Influence of elastic foundation structures on the rotor dynamics of drive trains

For large motor-compressor drive trains the influence of the foundation and the supporting structure is essential for the rotor dynamics and vibration behavior of the complete system and must be taken into account during the design process. This paper is a contribution to the understanding of how rotating machines that were originally designed for operation on rigid concrete foundations can be operated safely on flexible foundation structures. It will be shown, that despite the physically necessary reversal of some of the originally demanded criteria, a safe plant operation can be achieved. Examples of large motor-compressor systems show the principal difference between a rigid and a soft installation. The interaction of all system components is modeled in detail and compared to common Standards, like DIN 4024. The paper will give a guideline for performing such a complete system evaluation and discuss the acceptance criteria in a case study of a typical large motor-compressor application.