turn ignition ON, Alternator at full output, Current flows through warning lamp, transistors, and field coil to ground, causing the lamp to illuminate. Alternator at full output, Voltage from diode trio equals the battery voltage equal voltage on both sides of lamp lamp goes out.

Warning Lamp (continued) If the alternator fails, Voltage out of diode trio drops Lamp illuminates from the battery voltage If the battery fails, Battery voltage drops Lamp illuminates from the alternator voltage

Sample Battery Voltage Inside the Regulator IC1+Ic2 Ic2 Field Current Ic1 Sample Battery Voltage

Regulator Circuit When battery voltage is OK, D1 conducts T2 conducts Less current through T1 collector T3 turns Off Field current now reduced

Regulator Circuit (continued) When battery voltage is low, D1 is Off T2 is Off More current flows through T1collector Transistor T3 turns On Field current increases