Stray-flux and Current Analyses under Starting for the Detection of Damper Failures in Cylindrical Rotor Synchronous Machines

This paper proposes the analysis of stray-flux and current data under starting to detect damper faults in cylindrical rotor synchronous machines. These machines are typically employed in high power applications and their possible outages may imply huge costs for the industries or plants where they operate. The damper cage is a critical part of these machines and a potential source of catastrophic failures. However, few research works have provided feasible alternatives to monitor the condition of such element. This work analyses the viability of analyzing the electromotive force signals induced by the stray-flux in external coil sensors as well as current signals under starting to diagnose damper faults. The results obtained both with laboratory machines show that the analyses of those signals can provide very useful information for determining how the damper degrades over time. These results are valuable for field engineers since, nowadays, there are few available solutions that allow monitoring the condition of such element without motor disassembly.