Full definition
The effective power that a belt drive system must be capable of transmitting, calculated by multiplying the rated (nameplate) motor power by the service factor: Pd = Prated × SF. The service factor compensates for real-world conditions including driven machine load characteristics (uniform, moderate shock, heavy shock), daily operating hours, starting frequency, and environmental conditions. For example, a 50 HP motor driving a rock crusher (SF = 1.6) requires a drive designed for 80 HP. The belt profile and number of belts are then selected from catalog tables to meet or exceed this design power at the given RPM and pulley combination. Under-specifying design power is the leading cause of premature belt failure. Per ARPM (RMA), ISO 1081, and manufacturer selection guides.