Two years ago, a 120MW Westinghouse turbo generator rotor was transported by an Antonov An-124 cargo plane from India to Belgium. A high level project that showed Maintenance Partners’ expertise and competences in electrical repairs. Our customer was very satisfied with the works performed and has now sent a second rotor for rewinding.
Flashback to 2013
On Tuesday November 19 at 11h03, the Antonov An-124 landed at Brussels Airport. The Ukrainian cargo plane carried the cargo of 47.300 kg (rotor including its canister) from India to Belgium. Transportation by plane was chosen because of the urgent need for repair.
After unloading and customs clearance, the rotor was immediately transported to the Maintenance Partners workshop in Zwijndrecht for repairs.
Today, Maintenance Partners is rewinding the rotor’s sibling in its Zwijndrecht workshop. The rotor’s dimensions and output are exactly the same as the previous one. However, this time, the rotor transported by ship instead of an Antonov cargo plane.
The rotor is part of a power plant in the Middle East that operates three gas turbine driven Westinghouse generators with an output of 120MW each. Since the generators have been running for nearly four decades, wear and tear is starting to occur. In this particular rotor the risk of short-circuits is increasing day by day as the material degrades.
Although temporary repairs can be applied to prevent issues, a full rewind is the only solution that really extends the lifetime and avoids all risks that may occur.
Needless to say, fully rewinding a rotor that measures 9 meters in length and weighs 38 tons is a job of considerable size. A team of up to 8 electrical specialists will work round the clock to ensure delivery of the rotor by end of 2015.
During the rewinding of the rotor, improvements will be applied to improve durability. For example new antimagnetic retaining rings will be fitted to avoid oxidization and pitting that eventually leads to micro cracks.
Besides this, the insulation will also be upgraded from mica based material to nomex based material. This type of insulation is more durable and has a longer expected lifetime than traditional mica based insulation.
When the rotor is rewound and shipped to the Middle East, onsite repair works on the generator stator will begin. The goal of these repairs is to extend the stator’s lifetime and postpone rewinding of the stator.