Some Practical Aspects of Balancing an Ultra-Centrifuge Rotor

Abstract

In this paper the method of balancing centrifuge rotors for initial three modes based on practical experience is presented though, depending on the size of the centrifuge, more than one flexural modes have to be encountered. The object is to provide useful and practical information, as technical information on balancing of centrifuge rotors is hardly available because most of the work is shrouded in the clouds of the so-called secrecy.
The rotor is balanced in three stages. Firstly, individual components and sub-assemblies are balanced in traditionally low speed rigid rotor balancing machines. Secondly, the complete rotor is balanced by using modal balancing. Thirdly, the rotor is run in a high speed testing facility and rotor balance quality is checked at the operating speed. During the second and the third stages the rotor is run in its own bearings under vacuum and the data is acquired with the aid of a computer.