Komatsu Galeo PC138US-8 Shop Manual page 177

10 Structure, function and maintenance standard
LS select valve
1. During normal operation
Function
At the time of simultaneous operation of swing
q
+ boom RAISE, this valve prevents high swing
LS pressure from entering the LS circuit (PLS)
and also prevents the boom RAISE speed
from reducing by securing the pump flow at the
time of swing drive.
Operation
The pilot pressure is not generally applied to
q
the pilot port (BP) except for boom RAISE
operation.
In this state, the pump discharge pressure
q
(PP) pushes the valve (1) to open it and is led
to the pressure reducing valve (4) of the swing
valve. At the time of swing operation, there
occurs the LS pressure (PLS) suitable for the
load pressure, and the pressure is led to the
pump LS valve.
PC138US, USLC-8
SEN02549-02
43