Detailed Description
Tensile Load — The Engineering That Prevents Cable Failure
Every reeling cable experiences tensile load. The question is: how much?
| Reeling Scenario | Cable Weight per Meter | Reel Length | Total Suspended Weight | Required Tensile Capacity |
|---|---|---|---|---|
| Workshop reel | 0.2 kg/m | 20 m | 4 kg | 0.04 kN — minimal |
| Factory crane reel | 1.5 kg/m | 100 m | 150 kg | 1.5 kN |
| Large STS crane hoist | 5.0 kg/m | 80 m | 400 kg | 4.0 kN |
| Mining dragline (deep) | 8.0 kg/m | 500 m | 4 000 kg | 40 kN + dynamic |
| TBM trailing cable | 10.0 kg/m | 800 m | 8 000 kg | 80 kN + dynamic |
In the first two scenarios, a standard reeling cable with modest tensile reinforcement is adequate — the cable's own weight is light relative to the conductor cross-section. In the last three, the cable's own weight is the dominant load — and the tensile reinforcement must be engineered accordingly.
High tensile reeling cable is designed for the last three scenarios — where the cable weighs hundreds or thousands of kilograms and standard tensile reinforcement would be overloaded.Three Tensile Architectures — Choose Based on Application
Architecture 1: Central Steel Core
A single oversized galvanized steel wire rope (typically 6×19 or 6×36 construction) in the center of the cable. All copper conductors are stranded around it.
- Tensile capacity: 20–50 kN working, ≥100 kN breaking
- Best for: Maximum tensile load, ultra-deep drums
- Trade-off: Larger minimum bend radius (central steel rope is stiff)
- Applications: Mining draglines, TBM trailing cables, deep shaft hoisting
Architecture 2: Distributed Steel Strands
Multiple smaller steel wire strands (6–12 strands) distributed through the core assembly — typically one steel strand per conductor bundle.
- Tensile capacity: 10–30 kN working, ≥50 kN breaking
- Best for: Balanced tensile load distribution, improved flexibility
- Trade-off: Lower total tensile capacity than central core
- Applications: Large crane hoists, ship-to-shore reels, moderate-depth mining
Architecture 3: Double-Layer Steel Braid
Two layers of galvanized steel wire braid — one inner, one outer — with the core assembly sandwiched between them.
- Tensile capacity: 15–35 kN working, ≥75 kN breaking
- Best for: Torsion-resistant applications, combined flex + tension
- Trade-off: Heavier, more expensive than other architectures
- Applications: Offshore winches, combined reeling + festoon, dynamic marine
Tensile Safety Factor — The 5:1 Rule
IEC 60204-32 (Safety of machinery — Cable reeling equipment) requires a minimum tensile safety factor of 5:1 — the cable's breaking strength must be at least 5× the maximum working tension.
Working tension is the sum of:
- Static cable weight: The weight of all cable unwound from the reel and hanging freely
- Dynamic load: Acceleration forces when the reel starts and stops — typically 1.5–2× static weight for high-speed reeling
- Payload tension: If the cable is pulling a load (e.g., crane hoist), the payload weight adds to the tension
- Bend resistance: The force required to bend the cable around the drum at the take-off point — typically 5–10% of static cable weight
Deep Drum Considerations
On a drum with >10 layers, the innermost cable experiences not just the tension of the outermost layer, but the sustained compressive force of all layers above it. At 15 layers deep with 60 kN winding tension, the bottom layer experiences approximately 900 N of radial compression per linear meter — equivalent to a 90 kg weight pressing on every meter of cable.
High tensile reeling cable addresses this through:
- High-density filler stranding: Minimal void space in the core assembly — the structure resists compression without deforming
- EPR core insulation: Maintains thickness under sustained compression — PVC would permanently thin
- Reinforced inner sheath: An additional CR or NBR rubber layer between the core and the tensile reinforcement absorbs and distributes compressive load
Why Choose Yichi Cable High Tensile?
- Calculated tensile engineering: We calculate the required tensile reinforcement loading based on your reel length, cable weight per meter, drum depth, and winding tension — not a catalog "high tensile" claim
- 5:1 safety factor verified: Every production length is proof-tested at 2× working tension (40% of breaking) — confirming no yield, no strand slippage, and no jacket cracking under load
- Three architectures, one application review: We select the optimal tensile architecture for your specific application — central core, distributed, or double braid — based on engineering, not availability
- Drum compression modeling: For drums >10 layers, we model the compressive load at the drum bottom to verify that the core assembly maintains structural integrity throughout the cable's service life