Causes of high-voltage no-load vibration
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After the shaft extension bearing of the 6KV, 560kw centrifugal fan in my coking plant and the second-stage high-voltage motor burned out, we replaced it and found that the no-load test run vibration was 3.6---4.2mm/s. The vibration of the connected fan load test run is smaller, but it is still a bit over the standard of 2.6-3.6mm/s. The bearing temperature is normal, and the current and stator temperature are also normal. Please tell me, brothers!
The bearing must be replaced by a counterfeit product. The no-load vibration is large. You should check whether the axial or radial vibration is large. The radial vibration poses a greater threat to the motor bearings and equipment.
‘High-voltage electricity is no-load', haha. Sliding bearing? If the bearing is burned out, does it also affect the journal? Is there any problem with the lubricating oil? If the vibration value fluctuates, it may be caused by vortexing of the oil film or friction. Depends on the vibration spectrum.
According to what you said, the large vibration may be due to an installation problem. It needs to be re-aligned and the levelness and coaxiality checked. However, if the vibration is large at no-load, you can install a valve at the air inlet, close it when it is no-load, and open it when it is blowing. This will achieve good results and reduce the noise at the same time.
The bearing clearance is large or eccentric! Sooner or later something big will happen!
Thank you, everyone, the motor vibrated loudly during the test run alone. The radial vibration was large in the horizontal direction. After the fan was connected, the vibration was smaller, but the horizontal vibration was still a bit large at 3.2-4.1mm/s. We only have the HY103 vibration meter, and the bearing temperature is positive. Normally, the lubricating oil was normal. When the bearing was burning, the bearing seat and the shaft were locked, and the shaft was somewhat damaged. We gently dealt with it, and the bearing seat and the bearing outer ring were locked. We also repaired the bearing seat. During installation, the outer ring of the NU219 bearing was relatively loose. That was just the case.
Rolling bearings. If the outer ring of the bearing is loose, it will also vibrate a lot. Why didn't you deal with it at that time?
Check the ground angle first, and then see if the speed is critical. Then check the bearings. It is best to use imported ones.