The crane has no movement when getting on the car, so the maintenance will be done

Fault phenomenon

1. When the car is idling, there is no movement of the slewing or the main and auxiliary winches
The pressure gauge that controls the pressure during idle is only 1.3MPA
3. The pressure on the main oil circuit pressure gauge is very high
When the engine speed reaches 1800r/min, the operation is normal

Fault cause analysis
1. Both the turning and main/auxiliary winches on the car have brake cylinders, and if there is no action, it is basically certain that the brakes have not been opened
2. The low pressure in the control oil circuit of the car causes the brake to fail to open
3. There is a pressure relief area in the control oil circuit, which causes the control pressure to not rise and the brake to not be released
4. Damage to the oil pump in the control oil circuit

Troubleshooting methods and results
Based on the observed fault phenomena on site, we can start from the aspect with the highest frequency of faults and the easiest to handle. Firstly, adjust the pressure of the control oil circuit. When the pressure is adjusted to above 3mpa, the action will be normal and the fault will be eliminated. If there are other parts that have problems, the same fault phenomenon will also occur.