| 摘要 |
2085594 9120176 PCTABS00009 A dc power supply (1) for a dc arc torch comprising: a controlled switch (2) and an inductance (3) connected in series, in use, in circuit with a source of direct current and an arc torch (6); a free-wheeling diode (9) connected, in use, to be reverse biased when the switch (2) is ON, and forward biased when the switch (2) is OFF to maintain current flow through the arc and the inductance; a switch driver (10) to cycle the switch ON and OFF; and a feedback circuit (11) having a current sensor (12) associated with the circuit and connected to the switch driver (10) to control the duty ratio of the switch in accordance with the current flowing through the arc.
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