Axis vibration problem
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Hello, experienced colleagues in the marine industry: What are the causes of high and very high vibration alarms in bearings of large-scale machinery or small equipment? Why? I would appreciate some guidance from the experienced sea friends here. Thank you!
As far as I know, excessive bearing vibration is caused by a clearance that is not within the standard values during installation. If an alarm is triggered, it indicates that some component of the bearing is damaged, such as the inner ring, cage, rolling elements, or even the outer ring; such faults are usually accompanied by abnormal noises. Another reason is that misalignment of the coupling or dynamic imbalance can cause significant vibration in the bearings.
What was said upstairs is quite comprehensive, focusing mainly on the situation with small pump units. In fact, large-scale units mostly use sliding bearings, and the reasons for vibration are similar to those mentioned above; in addition, there are issues such as insufficient interference between the bearing shells and oil film oscillations. It should be noted that these units typically use fixed vibration detection probes to measure the vibration of the rotor, with the unit of measurement being um. This differs from the method used for measuring vibration in small pump units, where the vibration intensity of the bearing housing is measured in mm/s.