| 摘要 |
A control circuit for a wire cutting electric discharge machine comprising: a power circuit for applying a pulse voltage at a working gap between a wire electrode and a workpiece; a idscriminant circuit for detecting a discharge status of the working gap, said discriminant circuit detecting the voltage at the working gap and generating a first output signal in the event said voltage remains below a standard voltage within a predetermined time period after a time when a pulse voltage is applied to the working gap; a counter for calculating the number of first output signals generated by the discriminant circuit; a discharge-ON time interval setting circuit for setting a discharge-ON time interval during which a discharge current is actually passed through the working gap; a discharge-OFF time interval setting circuit for setting a discharge-OFF time interval; a pulse control circuit for controlling the discharge-ON and OFF time intervals in accordance with signals from the discharge-ON and OFF time interval setting circuits, said pulse control circuit extending the OFF-time intervals of thelse when the calculated value of the number of successive first output signals, in the counter, reaches a set value; and a drive circuit for driving, by means of the output of the pulse control circuit, a switching element which is connected into the power circuit
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