The process crane, for an ABB plant in Sweden that manufactures transformers, was commissioned to be able to handle increasingly large loads. The predecessor’s maximum lifting capacity was 300t.
This weight increase required the investment in a new crane, and Kranbau Köthen was commissioned for its development and production. A special feature had to be considered because the centre of gravity of the transformers is distributed very unevenly. The crane therefore must adapt accordingly to ensure smooth and delicate lifting and lowering of the heavy load.
Based on these requirements, Kranbau Köthen engineers developed a crane and a special heavy-duty shaft end support. It consists of two carriers whose spacing is changed by lead screws. The two attachment points on each carrier are also adjustable, so that each of the four winches can be positioned separately. The transformer can therefore always be attached in such a way that its weight is evenly distributed over all four attachment points. In addition, the entire shaft end support is rotatable. It is suspended on a very large load-measuring bolt.
Other special features include three auxiliary strokes, each with a loading capacity of 20 tons, and an extraction system on the trolley travelling winch. This is to protect the transformer from abrasion debris during the assembly process.
The cables are guided on the crane girder to the 30-metre-wide bridge using a standard igus E4 4040HD energy chain is used. In this case, the extras included double strain relief and a floating moving end, to compensate for any lateral misalignment and wheel clearance in the trolley drive. Because of the benign environmental conditions (normal climate, no high travel speed), cables with PVC outer jacket can be used in the ABB crane. They are more cost-effective than TPE cables and also generate less abrasion debris than PUR jackets (ensuring cleanliness). The electrical connection between the two shaft end supports, which can be moved towards each other, is also ensured with energy chains and chainflex cables from igus. Here, E4 e-chains are also used.
Following a factory acceptance test at the German factory, the crane was loaded on several flat-bed trucks and transported to Sweden. Part of the route was by sea, so ferry loading of the fragile cargo was inevitable. After installation by Svenska Lyft, ABB carried out a final test and final inspection; 625 tons of test weight (corresponding to 125 percent of the maximum nominal load) had to be provided for the acceptance test. Tests of the emergency stop device at full speed were also part of the test series.
Maik Stern, head of production at Kranbau Köthen said: “After all, as a globally leading technology company, ABB is also a specialist in the field of crane technology and therefore also a critical customer.”