Babbitt Bearing frosting or swelling?

Did this set-up run with these type of bearings before this happened?

If this is a repair job and the oil pressure and temperature did not change from what it was before, his statement is indeed incorrect. If it is a test on a new set-up that has never run like this before then it could be the case but it should be further investigated.

Bearing frosting seems to only happen if there is an electrical charge to the shaft or other parts of the bearing house so the oil pressure or temperature has nothing to do with it (I think).

This was a repair job and the oil pressures and temperatures did not change from the original config.

Bearings frosted over or swelled? Did he conclude this based on inspecting the bearings? Or on the way the machine was running?

22 psi is pretty high supply pressure, and 85F is very low supply temp. So there is a problem there, I would expect about 15psig and 110 to 120 F.

I thought this was a turbine? Why does a turbine have a pinion?

Babbitt bearings do not swell, so that is nonsense. Carbon rings in the seals can certainly swell and grab.

What was the actual vibration level and please describe the entire machine train.

His conclusion is purely conjecture at the moment as disassembly is forth coming. It was based on what we saw on a 30 second run as vibration of 1.5 mils shut us down.

22 psi is our normal starting pressure, 33 psi is normal running pressure. 85 degrees is our min oil temp, 140 normal running temperature.

This is a centrifugal compressor the pinion comes into play as this is operated off a large bullgear assembly.

As we were only able to an unloaded idle setting the vibration limit of 1.5 was obtained as climbing.

The machine train is an IR C-150 at one end connected to a GE motor in the middle connected to a two stage IR booster. (5MW, 750 psi output @ 25-30Lbs/sec).

Carbon seal failure was the reason for the overhaul in the first place.

I have another identical machine.

I have a couple of questions, if I may:-

1. Did the bearings and carbon glands come from spares/supplier.

2. Were bearing and carbon gland clearances checked? e.g. leads of bearings, carbon gland segments scraped in correctly.

It has been my experience that white metal bearings always needed scraping in...........rule of thumb clearance where not stated 0,001" /1" of diam. of shaft + 0,001' e.g. for a 3" shaft clearance would be 0,004" clearance.

When scraping in carbon rings check each segment with bearing blue for 80% contact on shaft as well as correct clearances.

buenos dias , mira segun veo tu pregunta estas trabajando con un turbocompresor , del tipo centac ir . en estas maquinas llevan los sellos de carbon asi como los cojinetes de babit .. en este caso si la temperatura es un poco baja y la presion esta ok . solo que quiza solo cambiaste los cojinetes y no verificaste la flecha , a mi me paso , solo que yo cambie el kit completo , y no solo el cojinete .. , habria que ver que datos te arroja ,

vibracion ?

temperatura?

presion aceite ?

verificacion de filtros de aceite

verificacion de calentador de carter

con estos valores puedes diagnosticar que paso , igual tienes otros problemas ..

"Good day, looks like a question on the working of a turbocompressor of the type of centac from IR. In these machines wear of the carbon seals wear like babbit bearings in this case if the temperature is a little low and the pressure is ok you only will need to change the bearings and verify the flange, to me it seems you need change the complete kit and not only the bearing ,we will need to see what data it gives."

Vibration

Temperature?

Oil quality?

Verrify oil filters

Verfiy the heat of housing?

With these values you can diagnose the problem, equally other problems.

That is not perfect, but pretty close..

Does this turbine power a generator?

If so, what brand and output capacity would help.

What is input PSI,output PSI,RPM, etc.

Only only 2 minutes run time?

Something's not right from the start.

Who poured and clearanced the babbit?

More info is better than less.

Was re babbitting a part of the repair procedure? If so, what was the method adopted for the repair, was the babbit poured or sprayed? In both the cases, it is essential that the babbit is fully bonded with the shell so there is a complete heat transfer between the babbit and the shell and on to the cast iron block of the compresser. If there is not 100 percent contact, the babbit would overheat and swell causing a lubrication failure. You can find this by taking out the bearing and using ultrasonic check to find out if the babbit has fully bonded with the shell

good luck,

vshwn7@aol.com

Thank you all for your insight it is greatly appreciated. This is in fact a IR Centac, C-150 feeding a two stage booster, that has, enhanced performance. Both 5th and 6th stages required rework due to blade cracks and carbon seals leaking. They were sent out for repair minus the bull gear assembly. It was three weeks between reassembly and test run.

The oil temperature initially was 110 deg, it cooled down to 75 deg through the oil/ water heat exchanger while waiting between start attempts.

The oil was DTE797, new and filtered prior to servicing tank.

The filters were new IR filters.

The vibration on start would reach aprox. 0.3-0.5 mils as we obtained idle speed they would level out momentarily then begin to climb to our shudown level of 1.5 mil with no sign of leveling out again. The machine would shut down.

We will be tearing down this unit tonight so I will have some new question probably. Thanks again.