1. Fault Phenomena
The rotating speed is normal, but the rotating pressure is too high and there is periodic vibration sound.
2. Fault diagnosis and troubleshooting
(1) Check whether this phenomenon exists in one or both directions at first. If only one direction exists, then there is a problem with the overload safety valve on the rotary motor. After overhaul or replacement, the fault can be eliminated.
(2) If this phenomenon occurs in both directions, observe whether the rotary brake solenoid valve acts at the beginning of the turn. Touch the outlet hose of the rotary brake solenoid valve and check for a sense of pilot pressure oil flow. If there is no sound of rotary brake valve acting and no sense of hydraulic oil flow, check the terminal of the solenoid valve wiring and the related wires. Are there poor contacts or open circuits? If abnormal, repair and troubleshoot.
(3) Although the swing brake solenoid valve is energized, it has neither sound of swing brake solenoid valve action nor sense of pressure oil flow, which indicates that the swing brake solenoid valve is faulty and the faults can be eliminated after replacement.
(4) When turning back at the beginning, if the rotary brake solenoid valve makes an action sound and there is a sense of flow of pilot pressure oil when touching the outlet hose of the solenoid valve, check the oil discharge of the rotary reducer for impurities such as metal powders and check the vibration sound of the reducer housing. If impurities and vibration sounds are found, then the gears in the rotary reducer, and Bearings and oil seals are damaged to varying degrees and can be eliminated after corresponding repairs.
(5) If there are no impurities in the oil discharge of the rotary reducer and no abnormal noise in the housing of the reducer, the rotary brake is faulty. After repair or replacement of the excavator, the faults can be eliminated.
