July/August 2020

www.drivesncontrols.com July/August 2020 41 RENEWABLE ENERGY n The prototype wind turbine blade being tested at the Offshore Renewable Energy Catapult centre in Blyth. The Lightweight Manufacturing Centre has hosted the blade development. Its director, Professor Iain Bomphray, points out that LMC was established to help manufacturers to develop lightweight structures. “Our cross-Catapult collaboration working with ACT Blade on this exciting technology has allowed us to do exactly that.” “The ACT Blade team has pushed the limits of what is physically possible, putting UK technology in pole position in the innovation race,” adds Dr Stephen Wyatt, director of research and disruptive innovation at ORE Catapult. “It’s also an inspirational story, showing how an Eureka moment can be turned into a future export that could generate billions in revenue for the UK.” The prototype blade is undergoing further testing in preparation for installing three blades on a wind turbine at the Myres Hill Wind Farm in Scotland. n Low-maintenance belts replace gearboxes in wind turbines Most wind turbine manufacturers rely on gearboxes or hydraulics to adjust the angles of the blades on their machines to adapt to changing wind conditions. One exception is the Chinese turbine company Xinjiang Goldwind Science and Technology – known simply as Goldwind – which is using timing belts to adjust the angles of its blades to respond to changing wind conditions. It argues that belts are a simpler alternative to gearboxes and are less prone to vibration. They also need little maintenance – a major factor for systems located at the top of turbine towers, especially those located offshore. The low-wear belts that Goldwind is using are corrosion-resistant and do not need any lubrication – key advantages over conventional metal designs especially in offshore turbines which are continually exposed to salty sea air. “In comparison with gearbox solutions, a simpler design that uses drive belts is alsomore cost-effective andmore efficient in the long term,” suggests Ralf Marwede, from the German belt-maker Continental which is now supplying Goldwind withmore than 100kmof belts every year.“If there is a defect, the system can also be repaired very quickly because only the belt needs to be replaced, not the whole gearbox.” In 2018, Continental invested around €2m to build a new belt-making facility in Dannenberg in Germany to meet the Chinese company’s demand. The facility could be expanded to meet anticipated increases in demand for wind turbine timing belts. In addition to drive belts, Continental also supplies Goldwind with mounting elements, films that reduce wind resistance, and hydraulic lines. The belts allow the rotor blades on Goldwind’s turbines to be adjusted at any time without needing gears or hydraulics. The patented low- maintenance belts combine Continental’s Synchrodrive and Synchrochain technologies – the first time that this has been done. They incorporate galvanised steel cords and are coated with an abrasion-resistant polyurethane, which forms the teeth and the back of the belt, and connects with the tension member. The two opposing impact directions of the steel cords and their strands result in neutral running properties, making the belts extremely resilient. It is not uncommon for these belts to experience around 12 million reverse bending cycles. A special fabric is used to reduce wear, absorb noise and provide a stable structure for the timing belt. “This enables us to significantly improve the belt’s performance yet further,”explains Marwede. The fabric reinforces the teeth and improves run-in behaviour which, in turn, boosts efficiency. Belts have advantages over metal power transmission technologies in the damp, salty conditions encountered by offshore wind turbines. Photo Goldwind Continental has invested around €2n in its Dannenberg plant to manufacture timing belts for Goldwind’s turbines. Photo: Continental

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