Bevel-helical speed reduction gearboxes B2 Values for flanged shaft gear units on request Ma B2-HH-8-A

Flender/Flender Gear Units/Bevel-helical speed reduction gearboxes B2

mmon. The NLL discrepancy signal obtained for the GMM with the diagonally constrained covariance matrices is represented by the continuous line in gure 5 (). The limited covariance matrix used by the GMM results in NLL discrepancy signal which is sensitive to the operating conditions and subsequently not well suited for detecting the fault induced signal component. The NLL values obtained for the full rank covariance GMM model is represented by the dashed line, and the dash-dotted line illustrates the conditional NLL values. The NLL discrepancy signal obtained for both the full rank covariance GMM model and the conditional NLL discrepancy signal are very similar. This indicates that the joint density distribution did not manage well to model the non-linear correlation between the signal segments and the pinion rotational frequency. In this scenario conditioning the NLL on the operating condition did not serve to render the NLL more robust to the time-varying operating conditions. However the NLL values obtained for the operating conditions (gure 5 ()) may still be benecial. Those sections of the vibration signal which were generated under operating conditions which are not well representative of the typical operating conditions may be discarded. For instance, gure 5 () may be used to determine that the rst 0.4 seconds of signal should be discarded and not used to compute the NLL synchronous average. () pinion tooth incrementavg. NLL () gear tooth incrementavg. NLLFigure 6: () The synchronous averages of the signal segment NLL values which correspond to the 2 teeth on the pinion, and () the synchronous averages which correspond to the 4 gear teeth. Figures 6 () and () respectively indicate the NLL synchronous averages with respect to the pinion, and the gear. The NLL signals are generated with the unconditional full rank covariance GMM with 2 components. These synchronous averages are computed by using the whole (noisy) NLL signal, which includes the rst 0.4s dur