Design, Fabrication and Testing of a Direct Drive Electric Powered Hammer Mill Machine

Abstract

This research designed, fabricated and tested a direct drive electric powered hammer mill machine. A 3 HP electric motor with speed of 1800 rpm was used to power the mill. The fundamentals of machine design, mechanics of machine and basic workshop technology were applied in manufacturing the mill. The calculated design values for maximum centrifugal force of the beaters mounted on the rotor and the maximum machine shaft diameter of the mill are 27 KN and 12 mm respectively. The working principle of the mill is based on repeated combined hammers (beaters) impacts and collisions of the materials being milled with the housing of the milling compartment. Tests were carried out on the mill using dry maize, dry millet, dry stock fish and the combination of dry maize, dry millet and dry stock fish as samples to determine the mill productivity and milling efficiency. In determining the productivity and milling efficiency of the mill, the initial masses of the samples were made equal.  The dry stock fish sample produced the highest mill productivity and milling efficiency. The actual mill productivity of 45.05 kg/h and milling efficiency of 91.12 % were obtained by averaging the mill productivities and milling efficiencies obtained when the samples were tested. From the calculated values of the actual mill productivity and milling efficiency, the mill performance is satisfactory.