Off-axis vibration-elimination system of eccentric rotors with use of multiple automatic ball balancers

Abstract

An automatic ball balancer (ABB) is a device that is used to automatically balance eccentric rotors. The main principle of working such a device is based on the self-synchronization phenomenon. It is typically used in rotary machines with unknown or variable imbalances. The automatic balancing process requires an ABB unit be installed on an eccentric rotor axis; thus, its application is very limited and usually comes with a redesign of the rotary machine. This paper presents a new method to eliminate the vibration of rotary machines by the use of multiple ABBs mounted away from rotor axis. The ABB, unlike the commonly used vibrator with the fixed eccentricity, has ability to adjust eccentricity during the operation. That ability allows to achieve dynamic equilibrium by the use of only two ABBs. The article introduces theoretical bases of dynamic equilibrium in the steady state of a rotary machine system with multi ABBs and proves the existence of a dynamic equilibrium with the use of only two ABBs. It also contains the optimization results of a system with the use of up to five ABBs. The objective function was defined as to minimize the size of ABBs. The smaller size of such ABBs allows us to significantly extend the range of their application.