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Independent Frequency verification needed (impossible numbers?)|
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The CSI Software has given the exact same frequency values for 2 bearings:
(I have these two bearings on 1 machine..) NTN NUP2213: (in Orders) .436 ftf 3.83 bsf 8.28 BPFO 10.72 BPFI Same numbers for NTN NU 238 The probability of this seems to me to be vanishingly small.. Can anyone confirm these numbers? |
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Martin,
I don't find the NUP 2213 in my DB. However, I have an NTN NU2213 and an NU2213E. Numbers for them are: NU2213: 0.4298, 3.4913, 6.8769, 9.1231 For the NU2213E: 0.4198, 3.0365, 6.7166, 9.2834 The "P in the number just means it has a shield one side (they call it a loose plate). Use the numbers for the NU 2213 instead of the 2213E. The numbers you had for the NU238 are the same ones I have. Dave This message has been edited. Last edited by: RRS_Dave, |
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Martin,
RBMWare Version 4.81 gives those numbers for the nu238 but the nup2213 is listed as follows: .430 ftf 3.496 bsf 6.878 bpfo 9.122 bpfi Nothing on the ntn website to confirm or deny this info. Good Luck, Danny |
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Are these the number listings you see in your Software?
Looks like the "e" at the end has something to do with the frequencies number, huh? ![]() |
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Ralph,
About 25 years ago when I first started seeing the E suffix it stood for "Extra Capacity". Some internal redesigns allowed for higher load ratings and thus slightly different defect frequencies. I don't really know if both styles are still made or if the "E" has become the defacto standard. dj |
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Before the E used to be that there in some cases was added a ball in the bearing, now that is standard and the E is dropped. So that increased the alternatives on what data to look for in a FFT from a bearing so the brutal way is to look for several bearing data until it matches the FFT, and then the variations due to geometry changes due to wear, mounting etc.... I usually adjust speed a bit to get a match. Once in a while you get a perfect match, just like that, then you better look for what´s wrong, it´s normally not that perfect IRL. Olov
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Hi-
When you run into frequency issues, stop by http://www.sourceindex.com. By using the DEMO on the quick click menu you can search over 250,000 base bearing frequencies. Visitors get free searches to try theThe Bearing Expert database. |
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Impossible numbers mystery solved:
In RBMware, when you look up a bearing, the lookup function automatically fills in the values into the frequency calculator. It doesn't matter if you put a different bearing number in the calculator, it uses the physical charcteristics from the last bearing looked up. so lookup the bearing you want to autoload the physical data. This may be the source of some the complaints I have seen about CSI bearing freq calcs |
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Dave,
If I'm not mistaken a lot of the bearings in CSI file were entered by customers, not by CSI. I can't remember where I got it, but I actually have a NTN Canada program that has all their fault frequencies in it. Heres what it has: NUP2213 BPFO 6.878 BPFI 9.122 BSF 3.496 FTF (Rotating Outer Race):0.570 FTF (Rotating Inner Race):0.430 NU238 BPFO 8.282 BPFI 10.718 BSF 3.835 FTF (Rotating Outer Race) 0.564 FTF (Rotating Inner Race) 0.436 Rich Pratt |
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Rich:
Those concur with my database. Howard Howard W Penrose, Ph.D., CMRP President, SUCCESS by DESIGN Reliability Services Author: "Physical Asset Management for the Executive (Caution: Don't Read this on an Airplane)" and; "Electrical Motor Diagnostics: 2nd Edition" |
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Posting Boards
Machinery Condition Monitoring and Predictive Maintenance
Posts About vibration/alignment/balance
Independent Frequency verification needed (impossible numbers?)
