Basic rating-life adjustment

Adjusted bearing life

Inputs

Declared dynamic ratingCUser-entered basic dynamic load rating for the stated bearing configuration.

Declared equivalent loadPUser-entered equivalent dynamic load; factor selection and load derivation are excluded.

Declared life exponentp—Use a stated matched exponent; 3 for ball or 10/3 for roller is not selected here.

Declared reliability factora₁—User-entered scalar from the stated governing source and reliability basis.

Declared material factora₂—User-entered scalar for the stated material/process condition; no lookup is used.

Declared other-life factora₃—User-entered scalar for stated operating effects; no condition is inferred.

Declared rotating speednConstant speed used only to convert stated revolutions to operating hours.

Basic rating life

125

million rev

Product of declared life factors

Declared-factor adjusted rating life

125

million rev

Declared-factor adjusted operating life

1,736.1

L10 = (C/P)^p; Ladj = L10·a1·a2·a3; hours = Ladj·10^6/(60n)

A first-pass number, not a code check, certification, or approval. Read the method and its limits below. What this is and is not.

Calculation snapshot

Formula version 1.0.0

Declared dynamic rating	25
Declared equivalent load	5
Declared life exponent	3
Declared reliability factor	1
Declared material factor	1
Declared other-life factor	1
Declared rotating speed	1200

Basic rating life	125 million rev
Product of declared life factors	1 1
Declared-factor adjusted rating life	125 million rev
Declared-factor adjusted operating life	1,736.1 h

L10 = (C/P)^p · Ladj = L10·a1·a2·a3 · hours = Ladj·10^6/(60n)

NHBB bearing load ratings and life: https://www.nhbb.com/knowledge-center/engineering-reference/ball-roller-bearings/load-ratings-bearing-life

This printout is a record of displayed inputs and deterministic formula output. It is not an approval, certification, or engineering conclusion.

Method

Calculate basic rating life and a stated-factor adjustment from dynamic rating, equivalent load, exponent, life factors, and speed.

L10 = (C/P)^p; Ladj = L10·a1·a2·a3; hours = Ladj·10^6/(60n)

When

Don’t

This is a basic rating-life calculation with all reliability, material, and other factors supplied by the user. It is not a bearing selection, factor lookup, reliability prediction, variable-duty, misalignment, lubrication, temperature, mounting, static-adequacy, safety, or approval analysis.