Operation CHARM: Car repair manuals for everyone.

Circuit Description

CIRCUIT DESCRIPTION

The generator generates AC voltage in its windings as it is belt-driven by the engine. The rectifier converts this AC voltage to DC voltage. The voltage regulator, a component which is included in the generator frame, has a primary function of controlling the generator's output to meet electrical system requirements. The regulator also controls the charge warning lamp. Fuse 17 supplies battery voltage to the charge warning indicator. With the engine not running and the ignition switch in ON, terminal L of the regulator is grounded internally and the indicator lights up. A small amount of current provided by both the charge warning lamp and the pre-excitation resistor is used to "excite" the magnetic field windings to start the charging process.

With the engine running and the generator charging, terminal L voltage rises and the indicator goes out. If the generator fails to charge, terminal L remains below battery voltage and the indicator remains lit.