| 摘要 |
<p>PURPOSE:To take out a screw fastening completion signal without remodeling a marketing AC motor-driven driver by confirming the completion of screw fastening by detecting variations in an effective value component of an alternating current flowing to the AC motor-driven driver and an absolute value component. CONSTITUTION:An electric current sensor 1 detects an electric current flowing to a motor-driven driver. A synchronous signal circuit 2 outputs a pulse signal in synchronism with an electric power supply frequency to a synchronous rectification circuit 4. An amplifying circuit 3 amplifies a detecting signal, and outputs it to the synchronous rectification circuit 4 and a full wave recitification circuit 7. The synchronous rectification circuit 4 takes out the electric power supply frequency and an in-phase component, and processes them by a low-pass filter 5 and a voltage comparing circuit 6, and judges the existence of an effective value component of the electric current. The full wave rectification circuit 7 converts an alternating current all into a (+) direct current, and judges the existence of an absolute value component of the electric current through a low-pass filter 8 and a voltage comparing circuit 9. The completion of screw fastening is confirmed from variations of these effective value component and absolute value component.</p> |
