| 摘要 |
PURPOSE:To eliminate the cause for the buckling and disconnection of a welding wire before they occur and to save the labor for welding works by detecting the feed speed of the wire with a feed system, judging the feeding fault from the signal thereof and stopping a wire feed motor. CONSTITUTION:The feed speed of a welding wire 7 is detected with a speed detecting roll 7, and the output proportional to the feed speed by a speed generator 8 is inputted as a signal B to a comparator 16. The comparator 16 compares this with the reference signal A of an electric power source 14 and discriminates the deviation thereof. Then the feed speed of the wire 2 drops on account of a certain cause and the signal B falls below the signal A, the comparator 16 supplies the output signal thereof to a pulse generating circuit 21 by which a thyristor 18 is conducted. As a result, the voltage of an electric power source 20 is applied to a relay driving circuit 21 and normally closed contacts 12' are opened, by which a wire feed motor 9 is cut off from power source 13 and the wire feeding is stopped. |
