RETARDER

The compressor builds up & maintains air pressure required to operate air brakes & are either gear driven directly from the engine or belt driven. Most compressors use the truck’s lubrication & cooling systems, some are self-lubricated & some are air cooled. All compressors run continuously while the engine is running, but air compression is controlled and limited by a governor which loads or unloads the compressor. In the loaded stage, air is pumped into reservoirs. In the unloaded stage (with two cylinder compressors), the compressor pumps air back and forth between the two cylinders without supplying the reservoirs.