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Final straight: last large part of U6 is set back in place
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The upper rotor was reinstalled in generator unit 6 (U6) on Tuesday (31) afternoon. It was the last large part of the machine to be returned to its place. The replacement, using overhead cranes, was overseen by technicians and engineers from Itaipu, responsible for the work. Now, only smaller parts are still missing, along with a few minor adjustments before the machine get back to producing energy.

A type of giant bearing, the upper rotor has 16 arms, is 22 meters in diameter and weighs 110 tons. According to engineering personnel, its job is to support the radial load of the generator and turbine. With the machine shutdown, the part underwent complete inspection and returned to the machine as good as new.

The superintendent of Maintenance, Marco César Castella, stated that U6 was expected to be assembled and ready for preliminary testing by the end of February. “Work is being brought forward”, he said, indicating that the plan is for the machine to return to the system by April 6.

There is good reason for optimism. Last Saturday (28), the assembly team gauged the verticality of U6, to check whether the gyrating set is aligned.  The result was positive. “This is one of the most important tests”, explained the superintendent.


U6 has been shutdown since September 2010, when the plant maintenance team noted a crack in the lower wear ring. As it is one of the last parts, the whole unit had to be broken down – unheard of in the plant’s 28 years of operation.