Elevated vibration
Growth of vibration velocity is the parameter by which standard monitoring systems assess machine condition without disassembly. The register contains 66 industrial-test cases; the median reduction in vibration level is 46 %.
Causes of vibration growth
Vibration arises where mating geometry is disturbed. Increased radial clearance, raceway ovality, rolling-element damage and shaft misalignment convert part of the supplied energy into housing oscillation, and the vibration velocity level rises long before the unit fails.
Mechanics of oscillation growth
- Increase of radial clearance. Clearance in a bearing support turns rotation into runout: the shaft gains freedom of movement transverse to the axis, and each revolution responds with an impact component in the spectrum.
- Raceway and rolling-element defects. Spalling and smearing generate periodic impacts at frequencies that are multiples of the rotational one. It is by these that standard diagnostics distinguishes bearing wear from imbalance.
- Disturbance of gear mesh. Wear of the tooth profile and increased backlash disturb the smoothness of torque transmission. The tooth-mesh frequency emerges in the spectrum, and the load on the supports increases.
Measurement procedure
Vibration velocity is measured at the control points of the bearing supports in three directions — vertical, horizontal and axial — under steady-state operation. Assessment is made by the root-mean-square value in the 10–1000 Hz band; zone boundaries are assigned under ISO 10816 depending on power rating and support type.
Vibration is an integral indicator: it responds to clearance, surface defect and misalignment simultaneously. For this reason, in some of the reports cited noise was also recorded alongside it, and less often clearance and unit temperature.
Treated assemblies
Vibration velocity and acceleration were measured at control points on the unit and its supports; among the treated components, bearings, compressors, electric motors and gearboxes occur most often.
Equipment types
Test reports
Fifteen reports with the maximum recorded reduction out of 41 containing an instrumental measurement of the vibration level. The full list is in the catalogue.
| ENTERPRISE | YEAR | CHANGE | PARAMETER MEASURED |
|---|---|---|---|
| Pervomaisk SE “KHIMPROM” | 2001 | ↓ 64–68% | bearing housing vibration, 190 and 110 → 60 and 40 µm |
| Zaporozhstal OJSC | 2013 | ↓ 59–89% | vibration velocity at control points, 1.23–1.71 → 0.10–0.70 mm/s |
| UKROLIIA LLC | 2007 | ↓ 57–68% | gearbox housing vibration velocity, 6.45–14.2 → 2.14–5.44 mm/s |
| DALCANADA Ltd | 2004 | ↓ 56–83% | upper reducer vibration, two points, 500 h |
| JSC “Rzhevsky Sakharnik” | 2009 | ↓ 55–69% | vibration velocity at engine and compressor points, 3.2–6.3 → 1.1–3.1 mm/s |
| Gorlovskiy Machine-Building Plant | 2006 | ↓ 52–79% | vibration velocity at the measurement points, 2.05–7.38 → 0.684–3.55 mm/s |
| Almaty Railcar Repair Plant | 2002 | ↓ 50–86% | vibration velocity on the carriage apron, 1.6–5.7 → 0.8–1.8 mm/s |
| AVIASTAR-SP JSC | 2008 | ↓ 48–72% | vibration velocity at the spindle bearings and bed, 0.4–2.9 → 0.2–1.4 mm/s |
| SKLO LLC | 2001 | ↓ 47–67% | vibration velocity, stages I and II, 1.5–2.4 → 0.8 mm/s |
| PJSC KhMZ Svet Shakhtera | 2013 | ↓ 46–56% | vibration velocity at the test points, 4.08–8.67 → 1.88–4.43 mm/s |
| UK EPK JSC | 2008 | ↓ 44% | peak vibration acceleration of the bearing, 103 → 58 m/s² |
| PrJSC Zaporizhzhia Iron Ore Plant | 2006–2021 | ↓ 36–45% | engine block vibration velocity, 0.9–11.3 → 0.4–9.1 mm/s |
| Gidroprivod JSC | 2002 | ↓ 33% | headstock vibration at 165 rpm, 5.4 → 3.6 mm/s |
| Kaustik JSC | 2002 | ↓ 24–41% | vibration velocity in the pump and motor bearings, 1.93–3.83 → 1.26–2.72 mm/s |
| Zmiivska TPP, turbine shop | 2005 | ↓ 23–66% | vibration acceleration of pump and motor bearing housings, 12.9–224 → 9.05–56.9 m/s² |
All 66 cases in the catalogue →
Documents of the cases with an instrumental measurement: plant commission reports — 31, signed test protocols — 9, other documents — 1; the document type is stated on the case card.
Limits of data applicability
- Applicability. The figures relate to the equipment and operating conditions of the enterprises named in the reports; on a different unit the result depends on initial wear, load and oil.
- Source document. A scan of the original report is published under every case; if the card and the scan disagree, the scan is authoritative.