Cable failure within a dynamic-cable track can lead to costly, yet, in most cases, easily avoided, downtime. David Smith of U.S. Tsubaki Power Transmission LLC (Wheeling, IL) points to several important considerations for maximizing the performance life of cables running through your plant’s power-transmission-equipment systems.
— Jane Alexander, Managing Editor
Proper cable selection
Incorrect cable designs are often installed in a dynamic-cable track. Given the high rates of motion and speed under which cable tracks perform, be sure to select and install a cable specifically designed to operate in your particular environment or application.
Proper cable-track sizing
To achieve maximum life from your cables, assure ample amounts of free space within the cable track. At a minimum, cables should have 10% free space around them, with a maximum fill rate within the cable track not to exceed 60%. As the speed and cycle rates of a cable track increase, the cables must have adequate space to operate properly.
It is also imperative for the cable track to have the proper bend radius. Dynamic cables are generally designed to operate with a bend radius that’s greater than 7.5 times the outside diameter of the cable. A tighter radius will reduce the performance life of your cables.
Every cable requires effective strain relief as it enters and exits the cable track. This strain relief ensures that proper cable length remains within the track as it cycles back and forth. Insufficient strain relief is one of the most commonly overlooked considerations during cable installation.
Proper strain relief often can be accomplished by simply zip-tying the cables to the strain-relief fingers that have been molded into the cable-track brackets.
Internal vertical dividers
Another often-overlooked consideration involves the use of internal dividers within the cable track. Vertical dividers between the cables ensure that each cable is confined to its proper location and spacing within the track and is unable to cross over or “tangle,” with the other cables. Keeping your cables in proper alignment will help extend their performance.
Cable-carrier material selection
Even with proper strain relief, relative motion between the cables and cable carrier crossbars can result in some scuffing of the cable jackets. By selecting a crossbar design/material that best interacts with the cable jacket material, you can reduce or eliminate that scuffing.
For example, a nylon cable track with aluminum crossbars is much friendlier to the PVC jackets of most electrical cables than a standard glass-fiber nylon cross bar. MT
David Smith is director of sales for the Milwaukee-based KabelSchlepp Division of U.S. Tsubaki Power Transmission LLC. For more information on dynamic-cable tracks and other power-transmission topics, visit ustsubaki.com.