STRUCTURE, FUNCTION, & MAINTENANCE STANDARD HYDRAULIC PUMP 12O FUNCTION The EPC valve consists of the proportional sole- noid portion and the hydraulic valve portion. When it receives signal current i from the pump controller, it generates the EPC output pressure in proportion to the size of the signal, and outputs it to the LS valve. OPERATION 1. When signal current is 0 (coil deenergized) When there is no signal current flowing from the controller to coil (5), coil (5) is generalized. For this reason, spool (2) is pushed to the right in the direction of the arrow by spring (3). As a result, port PEPC closes and the pressurized oil from the main pump does not flow to the LS valve.
At the same time, the pressurized oil from the LS valve passes from port PSIG(PM) through port PT and is drained to the tank. 08890 PC210/240-7K 10-49