Need Reason & Remedy for Repeat Bearing Failure in Multi Stage Feed Water Pump - CR4 Discussion Thread

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rajendra sharma Participant Join Date: Jul 2016 Posts: 2	Need Reason & Remedy for Repeat Bearing Failure in Multi Stage Feed Water Pump 07/30/2016 10:30 AM
	Feed water pump make SIHI, model MSMA 10005 9AA511OX, 5 stage, diff. pressure 54bar, capacity 84cum/hr, 2950RPM, bearings used on DE 2no. 7312, face to face arrangement, journal bearing on suction side Pump operated with VFD, normally at 45 to 48bar & capacity 42cum/hr Pump was overhauled in end Mar 16, by OEM, first bearing failed due to overheat in Jun 16, followed by failure within one month and again within a week Recent failed bearing indicate damage due to flaking on inner race & discolouration on outer race, on bearing towards pump. No indications on other bearing on coupling side Shaft deflection was checked & found 0.15mm Bearing fit on sleeve & bearing housing are satisfactory One leak is there on threaded joint on hydraulic balancing pipe at delivery side of pump. Temporarily arrested by bandage as damaged fitting can be replaced only during total shut down Bearing running at temperature 75deg c continues and vibration readings increase day by day Need cause for high axial force on shaft towards pump causing bearings to run at high temperature and subsequent damage. What is the remedy. Stand by pump has not had failure of bearing, though both pumps have undergone overhauls with OEM, almost every year. Location of pump is in Malaysia Need to understand cause for bearings running at high temperature and subsequent damage and the remedy. BR
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phoenix911 Guru Join Date: Aug 2007 Posts: 23647 Good Answers: 420	#1 Re: need reason & remidy for repeat bearing failure in multi stage feed water pump 07/30/2016 11:07 AM
	Ok,... You gave a lot of information on the failure.... how olé about some information on the pumps environment, to start with, Was the pump shaft checked for straightness? You have to confirm it and not take the OEM's word for it. On the pump, how many GPM or LPM does it do? what is the inlet and outlet size on the pump? on the inlet, what is uninterrupted the length of straight pipe (valves, elbows, flex joint) and how far down stream is the first elbow on the inlet side? we'll start with these first. __________________ “ When people get what they want, they are often surprised when they get what they deserve " - James Wood
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JE in Chicago Guru Join Date: Apr 2008 Location: Chicago Posts: 3990 Good Answers: 144	#17 In reply to #1 Re: need reason & remidy for repeat bearing failure in multi stage feed water pump 08/02/2016 3:32 PM
	370 GPM __________________ High Tolerance is Beautiful
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phoenix911 Guru Join Date: Aug 2007 Posts: 23647 Good Answers: 420	#18 In reply to #17 Re: need reason & remidy for repeat bearing failure in multi stage feed water pump 08/02/2016 4:01 PM
	Lets start at the top... __________________ “ When people get what they want, they are often surprised when they get what they deserve " - James Wood
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lyn Guru Join Date: Oct 2008 Posts: 42355 Good Answers: 1693	#2 Re: Need Reason & Remidy for Repeat Bearing Failure in Multi Stage Feed Water Pump 07/30/2016 1:03 PM
	1. Mount the "standby pump". 2. Send the failing pump back to supplier and ask the to find cause of high axial force on shaft towards pump. If you can't figure this out with the pump in front of you, I submit that the forum will be using a trial and error failure analysis method that will not help much. No offense meant to any members here.
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SolarEagle Guru Join Date: Mar 2007 Location: by the beach in Florida Posts: 33392 Good Answers: 1817	#3 Re: Need Reason & Remidy for Repeat Bearing Failure in Multi Stage Feed Water Pump 07/30/2016 1:41 PM
	It sounds to me like these bearings are not properly lubricated....or that the bearings are improper performance class.....or the bearings are made from substandard materials....or the bearings are experiencing grease breakdown from environmental exposure....or there is electrical currents being discharged across bearings.... "Once the dielectric breaks down in oil film protecting the bearings, the flow of ground current through the bearing leads to arcing and damage." http://www.skf.com/us/products/bearings-units-housings/ball-bearings/angular-contact-ball-bearings/single-row-angular-contact-ball-bearings/single-row/index.html?designation=7312%20BEGAM http://ecmweb.com/motors/diagnosing-understanding-motor-bearing-currents __________________ All living things seek to control their own destiny....this is the purpose of life
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lyn Guru Join Date: Oct 2008 Posts: 42355 Good Answers: 1693	#4 In reply to #3 Re: Need Reason & Remidy for Repeat Bearing Failure in Multi Stage Feed Water Pump 07/30/2016 1:49 PM
	How so? "Stand by pump has not had failure of bearing, though both pumps have undergone overhauls with OEM, almost every year."
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SolarEagle Guru Join Date: Mar 2007 Location: by the beach in Florida Posts: 33392 Good Answers: 1817	#7 In reply to #4 Re: Need Reason & Remidy for Repeat Bearing Failure in Multi Stage Feed Water Pump 07/30/2016 3:12 PM
	The motors may not be identical.... http://ecmweb.com/content/motor-and-drive-compatibility-must __________________ All living things seek to control their own destiny....this is the purpose of life
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phoenix911 Guru Join Date: Aug 2007 Posts: 23647 Good Answers: 420	#6 In reply to #3 Re: Need Reason & Remidy for Repeat Bearing Failure in Multi Stage Feed Water Pump 07/30/2016 2:41 PM
