| 摘要 |
PURPOSE:To reduce a short-circuit current and electrolytic action, by applying voltage from a switching element into an output of a regulating means which generates an output when an on-off time oscillator outputs an on-time pulse and when the voltage between a workpiece and an electrode is in a level or more. CONSTITUTION:An oscillator 8 starts oscillation from off-time turning on a transistor 4 through an OR circuit 9 by the output of an on-time pulse and applying voltage between a workpiece 2 and an electrode 1, and comparators C1, C2 generate an output when the voltage is in high and low voltages VL1, VL2 or more. When the voltage decreases to the high voltage VL1 or less due to a discharge, a power supply generates no output of the comparator C1 generating a pulse from a pulse generator circuit 6 to stop the oscillator 8 through an AND circuit 7 and to be input to the transistor 4 through the OR circuit 9, and after the pulse is finished, the oscillator 8 starts the oscillation from the off-time. When a short-circuit takes place, the pulse generator circuit 6 is cleared by trailing the output of the comparator C2, and the oscillator 8, receiving an output of small pulse width, stops. The pulse generator circuit 6 is not triggered when no discharge is generated and the voltage is applied by the width of the on-time pulse of the oscillator 8.
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