# Loads

Minimum, equivalent dynamic and equivalent static bearing loads
 Minimum load For additional information → Requisite minimum load Frm = 0,02 C Perform calculations Equivalent dynamic bearing load For additional information → Equivalent dynamic bearing load Fa/Fr ≤ e → P = Fr + Y1 Fa Fa/Fr > e → P = 0,67 Fr + Y2 Fa Perform calculations Equivalent static bearing load For additional information → Equivalent static bearing load P0 = Fr + Y0 Fa

Symbols:

 C basic dynamic load rating [kN] (→ product tables TQI and TQO designs) e calculation factor (→ product tables TQI and TQO designs) Fa axial load [kN] Fr radial load [kN] Frm minimum radial load [kN] P equivalent dynamic bearing load [kN] P0 equivalent static bearing load [kN] Y, Y0 ,Y1, Y2 calculation factors (→ product tables TQI and TQO designs)
Comparative load ratings

For rolling mill applications, load ratings are not necessarily calculated according to ISO 281. Instead, they are often calculated by a different method based on a rating life of 90 million revolutions (500 r/min for 3 000 operating hours). These comparative load ratings are provided in the product tables because a direct comparison between the comparative and ISO load ratings is not possible, even if the comparative ratings are converted for 1 million revolutions (ISO life definition).
These comparative load ratings may not be used to calculate an ISO rating life. They may only be used together with the comparative rating life and equivalent load equations specified as follows:
LF10 = 90 (CF/PF)10/3
or
LF10h = (CF/PF)10/3 (1 500 000/n)
where

 LF10 comparative rating life [million revolutions] LF10h comparative rating life [operating hours] CF comparative dynamic load rating to give a rating life of 90 million revolutions [kN] PF comparative equivalent dynamic bearing load [kN] (→ table 1) n constant rotational speed [r/min]