We are analyzing some 24,000 - 30,000 rpm motorized spindles equipped with ceramic bearings that are classed at ABEC9. I don't have specific bearing numbers, don't know the DN#, or the specific type of lube being used (yet).

The vibration data for the first few units we have looked at has what I would normally call a very noisy signature if they were regular steel bearings - broad-based noise floors out to 30X (running dry??), some asynchronous components in the 4X - 12X range (primary brg faults?), and some high-frequency components in the 50-60x range (lube / natural frequency).

I would like to hear from anyone having experience with high speed motorized spindles, especially if using ceramic bearings, regarding the general signature content on these high speed units. In addition to the bearing signatures, any comments on what frequencies might be introduced by the high speed motor would be appreciated was well.

Thanks,
Stan