In calculations of horizontal and lifting belt conveyors, the value of the preliminary tension of the belt is determined, as a rule, by the condition of absence of slippage of the belt on the drive drum and is calculated by the well-known formula. Increasing the traction capacity of a single-drum belt conveyor drive is an important problem, the solution of which makes it possible to significantly reduce the maximum tensile forces in the belt by reducing its pretension. The use of atmospheric pressure to increase the traction capacity of the drive is one of the cardinal ways to solve this problem.