| 摘要 |
PROBLEM TO BE SOLVED: To provide a power supply device that achieves improved welding quality by constantly controlling a welding current during the energizing for welding or a ripple of inter-electrode voltage to reduce the fluctuation of the effective energizing value. SOLUTION: With the start of energizing for welding, the welding current rises nearly linearly, and at the point where the welding current is increased to the upper limit reference value SU or above, a switching control signal CS changes from the H level to the L level. As a result, the switching element is turned off at the power supply part, and the welding current decreases with lapse of time. Then, at the point when the welding current is decreased to the lower limit reference value SL or below, the switching control signal CS changes from the L level to the H level, the switching element is turned on again, and the welding current starts increasing. Thereafter, similarly, the increase and decrease of the welding current are alternately repeated in an indefinite cycle between the upper and lower limit reference values SU, SL.
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