Published: 2026-08-24
Port gantry cranes and ship unloaders operate at high intensity day and night, with drum cables frequently retracted and extended. The most frustrating problem is broken cores. Many customers attribute broken cores to 'poor cable quality,' but in fact, most are caused by mismatched selection parameters.
The physical mechanism of conductor breakage is very simple: as the cable is repeatedly bent with the reel, the conductor experiences alternating stress, and the copper wires break one by one under bending that exceeds the fatigue limit. The factors that truly determine its lifespan are three parameters — bending radius, tensile elements, and conductor structure.
The minimum bending radius of a standard rubber-sheathed cable is about 6-8 times the outer diameter, while drum conditions require 4-5 times the outer diameter or even less. If the drum diameter is too small, the cable will be repeatedly bent and pressed between layers during winding, and the copper wires are bound to break first. Secondly, drum cables must have a central tensile filler (high-strength fiber rope or steel wire core), otherwise the weight of the cable plus the pulling force will be entirely borne by the conductor, and conductor breakage is only a matter of time. Thirdly, the conductor should be made of multi-layer stranded fine flexible copper wires; the smaller the diameter of the individual strands and the more reasonable the stranding pitch, the better the bending fatigue resistance.
Selection Recommendations: For port drum cables, the drum diameter, reeling speed, and sag length should be clearly specified, and then the manufacturer can calculate the bending radius and tensile strength according to the working conditions. Shanghai Suoqi drum cables are designed for bending at 5 times the outer diameter and a reeling life of over 100,000 cycles, supporting customization of the tensile core and conductor structure according to the actual port working conditions.
About Shanghai Suoqi
Shanghai Suoqi Electric Wire & Cable Co., Ltd. is a specialized cable enterprise focusing on the research and development, design, production, and sales of special flexible cables. The company's products cover a series including reel cables, flat cables, drag chain cables, encoder cables, polyurethane cables, seawater-resistant cables, seawater-resistant network cables, and high-altitude vehicle cables, which are widely used in ports machinery, mining, industrial automation, marine engineering, and other fields. For more product information or inquiries, please call 13311756197 (same number on WeChat).