| 摘要 |
PURPOSE:To prevent an electrode and a workpiece from being damaged by providing a detector part for detecting abnormal discharge in a gap of processing, a timing pulse generator part, and a processing pulse voltage control part, and extinguishing the abnormal discharge immediately after it is produced. CONSTITUTION:Processing gap voltage VG is applied to an A terminal of a comparator 15, while reference voltage VB is applied to a terminal B. In an abnormal discharge pulse, VG does not exceed VB,but in normal discharge VG exceeds VB. Accordingly, the comparator 15 can detect the abnormal discharge. In the normal discharge, a pulse width is not changed, while in the abnormal discharge the pulse is turned off after a prescribed period of time being elapsed. Thus, the abnormal discharge pulse is also turned off to extinguish the abnormal discharge. |
