Hello Members, I would like to discuss a case regarding the installation of a Frequency Converter after the overhauling of a Motor & Generator. During trail runs, high vibrations were detected, leading to the discovery of an issue with the Motor bearings. The Motor was sent for bearing replacement and Dynamic Balancing, followed by shaft realignment. While the vibration at the Motor side decreased, the levels remained the same at the Generator side. Despite efforts to reduce vibrations through balancing, the Generator N.D.E Vertical Vibration actually increased. Further attempts to reduce vibrations by adding weight did not have the desired effect. We recommended checking the Anti-Vibration Mounts and are awaiting a response. See the changes in vibration levels before and after the adjustments. Looking forward to your input on this matter. Regards, Kishore Kumar Agguna.
Are you using a 2115 Single Channel Emerson Analyzer? If so, which version of software are you currently using for analysis - 4.81 or a later version? I am interested in analyzing the data from your attached spectrum and would appreciate if you could share a small extracted database with me. This will allow me to examine your data more closely. Please email it to me at F86sabra@comcast.net. Thank you, Ralph Stewart. Subject: FREQUENCY CONVERTER BALANCING ISSUE Greetings, I would like to seek your input on a recent case involving a Frequency Converter. After the Motor & Generator underwent overhauling and the equipment was installed, high vibrations were observed during trial runs. Following the identification of Motor bearing issues, the Motor underwent bearing replacement and dynamic balancing. Subsequent shaft alignment was conducted post-Motor repairs, resulting in decreased vibrations on the Motor side while vibrations on the Generator side remained unchanged. Despite attempts to reduce vibrations through balancing, the Generator N.D.E Vertical Vibration actually increased from 3.6 mm/sec to 6.9 mm/sec (1x increased from 2.6 mm/sec to 5.5 mm/sec). Further balancing efforts, including the addition of 90 grams on the Cooling Fan, resulted in increased vibration levels. Finally, with the addition of 190 grams, the Generator N.D.E Vibration reduced from 5.07 mm/sec to 3.1 mm/sec (1x reduced from 3.3 mm/sec to 0.5 mm/sec). To address this issue, we are considering checking the Anti Vibration Mounts and await further guidance. BEFORE AFTER D.E V 2.655 2.088 D.E H 2.71 2.682 D.E A 1.276 1.499 N.D.E H 5.079 3.1 N.D.E V 3.611 6.998 N.D.E A 1.68 1.934 - kishore kumar agguna
Hello Ralph Stewart, the equipment in question is not CSI Equipment, but rather the Wilcoxon MAC 810. Hi Ralph, I noticed that you are utilizing a 2115 Single Channel Emerson Analyzer. Can you please confirm which version of the software you are using for analysis? If possible, could you provide a small extracted database containing the data from the posted spectrum for further analysis? Your input would be greatly appreciated. Thank you, Ralph Hello all, I would like to share a case for discussion regarding a Frequency Converter. After undergoing Motor and Generator overhauls, vibrations were detected during trial runs. While the Motor side vibrations decreased after addressing bearing issues and dynamic balancing, the Generator side vibrations remained the same. Despite efforts to reduce vibrations through balancing, the Generator N.D.E Vertical Vibration actually increased. The addition of balancing weight on the Cooling Fan did not yield the desired results. We are currently investigating Anti Vibration Mounts for a solution. BEFORE D.E V: 2.655 D.E H: 2.71 D.E A: 1.276 N.D.E H: 5.079 N.D.E V: 3.611 N.D.E A: 1.68 AFTER D.E V: 2.088 D.E H: 2.682 D.E A: 1.499 N.D.E H: 3.1 N.D.E V: 6.998 N.D.E A: 1.934 Thank you, Kishore Kumar Agguna
Hello everyone, have you inspected the tension of the generator cables? It's possible that they are exerting pressure on the generator, which could be impacting the effectiveness of the N.D.E. Anti Vibration Mount. If the mounting is not working as intended, it may result in increased vibration levels on the generator side. If you are experiencing balancing issues with your frequency converter equipment, it's important to address them promptly. In a recent case involving motor and generator overhauling, vibrations were observed during trial runs. While motor repairs helped reduce vibrations on the motor side, vibration levels remained high on the generator side. Attempts to balance the equipment led to an increase in N.D.E Vertical Vibration, highlighting a potential issue with the anti-vibration mounts. It is recommended to thoroughly check the mounts for any potential issues that may be contributing to the vibration problem. Your attention to this matter is greatly appreciated. For any further inquiries or to discuss this matter further, please contact Rob Drumheller Jr., Operations Manager at the University of Florida Facilities Services in Gainesville, FL at 352-538-4412. Thank you, Kishore Kumar Agguna
Hello Kishore, The presence of antivibration mounts beneath a fabricated frame can lead to a soft foot issue. I recommend conducting vertical measurements on all motor feet, the driven unit, and the antivibration feet on the frame. If there is excessive vibration at any of these points, try slightly loosening that particular foot to see if the vibration diminishes. A change in vibration levels could indicate a soft foot problem, causing twisting of the motor frame and potentially affecting the bearings, leading to vibration issues. Best regards, Gary Latham Subject: Troubleshooting Frequency Converter Balancing Problem Greetings Members, I seek your insights on a recent case involving a frequency converter. Following the overhaul of the motor and generator, the frequency converter exhibited high vibration during trial runs. After identifying and addressing a motor bearing issue, which included bearing replacement and dynamic balancing, shaft alignment was performed. Although vibration decreased on the motor side, it remained high on the generator side. Attempts to reduce vibration through balancing resulted in an increase in vertical vibration on the generator's non-drive end, while adding weight to the cooling fan. Despite efforts to balance by adding weight, vibration levels continued to rise. However, there was a reduction in vibration on the generator's non-drive end. We recommend inspecting the anti-vibration mounts and eagerly await their response. BEFORE: - D.E V 2.655 - D.E H 2.71 - D.E A 1.276 - N.D.E H 5.079 - N.D.E V 3.611 - N.D.E A 1.68 AFTER: - D.E V 2.088 - D.E H 2.682 - D.E A 1.499 - N.D.E H 3.1 - N.D.E V 6.998 - N.D.E A 1.934 Regards, Kishore Kumar Agguna
