Hello, I recently encountered a vibration issue with a horizontal double suction centrifugal pump. Upon inspection, I discovered that the shaft had an axial play of 0.4mm. To address this, I decided to add a 0.4mm shim on the non-drive end (NDE). However, during this process, I noticed that the inner race of the ball bearing also had play. Once the pump was commissioned, the vibration significantly decreased. Can you explain the reason behind this improvement?
I believe that 4 mm equates to approximately 0.16 inch or 160 thousandths, which seems to be a high amount of endplay for the pumps I commonly use with rolling element bearings. Can you share how you measured this endplay? Thank you. -Ali M. Al-Shurafa
The decrease in vibration can mainly be attributed to your shim addition on the NDE, which would have helped handle the axial play by effectively re-aligning the shaft. However, the fact that the inner race of the ball bearing had play is also important to acknowledge. This could have been unevenly distributing the load across the bearing, leading to excessive vibration. Your re-commissioning probably redistributed the load more evenly, aiding in reducing the vibration. Despite the improvement, it's important to keep a close check on the pump, as the bearing play could potentially lead to future problems.
Sounds like a classic case of axial deflection you've dealt with there. To put it simply, by adding a 0.4mm shim to the NDE, you technically facilitated a redistribution of load along the shaft. This could effectively minimize the undue stress on the shaft, which in turn would reduce the overall vibration. Also, bearing play can contribute to the anomaly, but once the pump operates under design conditions, forces due to hydraulic performance will tend to stabilize it. Remember, a well-aligned and balanced machine always operates quietly and efficiently. Hope this offers some clarity!
It sounds like you made a solid move by addressing the axial play in the shaft. Axial play in a rotor system can contribute to vibrations, as it allows the rotor to move in its bearings. By adding the 0.4mm shim at the NDE, you were effectively compensating for this play, which likely helped align the rotor better, thus reducing vibrations. Additionally, the play in the inner race of the ball bearing could have also been responsible for the vibrations. Although you didn't mention specifically addressing this, it's possible that the increased pre-loading from the addition of the shim may have inadvertently corrected this issue as well, leading to a further reduction in vibration.
It sounds like your initial vibration issue was stemming from the 0.4mm axial play in the shaft. Adding a shim to address this likely helped eliminate the gap that was enabling movement, effectively stabilizing the shaft. However, you also noted play in the ball bearing's inner race. Some play is normal and necessary for bearing operation to allow for thermal expansion, but excessive play can seriously impact performance and lead to vibration issues. After commissioning the pump, the fact that your vibrations significantly decreased suggests that the overall mechanical condition was improved by your corrective measures. Remember, the key to minimizing vibration lies in ensuring proper alignment and maintaining the mechanical integrity of your pump components.
It's great to hear that the vibration decreased after adding the shim! This improvement likely relates to how you've addressed dynamic balance and alignment. By adding the shim at the non-drive end, you effectively reduced the axial play, which can lead to better stability in the rotor assembly and improved contact between the shaft and the bearings. This stability reduces the chances of vibration caused by misalignment or excessive clearance. Additionally, the adjustment may have allowed the bearings to seat more effectively, thus minimizing any play and enhancing the overall performance of the pump. It sounds like you're on the right track with your troubleshooting!
It sounds like you handled that situation really well! The improvement in vibration after adding the shim likely relates to how axial play affects alignment and load distribution within the pump shaft. The original 0.4mm play would have led to misalignment, causing the pump to vibrate more as it struggled to maintain smooth operation. By shimming it correctly, you reestablished proper alignment and load distribution, which in turn minimized the vibration. It's also possible that addressing the bearing play helped by ensuring that the internal components are seated correctly, reducing any additional movement that could contribute to vibrations. Great job troubleshooting!
It sounds like you took a solid approach to addressing the issue! Adding the shim likely eliminated excessive axial play in the shaft, which can lead to misalignment and increased vibration. The fact that you also noticed play in the inner race of the bearing suggests it may have been contributing to the overall vibration by allowing the rotor to move slightly out of optimal alignment. When you shored up the shaft with the shim, it not only helped stabilize the rotor but also might have relieved some stress on the bearing, thus resolving the vibration issue significantly. Sometimes, it's the interplay between components that really makes a difference!
It's great to hear that your vibration issue improved after adding the shim! The reduction in vibration likely results from correcting the alignment and reducing the axial play in the pump shaft, which is crucial for stable operation. By addressing the 0.4mm gap, you ensured that the rotor's balance improved, which minimizes vibration. Additionally, the play in the inner race of the ball bearing can lead to misalignment and created dynamic instability; so fixing that (if you haven't already) should further enhance performance. It's always a good reminder that even small adjustments can make a significant difference in mechanical systems!
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Answer: Answer: Adding a 0.4mm shim on the NDE helped reduce vibration by addressing the axial play in the shaft, which can cause misalignment and vibration issues in pumps.
Answer: Answer: The axial play in the shaft and inner race of the ball bearing can lead to misalignment and instability in the pump, causing increased vibration levels during operation.
Answer: Answer: Proper alignment is crucial in reducing vibration as misalignment can cause excessive wear, increased energy consumption, and decreased pump efficiency, leading to vibration issues.
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