Traditional methods of grading potato tubers require high labor-hour, cause fatigue
to workers and has low output. Hence, engine driven machine capable of grading
potato tubers into different size classes was evaluated. The grader prototype
consisted of feeding table, grading cylinder and catchment tray. Grading capacity,
grading system efficiency, mechanical damage and fuel consumption were used to
determine the performance of the machine. Split-split-plot experimental design where
grading cylinder speeds (10, 15, 20 rpm) were the main plots, angle of inclinations
(5, 10, and 15°) as sub-plots and feeding rates (20, 30, 40 Kg.min-1)as sub-sub-plots
with three replications were used. The results indicated that grading capacity and
fuel consumption increased with increasing cylinder speed and feed rate while
percentage mechanical damage and grading system efficiency decreased with
increasing angle of inclination. The maximum grading system efficiency of 97.57%
and 97.67 % was observed, when the machine was operated at speed of 15rpm, angle
of inclination of 5° and feed rate of 20 and 30 kg.min-1, respectively. From the
performance indices, it can be concluded that the performance of the machine is very
much acceptable with high prospect for extending the technology for small and
medium scale farmers and potato whole sellers along the value chain.
