The magazine of Friedhelm Loh Group

The magazine of Friedhelm Loh Group

Experience – Energy

The cable harness experiment

3D engineering. Laying individual cables around 120 metres long in a wind turbine per phase makes for a complex and time-consuming project, with challenges arising right from the planning stage. An experiment conducted by Nordex has shown that using software offers huge potential savings and ensures a high degree of precision.

Text Thomas Schmelzer ––– Photography

Two teams, one task – survey a wind turbine’s machine housing to lay 50 cables. Nordex – the world’s fifth-largest manufacturer of wind turbines – hoped its experiment would confirm whether supporting cable harness planning with software does indeed reduce the time needed for engineering. The results paint a clear picture. While the engineers on one team measured cable lengths by hand using a prototype, their colleagues took a quicker route with some help from digital technology.

Perfected sheet steel processing

With some help from the Eplan platform, the electrical engineers at Nordex aim to standardise.

Development engineer Enrico Durka used to mark out drilling patterns with a template when manufacturing enclosure and switch boxes. Now he generates the drilling pattern in Eplan Pro Panel and send it directly to the machining centre as a file.

The advantage: The software records all installed components – with all the details gleaned from parts lists and circuit diagrams.

The result: Tasks are completed with greater precision and in less time.

The use: Drilled enclosures, which used to take several weeks to deliver, are now supplied in 48 hours to one week at most.

Martin Richter, responsible for cable harness planning at Nordex, still remembers the experiment well. “The two team members who measured by hand needed a full working day to record the exact values,” he says. It was much faster on the computer. “Thanks to Eplan Harness proD software, their colleagues were able to finish the same task in just a third of the time.” Further testing confirmed the result, and the error rate dropped significantly. “Deviations in the lower centimetre range mean the wiring path at Eplan always fits – so you don’t have to plan for any additions, even with long cables,” explains Richter.

Calculating the cables’ exact route – to the tower and from enclosures to the consumers – takes time, which is why Eplan Harness proD software maps it out quickly and easily in a 3-sD model. Explaining the advantage to this, Richter says: “The cable harnesses run along the inner side of the machine housing, which is what makes judging the length so taxing.” This is where Eplan plays its trump card, ascribing properties – such as control points, bending radii and even the positions of cable ties and earthing straps – to every single cable. “In the end, we benefit from the fact that all cable lengths, connector variants and other details are clear and consistent,” says Richter.

To determine the length of wires, the electrical engineers at Nordex call upon a tried-and-tested duo – Eplan Pro Panel and the Smart Wiring module. The data from the 3D assembly layout and the circuit diagram’s connection information form the basis of this team’s work, with Eplan Pro Panel calculating the necessary length of the wires with some help from precise 3D routing. These calculations then form an electronic master file, which is sent to someone outside the company to create the wires. Wolfgang Conrad, Head of Enclosure Development at Nordex, says: “We now plan any new enclosures exclusively with Eplan Pro Panel and the Smart Wiring module, which ensures they meet a high standard of quality.”

Recognising errors immediately

One of the many advantages to Nordex’s and Eplan’s collaboration is that complex cable harnesses can now be calculated to the nearest centimetre. The company is reaping the full benefits of Eplan software in terms of 3D assembly layout in enclosures, too. “All components used – right through to screws, bolts and washers – are accurately recorded and automatically assigned to a project,” says Conrad, commending the outstanding quality of the circuit diagrams. Inconsistencies on a physical level, meanwhile, are spotted immediately.

Faster sheet steel processing

Nordex produces its series in vast numbers and is a classic series manufacturer. Its main production facility was transformed into a cutting-edge assembly line early on, with enclosures migrating from station to station on five different lines and gradually forming a complete unit. Besides the centre box, seven decentralised enclosures and switch boxes for separate functions are installed into each machine housing.

Automated assembly line

Besides for standardising its database, the wind turbine manufacturer also uses software to automate its assembly line. “Our goal is to tap into the opportunities opened up by standardised development and production as much as possible,” explains Conrad.

Nordex’s electrical engineers are now therefore eager to digitize the entire wind turbine in one go. Even today, more than 500 sensors are built into a single turbine – and this is set to rise. “If we want to have a realistic, digital test model, we can do away with a real prototype for engineering purposes and produce an initial sample for manufacture straight away,” says Dr Klaus Faltin, Head of Electrical Drives and ­Design at Nordex. “In future, we will incorporate Eplan Viewer even further into our work – integrating it straight into production lines, for example,” says Faltin. Testing is underway…

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