HARNESS AS-WIRING 1911531 - Caterpillar

The conveyor drive hydraulic system is an open-center system. Hydraulic oil flows from the hydraulic oil tank to the dual unit pump, to the upper conveyor and lower conveyor motors, and then back to the tank. Each unit of the dual unit pump drives one motor. Anytime the engine is running, the conveyor drive pump is discharging hydraulic oil. The oil from each unit flows through a pilot operated relief valve that is controlled by auxiliary hydraulic pressure. When the conveyor on-off control is at "On", auxiliary pressure is applied to the valves, closing the valves and causing the hydraulic oil to flow to the conveyor motors. When the conveyor on-off control is at "Off", the auxiliary pressure is cut off from the valves, the valves open, and the hydraulic oil flows through the valves to the return manifold.Return oil from the conveyor system flows to the return manifold, through a 10 micron filter, through the oil cooler, to the oil tank. If the filter elements get clogged, a 40 psi relief valve will open and allow the oil to flow directly to the tank, bypassing the filter and the oil cooler. A thermostat valve will open to bypass the oil cooler if the oil is cold.