Direct current supply (1) for a direct current arc torch (6) comprising: an input terminal (4,8) allowing connection to a direct current source and an output terminal allowing connection to electrodes ( 5,7) an arc torch; a controlled switch (2) as well as an inductor (3) connected in series between the input terminal and the output terminal; a freewheeling diode (9) connected so that, in use, it has a reverse bias when the switch (2) is on, and a forward bias when the switch (2) is in the off position so to maintain the passage of direct current in the arc and the inductance (3); as well as a return circuit (10) provided with a current detector (11) intended to detect the instantaneous value of the current passing through the arc, and a control terminal (26) connected to the switch (2), the return circuit, during use, supplying a control signal to the control terminal (26) in order to place the switch (2) in the on position when the instantaneous value reaches the first level and in the off position when the instantaneous value reaches a second level.
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