With storage losses of potatoes due to, among others reasons, mechanical damage to tubers at harvest it necessary to search for new potato harvester working sets. This paper presents the results of comparable field studies on rotary sets separating and crushing soil clods, mated with a rod elevator, taking into special consideration the effect of working sets on the extent of mechanical damage to potato tubers. Using a prototypical potato harvester with rotary working sets on clay soils resulted in a 1.5 to 2-fold increase in soil separation as compared a serial harvester and the extent of mechanical damage to tubers did not exceed 3 %.