JPS54122652A - Ac arc stabilizer - Google Patents

Abstract

PURPOSE: To utilize the polarity inversion signal of the arcing voltage for the gate signal of the auxiliary thyristor, and to make good the noiselessness of the AC arc stabilizer, by connecting the second capacitor to the gate of the main thyristor, and by impressing the forward bias at a phase dissimilar to the first capacitor.

CONSTITUTION: In the high frequency generating circuit of the stabilizer, the capacitor 27 is charged through the resistor 9 and diodes 15, 19, when the terminal (a) is standing at (+). The capacitor 25 is discharging through resistors 21, 22, and is impressing the reverse bias on the gate of the main thyristor 31 for improving the moiselessness. While this period, a reverse bias is being impressed on the photothyristor 29 which is never put on even if the gate signal is inputted. When the terminal (a) is standing at (-), a forward bias is impressed on the photothyristor 29 which is then put on, if the gate signal for the polarity inversion of the welding current is inputted. At the same time, the main thyristor 31 is put on, and the charge being charged into the capacitor 27 is discharged from the primay side of the high frequency transformer 33. The photothyristor 30 and the main thyristor 32 act placing a lag of a half cycle.

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