The formula to calculate the rating life of a roller bearing in hours is:

\[ L_h = 500 \left( \left( \frac{1000000}{30000 \cdot N} \right)^{0.3} \cdot \frac{C}{P} \right)^{3.33} \]

Where:

• \(L_h\) is the rating life of the roller bearing in hours.
• \(N\) is the speed in revolutions per minute (rpm).
• \(C\) is the basic load rating in kilogram-force (kgf).
• \(P\) is the bearing load in kilogram-force (kgf).