| 摘要 |
PURPOSE:To reduce the power consumption by providing demagnetizing pulse generating means for erasing the residual magnetization in a step motor so that the normal pulses are fed to the step motor while having their width stepwise shortened or enlarged. CONSTITUTION:Under the condition gaving a step motor 96 driven in a normal manner, in case the output T4 of a detecting circuit 95 has no ''H'' signal within the detecting time, it is judged that the rotor has failed to be driven by the drive pulses. Then, auxiliary drive output T2 is fed from the auxiliary drive pulses P2 of a waveform composing circuit 92 to the step motor 96, and then pulses P3 inverted from the pulses P2 are generated from the composing circuit 92. At this time, a current flows in the direction opposite to the direction of the current flowing through the coil of the step motor 96 under the auxiliary driven condition so that the influences from the residual magneticism in the step motor can be eliminated thereby to eliminate the saturation time of a saturatable magnetic path in the case of an integral stator. |
