Torsional vibrations analysis of a synchronous motor-compressor drive train

Thorough torsional vibration and stress fatigue analysis is presented for synchronous-motor drive train. The mathematical model with viscous torsional damping is derived. Complex Modal Reduction Technique is adopted to efficiently solve complex torsional systems with viscous damping. Numerical techniques have been developed to solve for fatigue life, represented in term of the allowable number of starts of the train, using complete and modally-reduced models. The fatigue prediction which is a function of stress amplitudes and frequency is used to evaluate the accuracy of the Complex Modal Reduction Technique and compared to full model solution. Thee results of the linear reduced-model display high accuracy when compared to the full model solution.