Development and Characteristic Study of a Small Rotor Eddy Current Damping System
Date Issued
2005
Date
2005
Author(s)
Prajna, Budi
DOI
zh-TW
Abstract
When a conductive material is subjected to a time-varying magnetic flux, eddy-currents are generated in the conductor. These eddy-currents circulate inside the conductor generating a magnetic field of opposite polarity as the applied magnetic field. The interaction of the two magnetic fields causes a force that resists the change in magnetic flux. Due to the internal resistance of the conductive material, the eddy-currents will be dissipated into heat, consuming the kinetic energy of the vibrating element, the conductor or the magnet, which causes the time-varying magnetic flux, and thus producing a damping effect. The aim of this thesis is to develop a reliable and high performance of rotor eddy-current damping system which satisfies the damping capability needed to absorb the lateral vibration of small rotating machinery. This thesis will first investigate and analyze numerous literature surveys on working principle of rotor eddy-current damping. The thesis then advances to estimation of numerous design factors and variations of fabrication process. Theory model analysis as well as finite element analysis are being used to understand the influence of different design variables on the damping system. Dynamic characteristic testing is applied to evaluate the damping system performance by comparing damping force, damping ratio and damping time constant on various designs. Finally, this thesis proposed a novel double ring magnet arrangement and a novel Hallbach ring magnet arrangement, which improve the damping system performance by increasing the damping ratio by 2~4 times. Eddy-current rotation restriction magnet arrangement is also being introduced which has been proven to greatly improve the instability problems during the high speed operations.
Subjects
渦電流減振
小型轉軸
多樣化設計
效能評比
實驗與分析
eddy-current damping
small rotor
variety designs
performance evaluation
experiment and analysis
Type
thesis
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