Service Manual User guide

SECTION 3 - CHASSIS, PLATFORM & SCISSOR ARMS
3-18 – JLG Lift – 3121322
Operation
3 Sections to the pump:
• Section 1 (22.5cc/rev - 51 L/m) Main flow to control
valve
• Section 2 (8cc/rev - 18 L/m) Secondary flow to control
valve
• Section 3 (2cc/rev - 4.5 L/m) Flow to steering valve
Pump Flow
• Flow from the first 2 pump sections to the control valve
is protected by dump valves which normally open to
tank ports. To generate hydraulic power to the control
valve, the dump valves need to be activated. Section 1
valve for main flow and section 2 valve to enable high
drive speed.
Figure 3-16. Gear Pump
Table 3-5. Gear Pump Specs.
FIRST STAGE
Displacement 22,8 cc/rev
Rated Pressure 2611 psi (180 bar)
Peak Pressure 2901 psi (200 bar)
Maximum Speed 3000 rpm
Minimum Speed at Rated Pressure 1000 rpm
SECOND STAGE
Displacement 8,4 cc/rev
Rated Pressure 3626 psi (250 bar)
Peak Pressure 4061 psi (280 bar)
Maximum Speed 4000 rpm
Minimum Speed at Rated Pressure 1000 rpm
THIRD STAGE
Displacement 2 ,09 cc/rev
Rated Pressure 3626 psi (250 bar)
Peak Pressure 3916 psi (270 bar)
Maximum Speed 4000 rpm
Minimum Speed at Rated Pressure 1000 rpm