Permanent automatic rotor balancer for rotors operating above critical speed

Abstract From the Canadian patent

A pair of balancing weights are mounted on opposite sides of the center line of the rotor for movement about the axis of the rotor. The weights are automatically locked against movement about the axis of the rotor when the rotor is rotating below critical speed and automatically released for free movement about the axis of the rotor when the rotor is rotating above critical speed. The weights are exemplified as roller cages. The balancing weights are variously locked by mechanical clutches actuated at critical speed. The clutching for the weights is either individual or such that the weights are necessarily locked against movement and released simultaneously. Centrifugal force is used to …