PURPOSE: To increase the output of a motor by a method wherein a power, enlarged than the input thereof, is produced in the rotary body effecting planetary revolution utilizing the meshing effect of an internal gear, a gear, a sun gear and the like.

CONSTITUTION: When a pulley 2, integral with a boss 1, the sun gear 11 and the like made four revolution, the gears 7, 8 make one revolution by three turns thereof along the internal gear 6, however, the whole of the machine makes one revolution at the same time. An external reaction with respect to the revolution of the machine is not existing at all, therefore, a canceling loss of the output due to the reaction is also not existing, and the machine converts the power, increased than the input therefor, into an electric power most efficiently in the machine under being revolved. The electric power is outputted to the outside of the machine as an electric current which has no resistance with respect to the revolution of the machine and, therefore, the output, stronger than the input, may be obtained by rotating the electric motor.