Improveed passive electromagnetic damper and its application
Liu Shu-lian1; Zheng Shui-ying2
1. School of Mechanic & Automotive engineering Zhejiang University of Science and Technology Hangzhou 310023; 2.Institute of Chemical Machinery, Zhejiang University, Hangzhou, 310027
Abstract：To simply and reliably improve the rotor-bearing system stability and eliminate the oil whip online, one method of using an improved passive electromagnetic damper to increase the damp is proposed. Its configuration is similar to that of electromagnetic bearing, but no sensors and no closed loop control are needed. When rotor rotates, the electromagnetic damp is formed because of the eddy currents inside the surface layer of rotor to decrease the vibration. Increasing direct current can enhance damp, but the stiffness of system will be decreased and bring resistance torque and heat of damper. In order to improve the characteristics of damper and avoid decreasing the stiffness, one new method of increasing damp by adding extra circuit is present, based on not changing the configution and static current. By choosing the appropriate parameters of extra circuit devices, the damping coefficient of the improved damper is more evident than that of the original damper. When the improved damper is applied to the rotor bearing system, the experiment shows that the effect of decreasing the vibration and eliminating the oil whip is better with the improved damper.
2011, Vol. 30 
