Know Your Cables & Their Specs
The following information should be used together with other explanations and design recommendations in this Handbook.
Cables that have failed typically show the following symptoms:
■ corkscrewing where cables twist in themselves ■ knotting of conductors underneath the cable jacket ■ cables twist around one another within a cable carrier system ■ cables are sticking out between the cable carrier crossbars and getting caught in the bend radius
■ cables entangled with other cables and crossbars tearing them apart ■ loss of conductivity through simple breaking of cable conductors
An example of corkscrewing where cables twist themselves.
Common causes of cable failure when operating in a cable carrier system:
■ cables used are not designed for use in continuous flexing operation ■ cables are packed too tight inside the cable carrier cavities ■ the actual operating bend radius of the application is smaller than the minimum bend radius recommended by the cable manufacturer ■ cable carrier design is not cable friendly or optimal for the types of cables being used
Cable failure showing entangled cables and ruptured jacket.
Proper Unspooling Of Cables And Hoses
All too often those more commonly selected or used industrial cables are not designed for continuous flexing or bending operation as seen in cable carrier systems. They will quickly cork-screw and knot, especially when run within a tight cable carrier bend radius. Also, many standard industrial cables require a bend radius larger than most machinery applications allow and as a result, force these cables to run at a tighter than recommended radius. This will undoubtedly substantially reduce cable life. A cable specifically designed for continually-flexing tight bending radii must be selected.
Some commonly used cables also use a cotton tape between the inner conductors and the outer jacket. Due to the constant bending when operating within a cable carrier system this cotton tape will often bunch up underneath the jacket and crimp the conductors causing premature cable failure.
Cables with a built-in twist will develop a cork-screw effect more easily. Additionally, this inherent twist is further amplified by the constant flexing and relative-movement of the cable operating in a cable carrier until the cable conductors break. The best choice for a cable to be used in a cable carrier should be PVC/PUR/TPE/TPM jacketed. Cable jackets made of rubber or neoprene are generally not recommended. The latter two materials are too sticky and do not allow the cables to move easily relative to one another and the cable carrier. This will also contribute to the aforementioned cable knotting.
When installing cables or hoses into a carrier system, they should be laid into the carrier without twist and in accordance to the guidelines outlined in this Technical Handbook. Cables or hoses should not be simply pulled off the top of a reel. Instead, they should be properly uncoiled from a reel as shown in the illustration above.
Specifications are subject to change without notice. KSA-0810-GC
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