| 摘要 |
PURPOSE:To provide an arc welder which averts the no-load failure of a transformer for welding during the halt of welding and reduces energy consumption by the constitution in which an input on-off switch and cooling fan are turned off with delays respectively by prescribed time from the arc-extinguishing signal of a thyristor. CONSTITUTION:The input on-off switch 10 is inserted and connected between the primary side of the transformer 11 for welding and an AC power source and the cooling fan 15 is connected via a timer 16 to the AC power source in the arc welding machine which controls the output by controlling the phase of the thyristor 12 connected to the secondary side of the transformer 11. Said switch 10 is turned on in synchronization with the firing signal of the thyristor 12 by a control signal generating circuit 13 to prevent the primary rush current of the transformer 11; further the switch 10 is turned off with the delay by extremely short time from the arc-extinguishing signal to prevent the burning of the switch 10 and to economize electric power. The fan 15 is turned on in synchronization with the above-mentioned firing signal or in precedence thereto and is turned off after the prescribed time by the timer 16 upon emission of the arc-extinguishing signal to prevent waste of electric power. |
