To simply and reliably improve the stability of rotor-bearing system and eliminate the oil whip online, the method of using an improved passive electromagnetic damper to increase the damping effect was proposed. Its configuration is similar to that of electromagnetic bearing, but no sensors and no closed loop control are needed. When the rotor is rotating, the electromagnetic damping is formed due to the eddy currents induced inside the surface layer of rotor to mitigate vibration. Increasing direct current can enhance damping, but the stiffness of system will be decreased and the resistance torque and heat of damper will take place. In order to improve the characteristics of damper and avoid the decreasing of stiffness, a new method of adding extra circuit was presented, without changing the configuration and the static current. By choosing appropriate parameters of extra circuit devices, the damping effect of the improved damper is more evident than that of the original. The experiment results show that with the improved damper, better effect of reducing vibration and eliminating oil whip of rotor-bearing system can be achieved.%为了简单可靠地增加转子轴承系统的稳定性,在线消除油膜振荡等故障并抑制振动,提出了一种利用改进式被动阻尼器在线增加系统阻尼的方法.被动阻尼器结构类似电磁轴承,当转子旋转时,在转子表面形成电涡流因而产生电磁阻尼,抑制转子振动,但无需闭环控制,采用直流电流工作.增加直流电可以增加阻尼,但是电流增加会使系统的刚度减小,并且也会引起阻力距和阻尼器的发热,为了提高阻尼器的阻尼特性,又要解决刚度减弱问题,在不改变电磁阻尼器结构和静态电流的基础之上,提出了增加额外电路以增加阻尼的新方法,并通过计算选择合适的额外电路元器件的参数,改进后的阻尼器阻尼效果比原始的明显增加.把改进式被动阻尼器用于转子-轴承系统的油膜振荡在线消除,并与原始阻尼器的减振效果比较,实验证明:同样条件下,改进式被动阻尼器增加外阻尼在线消除油膜振荡故障和抑制振动效果更好.
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