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Maximum permissible pressure (Hydraulic
lift element) 207 bar.
Repair or replace the pump if capacity is
less than 75% of normal value.
c.
Relief valve pressure
Install a pressure gauge (-0-210 kg/cm
2
)
140 bar in the external jack tapping.
(auxiliary port) with the draft control lever
in the top most position and the engine at
full throttle the pressure should be as per
specification.
1. To avoid over heating of the system the
pressure test should not be maintained for
more than 30 seconds.
2. After completion of the test the draft
control lever must be return to the deepest
position other wise serious damage to the
hydraulic system may result. If the recorded
pressure is not as per the specification while
the relief valve is operating, the relief valve
spring must be checked.
If the relief valve is OK and not getting
specified pressure, either the compensator
spool has stuck in the fully opened position
or the pump efficiency is low.
d. Back Pressure
With the draft control lever in the deepest
position and the position control lever in
the full lower position, the gauge should
read zero.
e.
Speed of Lift and Lower
Move the position control to lift. Full lift
should be completed in not more than
three seconds.
Move the lever to lower and check that it
is possible to control the drop so that at
least two seconds are taken for a full drop.
f.
Isolating Valve Leakage
Raise the weights fully then close the
isolating valve.
With the control lever in “Lower” there
should be no more than 0.127mm drop of
the lower link ends in 30 seconds.
Open the isolating valve
fully after the above test.
g. Position Control Valve Leakage Test
Fully lift the weights (600kg) then return
the position control lever to a mid position.
There must be no more than 0.3mm drop
of the link ends in 30 seconds.
With the lever in the lowest position the
link ends must be not more than 127mm
from the ground.
WARNING :
WARNING :
Hy-tec Hydraulics
