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Increased vibration over time

Hello experts

A few days ago a bearing change was made and gas seal was connected to a centrifugal compressor, however, when the machine starts operating at a constant speed, the vibration values increase on the free and coupling side, it has been observed that the increase In the vibration values it is directly proportional to the temperature of the bearings, it is observed that the increase of the vibration at constant speed stops when the temperature becomes stable.

The temperature of the bearing shoes is within the alarm values, the temperature is normal (85 Β° C). 

Bearing type: tilting pad

Laser alignment was performed considering the thermal growth specified by the manufacturer The whole axis of interconnection of the machine was changed. 

The vibration values of the power turbine are low. 

The centrifugal compressor is of the brand Solar turbines and the model is C4021TAU-0155. 

I would appreciate your comments on this, attached information on the machine and the graphics obtained in the two starts.

sorry for the poor translation into English


Tags: CENTRIFUGAL, bearing, temperature, vibration, increase

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I think the alignment is probably not a problem in this case. the data you take for two time of running so it is a little bit to evaluate it. I would like to ask for some information before giving my ideal:

1. what type of gas seal installed (some type of DGS have barrier with cacbon seal)?

2. How about critical speed of the machine?

3. Could you correlate the speed, vibration trend and temperature for easy seeing of their relationship?

4. Could you plot the waterfall and APHT plot for seeing what going on with amplitude, phase and frequency?

5. what is the reason of changing bearing and Gas seal connected? what you done before it?

I see that the phase is not changed much and orbit more circular. It is not normal, my first thinking is about operating near resonance or unbalance issue but you said that the vib change together with bearing temp, so, it could be rubbing. Need more information to focus.

Hope that help/


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