I didn't understand at the beggining how it works the game, but finally I "energized" all the outputs.
Two things that could help a lot are: Show the relation of the gears respect the motor, at least as a hint for the player. And the other one is the belt consume 2 units. This is confusing when try to use at the first time, because I see 2 belts but I could only use one.
I have fun playing the game, I like it. Good work!
Nitpick: there is a bug with the belt that you cannot put to an output gear ( I supose this is intentional) but putting one belt to a gear and then put the mouse over the output gear, the last one works as it was conected :)