...can be a concise word for transformer+gravity+rotor.So,we intend to transfer a form of kinetic energy(translational,gravity fall) into another form of kinetic energy(rotational,angular fall) with a transformer,that may be considered as a simple "two-wheel gearbox".In a way, it is analogous to an electric transformer,this time with unseen but perceptible,recognizable  fields ,let's say "windings" (primary,secondary) and a common "core"/mass.A mechanical  likeness,parallelism is more important for us due to the fact that our transformer is related to an intended .. mechanical power deliver.The primary is comparable to the input shaft,the secondary to the output shaft.The input shaft/"wheel" is huge(gravity) so that we perceive and use it as an "falling"/accelerating rack-bar in permanent contact with our "tiny wheel"/the output shaft.No discussion about gear ratio...Looking to this arrangement as with "electric spectacles",it's as a step-down transformer;for us is more important to understand it as a multiplier gear,in which mechanical power is transffered from a large ("huge") gear to a small one.It trades  "current"(speed) for "voltage"(torque),by transferring power from a primary "unseen shaft" to our visible secondary shaft.The input/output power problem of this "gear-box" is not interesting,we are not engaged in an "overunity" search...anyway ,in a real world input>output.The self  knotty point,to put in a continuous motion this "transgravitor" is more engaging,a real soft gamble...if the things ,really appear what they are.Sometimes,illusion is a part of our life,a real/unreal questionable game with ourself.All the Bests!