Pump-Motor issue
Pump-Motor issue
(OP)
On our site, 45KW motor is installed instead of 37KW (Pump EMR , Name plate data suggests) since commissioning. This motor-pump unit has experienced increased vibration issues for previous 10 years. Can the increased KWs of motor cause vibrations in pump-motor unit?
Daren!
RE: Pump-Motor issue
RE: Pump-Motor issue
You need to be looking elsewhere for the source of vibration.
It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)
RE: Pump-Motor issue
10 years is already a very long time! Did you check for bearings failure, Misalignment, foundation damage? What about erosion? NPSH a...?
Do you have a PM program in place with regular monitoring of the equipment?
Let us know your findings.
Pierre
RE: Pump-Motor issue
RE: Pump-Motor issue
Check coupling and coupling alignment first and holding down bolts on the motor, pump and base plate.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Pump-Motor issue
@Tugboat : You may be right. It might have been kept large power motor intentionally.
@LittleInch: Alignment is okay. Bearing condition monitoring is performed on regular basis. There is flexible coupling. Overhauling is performed after two years. Don't you think that Low weight impeller, dia & change in flow characteristics can cause an issue ?
Daren!
RE: Pump-Motor issue
That means having the original pump data sheet and hydraulic requirements and comparing it to the current details.
The job for an experienced pump hydraulic engineer - not a hit and miss approach or supplying half clocked detail to a group of guys on a pump forum.
It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)
RE: Pump-Motor issue
Daren!
RE: Pump-Motor issue
It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)
RE: Pump-Motor issue
It has had increased vibration for 10 years, I would suggest a vibration analysis on the motor and pump. It's possible that the motor has bad bearings, or that it has a loose rotor bar, for example. If it has had increased vibration for 10 years, it seems to be operating well enough.
RE: Pump-Motor issue
Not to say that it is totally not possible either. Many of these small size pumps and motors often have very light, minimal pad type foundations. Is the foundation pad vibrating as well? If so, you might want to think about a new and heavier foundation.
--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."
RE: Pump-Motor issue
"Don't you think that Low weight impeller, diam & change in flow characteristics can cause an issue ?"
I have absolutely no idea because you have given us ZERO information about this. Has anything changed?
But 10 YEARS of this and only now you're wondering what could be wrong?
Was the pump ever balanced?
You need to measure this as all pumps vibrate to certain extent, especially at 35kW, but j=how are you noticing it?
What sort of baseplate / foundations do you have?
Does the pipework warm up or cool down and stress the pump in operation but then when it cools down it is all back in alignment?
Many things can casue vibration, but a "slightly" larger motor isn't one of them. IMHO.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Pump-Motor issue
I think you're saying previous 10 years from now. How long ago was commissioning? Did the increased vibration start immediately or later? (if later that contradicts the proposition that the motor size caused the vibration). Did the vibration increase all at once or slowly (if slowly that contradicts the proposition that the motor size caused the vibration).
RE: Pump-Motor issue
RE: Pump-Motor issue
Off hand, that flex coupling may be the bad actor here.
RE: Pump-Motor issue
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Pump-Motor issue
RE: Pump-Motor issue
When using victaulic couplings they should have tie rods across the coupling to make it act like a rigid joint. People make the mistake that a victaulic coupling is rigid joint (i.e. a flanged joint) It is not. I see this mistake all the time