偏心转子不仅受动载荷作用,还受静载荷作用。该文推导了转子同时考虑动、静偏心的气隙长度统一公式,利用数值方法计算出作用于转子的不平衡磁拉力(UMP),建立了UMP、静载荷(重力)、不平衡质量激励力作用下转子系统的运动微分方程。分析了动偏心和动静复合偏心情形下不计静载荷时和考虑静载荷时转子系统的轴心轨迹和位移频谱,讨论了静偏心方向、初始静偏心量对转子系统振动特性的影响。结果表明:静偏心方向影响转子轴心轨迹的位置分布,使位移频谱中幅值周期性变化,静偏心量的增加使位移频谱中出现4倍旋转频率的振动分量。静载荷对转子系统的作用可视为该静载荷方向上大小恒定的静偏心。
An eccentric rotor does not only occur with dynamic loads, but also has vibrations with static loads. A unified formula is given for the air-gap length for an eccentric rotor considering both the dynamic and static eccentricities. The unbalanced magnetic pull (UMP) of the rotor is calculated numerically. Differential motion equations are given for the rotor system for the effect of UMP, static load (gravity), and unbalanced mass excitation. The rotor shaft orbit and displacement spectra are analyzed for a dynamic eccentricity and a mixed eccentricity with a static load. The direction and magnitude of the static eccentricity are related to the vibration characteristics of the rotor system. The results show that the static eccentricity angle affects the rotor shaft orbit and makes the displacement frequency component amplitudes vary periodically. A harmonic appears at four times the rotating speed with increasing static eccentricity. The effects of a static load on the rotor system can be regarded as a static eccentricity in the direction of the load.