1. Failure phenomenon
The rotation speed is normal, but the rotation pressure is too high, and there is periodic vibration sound.
2. Trouble diagnosis and troubleshooting steps
(1) First check whether this phenomenon exists in one direction or in both directions. If there is only one direction, it means that there is a problem with the overload safety valve on the rotary motor. After repairing or replacing it, the fault can be eliminated.
(2) If this phenomenon occurs in both directions, observe whether there is a sound of the rotary brake solenoid valve at the beginning of the rotation. Touch the outlet hose of the rotary brake solenoid valve to check if there is a feeling of pilot pressure oil flowing. If there is neither the action sound of the rotary brake valve nor the feeling of hydraulic oil flowing, check the solenoid valve terminals and related wires for poor contact or open circuit. If it is abnormal, repair it and the fault can be eliminated.
(3) Although the rotary brake solenoid valve is energized, there is neither the sound of the rotary brake solenoid valve operating nor the feeling of pressure oil flowing, which indicates that the rotary brake solenoid valve is faulty, and the fault can be eliminated after replacement.
(4) At the beginning of the swing operation, if the swing brake solenoid valve emits an action sound and there is a feeling of pilot pressure oil flowing when touching the solenoid valve outlet hose, check whether there is metal in the drain of the swing reducer For impurities such as powder, check the vibration of the reducer housing. If impurities and vibration sound are found, it means that the gears, bearings and oil seals in the rotary reducer are damaged to varying degrees, and the fault can be eliminated after corresponding repairs.
(5) If there is no impurity in the oil discharge of the rotary reducer and no abnormal noise in the reducer housing, it means that the rotary brake is faulty. After the excavator is repaired or replaced, the fault can be eliminated.
