Pilot Control

In most case, the engines in hydraulic excavators drive three large hydraulic pumps. The two main pumps are for supplying oil at high pressure (up to 5000 psi @ 100 gpm) for the arms, swing motor, track motors, and accessories, and the third pump is a lower pressure (~700 psi) unit for pilot control. This circuit is used to control the spool valves so that less effort is required to operate the controls. Generally, the three pumps used in excavators consist of two variable displacement piston pumps and a gear pump, for example Concentric's high performance W900.

W300

Displacement: 0.8 - 5.7cc
Max. Pressure: 230 bar (3,335 psi)
Max. Speed: up to 6000 rpm

GC

Displacement: 1.0 - 11.6cc
Max. Pressure: 275 Bar (4,000 psi)
Max. Speed: 4,000 rpm

High/Low

Displacement: 1.0 - 22.8cc
Max. Pressure: 207 Bar (3,000 psi)
Max. Speed: 4,000 rpm

Multiples

Displacement: 1 - 161cc
Max. Pressure: 275 Bar (4,000 psi)
Max. Speed: 4,000 rpm

W600

Displacement: 3 - 12cc
Max. Pressure: 276 bar (4,000 psi)
Max. Speed: 700 to 4,000 rpm

WQ900

Displacement: 6 - 23 cc
Max. Pressure: 230 bar (3,400 psi)
Max. Speed: 500 to 4,000 rpm

W900

Displacement: 6 - 28 cc
Max. Pressure: 276 bar (4,000 psi)
Max. Speed: 500 to 4,000 rpm

Calma Series

Displacement: 6.2 - 23.7cc
Max. Pressure: 250 Bar (3,625 psi)
Max. Speed: 4,000 rpm

F12 Ferra

Displacement: 16 - 41cc
Max. Pressure: 276 bar (4,000 psi)
Max. Speed: 3,000 rpm

F15 Ferra

Displacement: 19 - 50cc
Max. Pressure: 276 bar (4,000 psi)
Max. Speed: 3,600 rpm

W1500

Displacement: 19 - 50cc
Max. Pressure: 276 bar (4,000 psi)
Max. Speed: 500 to 3,300 rpm

F20 & F30 Ferra

Displacement: 23 - 161cc
Max. Pressure: 276 bar (4,000 psi)
Max. Speed: 3,600 rpm

F20LS/F30LS

Displacement: 23 - 161cc
Max. Pressure: 276 bar (4,000 psi)
Max. Speed: 3,600 rpm

W1200

Displacement: 25 - 33cc
Max. Pressure: 214 Bar (3,100 psi)
Max. Speed: 700 to 3,000 rpm

D

Displacement: 3.81 to 13.33 cc
Max. Pressure: 207 Bar (3,000 psi)