Low-Speed Machines Vibration Monitoring- The Informative Brief
High-speed and low-speed machines generally cannot be measured with the same sensor.
The very low-speed machines where the vibration level is low more sensitive accelerometer is needed.
It needs to produce enough voltage for the data collector to measure.
The issue of unit conversion and integration are most important when testing low-speed machines (below 3 Hz or 180 RPM).
Hereunder are the points to consider while measuring low-speed applications:
• Use high-sensitivity accelerometers (500 mV/g) or (1000 mV/g).
• Follow ISO 20816 standards about sensor mounting, and mount the accelerometer in the load zone.
• Modify the machine's database to increase the FFT spectrum resolution.
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7moIn my experience sensor accelerometer with sensivity 500 MV/g only actuate the vibration value while difficult to analysis mechanical problem at low speed. For detect bearing damage may possible but with setting the time sampling for waveform
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7moDiva Erenst, CMRP, CAT II VA
Mobius Cat3 Condition Monitoring Technician @ Dickson Bearings and Transmissions Ltd | Vibration Analysis, Agricultural Engineering
7moCorrectly set collection parameters with a 100mv/g is more than enough.
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1yAgree. We do the same with our automated monitoring approach. Below 100rpm or so we install 500mV/g accelerometers. This can go all the way down to <1rpm. To be honest, I don’t think we’ve ever needed a 1000mV/g one but I’m sure that will happen sooner or later. The test is simply done in the configurations, where you can increase the sample length up to 54s @48kHz, or 110s @9.7kHz. Theoretically you could go longer than that, by combining the 8 simultaneous channels. Haven’t had to use that yet either.
VA CAT III, MLA II, CMRP- Rotating Equipment Vibration & Condition Monitoring & Reliability Engineer Kuwait Oil Company
1yWow.. Nice article. We have some high capacity barring gear motors with half rpm.. 0.5 rpm