Application of Hamm’s approximate method of electric power determination for transport means research

This paper presents Hamm's approximate method of determination of the consumed electric energy in three-phase asynchronous induction electric motors. The method gives brief and sufficiently exact information for a selection of advisable technical factors in working conditions. The basis of this approximate method is dependence of power factor cos φ upon electric motor load. Using empiric data, Hamm has developed a diagram for determination of electric power on the basis of measured current for three characteristic values of the power factor (cos φ = 0.7; cos φ = 0.8; cos φ = 0.9). The method is illustrated with a practical example where specific consumed electric energy of a pneumatic and a mechanical conveyor is determined. Results of the research have confirmed that mechanical conveyor is more favourable than pneumatic conveyor with respect to power.