METHOD AND APPARATUS FOR CONTROLLING GLOBULAR TRANSFER MODE IN INVERTER WELDING MACHINE

摘要

PURPOSE: A method and an apparatus for controlling globular transfer mode in an inverter welding machine is provided to reduce spatter in repulsion transfer in which CO2 gas is used as a protection gas by sensing whether voltage is rapidly increased in the arc state during large electric current welding. CONSTITUTION: The method for controlling globular transfer mode in an inverter welding machine comprises the steps of converting level of control signals by passing the actual voltages through a voltage signal conversion part(20) after obtaining positive and negative actual voltages generated during welding through a voltage detection part(10); inputting the amplified signals into a discrimination part(50) by passing only signals having a large voltage variation width per direct current and unit time and amplifying the passed signals after detecting voltage signal variations in the arc state by passing the control signals through a low-pass filter to remove noise and analyzing voltage signals in a differential circuit(40); memorizing the detected signals into a latch circuit(60) by detecting signals at the ascending corner of output signals of the discrimination part(50) after outputting the inputted signals as positive if the inputted signals are higher than the standard signal by comparing the inputted signals with a standard signal in the discrimination part(50); operating a timer circuit(Td)(70) if it is a point of time for sensing signal conversion of the latch circuit(60) so that the signals are outputted into a timer circuit(Tr)(90) after the setting time; and turning off switches connected to an output terminal of the welding machine in a series during the timer time so that welding current is flown only through resistance(R) of a radiation plate.