Equation (17–9) give us a fundamental insight into flat belting. If Fi equals zero, then
T equals zero: no initial tension, no torque transmitted. The torque is in proportion to the
initial tension. This means that if there is to be a satisfactory flat-belt drive, the initial
tension must be (1) provided, (2) sustained, (3) in the proper amount, and (4) maintained
by routine inspection.