The Investigation Of The Interaction Between Moving Non-ferromagnetic Conductor And Permanent Magnet

The interaction between magnet and moving non-ferromagnetic conductor is a kind of electromagnetic induction applied broadly. Its principle is applied extensively in the fields of magnetic braking, magnetic levitation, magnetic levitation bearing, inductive detecting and so on. A novel noncontact driving mode that a permanent magnet can be driven to rotate around the central axis of itself by a non-ferromagnetic conductor moving near the permanent magnet is deduced in this paper by theoretical analysis based on researching of the interaction between permanent magnet and moving non-ferromagnetic conductor. This driving mode is realized by experiment. From the molecular current viewpoint, an analytic expression of the magnetic field distribution of a rectangular permanent magnet used in this paper is computed and deduced by the Biot-Savart's law. The relationships among the forces on the magnet, the magnetic field intensity, the velocity and the conductivity of the conductor are computed quantitatively with MATLAB from the basic Faraday's electromagnetic induction law, Ohm's law and Ampere's law when the magnet is in a static state. To prove the correctness of the theoretic model used in this paper, a new experimental setting which is implemented on an air track made of aluminum alloy to research the magnetic damping effect is designed to measure the magnetic damping force. In this way, the influences to magnetic damping effect produced by the interaction between moving permanent magnet and non-ferromagnetic conductor because of gravity and friction are eliminated. The analytic expressions of all related physical parameters are deduced and the experimental result acquired by homemade equipment coincides with theoretic calculation. Finally a new explanation for the magnetic levitation produced by the interaction is proposed by self-inductive theory, and the inexplicit explanation on the principle of magnetic levitation experimental apparatus by PASCO Company is clarified and the reason is presented for that the lift phenomena can only be observed in constrained case.