A planetary gear system , comprising: a plurality of compound planet gears configured to orbit around a primary rotation axis and each including three gear stages; a first non-fixed annular gear configured to rotate about the primary rotation axis and operatively meshed with one of the three gear stages; a second non-fixed annular gear configured to rotate about the primary rotation axis and operatively meshed with one of the three gear stages; a fixed annular gear with a central axis that is coaxial with the primary rotation axis and operatively meshed with one of the three gear stages; and a non-fixed sun gear configured to rotate about the primary rotation axis and operatively meshed with one of the three gear stages, wherein the three gear stages include a larger planet gear stage having a larger pitch diameter, a smaller planet gear stage having a smaller pitch diameter less than the larger pitch diameter, and a smallest planet gear stage having a smallest pitch diameter less than the smaller pitch diameter, characterized in that a rotational input to the non-fixed sun gear results in opposite rotational outputs of the first non-fixed annular gear and the second non-fixed annular gear at substantially the same frequency of rotation, wherein a ratio of a tooth count and/or a pitch diameter of the fixed annular gear to a tooth count and/or a pitch diameter respectively of the smaller planet gear stage to a tooth count and/or a pitch diameter respectively of the non-fixed sun gear is in the range of (110-200):(18-30):(80-150); a ratio of a tooth count and/or a pitch diameter respectively of the first non-fixed annular gear to a tooth count and/or a pitch diameter respectively of the larger planet gear stage is in the range of (110-200):(18-40); and a ratio of a tooth count and/or a pitch diameter respectively of the second non-fixed annular gear to a tooth count and/or a pitch diameter respectively of the smallest planet gear is in the range of (110-200):(20-26). a plurality of compound planet gears configured to orbit around a primary rotation axis and each including three gear stages; a first non-fixed annular gear configured to rotate about the primary rotation axis and operatively meshed with one of the three gear stages; a second non-fixed annular gear configured to rotate about the primary rotation axis and operatively meshed with one of the three gear stages; a fixed annular gear with a central axis that is coaxial with the primary rotation axis and operatively meshed with one of the three gear stages; and a non-fixed sun gear configured to rotate about the primary rotation axis and operatively meshed with one of the three gear stages, wherein the three gear stages include a larger planet gear stage having a larger pitch diameter, a smaller planet gear stage having a smaller pitch diameter less than the larger pitch diameter, and a smallest planet gear stage having a smallest pitch diameter less than the smaller pitch diameter, characterized in that a rotational input to the non-fixed sun gear results in opposite rotational outputs of the first non-fixed annular gear and the second non-fixed annular gear at substantially the same frequency of rotation, wherein a ratio of a tooth count and/or a pitch diameter of the fixed annular gear to a tooth count and/or a pitch diameter respectively of the smaller planet gear stage to a tooth count and/or a pitch diameter respectively of the non-fixed sun gear is in the range of (110-200):(18-30):(80-150); a ratio of a tooth count and/or a pitch diameter respectively of the first non-fixed annular gear to a tooth count and/or a pitch diameter respectively of the larger planet gear stage is in the range of (110-200):(18-40); and a ratio of a tooth count and/or a pitch diameter respectively of the second non-fixed annular gear to a tooth count and/or a pitch diameter respectively of the smallest planet gear is in the range of (110-200):(20-26). <EOS>