Well it is simple the smaller the pulley the more rpms it will turn. But however you also have to have the horsepower to make things faster in the same sense. Example on an electric motor you have a 3 inch pulley and the other end you have a 10 inch pulley wich means the motor has turned 90 times to the pulleys 30. Now if you were to turn the pulleys around you would get a whole lot more rpms but you would be lacking in torque. Example it would be like having a car you couldnt drive unless you had someone push you up to say 35mph this is how it works because you have to have horsepower and torque to get you started without these everything else is worthless!
Other people asked questions on various topics, and are still waiting for answer. Would be great if you can take a sec and answer them