Charging System Circuit Description. Pontiac Sun Runner - 4WD (Canada) 1998

For 1990-2009 cars

The generator provides DC voltage to operate the vehicle's electrical systems and to recharge the battery. The voltage output of the generator is controlled by a built-in IC regulator.

With the ignition switch in the ON position, battery voltage is applied through the IG-COIL METER fuse and the Charge Indicator to the IC regulator in the generator. When the generator is not rotating, the IC regulator provides a ground and causes the Charge Indicator to light.

AC voltage is generated in 3 stator coils. This AC voltage is converted (rectified) to DC voltage in the rectifier bridge. The DC output is applied to the vehicle's battery and electrical supply circuits at the BAT terminal of the generator. A separate output voltage is provided to the Charge Indicator. Since equal voltage is now being applied to both sides of the Charge Indicator, the lamp loses its ground and goes out.

The IC regulator is also connected to battery voltage through the generator BAT terminal. When the Battery is fully charged, the IC regulator senses this and reduces the output of the generator, preventing an overcharge condition. When the battery is drained, the IC regulator senses the low voltage and increases the output of the generator.