Upward thrust on vertical pump
Upward thrust on vertical pump
(OP)
what would cause this? Motor thrust upward taking out the bearing. Would assume if anything it would thrust in the downward direction.
TIA
TIA
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Upward thrust on vertical pump
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RE: Upward thrust on vertical pump
RE: Upward thrust on vertical pump
6stage
4160v motor
1500hp
rigid coupling
correction to previous post should have read motor shaft thrust upward.
RE: Upward thrust on vertical pump
are you talking about the motor bearings or the pump seal?
is the pump/system meeting the listed performance (ie flow and head)?
RE: Upward thrust on vertical pump
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"What gets us into trouble is not what we don't know, its what we know for sure" - Mark Twain
RE: Upward thrust on vertical pump
RE: Upward thrust on vertical pump
took out the top bearing but not the bottom.
shaft show signs of scoring/gouging on only one side.
cavatation???
RE: Upward thrust on vertical pump
took out the top bearing but not the bottom.
shaft show signs of scoring/gouging on only one side.
cavatation??? "
What bearing are you talking about, pump line shaft bearings, thrust assembly bearings (assuming it has a thrust assembly) or motor bearings.
You would be better served to write a clear description of what is going on, describe the pump configuration and a clear description of the failure, number of hours run etc .
Crystal ball gazing is a dying art!
RE: Upward thrust on vertical pump
thrust bearing was smeared
sorry for short answers info is slow and confusing as it comes in
RE: Upward thrust on vertical pump
Johnny Pellin
RE: Upward thrust on vertical pump
RE: Upward thrust on vertical pump
If the pump rotation is wrong, you will still get a delivery pressure , but the upthrust will be excessive and wipe out your bearing. Indication of wrong motor rotation will be high motor current and low flowrate.
Offshore Engineering&Design
RE: Upward thrust on vertical pump
long story short, stray voltage thru the lower motor bearing was found.
thanks to all for their responses.
RE: Upward thrust on vertical pump
He described this as a rigid coupling. This would suggest to me a pump with no thrust bearing. In fact, the pump would have no true bearings at all, only line shaft bushings. All thrust loads would be taken by the upper motor bearing, typically. We use this configuration commonly on deep well pumps and multi-stage vertical turbine pumps (sometimes called "can" pumps). I am still not convinced that the stay voltage problem is the root. The description of the shaft scored deeply on one side and the failure of the upper motor guide bearing sounds like up-thrust more than stray current. There may be more than one problem.
Johnny Pellin
RE: Upward thrust on vertical pump
1500 hp verticals?
RE: Upward thrust on vertical pump
you last description is correct on the pump configuration
that is why i initially thought of cavitation
you may also be correct as to more than one event causing the failure of the motor but we have not found a mechanical cause. i have looked @ flow rates during the failure and am getting flow rates from prior "normal" operation to compare
last step is to pull the pump and look at it
thanks
RE: Upward thrust on vertical pump
I believe the largest pumps of this configuration in our plant are 1000 HP. But a 1500 HP example would not be beyond reason. I have seen papers written about pumps of this type up to 5000 HP and larger.
Johnny Pellin
RE: Upward thrust on vertical pump
RE: Upward thrust on vertical pump
this is a B pump and the A pump has not had this problem
repair history for this pump included a water incursion (leak) and an oil leak
RE: Upward thrust on vertical pump
Are the units on a common or separate discharge line/s?
RE: Upward thrust on vertical pump
RE: Upward thrust on vertical pump
Cameron
Union Pump Co.
Houston, Tx
RE: Upward thrust on vertical pump
RE: Upward thrust on vertical pump
RE: Upward thrust on vertical pump
turns out the problem was with the motor not the pump.
stray current caused the failure to the bearings and things went south from there.
Steven C
Senior Member
ThirdPartyInspections.com