초록 ▼

An arc welding power source supplies a high voltage for the reignition of an arc after the polarity reversal of a welding current to prevent the destruction of circuit elements and ensure the stable and positive polarity reversal despite its reduced size, and also the occurrence of a spike voltage i

An arc welding power source supplies a high voltage for the reignition of an arc after the polarity reversal of a welding current to prevent the destruction of circuit elements and ensure the stable and positive polarity reversal despite its reduced size, and also the occurrence of a spike voltage in a main circuit during the polarity reversal of a large current or alternatively the welding current during the polarity reversal is controlled to suppress a spike voltage during the current reversal.

대표청구항 ▼

A power source for arc welding comprising: first frequency converting means including a first rectifier for converting a first low-frequency AC voltage to a DC voltage, and a first inverter for converting said DC voltage to a second AC voltage; a transformer for converting said second AC voltage to

A power source for arc welding comprising: first frequency converting means including a first rectifier for converting a first low-frequency AC voltage to a DC voltage, and a first inverter for converting said DC voltage to a second AC voltage; a transformer for converting said second AC voltage to a third AC voltage suitable for welding: second frequency converting means including a second rectifier for converting said third AC voltage to a DC voltage, and a second inverter for converting said rectified DC voltage to a controlled AC voltage; means for applying said controlled AC voltage generated from said second frequency converting means to materials to be welded together to apply a welding current thereto; means for selectively setting the magnitude of said welding current to either of a first set value suitable for the welding of said materials and a second set value suitable for positively reversing the polarity of said welding current; means for controlling the operation of said welding current setting means to select said second set value during the polarity reversal of said welding current; and means for inhibiting, at the time of reversing the polarity of the output current from said second inverter, the polarity reversal of said output current when said output current is in excess of a predetermined upper limit value.