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Hi friends we are facing high temperature issue in Water feed pump NDE ball bearing (7309 ( 2 bearings Back to back arrangement)).

Pump specifications are given below

200 KW

Rated pressure 11 Bar

Sump lubrication type

Manufacture :Thermomechnica pumpfeed 1 pump



Overall pump vibrations are well within the limit ( 4 mm/s rms at POV)

We have dominant frequency at 1X, 2X along with 6X(VPF).

Pump NDE bearing reached to 60 degrees within 2 hours of operation whereas Pump DE bearing temperature found as 45 degrees. All other identical pumps maximum Pump DE & NDE temperatures are found as 44 & 45 degrees.

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Original Post

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I assume you mean 60 deg C (140 deg F). This is not a temperature that would make me overly concerned but since I don't know the previous history I would ask you if there was any recent maintenance that might explain?

There are several main reasons for high temps: Poor lubrication, excessive lubrication (I find this to be unusually common but more typical of greased bearings), improper preload (these are duplex paired - which requires a preload design). Was this properly applied? Finally, high levels of misalignment can result in this condition.

Regards

Jim P

Last edited by Registered Member

Thanks Mr. Kishore.

Shaft alignment is within tolerance. Do you mean bearing misalignment I need to check?

This is a sump lubrication type 7309 ball bearing (2* Back to Back).

Rub where we can expect? Is it between oil seal and shaft?

Pump DE bearing temperature is normal whereas NDE is 15 degrees higher(this very abnormal compared with other identical pumps)

Pump shaft, wear ings and bearings are recently replaced!

Thanks Mr. Jim

Shaft alignment is within tolerance. Do you mean bearing misalignment I need to check?

This is a sump lubrication type 7309 ball bearing (2* Back to Back). image0061619262901118_image001image003image004

Pump DE bearing temperature is normal whereas NDE is 15 degrees higher(this very abnormal compared with other identical pumps)

Pump shaft, wear ings and bearings are recently replaced!

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  • 1619262901118_image001
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  • image004: High temperature
@Registered Member posted:

So the next logical question is:

Did the higher than expected temperatures occur right after "Pump shaft, wear rings and bearings are recently replaced!"  ?   If so, that is a logical place to investigate....look closely at the maintenance performed and see what may have occurred that would explain higher temps

Thanks. Yes bearings and seals are replaced recently. I'll check the shaft temperature near to bearing oil seal.

@Registered Member posted:

Seems Flow induced Vibration .Is temperature trend increased ,stable or decreased .Keep monitor regular basis ,check assembly errors & Lubrication opportunity arrived .

As of now Vibration readings are normal , do not too worry .

Thanks Kishore,

Temperature is increasing gradually.

We have protection tripping logic has installed at Pump bearing temperature.. That's why we are monitoring closely. Do you think bearing housing imperfections may leads to high in temperature?

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