Self-excitation of non-synchronous rotation of closely spaced unbalanced rotors

The results of experimental studies of the process of self-excitation of rotation with close coaxial arrangement of thin-walled disks, as well as rigidly and movably installed screens coaxially located with them, are considered and analyzed. Self-excitation of rotation was observed only when one dynamically unbalanced rotor (disk) rotated with a frequency of more than 50...150 Hz and when circular vibration of an initially non-rotating second rotor (disk or screen) was excited, located coaxially at a distance of 1...4 mm from it on a common rigid base. The self-excitation of the rotation of the rotor installed on an electric motor not connected to the network was not synchronous with the rotation speed of the dynamically unbalanced rotor rotated by the electric motor. With a rotor (disk) weight of 0.5 N and an initial distance from the screen of 3...3.5 mm, the force causing repulsion of the movable screen from the rotor was about 2.5...2.7 N, and the torque was about 0. 01 Nm. When the distance between the surfaces of the coaxially located dynamically unbalanced rotating rotor and the initially stationary disk or screen was more than 5...6 mm, the process of repulsion and self-excitation of rotation of the screen or rotor was not observed. The rotation of a well-balanced rotor in the absence of circular vibration of the second rotor or screen, even with a distance between them of 1...1.5 mm, other things being equal, also did not lead to their forceful interaction and self-excitation of rotation.