**7. Conclusion**

Dynamic rotor faults cause dynamic changes of rotor electromagnetic field and MMF and therefore the motor current AM and PM together creating JAPM.

Based on this theory, the new diagnostic method MCDA was developed. Basic properties of AM and PM at rotor faults were presented. The analyses of IM current and current signature at rotor faults together with mathematical equations for low and high autospectral magnitudes computation were derived. These equations were verified by simulation and experimentally and the possible low and high autospectral magnitudes variation due to IM current nonstationarity and DSP errors were discussed.

Two demodulation methods based on Hilbert transform and space transform are presented. Space transform gives the same results as Hilbert transform.

The phase demodulation extracts the fault PM current. PM can be used for the research of rotor magnetic field phase changes and oscillation and for the sensorless rotor magnetic field speed measurement. PM fault indicators are dependent on the motor load.

The amplitude demodulation extracts the fault AM current. The simple spectral peaks at fault frequencies *fsp* and *fr* are the dynamic rotor faults indicators almost independent on IM load and inertia. It was also proved that MCDA fault indicators are not influenced by the time varying load.

The presented diagnostic method is very clear and can be easily used for a reliable rotor faults diagnostics in a real time or for continual IM monitoring.
