| 摘要 |
<p>PURPOSE:To prevent the scale-up of a device by using a resistor for inhibiting rush currents at a time when charging a filter capacitor for suppressing short circuit currents. CONSTITUTION:An electromagnetic contactor 21 is closed while a GTO thyristor 23 for a short circuit being brought to an OFF state prior to operating a thyristor inverter 8, and charging currents are caused to flow through a filter capacitor 7 through a current limit resistor 22. When the filter capacitor 7 is charged completely, the GTO thyristor 23 for a short circuit is turned ON, and the thyristor inverter 8 is operated. When the accident of the short circuit of an arm is generated in the thyristor inverter 8 during working, an OFF command is transmitted over the GTO thyristor 23 for a short circuit and the electromagnetic contactor 21. Since the GTO thyristor 23 for a short circuit is brought quickly to the OFF state, the increase of short circuit currents is inhibited by the current limit resistor 22.</p> |
