The Experimental Rotordynamic Stability Evaluation Method Using Magnetic Excitation System for an Integrally Geared Compressor

Abstract

In turbomachinery, evaluation of rotordynamic vibration characteristics during various operations is very important for verifying the reliability of rotordynamic design. In the past, the rotordynamic stability measurement method using magnetic bearings have been applied to inline compressors. However, it is difficult to mount magnetic bearings on integrally geared compressors due to space limitations. Therefore, the authors have developed compact magnetic exciters which enable to be incorporated into the casing and it can excite rotor vibration mode directly. This technique was applied to a two-stage geared compressor, and the natural frequencies and log decrements were accurately measured. These test results demonstrated the effectiveness of the developed rotor excitation method for an integrally geared compressor.