Defective 15MW Generator rotor was rewound and brought back to design parameters with state of art rewinding technology. Condition of the rotor was assessed by diagnosis tests and noticed weak ground insulation and inter turn shorts. Reengineering of the winding, slot contents, end winding bracers assembly and rewinding had been carried. Clean room had been constructed in workshop for rewinding job.

Hot pressing and reshaping assembly arrangement was made exclusively for this rotor. NDT tests on rings had been performed. Rings were assembled with ground insulation composite layers. Tests such as IR, PI, OR, AC Imp, RSO and PD are performed to assess the status of winding before and after high speed balancing. Test results satisfied healthy status of winding.