June 14 - A Liebherr 1000 EC-B 125 Litronic tower crane has been used for the first time to erect a wind turbine at the Prechtaler Schanze wind farm in the Black Forest, Germany.
The 1000 EC-B model was used to lift and erect an Enercon wind turbine with a hub height of 146 m and a blade diameter of 115 m. With a 31.5 m jib and hook height of 164 m, the crane was still able to hoist 100 tonnes using four lines.
Since the turbine was being erected on a small, steep hilltop in the middle of the forest, Enercon stipulated that the lift required a flat-top tower crane, due to the smaller surface area required to erect the machine. The jib used was also very short, meaning that no additional site clearance work was required for its assembly.
In addition, said Liebherr, the logistics involved in transporting the 1000 EC-B machine was much more simple, since the crane's components could be moved in small packages on trucks.
A compact Liebherr LR 1200 crawler crane was used to assemble the tower crane to its initial hook height of 39 m, from where the machine erected the turbine and climbed up the turbine tower using its own climbing equipment to a freestanding hook height of 110 m.
The crane was guyed to the wind turbine at a height of 100 m. Using this single guying, the crane climbed to a final hook height of 164 m, explained Liebherr. The erection of the wind turbine took around four weeks.
Liebherr noted that locations chosen for wind turbines generally have harsh wind conditions, which can adversely affect cranes. The benefit of tower cranes is that they can operate safely in winds of up to 65 km/h.