This article from Igus explains how the type of energy chain and cable selected for a given application can impact on the machine's energy consumption, with modern products offering the potential for significant savings in energy costs.
Energy chain systems not only transport energy, data and media to machines and systems, but they also influence energy consumption and, therefore, operating costs. The amount of pull-push force, or driving force, required to move an energy chain at a given speed will influence energy consumption, as will the weight and stability of the energy chain. Modern plastic energy chains and Chainflex cables from Igus UK can help to create machines that are more efficient in terms of energy consumption and operating costs.
Energy consumption can be drastically reduced by using the right materials and the right design, as recent tests at the Igus energy chain and cable laboratory now show. Consider, for example, an application with long travel distances and high fill weights. If a roller energy chain is used in place of a sliding application, friction losses are reduced. Tests show that with the same basic data (filling, chain length, speed and acceleration) the friction factor can be reduced from 0.3 to under 0.1. By using the roller energy chain, the tests showed a 37 per cent reduction in drive power compared with the equivalent sliding application.
Plastic versus steel
Such Igus roller energy chains for long distances have been in use globally for more than ten years. A good example is the 550m chain used in a taconite mine in Minnesota (USA); another is what is believed to be the longest plastic energy chain in the world so far, namely a 615m energy chain in the Czech lignite-fired power plant at Tusimice (see photo above). Metal chains are increasingly being replaced by lighter, lubricant-free plastic energy chains - even in harsh operating conditions. The latest example is in a steelworks in Isfahan (Iran), where dust, lubricants and oils impaired the function of the heavy metal chain that had to be pulled by the machine. Furthermore, cables were damaged by sharp chain edges and radiation from the sun.
Alongside the reduction in the friction coefficient illustrated by roller energy chains, there are further factors that favour efficient energy management, such as size and weight. Comparative tests in the Igus Technical Centre are said to have proved that 17 per cent drive power can be saved with smaller energy chains that are as robust as larger chains thanks to their careful design. For these tests a strong energy chain from the E4 range was chosen. This is a comprehensive, modular system that can be used to realise almost all applications from side-mounted and hanging applications through to long travel distances of over 200m. The new E4.1 generation of energy chains, which has been available since 2008, offers a wealth of application possibilities, since features from previous energy chains have been merged with new elements in one new design.
Chainflex cables for energy chains can help directly in reducing energy consumption. According to Igus, the latest tests show that the use of high-grade sheathing and insulating materials can, ultimately, reduce energy consumption by between 5 and 30 per cent, depending on the combination of cross-sections and cables used. The result is that the drive power requirements can be reduced by around 17 per cent.
Optimised sheathing materials, matched to the energy chain application, can achieve low friction. In addition, high-quality sheathing materials can be extruded with an extremely thin wall, which saves up to 18 per cent in weight compared with conventional cables. Insulation materials must also be considered. With high-quality materials, significantly higher current-carrying capacity can be achieved with the same core cross-section or, the cross-sections can often be reduced without the electrical performance being diminished. This, again, allows weight reductions of up to 30 per cent.