Hydraulic features play an essential role in the success of Komatsu's PC200LC-8 excavator.
Realizing the awesome power of hydraulics makes it easy to forget that it is still a rugged, precise, and highly reliable means of control. That's why Komatsu continues to use hydraulic joysticks and other controls in their hydraulic excavators, such as their new PC200LC-8. Peter Robson, excavator product manager at Komatsu, says, "The hydraulic implements continue to be hydraulic controlled due to their long term reliability and durability."
But that doesn't mean the PC200LC-8 is low tech. It features Komatsu's HydrauMind system that matches pump speed to engine speed for maximum power and fuel economy. HydrauMind is a closedcenter system with pressure compensation and load-sensing valves that transmit just enough hydraulic power to satisfy load requirements. Pilot pressure for controlling the hydraulics is 470 psi.
The excavator also features five working modes that automatically adjust the hydraulic system to the task at hand. For example, Lifting Mode increases maximum operating pressure by 7%, whereas Economy Mode adjusts flow and pressure for maximum fuel economy.
To keep the PC200LC-8 running reliably, Komatsu engineers specified filtration for pressure lines. Robson explains, "All of Komatsu's conventional excavators come standard with 100-µm high-pressure in-line filters (screens) installed at each pump discharge port to provide added protection from hydraulic system contamination." Another precautionary feature is a partition separating the pump and engine compartments. This would prevent hydraulic oil from spraying on the engine in the unlikely event of hose failure.
The PC200LC-8 is powered by a Komatsu diesel engine that delivers 148 hp @ 2000 rpm at the flywheel to drive hydraulic pumps for all work operations. A variable-displacement, axial-piston pump drives a pair of axial-piston travel motors in a hydrostatic drive for propulsion. Maximum pressure for the hydrostatic drive and implement circuits is 5400 psi.
The main pump also provides hydraulic power for an axial-piston swing motor, and for boom, arm, and bucket cylinders. The swing motor drives a planetary gearbox that develops up to 49,907 lb-ft of torque to turn the cab house at up to 12.4 rpm. As with the main pump, motors, cylinders, and gearboxes are Komatsu designed and manufactured.
