The 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.

The 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.