(1) First, check the power system: For hydraulic-driven cranes, confirm whether the hydraulic oil level is sufficient and whether there are leaks in the pipelines; for motor-driven cranes, check whether the motor voltage/current is normal to rule out insufficient power.
(2) Next, check the transmission components: Inspect whether the steel wire rope is excessively worn (which may cause slipping) and whether the winch gearbox is short of oil or has worn gears—reduced transmission efficiency can lead to weak lifting.
(3) Finally, check the safety devices: Confirm whether the load moment limiter is falsely triggered (power output may be restricted if the load is close to the rated value); check whether the lifting brake is not fully released (which would create frictional resistance).