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At the heart of Itaipu: inspecting the generator
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“Maintenance is cleaning”. This is the philosophy of expert technician Paulo Henrique de Nóbrega, from the Generator Equipment Maintenance Division (SMMG.DT, in Portuguese), in charge of the electric maintenance team for the U07 generator. 


While the mechanics team dedicates themselves to changing radiators, the electricity team equipped with flannel rags and other gadgets cleans and inspects the generator.


To do this the SMMG.DT crew splits into three work fronts. All three thoroughly examine all the electrical connections in the generator, from the 60 mm brushes inside the slip ring all the way to the 4 meter high statoric bars in the stator.


Before that, a mental image: picture the rotor connected to the turbine and spinning at top speed. Around it, the stator, very still and filled with copper bars. This interaction creates the magnetic field that generates Itaipu's power. Well, so to speak.


After all, generating this power requires an electromagnetic induction, an initial excitation. In the slip ring, an inner compartment located right below the generator unit closing lids, the electricity crew inspects the graphite brushes. They are the ones that convey the initial excitation to the generator.


Then it is time for the flannels to go into action. In an area called “round bus bar”, also in the generator, Nóbrega's team cleans the stator bars. “Cleaning is preventive maintenance”, the teacher shared again. Two weeks before, Nóbrega had trained a group of technicians on stator bar soldering, constantly insisting on this initial lesson.


Bionic eyes


According to Nobrega, working on the generator demands “self-control” from the technicians. Each tool going in has to be recorded. Nothing stays behind in the generator. “A small pin between the coils may turn into a major problem”, he said. The metallic ends may corrode the bars and could go as far as bringing the entire machine to a halt.


After using a simple flannel rag, the electricity team under supervision by the Lab (SMIL.DT, in Portuguese) then makes use of a 37,000 dollar device to look for small objects that may be loose in the generator. A camera works as the technicians' eyes; it sneaks around the part, captures images and conveys them to a monitor. Places that are invisible to the naked eye can thus be seen.


“When we are working in here we have to forget about the world outside. We have to put our minds to it and focus only on this job”, said Nóbrega in closing.