When it comes to magnetic bearing condition monitoring it is obvious that neither the traditional bearing fault mechanisms nor the traditional monitoring methods will apply here.
I wonder what is an appropriate test method to verify the condition and rotational stability of magnetic bearings in large high speed rotating equipment under actual load / speed conditions? I am looking at the use of spectrum analysis and demodulation techniques of the excitation current and feedback signals. Some kind of a MCSA technique: Excitation Current Signature Analysis, ECSA!
Anyone has ever tried this?
Regards,
Arie Mol
NL

Hi Arie,

I use to do vibration analysis on some large compressors equiped with magnetic bearings, this was some years ago. I remember with vibration analysis, random sub-harmonics and broadband multiples indicated rotor dynamic instability and this was monitored in conjunction with the current level readouts for each bearing.
Again this was some 15 years ago, I'm sure there are more advanced techniques these days to evaluate mag bearing stability but, can't say that I've used them though. However, I can see the possible use of Ultrasound and IR Thermography being put to good use for this application.

Cheers...Rajan Muthukrishnan