After the motor’s bearings were replaced, the motor vibrates heavily
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After replacing the bearings, with the motor’s base firmly secured, the horizontal vibration of the motor reached 3.8 mm/s. After releasing the footings, the horizontal vibration is 1.5 mm/S; the motor power is 45 KW, the speed is 2950, and it is a power-frequency motor. It was suspected that the feet were loose, but even after cleaning the base areas and adding shims, it didn’t help.
Such problems are caused by the motor not being level, as well as poor alignment of the couplings. For reference.
Check the tightness between the outer ring of the bearing and the bearing cover, replace the bearing, and check the coaxiality.
It should be the soft feet; try leveling it with a dial indicator
It’s best to plot the spectrum to see on which harmonics the amplitude is highest, so as to make an accurate judgment
While the motor is running, one or two foot bolts can be slightly loosened to check the vibration level; if the vibration does decrease, it is likely that the bolts are not properly secured. During adjustment, a gauge can be used on the motor foot; it reads 0 when the connection is loose. After tightening, observe the degree of deformation of the base, and then add an appropriate amount of copper sheet accordingly. We’ve found quite a few similar problems. It seems that the motor housing lacks sufficient rigidity; even a slight tightening of the bolts causes significant vibration, and one motor had to be secured with only 3 bolts.
Have you confirmed that the rotor bearing position is correct and that there is no wear on the motor end cover?
With us as well, when the motor is turned on, there is vibration; and once it starts moving, the vibration becomes more severe
It’s better to measure the spectrum in order to make a judgment
This situation is usually due to a problem with the motor not making proper contact
This is a great suggestion; the original poster can give it a try