Multiple faults detection in low voltage inverter-fed induction motors

This paper presents a novel procedure to detect the most frequent faults in inverter-fed induction motors, i.e. stator short circuits and bearing defects, even in case of simultaneous presence. The procedure is based only on the analysis in the frequency domain of electromagnetic signals (one-phase stator current and stray flux around the motor), by evaluating in the experimental measurements the amplitude of the harmonic components at characteristic fault frequencies. A methodology based on high sampling frequency and filtering process allowed to distinguish not only the presence of single and multiple faults, but also the progression of these faults, from an early stage to a more serious condition.