| 摘要 |
PURPOSE: To make the the damping of a stepping motor small and reduce its torque required when it is driven subsequently, by so smoothing the buildup of its excitation current as to be varied following the charge-discharge curve of a resistance-capacitance circuit if its rotary speed is smaller than a fixed value after a reference voltage in its driver is so varied that its excitation current is reduced. CONSTITUTION: A driver of a stepping motor performs the switching of a current limiting transistor 3 by the output of the comparator for comparing the excitation current of the stepping motor with a reference voltage 37. Further, after the reference voltage 37 is so varied as for the excitation current to be reduced, if the continuing term of a subsequently applied pulse is larger than a predetermined value, the excitation current is made small. Also, a recovery means is provided whereby the reference voltage 37 when the foregoing reference- voltage varying means is released is recovered following the charge-discharge curve of a resistance-capacitance circuit. The excitation current is so operated as to be increased gradually using this recovery means before and after the application of the pulse. |
