Bearing metal temperature increase

[multistage]

I'm working with a Nuovo pignone compressor with babbitt bearing that 2 RTD mounted on them.During last 3 month bearing metal temperature increased steadily from 85 c to 127 c but oil drain temperature has not changed .I should mention vibration and process condition has not changed.
I'm curious to know have anybody ever face this kind of problem and should we take an immediate action?

 

[3DDave]

Seems like a sensor problem. Is it possible the leads are conducting heat from the sensor and the air has gotten warmer? (Seems like a big air temp difference, but it's one of the problems with surface temp sensing)

I would try to confirm both the oil drain and the RTD sensors to make sure they are reading correctly.

 

[JJPellin]

We recently had this situation and found that we had a bad card in the Bently Nevada rack. It seems unlikely for two probes to drift high at the same time. If there is a common element in the monitoring system (like a single card in the monitor), it can occur. I would not consider run-off oil temperature as a strong indication that this is not real. We have had failures where the oil return temperature did not change significantly. If I could shut down at low or no cost, I would shut down and investigate. If I could not shut down,I would have instrument tech push a signal from the field into the monitor to verify that it was not a wiring or monitor problem.

Johnny Pellin

 

[romke]

it is very likely that it is a sensor problem. most Babbitt types of bearing material would be rather unhappy with the higher temperature you describe.