bearings combination of vertical motor 3

[lahcen]

Hi;
we have in our plant a vertical pump (EBARA) with 10 stages; to pump propane.
the driver of this pump is a electric motor (Fuji electric).
my question is how to mount driving side bearing (which figure is correct? fig1 or fig2?
All information is attached.
Thanks.

 

[edison123]

What is the difference between the two figs? You need to be more clear.

People will hesitate to download zip files.

Muthu

http://www.edison.co.in

 

[flexoprinting]

I'm thinking this application might require thrust bearings and if that is the case the instructions are normally supplied with bearings. I googled your make of pump and came up with a lot of information on various pumps but think you will need to look up that specific motor to find out. Link
We have an application where the bearings are mounted face to face while the burnished dots must be lined up as well. Very interesting pump though.

Chuck

 

[lahcen]

Hi Mr Edison123;
I think it is clear, the deference is the arrangement of driving side bearings (7312AT DBD + 2KL10AC3).
Thanks.

 

[lahcen]

Hi Mr Flexoprinting;
thanks for your help.

 

[flexoprinting]

Hello Lahcen

Unfortuneatly I could not find any information to your specific motor but I located this Emerson manual which explains the procedure on pages 13 and 14, you will need a dial indicator to set bearings.

Link

Chuck

 

[ScottyUK]

lahcen,

It is normal for this type of pump to develop a significant downward thrust, so the angular contact bearing must be arranged to resist this thrust. Angular contact bearings of the type used in this motor are generally provided with preload, possibly in the form of springs, to prevent the rolling elements from skidding under light load. I don't recognise the full bearing type (2KL10A) but a 7312 is definitely an angular contact type so I'm guessing that this is an assembly of angular contact and guide bearings supplied as a set.

 

[lahcen]

thanks flexoprinting for your help.

 

[lahcen]

ScottyUK;
your reply is very helpfull, but there isn't spring,there is inner rings (2KL10A C3).
Thanks.

 

[Skogsgurra]

There should be springs (aka Wavy Washers) between the bearings to distribute the load evenly between the bearings. Is that what you call "Inner Rings"?

Without them, you have a static indeterminate case and only one of the bearings may take all the thrust.

Gunnar Englund

http://www.gke.org

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Half full - Half empty? I don't mind. It's what in it that counts.

 

[electricpete]

wavey washers or springs are not necessarily a requirement for these bearing combinations. I've seen similar arrangements in pumps without wavey washers. Wavey washers minimize skidding or sepration of an unloaded bearing. The separation of the bearings can be limited by the geometry/assembly, and the 2KL10AC3 upthrust bearing is probably shallow contact angle to minimize skidding while unloaded during normal downthrust operation. Larger and faster bearings are more likely to require springs. I agree it's important to check all available information regarding any extra hardware including springs and spacers, and also any assembly instructions (how much do you tighten the locknut).

You have a tandem pair for downthrust and a single upthrust. The difference between figures 1 and 2 is whether to put the tandem downthrust or the single upthrust bearing on top.

The letters "DBD" describe the arrangement, as shown Figure 3.6 here

http://www.nsk.com.br/upload/file/NSK_CAT_E1254f_148-151.pdf

The DBD arrangement matches your figure 1, so that's the intended arrangement.

If we consider the tandem downthrust pair to act like a single bearing unit, then the difference between DBD and DFD arrangements is analogous to the difference between more familiar 2-bearing (duplex) back to back (DB) and face to face (DF) arrangements


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(2B)+(2B)' ?

 

[ScottyUK]

Thanks Pete - learned a little more about the coding letters.

 

[lahcen]

Skogsgurra
I forget word "spacer", i mean inner spacer ring(L) and outer spacer ring (k).
like the picture.

 

[Skogsgurra]

OK, that makes it more understandable.

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[lahcen]

Thanks electricpete, your reply is very helpfull, but the problem is the over heating of the driving side of the motor.
I think the problem is the method of arrangement of spacers between bearings.

 

[flexoprinting]

Well that is not good, possibly a minor detail missed. Assuming the housings were clean and undamaged many times the wrong grease or even too much of the correct grease can overheat bearings.
Excellent post Electricpete!

Chuck

 

[lahcen]

thanks flexoprinting, i will check what you propose.

 

[electricpete]

thanks flexo and Scotty.

... and the 2KL10AC3 upthrust bearing is probably shallow contact angle to minimize skidding while unloaded during normal downthrust operation

Sorry, I was mistaken on that point. I initially thought 2KL10AC3 was a bearing, but now realize it is a spacer. So you have three identical 7320AT bearings in that DBD arrangement. I'm not sure exactly what the T means, but I think the A means 30 degree contact angle, so it's not a shallow contact angle (15 degrees is typical shallow contact angle for non-active bearing in a back to back pair). So when unloaded, that bearing will have to rely more on preload from assembly to prevent skidding.

As for your overheating, what makes you think it was an assembly problem? (did motor bearings run cool until disassembled / reassembled?). There are a lot of possible causes of hot bearing other than assembly: overload, Misalignment, lubrication (by the way is it grease or oil lubricated?)

Focusing on assembly, we can talk about some generalities: of course we know the preload / clearance of the assembled bearing depends on the assembly, and resulting axial positioning of the inner race relative to outer race for each bearing. Overheating could be the result of either one: too much preload created by the assembly method (and loading level) or too much clearance resulting in skidding. Disassembly of a removed set of bearings for inspection after overheating might give some clues on which is occurring.

Getting into specifics of your assembly would be a challenge for me. I would guess that the particular spacer photo you show above would go between the bearing housing and the first or last bearing housing in that stack… in that case the flat side should be against the bearing (you don't want that thin rim pressing against the outer ring). I'm not sure how many spacers you have total or what their shapes are. If you give more details then maybe I could give some guesses (but other people on here like Tmoose could give waay better guesses). Of course getting hold of a drawing or talking to motor OEM (or possibly bearing manufacturer) is the most reliable way to get good advice.


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(2B)+(2B)' ?