Physical Mechanism of Eddy Current Demagnetizing Effect for Eddy Current Brake

This article researches both the mathematical relation between the braking force of eddy current brake and the speed of the moving conductor and the relationship between the average air-gap flux density and the velocity of the moving conductor respectively which result in the ambiguity of the physical mechanism of eddy current demagnetizing effect. The theoretical methods for obtaining the distribution of the excitation magnetic field, the eddy current magnetic field and the air gap magnetic field of eddy current brake were presented. Then the impacts of the excitation magnetic field and eddy current magnetic field on the distribution of air gap magnetic field were got through contrastive analysis and then the physical mechanism of eddy current demagnetizing effect is obtained. Finally, the influence of the eddy current demagnetizing effect on the design and control of eddy current brake was discussed in depth. The correctness of these theoretical calculations was validated by experiments on the retarder synthetic performance test bench or the finite element numerical calculation.

The Design and Implementation of Experimental Apparatus of Magnetic Levitation

Completed the design of experimental apparatus of magnetic levitation based on ADuC832 microcontroller and discussed the experimental results, the relationship between the forces on permanent magnet and the velocity of non-ferromagnetic conductor can be measured with strain gauge position sensor and photoelectric sensor. A magnet can be non-contact driven to rotate around its central axis by moving conductor, the relationship between the rotational speed of permanent magnet and the velocity of conductor can measured with bias circuit, verifying the correctness of the theoretical analysis. The experimental apparatus of magnetic levitation is well applied in experimental teaching.