Vibration of the centrifugal compressor increases
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A Siemens air compressor with a 5-stage compression system stopped due to an electrical fault; no repairs were carried out. After it was restarted, the load remained the same as before it stopped, and no adjustments were made to its operation. However, the vibration of the first order doubles, the vibration of the second order increases slightly as well, while the vibrations of the other orders remain unchanged. It was checked that the oil system is also normal, with normal inlet resistance; in short, no changes were detected in any other parameters. Could you help analyze the possible reasons for the increase in primary vibration?
What size of unit? Composition form? What causes the vehicle to shut down due to electrical issues? Is it related to motors/generators? The air compressor and vibrations are normal; the question is, what was it in μm before? What about now? Compared with the previous process parameters, are the guide vane IGV opening, temperature, and flow rate consistent? Are there any maintenance tasks to be carried out after parking?
Guide vane opening, check the anti-stall system, etc
It’s actually very difficult to determine the cause of this situation; it mainly lies in changes in specific parameters, which we are not entirely aware of. Sometimes even small changes in process parameters can lead to an increase in vibration. Without any parameters as a reference, all we can do is guess. By how much have your current vibration levels increased compared to before? If it’s not too large, it might gradually drop after running for a few days.
This post was last edited by czkzk025 on 2015-7-7 10:46. The vibration value was 9 microns before, and it is now 19 microns. The vibration alarm is at 85 micrometers. I’ve been driving it for over a week now, and the vibration remains unchanged; it’s very stable. There are basically no changes to the operation. The key point is that only the first-order vibration shows significant changes; the second-order coaxial component is slightly affected, while the other orders show basically no changes.
An electrical fault refers to a power supply interruption; driving the vehicle immediately after it stops without performing any repairs. The unit is STC - GV (80-5). It was 9µm before parking and 19µm after driving. All parameters are the same as before parking.
It’s probably caused by the partial shedding of something on the leaves.
Based on what you’ve described, it seems to be a multi-axis centrifugal compressor; check the inlet vanes.
It seems that after long-term use, deposits accumulate on the surface of the blades. When the machine is started again after it has been parked, these deposits fall off, which reduces the balance of the blades and leads to increased vibration. Based on the values you mentioned, it seems fine to continue operating the machine; just clean it during the next maintenance session
This vibration amplitude is not high; it is likely that restarting the machine caused the gas to act on the impeller, leading to changes in the deposits on it and thus affecting its dynamic balance. No major problems!
The amplitude is not high; it’s acceptable. Continue to monitor