High vibrations and high excitation current was noticed on 10.5 MW, 11KV Generator in one of the oil industry captive power plant. Diagnostic tests such as Megger, RSO, AC Imp. and Pole drop confirmed low IR value and inter turn shorts in rotor winding. Complete rewinding had been done to bring back the rotor to original design.
Retaining ring disassembly was carried with hydraulic removal fixtures under induction heating. Reengineering activities were carried by dissection of inner parts of winding. Cl. F slot liners and turn insulation materials had been procured. Shaping, insulation and insertion of finished coils in slots had been performed with necessary fixtures, heating facilities and Cl. F insulation materials. Complete winding was hot pressed and shaped for retaining rings insertion with required ground insulation composites. Final dielectric tests had been conducted before and after high speed balancing.
