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arshad bbc
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Damaged Thrust Bearing

08/02/2009 5:54 AM

sir

steam turbine is driving a induced draft blower through single reduction single halical gear box two turbine wheels are also mounting on pinon pinion locating taperland bearing is on out board side.taper land thrust bearing for slow speed gear is on the t wheel side maximum opperating speed for blower is 1080 rpm blower was working on 1040 rpm suddenly delta p of lube oil increased and rpm decreased temprature of thrust bearing of SS gear increased after hour running in his position stop the blower gear thrust bearing and thrust disk found badly dammage

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#1

Re: Damaged Thrust Bearing

08/02/2009 4:02 PM

Sorry to say that but, after all this almost incomprehensible text, what is your question? It seems that you have observed a failure in the lubrication system, bearing failures as expected, and... so?

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Dutchy
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#2

Re: Damaged Thrust Bearing

08/03/2009 3:17 AM

A picture tells a thousand words!

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Dutchy
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#3

Re: Damaged Thrust Bearing

08/03/2009 3:21 AM

By the way, without wanting to be obnoxious, using comma's would also increase the readability of your question.

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arshad bbc
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#4

Re: Damaged Thrust Bearing

08/03/2009 9:20 AM

my question was why it happen? i am giving u some more information bearing axial clearance was .017 . recommended cl is .018-.024 can this bearing damaged due to less cl than design cl is checked by dial indicator by bump check in presence of oil in bearing.

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Dutchy
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#6
In reply to #4

Re: Damaged Thrust Bearing

08/03/2009 10:46 AM

You can not reliably check for clearance in a bearing when there is oil present. Oil can remove several microns of free play in measurement when measured under low load (hand force), unless the oil has a very low viscosity. Also, in what way is the thrust washer damaged? Is it even wear or lobsided and what about the mating bearing part(s). If there has been a large amount of Radial play and/or a large amount of deflection due to excessive load then that can be one of the causes of bearing failure. Please also make sure to mention units because it seems to me that the clearance you mentioned would be in imperial units (this by the way would make my comment on measuring with oil less relevant).

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sb
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#5

Re: Damaged Thrust Bearing

08/03/2009 9:59 AM

We will like to have at least a line diagram of the system (at least I will) without that it is a bit difficult to answer.

The thrust bearing endplay is 0.017 against 0.018 min. And that too after running and probable damage ? (the temperature rise) - I assume white metal thrust bearing ? The white metal must have worn out quite a bit before the machine was stopped.

How many hours did it run before failure ?

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#7
In reply to #5

Re: Damaged Thrust Bearing

08/04/2009 8:34 AM

sorry there was an error in last writing thrust bearing end play was .17 mm against .18-.24mm bearing is fix geomatry taper land type with twelve segment this failure has occured after 15 day normal runnig suddenly rpm reduced from 1040 to990 after that with in two hour bearing and disc has dammaged

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arshad bbc
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#8
In reply to #5

Re: Damaged Thrust Bearing

08/04/2009 8:45 AM
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sb
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#9
In reply to #8

Re: Damaged Thrust Bearing

08/04/2009 9:22 AM

can you just put a single line diagram (not photo) showing the coupling, position of the failed bearing, turbine and various bearings.

On first view looks like lube failure

This can happen due to the insufficient coupling clearances (eg when the system is loaded, the growth of the shafts are to be accommodated by various clearances) if the clearances are insufficient this behavious is most obvious.

Failure of the lube system (choking of the lines,...)

There had been a few cases where we have seen that the entry of the lube pockets were not properly formed (you are not on tilting pad- rather fixed bearings) and that has not formed the wedge- we had the problem in lobed journal bearing and the effect was exactly similar. The babbit destroyed, with tell tale burn colours on edges, journal damaged...

Will study the photos further and comment. In between check the above points.

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arshad bbc
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#10
In reply to #9

Re: Damaged Thrust Bearing

08/04/2009 9:52 AM

sir

coupling gap was 4.5 mm flexible rubber coupling lube oil line was no t choked because radial bearing has not damaged and only the acting side of thrust bearing has damaged other side was quiet normal bearing was not flat land that was taper land(fixed geometry) we check all lube lines there was no blockage my first question is the less axial cl would be cause of that failure? we have check axial cl with dial indicator by bump check in presence oil what will be oil thickness in both side of thrust bearing during bump check?

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arshad bbc
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#11
In reply to #9

Re: Damaged Thrust Bearing

09/05/2009 3:41 PM

my dear sb . i have sent you the photos of that machine.i think that you have studied the photos. coupling is flexible type. flex elements are rubber rollers.coupling gap was 5.4 mm. our inspection team has declared the root cause of that dammage is less clearence then required which is .17mm instead of .18 mm.while that clearence has been checked by dial indicator in presense of oil film in both side of bearing. my question is is the less clearence is the root cause of that dammage.?what is thickness of oil film turbo 46

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Anonymous Poster (1); arshad bbc (4); bhrescobar (1); Dutchy (3); sb (2)

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