Marks on bearing

[Feg]

Guys,

Can i ask for your opinion on the attached photos, i am hoping some of you might be able to shed some light on why this bearing gave problems. We opened this motor up because the DE roller (NU322) was running hot and making more noise than it should. The motor is a 315Kw 4pl B3 355 frame.

Regards

Feg

 

[edison123]

That's a typical rolling mark on the inner race. Nothing to worry about.

What about the rolling elements ? Any nick marks, pittings etc. ? The noise would be coming from them.

Check your lubrication. Both over greasing and under greasing cause heat.

 

[Feg]

Hi Edison,

Thanks for that, the grease plates were up at 89 deg C, looked to me like there was too much grease as the chambers were full and i think they should be only 2/3 full. Also the seal was hard and had a ring worn on the shaft, so i am thinking this might have been causing the extra heat. By the way this motor only done about 800 hours and ran hot after it came out of our stores we took it back out as the other motors of the same kind were running a lot cooler around this area.

Ferg

 

[edison123]

Hi Ferg

The grease chambers must be filled to max 50% during the initial packing. Make-up grease (a few tens of grams) must be pumped in at regular running intervals. A good OEM would give these numbers on the nameplate.

I think, in your case, the tech probably pumped in more grease on his route check.

 

[jasonf987]

Hey Feg,

if it came out of your stores and gave problems right away then it might be worth checking with them if they are storing the motors correctly and rotating the shafts as often as they should to prevent any bearing damage from occuring.