Residuals from models of the different time-frequency analyses have some different characteristics.
The CWT indicated sensitivities that the other TF methods did not. Although not currently
identified, they might prove to be useful. The WV-CW model gave the closest fit to the data in the
training set and its residual rose more than for other models. When the level of the residual from
modeling indicates damage may exist in machinery, more information can be obtained in the
modeling by further examination of the residual. If the damage is of a local nature, the time frequency
representation of the residual will show structures localizing the damage. Such structures
were observed in the measurements of current test waveforms changing size from 1/19 of a rotation
to about 2/19 of a rotation. Examination of such residuals from different kinds of faults in different
machinery might lead to the ability to classify the damage.