To prevent an electrode from colliding with a non-conductor and causing a breaking accident since the non-conductor is detected in an early stage, in an arc furnace in which the electrode is automatically lifted up and down by constant impedance control.
In this arc furnace controlled by constant impedance control in which the electrode lifting device 7 detects a voltage and a current on the secondary side of a transformer 13 for the furnace to automatically lift up and down the electrode 3 so as to fix their ratio, when the current on the secondary side drops to a minimum set value or less during operation, the load torque of the motor 10 of the electrode lifting control device supporting the electrode 3 becomes 40% of the torque obtained during normal operation or less, and this situation continues for about 5 seconds, automatic lifting is immediately stopped and the electrode 3 is lifted.
ITO KATSUYOSHI
EBATA HIROICHI
| JPS5322239U | 1978-02-24 | |||
| JPS4748535B1 |