| 摘要 |
PURPOSE:To generate high torque by energizing the coil of a step motor only for the fixed period, then shortcircuiting the coil to the time of switching the phase and discharging magnetic energy, thereby reducing the phase current at the phase switching time. CONSTITUTION:Transistors Q1, Q3 are conducted to flow a current through the third phase of a motor, and the Q1 is then interrupted. The current which is flowed to the third phase is divided into the current flowed to a diode D1 and the current flowed in reverse direction of the first phase to the diode D3 to reduce the torque, then the Q3 is interrupted, the Q1, Q2 are conducted, switched to the first phase, thereby generating the torque. Accordingly, it can prevent the current more than required from flowing through the coil by controlling ON or OFF the transistor Q1, and reduce the phase current at the phase switching time to accelerate the reduction in the current and reduce the reduction in the torque at the high speed time. |
