Kusintha kwa Rotary ndi mtundu wa kusintha komwe kumazungulira chogwirira kuti chiwongolere kuyatsa kwa cholumikizira chachikulu. Palinso mitundu iwiri yosinthira ma rotary, yomwe ndi mawonekedwe amtundu umodzi komanso mawonekedwe amitundu yambiri. Masiwichi ozungulira amtundu umodzi nthawi zambiri amagwiritsidwa ntchito limodzi ndi ma potentiometer a rotary pamapulogalamu, pomwe masiwichi okhala ndi ma poleti angapo amagwiritsidwa ntchito kwambiri posinthira dera lomwe likugwira ntchito.