| 摘要 |
<p>PURPOSE:To make it possible to embody both reduction in melting hours of an arc pass operation and uniform melting by providing a closing and opening device which switches over the output of each thyristor rectifier to single output or composed output in conformity with an operating state of an arc furnace. CONSTITUTION:Alternating current is converted into direct current power by switching on a disconnecting switch 2 and furnace vacuum breakers 3A to 3C by way of rectifier transformers 4A to 4C, thyristor rectifiers 5A to 5C and DC reactors 6A to 6C and supplied to a DC arc furnace 10. During this operation, switching devices 8A and 8B are closed while the switching devices 8C and 8D are opened in a melting period. Each of the rectifiers 5A to 5C are upper part movable electrodes 7A to 7C respectively, thereby generating arc between a furnace bottom electrode 9 and each of the upper part movable electrodes 7A and 7C and providing boring at three locations simultaneously. On the other hand, in a refining period, the switching devices 8A to 8D are opened and closed reversely and the rectifiers 5A to 5C, which are in a connected state in parallel, are connected to only the upper part movable electrode 7B, thereby generating one large current arc.</p> |
