30 n GEARS AND GEARBOXES January 2025 www.drivesncontrols.com Drum drive gearboxes: the efficient answer for heavy-duty conveyors? The UK mining and quarrying sector has cut its CO2 emissions significantly since the 1990s. According to the Office for National Statistics, the industry’s emissions nearly halved between 1998 and 2021, from just under 29,200 tonnes to just over 15,500 tonnes. Another heavy-duty sector, waste processing, has gone even further, curbing its emissions by 74% between 1990 and 2022. Yet, there is still a long way to go. According to McKinsey, the mining sector must reduce emissions by 85% by 2050 to meet climate targets. Quarrying, recycling and other heavy-duty industries must meet similar targets. Moving materials around mines, quarries and recycling facilities is an energy-intensive business. One study found that inpit transport accounted for around 40% of the German mining industry’s power demand, and half of its costs. This study also estimated that transitioning from diesel mine trucks to electrified belt conveyors powered by renewable energy could reduce emissions by 96%. But simply switching to conveyors may not be enough. A 2022 study found that belt conveyors at a Polish mine still accounted for half of its energy consumption. It concluded that developing more energy-efficient drive systems, including gearboxes, is essential to cut conveyor energy consumption and emissions. Replacing diesel trucks with belt conveyors can go a long way towards cutting energy costs and emissions. For many companies operating in heavy industries, switching from hydraulic conveyors to mobile electrified conveyors is the next logical step. Yet electrification still poses some challenges. Mobile electric conveyors tend to be larger and heavier than their hydraulic counterparts. To avoid adding to this significant footprint and weight, components such as electric motors and gearboxes must be light and compact. The drive systems must also be energy-efficient. Another challenge relates to a large variation in speed and torque requirements. While feeders tend to have high torque and low speed requirements, transfer stockpile conveyors deployed in other processes tend to need low torque and high speed, requiring much more power. Drive systems must be flexible enough to meet these requirements. Conventional gearboxes typically have a bevel helical, parallel helical or shaft-mounted designs. Due to their size and shape, these drives can only be installed outside conveyor head drums, adding significant weight. There are other downsides. Bevel-helical gearboxes consist of several parts, including shafts and bearings that require regular lubrication, leading to maintenance costs and downtime. These boxes also have exposed oil seals, which are a frequent cause of failure in arduous environments such as quarries and recycling plants. An alternative approach is to use a drum drive gearbox. These can have up to 72% less mass than equivalent helical gearboxes. A compact final-stage reducer inside the drive results in a small footprint. Because of their lower size and weight, these drives can be installed directly inside a conveyor head drum. They can also act as bearings, avoiding the need for a separate shaft and bearings. Fewer parts help to reduce the weight, upfront costs and maintenance. The enclosed oil seals of drum drive gearboxes eliminate the risk of faults caused by dust or water, cutting maintenance costs further, while extending uptime and lifespan. The latest track drives are designed with energy efficiency in mind. Installing any type of motor is easy thanks to simple IEC motor fittings. These drives can be fitted with permanent magnet (PM) motors, or hybrid motors that integrate PM, ferrite or neodymium magnets, along with synchronous reluctance (SynRM) technologies. Heavy industries will continue to cut their carbon footprints. Because conveyors can deliver significant energy consumption, they must be at the heart of any decarbonisation strategy. Drum drives can help to boost conveyor efficiency and reliability. They can also help quarries and recycling plants to cut costs by curbing maintenance and downtime.n Switching to electric conveyors can help heavy industries such as quarrying and recycling to cut their CO2 emissions, but they come with challenges. David Strain, technical director of the motor and gearbox supplier Technidrive, explains how drum drive gearboxes can help to solve these issues. This drum drive system (Technidrive’s 80M model) consists of a track drive inside the conveyor head drum, with a motor directly mounted onto this. It is designed for higherspeed, lower-torque conveyors. It has a power range is 2.2–18.5kW, and delivers up to 7kNm of torque. The company also offers track drive gearboxes from low-speed/hightorque to high-speed/low-torque versions. These have a power range of 0.12–11kW and a torque rating up to 12kNm, making them ideal for feeder applications. There are also gearboxes for winch applications with torque ratings of up to 42kNm, and complete drums with built-in gears for mid-to-large sized belt conveyors for tough areas.
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