The horizontal multi-stage pump experiences significant vibration at the bearing on the coupling side at 40HZ; it has been returned to the factory for repair
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The horizontal multi-stage pump experiences significant vibration at the bearing located at the coupling end at frequencies above 40 Hz; the vibration level is 8.4 mm/s. It has been sent back to the factory for repair, and the relevant parts have been replaced. The vibration level at the foundation is low, and vibration levels in other areas are also low. Only the pump and the motor at the coupling end exhibit high vibration levels. The vibration of the motor is not as severe as that of the pump. What could be causing this issue, and how can it be resolved?
Based on the information you provided, the following issues might be causing significant vibration at the coupling between the pump and the motor: 1. The coupling is unbalanced. It is necessary to check the balance of the coupling and make adjustments or replace it. 2. Fault in the pump or motor bearings. Check the bearing condition of the pump and motor for any abnormal wear or damage; if replacement is necessary, it should be carried out promptly. 3. The bearing seat or installation is poor. Check whether the bearing housing is loose or deformed, and whether it is installed correctly. 4. The pump shaft and the motor shaft are not aligned. If the pump shaft and the motor shaft do not rotate concentrically, it will lead to increased vibration, and realignment is required. 5. Axis bending. Check whether the pump and motor shafts are bent; if bending is detected, they need to be replaced. Considering the above possible reasons, it is recommended that you contact the manufacturer or professional technicians for inspection and repair. .
Check the following: 1. Are there any problems with the bearing at the drive end?； 2. Check the vibration spectrum to see if the vibration frequency is related to the order ； 3. Check whether the flow rate conforms to the characteristic curve.
Thirdly, in the past we used to switch between multi-stage pumps of the same type, and there was no such problem; we still have a few of those pumps, and switching them around never caused any significant vibration issues. The second option doesn’t meet those conditions, while for the first option, the bearings were replaced after it was sent back to the factory for repair