Case Study: Using Motor Current Signature To Detect Number Of Cracked Rotor Bars In Induction Motors

Mohamed Wahba, Reliability Manager, EzzSteel


Broken/Cracked rotor bar/s is one of the commonly encountered induction motor faults that may cause serious motor damage to the motor if not detected timely. Past efforts on broken rotor bar diagnosis have been focused on vibration analysis and current signature analysis using spectral analysis . These methods require accurate slip estimation along with high resolution data , and very pericise judgement of severity to confidently pull out the motor to the workshop with no doubt . This presentation will not only focus on collecting current signature , but also will cover the analysis part of spectral data to determine the number of cracked/broken bars along with the severity level and needed corresponding corrective actions . This will be clearly shown through two real case studies in my plant for two 1.2 MW induction motors .


– What is Motor Current Signature and how to use it effectively to complement vibration diagnosis.
– How to Collect data using MCS .
– Analysis of cracked/broken rotor bars and detecting the number of defected bars through MCS.


I’m Mohamed Wahba, a reliability manager in the largest steel producer in the Middle East ‘ EzzSteel’. I manager a large number of assets to achieve a failure-free environment with the highest performance. This is through running a solid monitoring system which applies all condition monitoring activities such as Vibration analysis, oil analysis, thermal imaging, laser alignment, field balancing, and motor current signature analysis.