Tips for Designing Cable Carriers

Of all the machine design details to worry about, cable carriers probably don’t top your list. Yet if you care about the reliability and uptime of moving machines, it pays to devote extra engineering attention to the carriers and the components within them.

A well-designed cable carrier will dramatically extend the life of cables and fluid power supply lines by protecting them from damaging bends, crimping, abrasive wear and crushing.

Unfortunately, some cable carriers are poorly-designed and can trigger the very same cable and supply line failures they were supposed to prevent, causing expensive machine downtime. The potential for failures can largely be avoided by following a collection of simple carrier design guidelines developed by our Systems Group.

Over the years, our engineers have designed, built and delivered thousands of populated cable carriers that have been implemented in a wide variety of servo and VFD applications on packaging, automotive and other industrial machines.

Here are some basic tips for designing populated carriers:

•         Calculate. Determine the minimum bend radius and clearances of all the components that will fill the carrier. Define the optimal carrier length and location of the fixed mounting points.

•         Weigh. Distribute the weight of the fill components within the carrier. Take the time to calculate the weights of individual components, and place the heaviest components on the outside of the carrier.

•         Influence. Consider the operating environment. Chemical exposures and thermal conditions can influence the design of cable carriers.

•         Divide. Split the carrier into separate cavities so the cables and hose can all move independently of one another.

•         Get Help. Involve your cable and carrier vendors in the design process. They work with carriers every day and can offer additional engineering expertise that will help you design a carrier that will go the distance.

For detailed engineering guidelines, download our technical paper on cable carrier design.

Protecting Cables From Oil Damage

Of all the chemical exposures that can affect the life and performance of electrical cables, oil is one of the most damaging. Used as a coolant and lubricant in many industrial and infrastructure settings, oil can inflict molecular damage on the polymers used for cable insulation.

Degradation Happens. When insulation polymers are exposed to oil over time, two degradation mechanisms can occur. Some polymer formulations will absorb the oil, causing the polymer to swell and soften. A loss of tensile properties results. Other polymers will lose their plasticizers when exposed to oil, causing a loss of flexibility and elongation.

Either way, oil exposure renders many polymer compounds ineffective as insulators. This attack on polymer properties can result in downtime, costly repairs and, in the worst case, hazardous electrical conditions.

Temperature extremes and other chemical exposures can exacerbate the damage caused by oils. The greater the intensity of the oil exposure and the operating temperatures, the faster oil will degrade insulating polymers.

Lasting Damage. Once it gets underway, oil damage is not reversible. But it can be prevented by selecting cables with inherent oil resistance.

Without a deep knowledge of the specific polymer compounds used in the cable you’re considering, it can be difficult to know which products can stand up to oils and for how long. Making matters worse, individual polymer formulations may not offer equivalent performance even if they have the same family name. Not all PVCs are created equal, for instance.

And that’s why testing is so important. To avoid oil resistance problems, engineers should pay close attention to UL tests, which help determine how a cable will react in the industrial oil environment.