In view of the problem of extracting fault characteristics from rotating speed changing gearbox with compound faults

a compound fault diagnosis method for gearbox based on morphological component analysis(MCA) and order tracking was proposed. According to the morphological diversity of the fault signals of gear and rolling bearing

the vibration signals of gearbox with compound fault could be decomposed into the harmonic component containing the fault information of gear

the impulse component containing the fault information of rolling bearing and the random noise component by using MCA. And according to the measured rotating speed

the harmonic component and the impulse component were then analyzed respectively by the envelope order analysis

and the compound fault diagnosis was carried out based on the envelope order spectra. Simulation and application examples indicate that the proposed method can effectively separate the fault characteristic signals of gear and rolling bearing under changing rotating speed

and it is superior to traditional envelope order spectrum method according to the effect of fault characteristic extraction.