| 摘要 |
PURPOSE:To prevent the introduction into arc discharge caused by the short circuit between a work piece and an electrode by allowing a gate means to be returned to a closing mode after an elapse of an electric discharge pause time set in advance since the decay of discharge current has been detected. CONSTITUTION:When a gap between a work piece 1 and an electrode 2 reaches the range of possible discharge by the operation of a source control device, discharge current starts flowing. After an elapse of an electric discharge time set in advance since the aforesaid discharge current has been detected, a gate control means 5 controls a gate means 4 to be set to an opening mode so as to allow voltage applied by a power source means 3 to be off. In the second place, when the decay of discharge current is detected by a discharge current decay means 7, the gate control means 5 allows the gate means 4 to be returned to a closing mode, thereby allowing the introduction into discharge to be repeated after the elapse of a discharge pause time set in advance, that is, after the restoration of insulation of working fluid in the gap between the electrodes. This constitution thereby prevents arc discharge caused by the short circuit between the work piece and the electrode, thereby enabling working accuracy to be maintained.
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