	If one pump works and the other doesn't, There a probabilty that the OEM that overhauled this pump, missed something. __________________ “ When people get what they want, they are often surprised when they get what they deserve " - James Wood
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lyn Guru Join Date: Oct 2008 Posts: 42355 Good Answers: 1693	#8 In reply to #6 Re: Need Reason & Remidy for Repeat Bearing Failure in Multi Stage Feed Water Pump 07/30/2016 6:09 PM
	"though both pumps have undergone overhauls with OEM, almost every year." <unsubscribe>
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phoenix911 Guru Join Date: Aug 2007 Posts: 23647 Good Answers: 420	#10 In reply to #8 Re: Need Reason & Remidy for Repeat Bearing Failure in Multi Stage Feed Water Pump 07/30/2016 9:26 PM
	Overhaul by OEM don't mean shit. We just had our distributor were we purchased our pumps from rebuild a pump where the pump shaft sheared, 3 years old. We installed the pump, and was leaking, I had maintenence tear the pump apart, wrong gaskets were installed as well as bearings. __________________ “ When people get what they want, they are often surprised when they get what they deserve " - James Wood
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Tornado Guru Join Date: May 2009 Location: Richland, WA, USA Posts: 21017 Good Answers: 795	#5 Re: Need Reason & Remidy for Repeat Bearing Failure in Multi Stage Feed Water Pump 07/30/2016 1:56 PM
	Is the motor specifically rated for VFD operation? __________________ In vino veritas; in cervisia carmen; in aqua E. coli.
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SolarEagle Guru Join Date: Mar 2007 Location: by the beach in Florida Posts: 33392 Good Answers: 1817	#9 In reply to #5 Re: Need Reason & Remidy for Repeat Bearing Failure in Multi Stage Feed Water Pump 07/30/2016 6:16 PM
	...and is the motor properly matched to the VFD..? __________________ All living things seek to control their own destiny....this is the purpose of life
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PWSlack Guru Join Date: Jan 2007 Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on. Posts: 32175 Good Answers: 839	#11 Re: Need Reason & Remidy for Repeat Bearing Failure in Multi Stage Feed Water Pump 07/31/2016 5:52 PM
	Is there an electrical fault that is causing a current to pass through the bearing? Only, the pump cannot be seen from here. __________________ "Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
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phoenix911 Guru Join Date: Aug 2007 Posts: 23647 Good Answers: 420	#12 In reply to #11 Re: Need Reason & Remidy for Repeat Bearing Failure in Multi Stage Feed Water Pump 07/31/2016 6:33 PM
	If you look really hard and squint... Really hard... You can see it.... I can...... Oh wait... That's, That's an airplane.... Never mind. __________________ “ When people get what they want, they are often surprised when they get what they deserve " - James Wood
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rajendra sharma Participant Join Date: Jul 2016 Posts: 2	#13 In reply to #12 Re: Need Reason & Remidy for Repeat Bearing Failure in Multi Stage Feed Water Pump 07/31/2016 10:55 PM
	Motor is OK & matched with VFD. So far unable to find solution. Will keep you informed on the cause. Thanks & Best Regards
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PWSlack Guru Join Date: Jan 2007 Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on. Posts: 32175 Good Answers: 839	#14 In reply to #13 Re: Need Reason & Remidy for Repeat Bearing Failure in Multi Stage Feed Water Pump 08/01/2016 4:15 AM
	That an investigation is underway is a good thing. The cause will be found locally, eventually. Good luck in chasing it down. <unsubscribes> __________________ "Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
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rwilliams Guru Join Date: Jul 2016 Posts: 1368 Good Answers: 105	#15 Re: Need Reason & Remidy for Repeat Bearing Failure in Multi Stage Feed Water Pump 08/01/2016 9:30 AM
	Quote from http://www.sterlingsihi.com/cms/index.php?eID=tx_nawsecuredl&u=0&g=0&t=1470147369&hash=2d647065ef67652c14fc4798a0e4ca827d429c27&file=fileadmin/Dokumente_WEB/Produkt_Kataloge/Fluessigkeitspumpen/Hochdruck/englisch/TC_FLS_SIHI_MSL_MSM_EN.pdf Axial thrust is hydraulically balanced by a patented balance drum system with a self adjusting throttling device. Residual thrust is absorbed by a generously-sized angular contact ball bearing. The balancing line is returned to the suction casing or in the upstream vessel. Perhaps the bandage is upsetting the balancing flow compensator, whatever that is... It wouldn't be the first time a self adjusting throttling device stopped working due to corrosion, contamination or galling perhaps to a temperature excursion. Assume the bearing that is failing is the one right at the suction connection
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Drew K Guru Join Date: Sep 2009 Posts: 1651 Good Answers: 71	#16 Re: Need Reason & Remidy for Repeat Bearing Failure in Multi Stage Feed Water Pump 08/01/2016 11:56 AM
	Was full vibration analysis done checking all axis of movement? Check that the motor is not driving an imbalance or vibration in the pump due to poor alignment. If the investigation determines a root cause please post it here for posterity and the satisfaction of your fellow contributors. Drew K __________________ Question: What is going on with the American's Government? Response: Who is John Galt?
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Users who posted comments:

Drew K (1); JE in Chicago (1); lyn (3); phoenix911 (5); PWSlack (2); rajendra sharma (1); rwilliams (1); SolarEagle (3); Tornado (1)

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