| 摘要 |
In an electric arc welder for creating an electric arc for melting and depositing metal from an advancing welding wire onto a workpiece, said welder including a power supply having a switch operated by a pulse width modulator for creating a series of current pulses having a fixed frequency and a conduction width determined by the command voltage of a control signal driving said pulse width modulator and an error amplifier for generating the command signal in accordance with a set point voltage, the improvement comprising: first set point means for creating a fixed set point voltage, second set point means for creating a ramp set point voltage increasing at a selected rate from a starting voltage to create a selected slope, a toggle means having a first toggled condition for connecting said first set point means to the error amplifier and a second toggled condition for connecting said second set point means to the error amplifier, means for creating a short signal when the wire shorts against the workpiece and means for toggling the toggle means from said first condition into said second condition in response to a short circuit signal. |
