A METHOD OF RESTORATION OF STATOR WINDINGS FOR GLOBAL VACCUM PRESSURE IMPREGNATION (VPI) WOUND GENERATOR STATOR AND THE RESTORED STATOR THEREOF

摘要

This invention relates to a method of restoration of stator winding for global vacuum pressure impregnation (VPI) wound generator stator comprising the steps of: detecting the fault of winding at the slots in the top or bottom bar location of a stator; removing faulted portion of the top bar only end to end when the fault is in top bar by cutting open the top insulation of the bar and removing the copper strip by cutting on both sides; in case of fault detected at the bottom bar, removing first suitable number of top bars beyond the bend zone on both sides by cutting and removing the strip on cutting; cleaning thoroughly the remaining portion of the winding after removal of bars and testing for high voltage withstanding ability; placing a new bottom bar with resin poor insulation cut only up to the bend, brazing to the strips to strip of incoming bar of the existing strips followed by placement of resin poor mica insulated top bars; globally impregnating the repaired job once again through VPI procedure, on placing bottles of accelerator at the corner of the oven along with spraying of the accelerator on me repaired job during curing to prevent incomplete reaction/polymerization of resins on mica tape and Rotating the job during post curing till the stipulated temperature of the oven is reached to prevent excess deposition of wet resin liquid in any pocket.