DESCRIPTION
Volvo S80 is equipped with either a 120 or 140 amp Bosch generator. Generator generates AC current which is converted to DC current in the DC bridge. Generator has a built-in charge regulator. Accessory drive belt transfers power from crankshaft pulley to power steering pump, air conditioning (A/C) compressor and generator. Belt tension is tensioned using an automatic belt tensioner. Belt is a Poly-V-belt. Generator with charge regulator can be diagnosed through the central electronic module. When testing generator, measure voltage between generator terminal B+ and generator case. Measure voltage no less than 10 seconds after starting engine.
OPERATION
The charge regulator is connected to the central electronic module via an L-signal. The L-signal is used to pre-magnetize the generator rotor and to transmit signals to the central electronic module telling the central electronic module that the generator is charging or not when the engine is running. When the engine is starting, the generator (GEN) does not charge. When the engine speed (RPM) passes approximately 550 RPM a delay of approximately 3 seconds occurs. After the delay a successive increase of charging begins.
When the generator (GEN) is at full load the increase ranges from 0-100% for a period of 6 seconds. If the engine speed (RPM) passes approximately 1300 RPM during the delay or the successive increase breaks the increase, full charging is obtained immediately. This is to successively increase the load on the engine during the start-up phase and to ensure the engine starts. If the L-signal is missing the generator will not start charging on start-up. Charge regulator can self magnetize the rotor and start charging in this way. This only happens at speeds in excess of approximately 2300 RPM. There is no successive charge engagement with self magnetization, the generator operates at full charge immediately.