I am facing problem in calculating the shaft torque for my system. Motor is driving pulley and that pulley is coupled with belt with another big pulley (plz refer attached file image). Motor power 19.4 kw, Torque- 71.8 Nm, Motor Rated speed- 2580 rpm, motor shaft dia=42mm Pulley dia (refer attached fig):- d1=124.78, d2=374.33, d3=124.78, d4=356.51, output shaft speed =291 rpm. (shaft dia is 80 mm) How to find the torque of shaft? plz tell me the methodology/procedure ...?