| 摘要 |
PURPOSE:To prevent generated torque from being lowered at the time of driving at a high speed without increasing applied voltage, by changing the distribution ratio of phase current distributed unequally stepwise, to drive a device, when driving frequency exceeds specified frequency. CONSTITUTION:By a constant-current driving circuit 2, a stepping motor 1 is properly driven and controlled according to a signal from a reference current value switching circuit 6 and a control circuit 3. By a driving frequency monitor 50 connected to the constant-current driving circuit 2, the driving frequency of the stepping motor 1 is always monitored, and when the driving frequency of the stepping motor 1 comes to the specified frequency, for example, when the driving frequency comes to one at which the generated torque begins to decrease, the decrease is detected by the control circuit 3, and optimum control is performed so that the lowering of the torque of the stepping motor 1 may be improved. |
