Improved powder selectro rotor

This utility model discloses a rotor system of power-screening machine, including lower fixed bearing, rotating cage of power-screening machine, upper fixed bearing and steady bearing; the steady bearing is installed under the lower fixed bearing; the stability is enhanced, the vibration of entire rotor system to increase abrasion of bearing won't be caused when the rotating cage of power-screening machine rotates fast with abrasion, so as to extend service life of bearing, reduce the failure rate of equipment, decrease assembly and disassembly of power-screening machine, so that the work load of operator is reduced, the work efficiency is enhanced and the production costs are reduced.