March 2019

62 n SERVICE AND REPAIRS March 2019 www.drivesncontrols.com Scottish 3.8-tonne gondola gearbox gets an overhaul T he UK’s only mountain gondola system, the Nevis Mountain Gondola, transports visitors from a base station near Fort William to a top station on Aonach Mor, 650m above sea level. The spectacular journey, which takes about 15 minutes, gives visitors breathtaking views of Ben Nevis, the Great Glen and the surrounding Scottish Highlands. The gondola was originally built for skiers, but is now popular with tourists all year round. The system hauls 75 six-seater gondolas at a speed of 3.2m/s on a continuous 4.6km- long steel cable, which alone weighs 40 tonnes. When fully loaded, the combined weight of the 300kg gondolas and 450 passengers can be 58.5 tonnes. At peak capacity, the drive system, which incorporates a 3.8-tonne Lohman & Stolterfoht planetary gearbox, produces a force of 98,500kg! As part of routine maintenance, SEW Eurodrive was asked to inspect, service and carry out any necessary repairs to the huge gearbox. An engineer supervised the removal of the box and its careful loading onto the back of a large wagon. The tricky mountainside location complicated the process but, once loaded, the gearbox was transported to SEW’s service and repair facility in Normanton, West Yorkshire. On arrival, the gearbox was disassembled and inspected. A 49-page digital report was produced on the condition of the box and its parts, including an oil analysis, digital photography and information on components that would need monitoring for future repairs. It was found that the 20-year-old gearbox was in good condition because it had been well maintained by the engineering team at the Nevis Mountain Experience. After cleaning the components, and removing small amounts of corrosion, new bearings, seals and O-rings were fitted, and the gearbox was re-assembled. After testing, the repaired gearbox was returned for re-installation and testing. The process was completed in three weeks and the box has been operating perfectly ever since. n A huge planetary gearbox that drives the UK’s only mountain gondola system is back in service carrying passengers up Scotland’s Aonach Mor mountain after being given a through overhaul. The huge planetary gearbox is now back in service hauling passengers up the Nevis Mountain Gondola Rapid response prevents pumping station from running dry with minutes to spare Essex & SuffolkWater operates an unmanned pumping station at its site in Herongate in South Essex. When a water pipe split, it flooded the station and crippled its electrical equipment, including a VSD and two of the three motors used to control the station’s treated-water transfer pumps. The pumping station provides water to 25,000 homes and 67,000 people in the Herongate, Warley and Brentwood areas, and is a strategic site in the utility’s supply network. The VSD is installed on the lead pump, which is in almost continuous operation, transferring up to 12 million litres of potable water every day from a sealed underground reservoir. “The pump was sitting on 70 feet of head when the pipework split,” explains Robert Wilson, manager of Essex & Suffolk Water’s electrical maintenance team.“Basically when the water hit the electrics, we lost the entire pumping station. We were able to maintain supply in the short term by using water from four on-site storage reservoirs. However, hourly trend analysis revealed that the water would run out by the evening, stranding our customers.” Wilson contacted Maldon-based Gibbons Engineering Group, which maintains the site’s drives under a service agreement. Gibbons quickly installed and commissioned a 110kW ABB VSD on the site’s only working motor. Thirty minutes before the water reserves would have run out completely, the Herongate site started pumping again.