Installing wire rope on crane

Содержание

Choosing a crane wire rope: Overhead Crane Cable

Items to be taken into account when choosing a wire rope:

Breaking strength

The workload that the wire rope is to be subjected to is the first item to be taken into account when choosing a wire rope. Depending on the workload and the safety factor we wish to apply, we will have the wire rope breaking strength.

Corrosion resistance

If the wire rope is to be used in corrosive environments, a wire rope with galvanized wires should be used. If there is any risk of moisture entering the wire rope, a plastic-coated core wire rope can be an option.

Twisting torque and rotation

We have to take into account that when a wire rope is bearing a load, it causes the following effects:

When the two ends of a wire rope are fixed, the force applied causes twisting at the fixed points.
When one of the ends of the wire rope is free and a load is attached, the wire rope tends to rotate.

The wire rope’s tendency to rotate increases with the load that it is bearing and the height. The degree to which the wire rope generates twisting torque depends on its construction. Non-rotation wire ropes have each layer of strands in a differing direction of lay to the previous one, which means that the twisting torque of each layer is compensated by the twisting torque of the next layer. For this reason, we call wire ropes with three layers of strands Non-Rotation, whereas we call wire ropes with two layers of strands ROTATION RESISTANT.

Fatigue resistance

Wire ropes deteriorate due to the bending fatigue they are subjected to when bearing a load and flexing on the sheaves and drums. The level of deterioration is determined by the number of sheaves, sheave´s diameters, drum diameter and the diameter of the strands in the wire rope. If there is high bending fatigue, a wire rope with small diameter outer strands or a compacted finish should be chosen.

Abrasion resistance

Abrasion takes place between the wire rope and the sheaves and drums. To prevent it, a wire rope with a high outer strand diameter should be used.

Crushing strength

In multi-layer winding applications, the wire rope should be installed with a tension of between 2% and 10% of the breaking strength in order to avoid crushing between layers and deterioration of the wire rope. Compacted wire ropes are recommended for multilayer winding. Always use wire ropes with a metal core and high filling factor.