| 摘要 |
PURPOSE:To stop electric discharge processing when the processing voltage drops in such a way that a discriminating circuit to detect and discriminate electric discharge condition in a processing void is installed on a timing circuit to set ON and OFF times for a pulse power source. CONSTITUTION:Clock pulses which are generated in an oscillating circuit 1 are fed for example first to an OFF timing circuit 2, and when the number of counts attains to the determined number, ON signals are given as output, and flip flop 19 is reversed to ON side. The, clock pulses are counted up to as many as the determined number by means of an ON timing circit 9, and OFF signals reverse the flip flop 19 through a gate AND1 to OFF side. Here, processing void condition is detected by means of a discriminating circuit 26, and when it discriminates any abnormal condition, such as processing voltage drop, etc., it keeps a switch element 21 through gates AND1, AND2 to be OFF. |
