Alternator Functional Diagram Alternator Functional Diagram DC Current

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 Three Diodes One per Phase Sample Battery Voltage Six Output Diodes Two per Phase Full -Wave Rectifier

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

Regulator Inputs • Control Voltage Input – 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 – 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 selfsustaining

Alternator Circuitry

Warning Lamp • Turn ignition ON, – 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

Inside the Regulator IC 1+Ic 2 Field Current Ic 1 Sample Battery Voltage

Regulator Circuit • When battery voltage is OK, – D 1 conducts – T 2 conducts – Less current through T 1 collector – T 3 turns Off – Field current now reduced

Regulator Circuit (continued) • When battery voltage is low, – D 1 is Off – T 2 is Off – More current flows through T 1 collector – Transistor T 3 turns On – Field current increases