| 摘要 |
PURPOSE:To get a brushless motor which is not influenced by the dispersion of the hysteresis of a magnetic sensor by connecting a delay circuit between the magnetic sensor, which controls the switching of a switching element, and an current limiting element. CONSTITUTION:A delay circuit 15 is interposed between a current limiting element 12 and a magnetic sensor 7. Through a force resisting against the inertia rotation of a rotor 2 exists as a repulsion between a magnet 6 for initial positioning and a permanent magnet 3 or 4, since there is delay time by the delay circuit 15 in addition to the hysteresis width of a magnetic sensor 7, a current is applied to a coil 5 for a period longer than before. Since the delay circuit 15 is set to a certain time, the vibration of the rotor 2 increases in acceleration gradually, and it comes to overcome the repulsion of the magnet 6 for initial positioning. Moreover, when the rotor 2 continues regular rotation, the delay time occurs in the same rotational direction as the rotor 2, so it hardly affects the current application time to the coil 5. |
