PURPOSE: To prevent voltage dependency resistors from being broken down at the time of short-circuit failure by providing series circuits for discharging elements more than two at the power source input side and further, connecting capacitors thereto and connecting the voltage dependency resistors to one ends of the series circuits.
CONSTITUTION: The series circuits for the discharging elements G2 and G3 more than two are provided to a power source input terminal or either one end in its vicinity of a welding power source. The capacitors C1 are connected in series to said series circuits and the voltage dependency resistors Z2, Z3 and Z4 are connected to one ends of said series circuits and the other ends of said circuits are grounded. By this method, at the time of short-circuit failure, the voltage dependency resistors are prevented from being broken down and a worker is prevented from receiving an electric shock.
Fujii, Koji
Nishida, Yoriaki
