# Thread: How we found the life of bearing

1. ## How we found the life of bearing

How we found the life of bearing in a motor with 1440rpm and 10n load on its pully.

2. The life of the bearing will be contingent on WHICH bearing you choose to use. The best way to determine this is to contact the bearing manufacturer.

Ron

3. As above the bearing life is dependent upon the bearing chosen for the job.

I'd suggest that if you don't have text material on hand to choose your bearing that you go to your local bearing vendor and get your hands on their catalogues, as any bearing seller worth their salt will have the calculation printed there.

In the mean time, you can go onto the www.skf.com site and use their bearing selection guide. The site also helps you to work out the bearing life based on the service duty. You will need technical data to select your bearing and subsequently to work out the bearing life.
Amongst the required data is the manufacturers recommended load, operational rpm and life rating in hours.

If you already have a bearing in place on the pulley and are seeking to know the theoritical time to failure (i.e. life left) then you will need to know what bearing it is. This will require the original vendors drawing or something of the like that details what is in place unless you have the ability, and want, to strip it back and find out for yourself. Knowing the pulley load is not enough - you must know what the load the bearing is rated for.
The general approach is to equate the theoretical limit of the bearing to the desired i.e. (force rating*rating life in hours*rating speed)^1/a = (force of application*desired life in hours*application rpm)^1/a where 'a' is a constant (based on the bearing type). You re-arrange for the desired life and solve.

If you are new to working with bearings I highly recommend you see your local vendor as they are generally more than happy to assist you with making your choice and will demonstrate how the life of the bearing is calculated..

4. Life of bearing depends on materials. which kind of materials used in bearings while manufacturing. there are different types of materials are used in bearings like Chrome Steel, Stainless Steel, Polyamide, Brass. Highgread materials improving life to bearings.

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