61 C is not a high operating temperature for a bearing, especially in an electric motor. 90 C is not unheard of.
The OEM has probably tested or theorised that the operating temperature would be around 60 and therefore set the problem alarm to 70 C. A 10 degree rise in temperature, not after...
I've plotted many misalignment vs. life curves and they all come out to show a dramatic difference between 2 & 4 minutes. Put up some app details and, although I can't guarantee good/fast timing, I'll show you what can happen.
30BC02XPP30A26
The 'X' is a separator. 30BC02 is the basic part number and the PP30A26 is the suffix.
'PP' = double shields
'30' = C3 clearance
'A' = snap ring groove opposite to filling notch
'26' = ABEC 3 or P6 internal tolerance
You need an SKF 6206-2Z/C3 N. Although since you only have...
Try www.aptitudexchange.com. It's SKF's maintenance forum I guess is the best way to describe it. Some things are free, some require a payment. There are lots of good tools for fault finding and lots of technical papers on various applications.
The primary intent of ABMA Standard 9 is to define load ratings and fatigue life. In my copy, which admitedly is not the newest version, it clearly states its purpose and mentions that "the bearing's ability to withstand static loading is also considered".
You're absolutely right...
Okay, I think I thought of a good practical explanation:
I get a lot of bearings sent to me after failure for review. Some fail due to overloading. Could be a pump, a motor, a gearbox, any dynamic application.
However, they failed due to plastic deformation of the material. Inappropriately...
Don't think it's a misprint....consider this:
Static equivalent loads are calculated and compared to the static capacity when the application is considered static, let's say less than 15 rpm. Dynamic life calculations are essentially meaningless in these cases.
Dynamic equivalent loads are...
Rule of thumb 3:1
That is the separation of the rails versus guide to guide on the rail should be 3:1.
OR
The separation of the guide to guide on the rail versus the separation of the rails should be 3:1.
Dynamic loading and static loading often differ by either a little or a lot depending on the equipment and speed and temperature and preload etc., etc..
Consider that in operation, load is added to the bearing as clearance is lost due to temperature differences between the inner and outer...
Start here......
http://www.skf.com/portal/skf/home/solutions?contentId=000911
Briefly:
What are the different bearings available, in particular what is the difference between roller bearings and white metal bearings and sleeve bearings?
**********roller bearings have rollers as the rolling...
Your rpm on a sealed bearing is going to be limited by the shaft size. You may have to consider low friction seals or shielded bearings instead of full contact sealed bearings. As well, most bearing mfg's pre pack with general purpose mineral oil grease. Synthetic will be a special order -...
The issue with asymmetric SRB's is that under load and/or high speed, the rollers are displaced inwards. This leads to unwanted edge loading, unequal loading, heat ...... potential premature failure.
SKF dropped the assymetric design in 1951.
Symmetrical designs are higher in capacity and...