| 摘要 |
<p>PURPOSE:To instantly restore an arc power source after restoring power supply so as to continue the operation without damage of quality by continuing a control signal to the gate of a silicon controlled rectifier in prescribed time after stopping of arc due to drop of power supply voltage. CONSTITUTION:When a supply voltage from a trunk line 11 is dropped or lost, an instantaneous drop compensation device 16 changes direct current power accumulated in a built-in capacitor into an alternating current so as to input it into a control circuit 15. Namely, the circuit 15 and the device 16 constitute a junction control circuit and as long as direct current power continuous, the control signal is continuously output to a gate of a silicon controlled rectifier(SCR) of an electric processing device 13 regardless of existence/nonexistence of input to the SCR main circuit. This continuation operation eliminates stop of arc caused by instantaneous drop of supply voltage and the control signal is supplied so that after normalization of power supply voltage, SCR, etc., are instantly operated, an arc is ignited again, and melting can be continued. Damage to be caused by instantaneous voltage drop is thus kept at minimum.</p> |
