Komatsu PC500LC-10R Shop Manual page 226

COMPONENT PARTS OF HYDRAULIC SYSTEM
FUNCTION OF MAIN PUMP PC-EPC VALVE
Upon receiving signal current (i) from the pump controller, it
generates EPC output pressure in proportion to that signal cur-
rent and outputs it to the PC valve.
OPERATION OF MAIN PUMP PC-EPC VALVE
When signal current from pump controller is zero (coil de-energized)
1.
When the signal current from the pump controller does not
flow through coil (2), coil (2) is de-energized.
2.
Spool (5) is pushed to the left by spring (4).
3.
Port (P) is closed, and the pressurized oil from the self-
pressure reducing valve does not flow to PC valve.
4.
The pressurized oil from PC valve is drained to the tank
through port (C) and port (T).
10-132
10 STRUCTURE AND FUNCTION
PC500LC-10R