Terry,
Are you talking specifically - Baker, PdMA, AllTest types of systems - leaving out the vibration / oil / thermography end of the analysis?
If so, I am familiar with the PdMA test equipment and do believe that their offline / online testing does allow PdM for some failures with trend plot capability for the various parameters measured.
In order to adequately monitor a motor, both the online and the offline PdMA tests should be performed. Some early models did only the online tests.