Experimental Comparison of Low-Cost Piezoelectric Sensors and Commercial Power-Quality Analyzers for Intermittent Stator Fault Characterization

Within the scope of predictive and preventive maintenance in industrial environments, fault detection in three-phase induction motors is crucial to reduce and, in many cases, prevent downtime and operational losses. Therefore, this work focuses on intermittent stator inter-turn short circuit anomalies, which can remain undetected by conventional monitoring systems due to their sporadic occurrence and weak signatures. In this sense, the main objective is to evaluate the sensitivity of low-cost piezoelectric sensors in comparison with power quality analyzers (PQAs) for the identification and characterization of stator faults under different operating conditions. The experimental campaign consisted of subjecting a three-phase induction motor to controlled insertion of a purely resistive impedance into the stator windings, enabling repeatable fault emulation. Different fault severities were reproduced through frequency modulation to generate intermittent short circuit patterns. Data were acquired simultaneously using piezoelectric sensors and a PQA. After the measurements, the recorded signals are processed using time–frequency signal processing techniques to compare the effectiveness of electrical variables and acoustic emission features extracted from both sensing technologies. Finally, preliminary results indicate that the proposed processing strategy enables low-cost piezoelectric sensors to detect inter-turn short circuit faults with satisfactory performance when compared with established power quality analyzers, supporting their potential as a cost-effective alternative for industrial condition monitoring applications.