Application of the Bispectral analysis in the diagnosis of cage induction motors

The article presents the analysis results and the most important findings and conclusions concerning the usage of Bispectrum Transform in the non-invasive diagnosis of induction motor, operating in a steady state. The authors evaluated the effectiveness of the bispectrum analysis application to assess the machine faults for selected signals: stator current, voltage proportional to the unipolar stream, vibration and acoustic pressure. Particular attention was paid to the following signals: stator current and axial flux. So far, they are rarely used in the Bispectrum Transform analysis. The article contains the most important results of the analysis, referred to the symmetrical motor operating with rated load torque. Measurements and analysis were performed for low-power motor, were was the possibility of implementation of the selected rotor damages. Numerical analyses were performed in Matlab software, using Bispectral Transform functions developed by the authors. The test results for the machine with selected types of rotor damage allowed to determine the suitability of Higher Order Transformation, in distinguishing selected damages in induction motors.