I was trying to identify the cause of a bad alternator from order tracking. Since the unbalancing (1st order) was not very strong, I had a hardtime finguer out what those higher order means.
A good alternator on the same machine (with all the resonents except those from the alternator itself) would be much different as shown below.
I have also compared measured vibration waterfalls of another "bad" alternaor with that measured by adding more unbalance to the flywheel. The results had a much stronger 1st order, while all the higher orders kept at the same levels.
The original data:
Data with added unbalancing: