AP-1200 ASPHALT PAVER Powerpack Caterpillar


The powerpack consists of a diesel engine, six hydraulic pumps mounted on a pump drive gearbox that is mounted on the engine flywheel housing, and a 55 amp alternator. The alternator supplies the 14 volt direct current electricity needed for various machine instruments and control valves. The hydraulic pumps supply the hydraulic oil pressure used for machine operation and control.

The engine is protected against dust and other foreign material in the intake air by a two-stage, paper element air cleaner. Air enters the air cleaner through the inlet tube and is given a cyclonic twist as it passes the pre-cleaner fins. From 75 to 90 percent of the contaminants are separated from the air by the fins. The separated contaminants are thrown from the main air stream and out the dust ejector valve. The pre-cleaner air flows through the main element which removes vitually all (99.9 plus percent) of the remaining contaminants. A safety element inside the main element provides continuous air cleaning if the main element is damaged and also while the main element is serviced.

Fuel for the engine is stored in a 49-gallon (185.4-liter) tank located on the left side of the machine. Fuel used for the screed heaters and for machine washdown is also drawn from this tank.

The pump drive gearbox drives all six hydraulic pumps in the direction of rotation opposite the engine rotation. The functions of the pumps:

1. Ground Drive Pump - supplies the hydraulic oil to the ground drive motor which provides the machine propulsion through a two speed transmission.
2. Right Conveyor Pump - supplies the hydraulic oil to the right conveyor motor which drives the right drag conveyor and right screw conveyor (auger).
3. Left Conveyor Pump - drives the left drag conveyor and left screw conveyor (auger) through the left conveyor motor.
4. Vibrator Pump - powers the screed vibrator motors which turn the screed vibrators.
5. Auxiliary Pump - supplies the hydraulic oil for the various hydraulic cylinders, including the steering system cylinder.

A sixth pump, mounted on the ground drive pump, circulates the wheel drive transmission oil through the filter.