| 摘要 |
<p>A power supply device comprises a DC power supply ( 12 ), a current sensor ( 14 ) for detecting gap current ( Igap ) flowing through the machining gap, a first switching element ( 16 ) connected in series between the DC power supply and the tool electrode ( 2 ), a first reverse current prevention diode ( 22 ) connected in parallel with the DC power supply and connected in series with the first switching element ( 16 ), a second switching element ( 18 ) connected in series between the DC power supply and the workpiece ( 3 ), a second reverse current prevention diode ( 24 ) connected in parallel with the DC power supply and connected in series with the second switching element ( 18 ), and a pulse controller ( 20 ) for controlling the first and second switching elements in response to gap current ( Igap ). From a first time ( t1 ) when electric discharge is generated across the machining gap, until a second time ( t2 ) when the gap current reaches the peak current during the ON time, both of the first and second switching elements are on. At the second time ( t2 ) only one of the first and second switching elements is turned off.</p> |
