In this paper, a new tool for crack detection in operating rotors based on wavelet theory is described. Customarily, two approximate methods of spectral analysis, i.e. ShortTime Fourier transform and Wigner distribution, have been used to analyse the vibration components of cracked rotors during run-up or run-down periods. However, for both methods, high resolution cannot be achieved simultaneo...

Reliability of rotating machinery has a significant relation with personal safety and economic efficiency. With the development of science and technology, the improvement of performance degradation of machinery becomes increasingly higher. Research of traditional reliability theory depends on failure data. Some lifetime data result in little or even no failure. For mechanical equipment, degrada...

Vibrations of the Jeffcott rotor are modelled by a three degree of freedom system including coupling between lateral and torsional modes. The crack in a rotating shaft of the rotor is introduced via time dependent stiffness with off diagonal couplings. Applying the external torque to the system allows to observe the effect of crack ”breathing” and gain insight into the system. It is manifested ...

The detection of faults in a dynamic system can help to avoid severe damage where system reliability and safety are essential. An induction motor can fail either due to internal faults such as short circuit of motor leads; broken rotor bar and cracked rotor end rings or by external faults such as phase failure, asymmetry of main supply and mechanical overload (Karami et al 2010). Detection and ...

-During normal operation of a three-phase AC induction motor, the magnetic flux in a healthy rotor forms a sinusoidal pattern. Typically, in healthy rotors, little residual flux will remain after the motor is de-energized. However, as rotor anomalies such as cracked or broken bars develop, a net residual flux may be established. This additional flux appears as a variation in the residual flux a...