Abstract: A clutching device that achieves torque modulation and/or speed trimming by manipulating only a fraction of torque transferred, but over a wider speed range, is provided. The clutching device has a planetary gear set connected to a prime mover. The planetary gear set includes a ring gear, a planet carrier with at least one planet and one sun gear disposed in the planet carrier the said planet gear engaged at one side with the ring gear, and at the other side with the sun gear. The device further includes a modulating device connected to the sun gear, and an output device connected to the planet carrier. Speed modulation between the prime mover and the output device is controlled by controlling the speed of rotation of the sun gear. Energy from the speed modulation is recoverable by the modulating device.