Field cases
Bearing field cases
Field cases from real machines: bearing diagnosis, condition monitoring and design reviews, with the numbers behind each decision. Customer names are removed.
| Case | In short |
|---|---|
| Cement mill gearbox | Cement dust in the oil damaged the bearings, then the gears. The spectra showed it months before the gearbox came out. |
| Ball mill pinion bearing | Standard vibration on the neighbouring bearing showed nothing until replacement day. An impact-based measurement flagged the outer-race fault months earlier. |
| Pumps away from their best efficiency point | Most pumps rarely run where they should. Straying from the best efficiency point drives cavitation, seal and bearing damage, and a large power bill. |
| Stacker-reclaimer slew bearing | At 10,000 tonnes an hour one bearing can stop the whole reclaim chain, and a replacement takes 9 to 14 months. Low-speed monitoring buys the time. |
| Rotary calciner at 3.5 rpm | Support wheel bearings turning at 3.5 rpm, where ordinary vibration analysis struggles. Three defects found 9 to 10+ months early and confirmed at teardown. |
| Cement mill counter shaft | A 2,500 kW mill counter shaft at 124 rpm moves to a located spherical roller bearing and a free CARB bearing. The life figure swings from 13,000 to over 200,000 hours depending on one axial-load input. |
| Crusher pulley shaft in a cement plant | A 300 kW belt-driven crusher shaft on two 23032 spherical roller bearings. Every formula checks out, yet no bearing load, life or shock factor is stated. With a realistic shock factor the life falls from about 370,000 h to about 13,000 h. |
| Fan bearing | A 6326/C3 fan bearing showed acceleration rising from about 10 to nearly 60 m/s² in about two weeks. No spectrum was needed: after replacement the trend dropped and stayed low, and the raceways showed fluting from electrical erosion. |
| Cement mill gearbox | Shock pulse, envelope and velocity spectra all showed sidebands at the speed of the intermediate shaft. The gearbox was opened in December: worn gear teeth, bearing wear and cement particles in the oil. |
| Paper machine press roll | A 55-tonne press roll on a 241/710 spherical roller bearing. A fault line at only 0.98 mm/s was acted on, doubled within eight days, and the bearing showed severe outer-race spalling in the loaded zone. |
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