....can be an important step,so to imagine a possible PM.
     Again,at:    www.msu.edu/user/brechtjo/physics/atwood/atwood.html    you can find a "play-ground" address ,to understand so easy the value of the time factor ,for a torque avalanche ,in a gravity fall evolution.
    All that we need :
     -to replace,in the torque relation,the mass difference with the arm difference
     -to imagine "something"...a cyclical,self-turning scheme
     -to "recognize" the specific task,function of the rotational inertia/flywheel/heavy hub/massive "pulley"...as in the "Atwood Machine with a heavy pulley" ,this evolution of an old physics lab-demo,into a  new smartly intuition, on net
          All the best! / Alex
			
			
			
				.....if we start with a well known concept , at  http://physicsphunhouse.com/physletbank_files/image036.png
...and play a possible (self...). variable/oscillatory leverage with a Class 2-3 lever arrangement , at :
www.geocities.ws/iacob_alex/Some_Drafts/text036.jpg
   Al_ex