RADIATOR GP 3122177 - Caterpillar

Rotate Circuit Systems Operation
ROTATE PUMP (1), ROTATE VALVE (2), DIRECTIONAL VALVE (3), TANK (4), CYLINDER PORTS (5), SOLENOIDS (6), NEEDLE VALVES (7), CHECK VALVES (8), ROTATE MOTOR (9), LINE RELIEFS (10), MAIN RELIEF (12)The rotate pump output (1) is directly proportional to engine speed. When directional valve (3) is in the neutral position flow returns directly to tank (4). Cylinder ports (5) are open when either solenoid (6) is energized. Flow passes through the check valve (8) to the motor (9). Return oil to tank (4) is restricted by needle valve (7) to limit the speed of the motor (9). Should rotate motor (9) stall, the main relief valve (12) will open and dump the flow back to tank (4). If the directional valve (3) is in the neutral position and rotate motor (9) is turned by an outside force, line reliefs (10) open and allow oil to flow to the opposite line allowing the motor to rotate.Speed Control Circuit
Speed Control Schematic (1) Pilot Line. (2) Pressure Reducing Valve. (3) Main Valve Stem. (4) Check Valve.When pressure is applied to pilot line (1) from the pilot control valve, pressure reducing valve (2) reduces pressure to the pilot cap on the main valve stem (3). The adjustable pressure from valve (2) regulates the amount the main valve stem (3) shifts. The adjustable amount the main valve (3) shifts will control the speed of the hydraulic motion in this circuit. When the pilot control valve is neutralized, pilot oil in the main valve stem cap (3) is dumped through the check valve (4) and back through the pilot control valve.