The reassembly of Itaipu's Generating Unit 6 (U6) moved into the final phase of work, this Tuesday (10th), with the descent of the rotor – the heaviest part and one of the most important of all. It is 1,760 tons in weight, 16 meters in diameter and 3.5 meters high. Itaipu technicians and engineers expect the work to be completed in 45 days and that the unit will start generating power again by the beginning of April, after a period of operational tests.
To support the weight of the rotor, two cranes were used – each one able to sustain up to a thousand tons. The operation, which began at 8 am, with the prior adjustments and leveling, at elevation 108 in the Power House, was accompanied by Brazil's CEO, Jorge Samek, and Paraguay's CEO, Efraín Enriquez Gamon, in addition to directors from both banks of the Itaipu and Brazilian and Paraguayan journalists. At 4 pm, the part was already leaning against the anchor block.
Jorge Samek noted that, in 28 years of operation, it was the first time that a generating unit has had to be completely disassembled. The action was necessary after the plant’s maintenance team discovered a crack in the unit's lower wearing ring, in September 2010. "We don't take chances with equipment maintenance and modernization," stressed Samek. "This is a hallmark of Itaipu. It’s an ongoing process that enables us, year after year, to beat records and be the most productive plant in the world," he added.
Work on the U6 coincided with the phase of renewing the company's staff, with the retirement of the first technicians and engineers and the entry of new employees – who are having the opportunity to get to know, piece by piece, how a generating unit operates. In Samek's view, knowledge management is the key to the process. "This possibility of uniting the generations was a great gift," he said.
Efraín Gamon noted that the work in the U6 is being done by Itaipu's own technicians – Brazilian and Paraguayan – which strengthens the learning and integration process. "This means we are learning how to do it. Both countries acquire the know-how of the technology necessary for a company as large as Itaipu," he concluded.
Function of the rotor
The weight and dimensions of the rotor are equivalent to the part’s importance in the generating unit. Composed of a cube, crown, poles and fastening and locking devices, the rotor is responsible – together with the stator – to transform mechanical energy into electricity. "It's a crucial piece," affirmed the Brazilian coordinator of the work in the U6, Cléber Pimenta, from the Generating Unit Mechanical Maintenance Division (SMMU.DT).
Maintenance Superintendent (SM.DT), Marco César Castella, pointed out that the restoration of the U6 is occurring without any incidents and the partial results, in this final phase of the work, are exceeding expectations. "The evaluation is excellent. We are completing the work as scheduled and, now that the maintenance work concluded, the unit will return to the system in better conditions," he said. For the reassembly, only one of the shafts and upper bracket are missing, in addition to smaller pieces.