Average of Fluctuating Load
When bearing load fluctuates, an average load which will yield the same bearing life as the fluctuating load should be calculated.
(1) When the relation between load and rotating speed is divided into the following steps.
| Load F 1 : Speed n 1 ; Operating time t 1 |
| Load F 2 : Speed n 2 ; Operating time t 2 |
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| Load F n: Speed nn; Operating time t n |
Then, the average load Fm may be calculated using the following equation:
where Fm:Average fluctuating load (N)
p = 3 for ball bearings
p = 10/3 for roller bearings
The average speed nm may be calculated as follows:
(2) When the load fluctuates almost linearly, the average load may be calculated as follows:
where
F min : Minimum value of fluctuating load (N)
F max : Maximum value of fluctuating load (N)
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(4) When both a rotating load and a stationary load are applied.
F R :Rotating load (N)
F S :Stationary load (N)
An approximate value for the average load Fm may be calculated as follows:
a) In the case of 
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