Hello, i'm novice at rotary engines and new member at this forum

I'm interested in these engines, and wanna ask question about stationary and rotor gears. All info, that i can find, says, that these gears ensures the rotor moves exactly 1/3 turn for each turn of the eccentric shaft, but then how rotor can move differently, if there would be no gears? Can it move more or less than 1/3 turn for each turn of the eccentric shaft? Sorry if question is dumb, but i'm novice and i like to know
P.S. sorry for my english, it's not my native language