Komatsu Galeo PC138US-8 Shop Manual page 224

SEN02550-01
Solenoid valve
When solenoid valve is "de-energized" (circuit
is closed)
Coil (1) is de-energized when no signal current
q
is supplied to coil (1).
Spool (2) is pushed back to the left with spring
q
(3) reaction force.
As ports (P) and (A) are closed, the pilot pres-
q
sure is not fed to the actuator through port (A).
At the same time, port (T) is opened, allowing
the oil from the actuator to drain to the hydrau-
lic tank.
42
10 Structure, function and maintenance standard
When solenoid valve is "energized" (circuit is
connected)
Coil (1) is energized when signal current is
q
supplied to coil (1).
Spool (2) is pushed to the right with push pin
q
(4).
As ports (P) and (A) are opened, the pilot pres-
q
sure is fed to the actuator through port (A).
At the same time, port (T) is closed, shutting off
the oil from the actuator to the hydraulic tank.
PC138US, USLC-8