Return to Master Table of Contents RIGHT SWING OPERATING CIRCUIT When the swing control lever is pushed to the right swing position, pilot pressure from the left side pilot valve is directed to SWING spool of the control valve. Output flow from PUMP(R) is goes to the swing motor. SWING MOTOR PUMP(L) PUMP(R) ATS0810L Figure 8 LEFT SWING OPERATING CIRCUIT SWING MOTOR When the swing control lever is pushed to the left swing position, pilot pressure from the left side pilot valve is directed to SWING spool of the control valve moves in the opposite direction and output flow from the PUMP(R) is goes to the swing motor.
PUMP(L) PUMP(R) ATS0820L Figure 9 SWING RELIEF VALVE AND MAKE-UP VALVE Whenever the spool is shifted to the neutral mode during swing operation, the possibility exists that surge pressure in the circuit - caused by inertial momentum of the upper works and correspondingly reduced pressure at the opposite motor port - could produce cavitation in the circuit. To keep that from happening, a relief valve is installed in the swing motor and a large-capacity make-up valve is connected to the entrance port of the hydraulic reservoir, helping maintain acceptable pressures on both sides of the circuit. NOTE: (3,840 psi) S470LC-V : 280.0 kg/cm Relief Valve Setting Pressure: S420LC-V :
270.0 kg/cm 2 2 (3,980 psi) TRAVEL OPERATING CIRCUIT Output flow from both halves of the pump assembly is directed to the right and left travel motors through the right and left sides of the control valve, and the upper works center joint. Page 9 Hydraulic System Troubleshooting, Testing and Adjustment SWING SWING RIGHT PILOT SWING LEFT PILOT SWING