| 摘要 |
PURPOSE:To lower driving current by reducing attraction of a rotor, by providing a function capable of detecting rotation of the rotor caused by disturbance at the time when the rotor stays stationary, and also of holding the rotor in a stationary position electromagnetically. CONSTITUTION:A depth B of a notch 4 of a step motor is set to 0.04mm., and area of the notch section is reduced to approximately two-fifth of the conventional area. As it is possible to weaken the attraction and also to make width of driving pulse narrower by doing this, drive-consuming current becomes smaller. And, in case when erroneous rotation of the stationary rotor 3 started taking place, this is detected to give a control pulse in the same direction as the driving pulse of the width of 1.5sec existing immediately before start of the erroneous rotation to keep the rotor 3 to the attraction side. After impression of control pulse by attraction, the rotor 3 is pulled back to a stationary stabilizing point 5 located in the neighborhood of the attraction side, so that it is corrected to the initial position. |
