Patent ID: 8440936
Filing Date: 2013-05-14
Classification: B23K

Abstract:
1. A welding power supply for supplying current to a welding electrode, comprising an output for output of current from the welding power supply, a direct current source with a plus pole and a minus pole, a switch device for control of the current from the direct current source to the output, a current meter for measurement of the current to the output, a control unit for control of the direct current source and the switch device, and an input device, which is connected to the control unit, arranged for input of at least a first set point for the current to the output, wherein the control unit is arranged to control the direct current source and the switch device to feed current to the output in the form of a series of alternating positive current pulses, which have a positive top value, and negative current pulses, which have a negative top value, and to lower the current in the current pulses from the negative top value and the positive top value to a negative switch value and a positive switch value, respectively, before switching between a positive current pulse and a negative current pulse, wherein the control unit is further arranged to control the switch device at least with regard to one of the point of time for lowering of the current in the current pulses and the level for at least one of the negative switch value and the positive switch value, in dependence of the measured current and the first set point; and wherein the negative top value depends on the first set point, wherein the negative switch value is set as a function of the first set point and wherein the switch from a negative current pulse to a positive current pulse occurs after the current has reached said negative switch value.