A Opening of strand in rotation resistant,low rotation and parallel closed ropes-in extreme circumstances the rope may develop a “birdcage distortion” or protrusion of inner strands.
Note-rotation resistant and low rotation ropes are designed with a specific strand gap which may be apparent on delivery in an off tension condition.These gaps will close under load and will have no effect on operational performance of the rope.
Cause/Action
>check sheave and drum groove radii using sheave gauge to ensure that they are no smaller than nominal rope radius +5% ZhongYing recommends that the sheave and drum groove radii are checked prior to any rope installation.
>Repair or replace drum/sheaves if necessary.
>Check fleet angles in the reeving system-a fleet angle in excess of 1.5 degrees may cause distortion.
>Check installation method-turn induced during installation can cause excessive rope rotation resulting in distortion.
>Check if the rope has been cut “on site” prior to installation or cut to remove a damaged portion from the end of the rope.If so,was the correct cutting procedure used?Incorrect cutting of rotation resistant,low rotation and parallel closed rope can cause distortion in operation.
>Rope may have experienced a shock load.
