A Heavyweight Generator Repair
Upon inspection, cracks were found on the rotor spider, which required the generator shaft and spider (weighing 21 tonnes) to be brought into Quartzelec’s Malaysian workshop for repair.
The first action carried out b y the Quartzelec team was to remove the outer rim from the spider. It was then inspected, and all measurements were recorded. The spider was cleaned, and a non-destructive test was carried out before six rotor ribs were welded and the spider was machined to size.
The outer rim was washed, cleaned and baked before machining was completed and prepared for the assembly process; the spider was cooled using dry ice, baked at 250°C and covered with insulation layers to reduce heat loss. This process is critical and involves a 60-tonne mobile crane to carry the spider and shaft to be inserted into the outer rim – all of which was completed within 30 minutes to avoid temperature loss and expansion.
The Quartzelec Malaysia team completed the intricate repair ten days ahead of schedule, to the delight of the client, who was able to get the generator back into operation much earlier than anticipated.