The reason of gear oil shortage in excavator rotation is analyzed.

1. Except for hydraulic motors and gearbox, other devices can not work properly.

2. Overwear of friction pairs of hydraulic motors leads to pressure oil leakage.

3. The main part of the hydraulic motor is broken, and the hydraulic motor itself emits abnormal noise.

4. Hydraulic motor overload due to improper adjustment of relief valve.

Cause analysis of failure of excavator hydraulic motor that can not rotate, failure inspection and maintenance plan:

1. Check whether the inlet pressure oil pressure of the hydraulic motor reaches the prescribed pressure, and then repair and check other devices.

2. Replace abnormal worn parts; Clean all parts carefully before assembly;

3. Dismantling and replacing broken parts; cleaning carefully before reassembly;

4. Check the setting pressure of load and relief valve.

Fault site inspection results: due to improper adjustment of relief valve, hydraulic motor overload.

Analysis of possible causes:

1. Adjust the secondary relief valve;

2. Problems with gear pump or central rotary joint;

3. Remove and clean the relief valve and install it.

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