Mieczysław Zając

This paper presents a method for positioning an electric drive with an elastic mechanical part by applying the inverse problem of dynamics. The presented assumptions take into account technological requirements and limitations of dynamic variables. The desired trajectory of the mechanical part of the electromechanical system has also been determined. On this basis, an algorithm for determining the control voltage waveform is proposed.

The paper presents the investigation results of the effectiveness of applying wavelet methods and the Wigner-Ville transformation in states monitoring of typical elements of the AC drive. As an example the electric drive system consist of the voltage inverter powering the squirrel-cage induction motor was showed. A case of complex mechanical load was also investigated. An influence of the decomposition level and the selection of the basic wavelet shape as well as an influence of the selection of the time period of the Wigner-Ville method on the faults detection sensitivity and the effectiveness of the diagnostic inference were examined.

This paper presents the results of an analysis of signals recorded in different inter-turn short- circuit states in the stator windings of a squirrel-cage motor operating under a constant load. The analysis was carried out in a time-frequency domain using a simple orthonormal wavelet base that can be used in a real system without the need to acquire specialist software. The choice of analytical was associated with the existence of a periodic energy flow between adjacent frequency bands, thus making it difficult to diagnose the Fourier analysis. The aim of the study was to gather data necessary for the development of a real-time diagnostic system. Magnetic axial flux, the zero voltage signal, the short- circuit current, vibration acceleration, sound pressure, electromechanical torque, currents and phase voltages were tested as diagnostic criteria. The paper presents the main results of the analyses of magnetic axial flux signal and conclusions.

In dynamics of milles driven with electric engines issues of the drive transmission systems nonlinearity will matter greatly, especially in case of the need to conduct the identification of faults. The paper presents an example of applying wavelet analysis for investigating chosen faults in the non-linear arrangement of the drive transmission so as: appearing of backlash in mechanical connections and damaging a roller bearing. Also a case of non-linear damping in the arrangement of the mill was taken into account.