Robust rotary encoders move the roof over Wembley Seven large sections that make up the roof construction of the new Wembley Stadium are controlled by rotary encoders. The Wembley Stadium in London is known around the world primarily as a venue for football matches. However, other events, such as concerts, are also held here, and Wembley will be the site of the 2012 Summer Olympics. The old stadium, which was built in 1924 as the Empire Stadium for the British Empire Exhibition, was demolished in 2002, completely rebuilt, and then reopened as the National Stadium this spring. Its 90,000 seats, movable roof, and the delicate arch, 133 meters high and visible from a great distance, make it the second largest stadium in Europe, after Barcelona, and the largest stadium in the world with a movable roof. It caters for the "typical English weather" and does not leave the public literally "standing (or rather, sitting) in the rain". The very highest demands with regard to reliability and safety were made on the entire mechanism of the seven large sections that make up the roof construction. After all, they have to be able to be moved in or out immediately, depending on the changes in the weather and to do this in any weather and after considerable periods at standstill. Each of the seven roof sections is moved by several planetary geared motors, through a rack and pinion construction. The motor control loops use rotary encoders from Baumer Hübner. The company manufactured a robust sensor combination, especially for this outdoor application, which combines an absolute encoder (13-bit, single-turn /16-bit multiturn) and two independently operating, purely mechanical, centrifugal switches on a common shaft. This maintenancefree sensor combination monitors not only the correct positioning of the entire roofing, but also the smooth running of the positioning motors fixed to each section of the roof. The redundantly implemented speed monitoring ensures that the maximum permissible speed of movement is never exceeded for even a moment. The encoders from Baumer Hübner are also to be found in the stadiums at Gelsenkirchen, Düsseldorf and Amsterdam, as well as at a sizeable number of other outdoor installations where the highest demands are made for toughness and reliability. Speed Link InfoService Request more information by e-mail Reader Service No. Reader Number Email Address 00865

Copyright © 2007 Thomas Publishing Company