BREATHER GP-POWER TRAIN 4948975 - Caterpillar

Illustration 1 g01430690
Generator Hydraulic System (OFF) (1) To return filter in hydraulic tank (2) To port "B" cooler manifold (3) Generator motor (4) Flow compensator spool (5) Pressure compensator spool (6) Bleed orifice (option) (7) Relief valve (8) Flow control valve (9) Generator control solenoid (10) Generator pump (11) Displacement piston cavity (12) Bias piston cavity (13) To port "L1" on auxiliary pump (14) From hydraulic tank port "2" (15) To tee on left propel pump (16) Generator manifoldWhen the engine is not operating, the bias piston spring forces the swashplate in the generator pump to the maximum angle. When the engine is started, the pump begins to produce flow. Supply oil is sent to the pressure compensator spool and to the flow compensator spool inside the pump. Supply oil is sent out of port "B" of the pump to port "P" of the generator manifold. When the generator is not operating, the generator control solenoid is de-energized. In this situation, supply oil is blocked at the spool of the generator control solenoid. As pressure increases in the system, supply pressure forces the flow compensator spool to shift against the combined force of the margin spring and signal pressure. This shift sends some oil into the displacement piston cavity and this shift causes the pump to destroke. As the swashplate angle decreases, the displacement piston uncovers a passage for oil to flow from the displacement piston cavity and into the pump case.At this point, supply pressure decreases, and the combined force from the margin spring and signal pressure causes the flow compensator spool to shift. This shift closes the passage for supply oil in order to reach the displacement piston cavity, and the swashplate angle increases. Eventually, the load sensing spool reaches equilibrium, and the pump operates at low pressure standby. The pump produces enough flow for system leakage at low pressure standby. System pressure at low pressure standby is equal to signal pressure plus margin pressure.Note: Low pressure standby is not independently adjustable. Low pressure standby may vary from one machine to another machine. Low pressure standby may also vary in the same pump as the system or pump leakage increases.
Illustration 2 g01430693
Generator Hydraulic System (ON) (1) To return filter in hydraulic tank (2) To port "B" cooler manifold (3) Generator motor (4) Flow compensator spool (5) Pressure compensator spool (6) Bleed orifice (option) (7) Relief valve (8) Flow control valve (9) Generator control solenoid (10) Generator pump (11) Displacement piston cavity (12) Bias piston cavity (13) To port "L1" on auxiliary pump (14) From hydraulic tank port "2" (15) To tee on left propel pump (16) Generator manifoldWhen the generator control switch is in the ON position, the generator control solenoid is energized. Pump supply oil flows through the flow control valve and across the generator control spool. The flow control valve can be adjusted in order to control the frequency of the generator.Downstream from the generator control spool, supply oil is sent out of port "A" to