Ideal massive gear. N rigidly coupled inertias with gear-ratio
ratio[1]/ratio[2], .., ratio[end-1]/ratio[end]
Input identical with massless gear 'GearNoMass'.
Gear ratios are defined by relative speed. The following specifications are equivalent
ratio = {6, 2, 1} ratio = {9000, 3000, 1500}
For memorising
ratio[1]/ratio[end] > 1 if flange_a faster flange_b.