Bearing failure at 36,000 RPM

I'm wondering if this rotor was equipped with a squeeze film damper arrangement to introduce support flexibility and damping. Squeeze film dampers are often used in applications where the rotor operates above the first critical, a likely scenario with a rotor speed of 36,000 RPM.

Turbomolecular pumps are used mostly in scientific and semiconductor processes for high-vacuum creation. They are usually supported by mag-lev bearings and any failures, i.e. particulate ingestion, loss of power to the bearings, etc are usually quite catastrophic. Using mag-lev bearings makes vibration monitoring a non-productive task. Visual inspections will reveal very little, and because of the nature of trying to get a system back to high-vacuum once exposed to water vapor in the atmosphere, opening up the system for inspection is usually discouraged. These pumps are multi-stage and most closely resemble small gas turbines with alternating rows of rotating and fixed blades. 

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