Abstract
Stepping motors have a high level of positioning control so that they are widely used in the field of OA machine tools and so on. Therefore, for the optimum design of these electromagnetic devices, it is necessary to analyze the dynamic characteristics of stepping motors. Stepping motors used in wristwatches are ones of the smallest stepping motors and are required a high accuracy of motion. However, it is difficult to obtain the accurate dynamic characteristics of them experimentally due to the small size. In this paper, the dynamic characteristics of a stepping motor for wristwatches are analyzed using the 3-D finite element method coupled with the electric circuit and the motion equation. In this analysis, the load of the gears is taken into account as the inertia of rotor in order to simulate the actual condition. The chopped voltage waveform is applied to the stepping motor. Thus, the time variations of the rotation angle and the exciting current are calculated, and the validity of our method is confirmed by the experiments.
