Method for Monitoring the Stator Core of a Powerful Turbo Generator

Abstract

The article is devoted to the development of an automatic method and device for monitoring the pressing of the stator core of a powerful turbo generator during its assembling at the manufacturer. The core is assembled and pressed in an upright position in separate parts; at each stage, it is necessary to monitor places with weakened solidity. The unevenness of the compaction density causes a relative displacement of the active steel sheets and losses of iron, as well as the appearance and development of certain defects (loosening of the teeth of the extreme packages, coloring of fragments of the active steel sheets, local closure of the sheets and heating of the packages), which can eventually cause severe accidents and failure of the turbo generator. Existing methods, including automatic ones, do not allow performing reliable monitoring. The method proposed by the authors for detecting places with weakened solidity is based on automatic measurement of the specific pressure of pressing during deformation of special control samples. A device for its implementation has been developed, which is a ring installed on the end surface of the core. Cells with control samples are evenly placed in the ring. The largest decrease in the sample thickness caused by the highest specific pressure corresponds to the smallest defect, and vice versa. As a pressure converter, it is proposed to use a flat metal membrane and a capacitive sensor with a digital output. The characteristics of the converter were calculated and experimentally verified. The specific pressure measurement results were processed using a special electronic unit. The device that has been developed makes it possible to improve labor productivity when monitoring the core, diagnose defects with greater reliability and eliminate them, and, ultimately, increase the reliability of the turbo generator as well as its durability.