| 摘要 |
PURPOSE:To improve stability of a welding arc by maintaining the specified extruding torque of the welding wire itself on a motor side with a speed reducer in an arc welding device and feeding the welding wire at a specified speed. CONSTITUTION:When armature current increases as a result of a fluctuation in a welding load in the stage of arc welding, the voltage drop Er increases in proportion to said increase and therefore a control input Ei decreases. The phase of the gate signal delivered from a phase control circuit 21 delays consequently and the conduction angle of a control element 30 decreases, thus controlling the increase in the armature current. When the armature current decreases, the output torque is returned to the set value by the operating process reverse from the above. When an armature voltage Em increases and the voltage drop Er corresponding to said voltage increases with an increase in the number of revolution of a push motor 29, the Er is fed back to the element 30, by which the torque of the motor 29 is increased. The feed torque on the push side roller is maintained roughly at the specified value below the rated number of revolution. |
