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what is the impact or influance of

what is the impact or influance of

what is the impact or influance of

what is the impact or influance of changing the cooling fan on non -drive end shaft of an vertical electric motor of 225 kw power with another which is not the same and it make noise?

RE: what is the impact or influance of


Different cooling capacity and different noise level. You have not provided much information.


RE: what is the impact or influance of

More or less cooling, more or less bearing loads, more or less vibration.

RE: what is the impact or influance of

Sorry,I will explain for more informations please try to understand me BECAUSE OF MY ENGLISH

this motor was in overhaull inspection (mechaniccally and electrically) all tincks were inspected ,but the only thinh the fan was broken and replaced by another oversized because we haven't the original one, so this none orginal fan makes noise and high temperatures of bearings the both side ( increasing until 95°C we stopped it) of the vertical motor.vibration normal for motor & pump 0.9mm/s & 1.2mm/s , widdings T° NORMAL

thanks a lot.

RE: what is the impact or influance of


If you replace an existing fan with a new, bigger one, I would expect different performance. Is the new expected to run at the same speed as the old one? I would expect the bigger fan use use more motor power. I would expect it to move more air, but is this air hitting your motor? If it isn't, I would expect increased temperature.

If you modify your cooling system and the temperature goes up, your modification does not work.


RE: what is the impact or influance of

If the fan is heavier then you will have more thrust loads on the (vertical) motor bearings - so higher bearing temperature.

What "noise" are you referring to in your first post? If it's due to having more radial vibration, then your bearing loads would be higher.

RE: what is the impact or influance of

I assume you have a TEFC motor with cooling fan at NDE that has a shroud around it. I also assume the increase in noise is audible and not necessarily vibrations, but it could be as well. A larger diameter fan wheel will reduce the blade tip clearance at discharge location. The noise may have a dominant tone (frequency) at #blades X rpm and harmonic frequencies. Similarly if the new fan wheel is thicker, then clearance to fan shroud would be reduced at air inlet. Normally a larger fan wheel should produce more air flow, but I suspect that either the reduced clearances or actual blade design may be producing less cooling air flow and raising bearing temperature. Can you provide photos or old and new fan wheel?


RE: what is the impact or influance of

Do you have any vibration readings before, can you compare them with readings now?

RE: what is the impact or influance of

Pictures of the two fans, with a tape measure and today's newspaper to provide some scale would be a help.

I don't recall ever seeing a motor cooling fan that was not a simple radial device, so direction of rotation should not come into play regarding efficiency and noise.
Along the lines of what others said, if the fan has a back plate, and was installed backwards, it might be blocking off a lot of the cooling air flow.

I'd expect two or even three radial fans of similar diameters and number of blades to provide similar cooling performance. If that is what you have, I'd look elsewhere for the overheating.

I'd expect aluminum or plastic motor cooling fans to have little impact on overall motor balance/unbalance, and thus 1X vibration, if somehow that is related to the increased "noise."

If you provide a more thorough description of the characteristics of the "noise" I expect it will reduce the number of posts (itself a type of noise) substantially.

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