The system includes a pair of stepping motors for controlling relative movement of the wire electrode relative to the workpiece with the velocity of movement being controlled as a function of gap voltage. For this purpose the system includes a voltage controlled oscillator having its input coupled to the machining gap and its output interconnected with the drive circuits for the two stepping motors. The system further includes a divider stage which becomes operable in the system responsive to drop of voltage indicating gap short circuit condition so that a drastically reduced number of stepping pulses are provided to the motors throughout the duration of the gap short circuit condition. After removal of the gap short circuit condition, an increase in voltage allows changeover through several different gating stages to again return the output of the voltage controlled oscillator to its normal frequency range so that the feed of the electrode relative to the workpiece is again continued.
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