ALTERNATOR GP-CHARGING 3529274 - Caterpillar

Introduction
Illustration 1 g02888145
(1) Main control valve (2) Main relief valve (3) Return passage (4) Parallel feeder passage (5) Valve for flow control (6) Passage (7) Orifice (8) Passage (9) Passage (10) Center bypass passage (11) Passage (12) Orifice (13) Drain passage (14) Drain line to tank (15) Signal line for flow control (16) Main pump pressure (17) Pilot line (18) Flow compensator valve (19) Swashplate (20) Main pump (21) Swashplate control piston (22) Pilot pump (23) Passage (24) Pilot manifold (25) Hydraulic tank (26) Passage (27) Orifice (28) Bucket control valve (29) Orifice (30) Check valve (31) Passage (32) OrificeThe main pump receives signal oil pressure through valve (5) and line (15). This signal pressure (pN) that is created in the main control valve is called flow control pressure. Flow control pressure flows to the regulator at the main pump in order to control the output flow of the pump. Flow control pressure is created during the following machine operating conditions.
All of the joysticks and travel levers/pedals are in the NEUTRAL position.
Any of the joysticks and/or travel levers/pedals are partially moved from the NEUTRAL position in order to perform a fine control operation.
A boom lower operation is performed alone.
Illustration 2 g01502101
Partial cross section of flow control valve (5) Valve for flow control (15) Signal line for flow control (26) Passage (31) PassageThe main pump oil flows through line (16), passage (26), and flow control valve (5). Flow control valve (5) shifts to the right and oil flow takes one of two paths. Part of the oil flows through orifice (12), and return passage (14) to hydraulic tank (25). The other part flows through flow control orifice (27) and line (15). Because the full flow is restricted by orifice (12), the signal pressure (pN) in line (15) becomes maximum. Signal pressure (pN) now flows to the pump regulator and