Experts in focus: Stuart Walker
Stuart Walker is the co-founder of RMS Ltd together with Dean Whittle. Stuart has many years experience in a wide range of condition monitoring applications. He shares his knowledge freely to help others in the industry.
Two of my favourite new features in the Motion Amplification software v3.1 HDR (High density recording) which gives super smooth detailed videos and motion vectors which show the direction of motion. Great example here of a resonance problem which shows 180 Deg out of phase motion. Stiffening the structure will have a positive effect on reducing the vibration levels as the natural frequency is moved away from the running speed vibration. Levels were 15mm/sec at 2980 RPM for ref in the video.
A great example of the detail you can see with the IRIS M Motion Amplification Camera. Some MA videos like this one of a paper machine drive make the problem look so obvious, but without the camera its a different story. I had a very close look touching and feeling before we shot with the MA camera. I did not appreciate the extent to which the previous base repair had failed until we put our MA eyes on it. Having the use of extreme amplification which was released in version v3.0 really helped in the visualization of this problem especially the cracks.
How not to fit a bearing! Excessive preload on a tapered sleeve and lock nut assembly. Think a chisel and hammer may have been involved here when fitting. We knew the problem before the bearing was removed, rotation plot works a treat. It’s a must to use time waveforms in vibration analysis. Still see today too many programs that just focus on spectrums and and overall trends.
I wish I’d had the Motion Amplification Technology over the last 26 Years. It just makes the job so easy at times. One motor was showing raised levels to 12mm/sec RMS at 1xrpm when compared to the others doing 1-2 mm/sec RMS. Data was via 2 remote sensors. Very difficult access, so we used the IRIS M MA camera from 20 meters away high on a nearby gantry using different lenses to see the full picture. We could easily determine from the MA no loose mounting components present. Just a flexing of the weak structure excited by the 1RPM of the motor. Closer inspection found two vertical stiffening bars missing! Must have not been replaced after previous motor removal. We are confident with these replaced and alignment check the vibration will be reduced.