| 摘要 |
PURPOSE:To permit the electric discharge machining in the stable state by exceedingly reducing the abnormal electric discharge generated in an electrode gap. CONSTITUTION:When working pulse is put into OFF-time by the turning-OFF of a switching element 7, the impedance ZG of an electrode gap 13 is put into restoration process. The impedance ZG of the electroe gap 3 is detected as a voltage value VG by a resistor 10 and input into a comparator 22. When relation VG>Vref1 is established as ZG restores, and the pulse signal outputted from a monostable multivibrator 29 becomes L level signal, a RS flip-flop 25 is set again through an AND element 23, and the operation is repeated, and working process proceeds. |
