Liebherr Introduces SX Boom System for Wind Turbine Erection

Enlarge Image The SX system allows wind turbines up to 495 ft. and 132 tons to be lifted by a 825-ton Liebherr.

April 25, 2017 – Liebherr has developed the SX boom system for its 750-tonne (825-ton) LR 1750/2 lattice-boom crawler crane and LG 1750 all-terrain cranes for erecting wind turbines. Using the SX system, the cranes can erect the latest generation of wind turbines with hub heights up to 165 meters (495 ft..) and component weights of up to 120 tonnes (132 tons). Previously, only cranes in the 1,000-tonne (1,100-ton) capacity class could erect these turbines. 

The SX system, which has been tested and is available now, differs from previous boom systems because its 3.5-meter-wide (11.5-ft.-wide) lattice sections are used in the bottom area of the boom rather than sections measuring just 3 meters (10 ft.) wide. The extended lattice sections increase the lateral stability of the boom, allowing it to deliver a higher load capacity.

The weight of the lattice sections also has been reduced, and an additional increase in lifting capacity is achieved with an extension to the SX system. Instead of 3.5-meter-wide (11.5-ft.-wide) lattice sections, two lattice sections each 14 meters (46 ft.) long (SX2 system) or three lattice sections each 14 meters in length (SX3 system) with a width of 6 meters (20 ft.) are installed in the lowest area of the main boom. This provides additional rigidity to the boom system, thus increasing its load capacity.

In order to install the 6-meter wide lattice sections in the boom, there is an extension adapter from 3 to 6 meters (10 to 20 ft.) on the pivot section for the turntable. At the top the 2/3 width of 6 meters is reduced to 3.5 metres by a second adapter.

Enlarge Image To transport the 6-meter-wide lattice sections, the two halves can be bolted together in the center and separated quickly.

When designing this system extension, Liebherr focused on ensuring it was highly economical. This means that crane operators only have to buy the 6-meter-wide sections and the adapters, in addition to the SX system. The challenge for the development of the 6-meter-wide lattice sections was transporting it on public roads. Liebherr solve the problem by making the wide boom sections in two halves that can be bolted together in the center and separated again quickly. To transport them, the individual halves are slightly offset longitudinally and then joined so that they mesh together like teeth. This means that a practical transport width of 3.5 meters can be achieved.

The complete SX system can be interchanged between the LR 1750/2 crawler crane and the LG 1750 all-terrain crane. To enable the higher lifting capacities of the SX system to be used, Liebherr has also developed a new fixed jib specially enhanced for this system. A runner is included and the head sheaves and a new hook block are designed so as to prevent the hook block becoming twisted.