NEG Micon, the second largest manufacturer of wind energy systems in the world, assembles windmill rotors in a factory in its Skagen facility in Denmark. For years, it used forklifts to move around windmill rotor heads under production. Now, however, it is using overhead travelling cranes installed Danish crane builder CT Kraner (now part of Danilift).

The advantages of cranes are obvious, says lead engineer on the project Carl Thomsen. “Cranes don’t need so much space on the floor,” he says. With cranes, NEG Micon was able to increase the number of units in production, he adds.

Thomsen designed the cranes and steelworks for 17 single-girder cranes running along three new 25m runways in the factory. He says the goal was to try to optimally distribute the many lifting gears in the factory.

The final design has the two outside runways equipped with six and seven 6m-span crane girders, each with a 5t capacity SWF Nova electric wire rope hoist. In the middle runway, four 12m-span cranes equipped with 3.2t hoists handle lighter parts.

Each of the cranes, controlled by their own push-button pendant, have their own photocell device to prevent collisions with the others on the runway. Each crane also has the SWF MicroMove frequency inverter system for smooth acceleration of the load, and a mechanical overload protection system.

The pre-assembled kit-form hoists include electrical and mechanical components. According to SWF, key-type joints cut assembly time, especially for electrical parts.

Thomsen estimates that the whole project, including design and steelwork, cost about Euros 250,000.