Great gusto

Austrian crane hire company Felbermayr used its new six-axle Liebherr LTM 1300-6.3 mobile crane at altitude at the Steinriegel wind farm. The crane was used to replace a defective gearbox, weighing 13 tonnes, on a wind turbine at a height of 65 metres. In total, the crane has a telescopic boom that extends 90 metres, providing lift heights of up to 120 metres.

First crane operator Robert Fuhrmann drove from the Felbermayr branch in Lanzendorf, south of Vienna, to the job site – a distance of around 115km. Then he had to negotiate a six-kilometre gravel track to the construction site which was at an altitude of almost 1,600 metres. Tight serpentine bends and gradients of over ten per cent were the main challenge. “The vehicle’s hill start aid is really great and served me well,” said Fuhrmann.

Due to the elevation of the mountain ridge the wind farm is subject to strong winds; these winds increased whilst the job then progressed.

“As the day went on the gusts got stronger and stronger,” Fuhrmann said, “so I just switched straight to the wind chart.”

As a rule, the permissible lifting capacities of cranes are calculated for speeds of up to nine metres per second. Liebherr’s ‘WindSpeed Load Charts’, however, mean that if the wind speed measured on the crane’s boom exceeds the set table wind speed during a job the crane operator can switch to a lifting capacity table with a higher maximum wind speed so that they can continue working – up to a maximum of 15.6 metres per second.

The final challenge was that the fitters in the nacelle had difficulty removing the damaged component; the old gearbox hung on the crane hook for many hours during the removal process. As a result Fuhrmann implemented the crane’s ECOmode control system to minimise fuel consumption and noise emissions by automatically disengaging the pump drive when no power was required.