Motor Reliability Statisitcs
Motor Reliability Statisitcs
(OP)
I am working in a pulp mill and it would be usefull to know if the percentage of failures that we experience due to certain causes, such as bearings, are online with what other plants are experiencing. For example if we had 70% of failures from bearing problems and the rest of the world had on average only 40% of failures caused by bearing problems then we would know to concentrate on breaings to improve reliability. Does anyone know of surveys/research that quantify failure rates?
Thank you,
Steven
Thank you,
Steven





RE: Motor Reliability Statisitcs
RE: Motor Reliability Statisitcs
1) Get IEEE Std 500, covering Equipment Relaibility Data for the Nuclear Industry. Although its data base was relatively small, representative data is a good starting point.
2) In the 80's I was involved in a Probabilistic Risk Assessment (PRA) for a very large HPI complex. I'll try to find the data.
3) An article recently appeared in "Maintenance Technology Magazine." Maybe, ithin the last 6 months? (I'm over forty so the memory, and other attributes, are not what they once were). It showed that across the board bearing failures were responsible for about 51% of all motor failures. You might want to check it out. Perhaps the author will reveal failure-rate data by industry.
4) Jbartos's commment has validity. In fact, did you know that IEEE Std 500, was produced by anonymous contributions of raw data?
RE: Motor Reliability Statisitcs
One statistic they report among the population they looked at (I can't find the motor-years off-hand but I know it's in there). Induction motor failures broken down as follows:
152 bearing failures
75 winding failures
8 rotor failures
19 Shaft or coupling failures
10 external device failures (?)
40 failures - not categorized.
I would think that for bearings in particular the definition of a failure is tricky. Many bearings are replaced based upon vibration readings on a planned basis without causing an unplanned outage. To me that is in keeping with a strategy of condition-based maintenance. Does it count as a failure?
RE: Motor Reliability Statisitcs
My memory wasn't as good as I thought!
The PRA study covered HV (230kV), MV (15kV) and LV (480V) distribution systems. Included were utility supply, in-plant generation, breakers, transformers, and cables, but no motors.
RE: Motor Reliability Statisitcs
I'm interested in the PRA study as I'm involved in a new installation with HV switchgear, transformers etc. If I could locate areas that need to be inspected better it would be helpful.
Perhaps you could provide me with a link thanks.
RE: Motor Reliability Statisitcs
Latest paper I presented was:
"Probabilistic Risk Assessment of Equipment Safety Systems"
Presented in the "Hazard Prevention Magazine"
The Journal of the System Safety Society, Vol 35, No. 3, 3rd Quarter, 1999. Their website is: www.system-safety.org
The references contained therein were also used in the HPI plant in 1982.
RE: Motor Reliability Statisitcs
There are several artciles written on survey reports. Please obtain this artcile which will give you an idea.
1.
"Assessment of the reliability of motors in utility applications - updated" by PF.Albrecht, JC Appiarius and DK Sharma, IEEE Transactions on Energy Conversion, Vol.EC-1,No 1 March 1986.
2.
Report of large motor reliability survey of industrial and commercial installations Part 1&2 by Motor reliabilit working group IEEE Transactions on industry applications, Vol 1A-21, No 4 July/August 1985.
Regards
RE: Motor Reliability Statisitcs
RE: Motor Reliability Statisitcs
RE: Motor Reliability Statisitcs
I work with a Reliability/Rotating Equipment group and our experience within our mining operation is probably a 60% /30% /10% for bearings/windings/others.
Relatively speaking,the failures we experience when compared with the large amount of motors we use,it is really small.Our Condition Monitoring efforts ,play a large part on keeping these numbers at a minimum.
GusD
RE: Motor Reliability Statisitcs
Regards
Phil Scott
RE: Motor Reliability Statisitcs
http://www.ga.com/triga/triga_italy/Lavori%20Congresso/session1/s1_Reliability%20Data%20Collection%20and%20Processing%20for%20Romanian%20.doc
etc. for more info