Reliable detection of rotor bar failures in induction motors operating in petrochemical plants

A compilation of industrial case studies for current based broken rotor bar detection in high voltage induction machines operating in water intake facilities and petrochemical plants is presented in this paper. A technique (Advanced Transient Current Signature Analysis, ATCSA) based on the analysis of the stator transient current is assessed and compared to the widely spread Motor Current Signature Analysis (MCSA) technology. ATCSA relies on the application of advanced signal processing tools that enable to track the signatures created by the fault components across the transient. These `transient signatures' lead to a reliable understanding of the machine condition and provide much more information than a single frequency peak in a FFT spectrum. The new method has proven to be valid to avoid false positives provided by the classical MCSA, such as those occurring under presence of oscillating load torques or cooling axial ducts. The work verifies the industrial applicability of the approach and its reliability in cases where the classical MCSA leads to false indications. The verification is performed on High Voltage induction motors operating in a petrochemical plant in Korea as well as on a water intake facility at the same country. Some of the motors had actual broken rotor bar faults and false positive fault indications.