20.08.2012

Power boom goes to work

Liebherr’s new Power boom may have made a new record in its first outing on an LR11350 crawler crane.

The new crane, equipped with its new concept boom was delivered directly to site in the Dutch town of Eemshaven for Scottish based crawler crane company Weldex working on a contract for Mammoet.

The crane lifted a Repower six Megawatt class turbine housing weighing 340 tonnes onto a 110 metre high tower in a single lift. The gross weight with rigging and blocks etc…was no less than 378 tonnes and the crane was rigged with 140 metres of boom. At the steep angle it was working the power boom configuration boosted the lift capacity by around 70 percent.
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The Liebherr LR1350 with 140 metres of Power boom placing the 378 tonne load after ‘walking it 10 metres’

Norbert van Schaik, Repower’s local site manager believes that this is one of the heaviest single wind turbine nacelles ever been lifted onshore by one crane in a single lift. In most cases at least the drive train is lifted individually, or even a large number of the components are only fitted once the housing has been placed.

The main advantage is the time saving, by eliminating the need for the often difficult assembly of the individual components at a great height. Other arguments include the shortening of the actual lifting times, and fewer waiting periods when the wind gets too strong, conditions which are both expensive and set nerves on edge.

“We could of course also have carried out the assembly of this machine housing with an LG 1750, but then we would have needed several lifts, and several more days to do it”, said Simon Langefeld, Repower team leader on the site.
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A closer look at the base machine

The Dutch coastal weather proved the point. After days of waiting, with the wind blowing in strong gusts, the men on the site only had a short window of opportunity with acceptable wind speeds for lifting the last tower segment and placing the assembled housing. And as the 18 metres long and seven metres high housing was being secured the wind gauge on the boom tip of the crane was already indicating that the wind was getting up again.

Brian Doherty and Mark Hall, the two crane operators normally based in Ireland, were delighted with the one-hour lift and particularly when they moved the crane 10 metres, with the load at 120 metres of height.

A total of two 6M systems from Repower were installed by the LR 11350-P1800 in Eemshaven, both serving as trials. Plans exist for 48 wind turbines of this type to be installed from 2013 onwards in the North Sea East offshore wind park, off the island of Heligoland.