中文摘要：

矩形水磁体与铝盘构成的非接触驱动系统中，在铝盘定速转动条件下，对通过电磁感应所驱动的磁体转动角速率、角加速度同时进行检测，发现角速度有周期性的微小波动，而角加速度在一负的最大值与正的最大值间周期性地变化，二者周期相同．从永磁体的分子环流模型出发，运用毕奥-萨伐尔定律，场叠加原理，导出了磁体绕中心转轴旋转到任意位置时，导体中的磁场分布解析表达式，依次对磁体角加速度与磁体受到的电磁驱动力矩进行定量计算，以驱动力矩与空气阻尼力矩的共同作用解释了角速度出现周期性微小波动与角加速度正负等幅变化的原因，通过与实验测试结果进行比较，验证了分析结果的正确性．

英文摘要：

Non-contact driving mode is composed of rectangular permanent magnet with a spin axes and a turning aluminum disc. Keeping the turning speed of aluminum disc in constant, and the angular speed and angular acceleration of magnet which is driven by electromagnetic induction is tested simultaneously. These are found that the angular speed has a tiny fluctuation periodically and angular acceleration vibrates between negative and positive maximum value with the same period. Starting from the viewpoint of molecular current,an analytic expression descri- bing the magnetic field distribution in space is derived from the Biot-Savart＇s law and principle of electromagnetic field superposition. And the angular acceleration and electromagnetic driving moment are calculated quantitatively when the permanent magnet rotates to any position. The reasons of angular speed appearing periodic tiny fluctuation and the angular acceleration vibrated between positive and negative maximum are due to the joint actions of driving moment and air damping, and this conclusion is consistent with the experimental result.