Compressors Bearings RTD

[HamzaNossair]

Hello,

Can someone verify the preferred bearing instrumentation arrangement?
- Two dual element RTD's per bearing, sometimes I heared about two dual element RTD's in the "highest loaded pad" as the specification implies, or a dual element pad in each of the 2 lowest pads

I understood that the journal bearings will be loaded between pads, is it much better than on pads?

 

[JJPellin]

Some bearings are load-on-pad (LOP) and some are load-between-pads (LBP). For a load-on-pad, I would place a dual element RTD in the trailing edge of the bottom pad. For the load-between-pad bearing, I would place a dual element RTD in the trailing edge of the pad just before the bottom (based on rotation). This is closest to the load zone at bottom center.

Of course, these are minimums. If you want additional certainty that you will detect any bearing failure and insist on full redundancy in the event of a probe failure, you can add additional probes. We have some machines with two dual probes in the loaded pad (LOP) or dual probes in both of the lower two pads (LBP).

Each option (LOP or LBP) has a proper application. For a given rotor-dynamics, either one might be advantageous over the other. I would not say that either one is necessarily better than the other. LBP is more common in our machines.


Johnny Pellin