The design features of the device and the process of operation of the new KS-0.3P clover grater and scarifier when wiping seeds from a bunch of meadow clover pad are provided in the article. Compared with the analogue KS-0.2, the new clover grater has an increased drum diameter of 0.45 m and a deck of 0.7 m and is additionally equipped with a pneumatic separation device, which contributes to an increase in productivity by 25...30 %. The purpose of the research is to study the effect of the drum rotation frequency of the KC–0.3P clover grater and scarifier and the feed of the starting material on the quality of seed wiping, to determine the range of their optimal values when agrotechnical requirements are met. During the experimental research the starting material was meadow clover wad obtained after having been cleaned of light, large, small impurities and seeds free from shells using an air sieve seed cleaning machine. The quality of the clover grater and scarifier was evaluated by two indicators - the degree of wiping and crushing of seeds. The supply of clover wad was regulated in the range from 0.3 to 0.5 t/h. The rotation frequency of the drum was changed from 700 to 800 min-1. The experiments were carried out three times. Adequate (with probability p = 0.95) regression models of the degree of wiping and crushing of seeds were obtained, the analysis of which let to determine the ranges of the optimal drum rotation speed of 775...800 min-1 and material supply of 0.48...0.50 t/h, when the specified agrotechnical indicators were provided: the degree of wiping not less than 95 % and crushing not more than 1.5 %.