Fault Phenomenon: SANY SR360 rotary drilling rig a loud impact sound occurs during lifting, subsequently unable to lift.

Troubleshooting Process:
– Checked gearbox: disassembly revealed planetary gear broken.
– Checked lubrication: gear oil contained large amounts of metal debris.
– Checked bearings: planet carrier bearings severely worn.
– Checked load: recent severe overload or impact operations.

Root Cause: The main winch gearbox planetary gear broke due to fatigue or instantaneous impact overload.

Required Parts: Replace main winch gearbox assembly or gear set.