The formula to calculate the effective force transmitted by the belt or chain is:

\[ F_t = \frac{974 \, 000 \cdot H}{N \cdot r} \]

Where:

• \(F_t\) is the effective force transmitted by the belt or chain in kgf-mm.
• \(H\) is the power transmitted in kilowatts (kW).
• \(N\) is the speed in revolutions per minute (rpm).
• \(r\) is the effective radius of the pulley or sprocket in millimeters (mm).