Janusz Petryna
Technical Transactions, Electronical Engineering Issue 3-E 2016, 2016, pp. 99 - 113
https://doi.org/10.4467/2353737XCT.16.269.6068The article presents the possibility of using axial flux signals in the fault diagnosis of low-power induction machines working under varying load conditions. The study involved cases of asymmetrical rotors and stators in steady state and transient conditions during start-up. The laboratory measurements were performed on a modified induction motor, which was equipped with a special coil built into the bearing shield allowing the measurement of the voltage proportional to the motor axial flux. Examples of the obtained waveforms and numerical data were supplemented by conclusions and a review of current knowledge concerning the application of the axial flux signal for the purpose of the fault diagnosis of squirrel cage induction motors.
Janusz Petryna
Technical Transactions, Electronical Engineering Issue 2-M 2016, 2016, pp. 53 - 64
https://doi.org/10.4467/2353737XCT.16.247.6046The subject of the study is to analyze the effectiveness of early detection of damage to the stator winding with two parallel branches in the cage induction motor, by evaluating changes in the waveforms of branch currents in steady state operation. Harmonic components of the Fourier spectrum of circulating current, defined as the difference between the transient values of currents in the branches of the winding, were adopted as the indicators of branch current change evaluation. For a given low-power motor, several cases of a section short- circuiting in one of the winding branches were examined, for both symmetric and asymmetric air gap and for resistive symmetry and asymmetry of the rotor cage. The studies show a greater influence of damages on the changes in the amplitudes of selected harmonics of the circulating current, in comparison to changes of the stator phase current corresponding harmonics.