In an eight-week operation St. Gallen, Switzerland-based company Emil Egger erected the country's second largest wind farm on the Jura mountain range near the border with France.
For the work it used two Liebherr crawler cranes, an LR 11000 and an LR 1700-1.0, which were working at an altitude of around 1,200 metres. The wind turbines were almost 140 metres high. The company installed six turbines, manufactured by Enercon, which are expected to produce 22 million kilowatt hours of electricity annually.
The operator of the LR 11000, Peter Stricker, commented, “The heaviest load cases on this construction site occurred during the lifts of the generators. Together with the hook block and slings, I had a gross weight of 71 tonnes hanging from my LR 11000."
The crane was equipped with a 114-metre-long main boom in order to be able to handle the greatest assembling heights of around 100 metres. With a gross weight of 65 tonnes, the rotors were somewhat lighter, but visually more spectacular than the generator or nacelle. The 40-metre-long rotor blades were mounted to the hub on the ground to form complete blade stars, lifted and installed. With a special device, these huge components could be swivelled into a vertical position during the lifting process.
In parallel with the 1,000-tonne crawler crane, the LR 1700-1.0 completed the erection of other wind turbines a few kilometres away. On the 99-metre main boom, a 12-metre jib angled at ten degrees provided sufficient lifting height.
"All the crawler cranes in our fleet are from Liebherr," said Emil Egger’s managing director Michael Egger. In addition to an LR 1250 from the Liebherr factory in Nenzing, Austria, the company also operates some of the most powerful cranes in Switzerland. "We rely completely on the Liebherr brand for crawler crane technology because these modern machines are extremely practical and user-friendly,” Egger continued. “The machines are simply 'state of the art'. And Liebherr's service leaves little to be desired – and not just for reasons of physical proximity to the manufacturer. If we have a major problem with our equipment, a mechanic is on site within two hours. And that's worth a lot."