Hello Gary Latham, I have conducted vertical vibration tests on all anti-vibration mounts. I observed a significant vibration of 6mm/sec on the AV mounts on the Generator N.D.E side. In response to your query about frequency converter balancing issues, having anti-vibration mounts under a fabricated frame can lead to soft foot problems. I recommend taking vertical readings on all motor feet, the driven unit, and the anti-vibration feet on the frame. If there is excessive vibration at any of these points, slightly loosening that foot may reduce the vibration. If this adjustment affects the vibration levels, it could indicate a soft foot problem causing twisting in the motor frame, which can lead to bearing damage and vibration. Regards, Gary Latham Hello Members, I seek your input on a frequency converter balancing problem. After overhauling the Motor & Generator and installing the frequency converter, high vibrations were detected during trial runs. Despite changing the motor bearings, dynamic balancing, and realigning the shaft, the vibration on the Generator N.D.E side remained constant while the Motor side decreased. Attempts to reduce vibrations through balancing led to an increase in vertical vibrations on the Generator N.D.E side. We added balancing weight to the cooling fan, but vibrations persisted. We recommend inspecting the anti-vibration mounts and await feedback on this matter. BEFORE AFTER D.E V 2.655 2.088 D.E H 2.71 2.682 D.E A 1.276 1.499 N.D.E H 5.079 3.1 N.D.E V 3.611 6.998 N.D.E A 1.68 1.934 Thank you, Kishore Kumar Agguna
Hi Kishore, from your account, it seems you've tried the traditional methods to control the vibrations. However, I'd suggest you emphasize on the coupling alignment, both angular and parallel, which can sometimes be the root cause of vibration issues. Also, while the motor bearings were replaced and balanced, was the same done for the generator? Unbalanced generator rotors can cause vibration. Finally, consider the Frequency Converter - it could potentially generate harmonic distortion leading to vibration. Regards.
Hi Kishore, it seems you've made some thorough efforts to rectify this vibration issue. The unchanged vibration at the generator side and even the increase in the Generator N.D.E Vertical Vibration is indeed puzzling after your interventions. One possibility could be a misalignment between the motor and generator. While you've realigned the motor shaft, there might be a need to look into a comprehensive alignment between the whole motor-generator set. Additionally, harmonic distortion from the frequency converter might also impact vibration readings. But, let's wait for the response about the Anti-Vibration Mounts as they play a key role in controlling system vibrations too. Keep us updated!
Hi Kishore, it's indeed a complex situation you're dealing with. From what you've explained, it seems like you've taken the correct initial steps- bearing replacement, dynamic balancing, and shaft realignment. The persistence and/or increase of the vibrations on the Generator side could stem from a variety of causes. One possibility could be structural resonance or misalignment issues within the generator itself. The anti-vibration mounts are definitely something to look into, but I'd also suggest checking for possible loosened bolts, considering operational frequencies, or even inspecting the foundation on which the entire system rests. At times, an improperly bolted or weak foundation can contribute to unwanted vibrations as well. Keep at it, and surely you'll get to the bottom of this.
Hi Kishore, it sounds like you’ve been doing a thorough job investigating the vibration issues. It's interesting that balancing and added weight didn't yield the results you expected. Have you considered if there might be an underlying resonance frequency issue or if the coupling between the motor and generator could be contributing to the problem? Sometimes, unexpected vibrations can originate from misalignments not visible at first glance. Additionally, checking the anti-vibration mounts should definitely help; they can significantly affect how vibrations are transmitted. Looking forward to hearing what you find out!
Hi Kishore, it sounds like you’ve been through quite a process already! It's interesting that the vibration levels are still problematic at the Generator side, especially after all those adjustments. Given that the Anti-Vibration Mounts could be a potential culprit, I'm curious to know if you've checked for any misalignment between the motor and generator during installation or if there’s any structural issue at the foundation level that might be amplifying the vibrations. Sometimes resonance can play a role too, so it might be worth looking into how closely the operating frequencies match the natural frequencies of the setup. Good luck with it, and keep us posted on what you find out!
Hi Kishore, it sounds like you’ve been through quite a process already! Given the persistent high vibrations on the generator side, it might be worth looking into any coupling misalignment or even the health of the generator itself, aside from the anti-vibration mounts. Sometimes the source can be quite unexpected, like an issue with the rotor or stator. It may also help to analyze any resonance frequencies, as sometimes structural factors can amplify issues at specific points. Keep us posted on what you find!
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Answer: Answer: High vibrations in the Generator after installing a Frequency Converter could be due to issues such as improper shaft alignment, unbalanced components, worn-out bearings, or problems with anti-vibration mounts.
Answer: Answer: To reduce vibrations in a Generator after installing a Frequency Converter, one can address issues like proper balancing, checking and replacing worn-out bearings, ensuring correct shaft alignment, and inspecting and maintaining anti-vibration mounts.
Answer: Answer: The increase in Generator N.D.E Vertical Vibration despite efforts to reduce vibrations could be due to factors like incorrect adjustments during balancing, inadequate maintenance of anti-vibration mounts, or unresolved issues with the Generator components.
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