Abstract: 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.

Key words: permanent magnet, non-magnetic moving conductor, angular speed, angular acceleration velocity, moment, non-contact driving