Design and Experiment of 300 HP Class Turbo Compressor with Hybrid Magnetic Bearings

High-capacity and high-efficiency turbomachinery, such as turbo blowers and turbo compressors, have been developed recently. In order to keep up with these trends, magnetic bearings are being increasingly applied to turbomachinery instead of air foil bearings. In this study, hybrid magnetic bearings are applied to a 300-HP-class turbo compressor, and a no-load test and full load test were performed to evaluate the performance of the designed magnetic bearings. The rotor speed could be increased up to 51,000 rpm in the no-load test, and 45,000 rpm in the full load test. The results indicated a low level of rotor vibration and stable performance of the magnetic bearings in both the tests. Owing to the cooling system that uses water and air, the problem of thermal expansion of the rotor in the axial direction. could be avoided. The estimated aerodynamic thrust force is approximately 407 N at 45,000 rpm under the full load condition; thus, it is verified that the thrust magnetic bearings have sufficient load capacity.