WIRE ELECTRODE BREAKAGE DETECTION METHOD AND APPARATUS

摘要

A method and apparatus for detecting breakage of a wire electrode in an electric discharge machining apparatus, and an apparatus for carrying out this method, whereby breakage of the wire electrode is detected by detecting a change in a current from a detection power source provided separately from the main power source. Current from the detection power source is applied through the wire electrode by a roller in contact therewith. When the wire electrode is unbroken, current passes from the detection power source, through the wire electrode, to an optical coupling circuit, the secondary of the latter driving and indicating circuit. When the wire electrode breaks, the power flow to the primary of the optical coupling circuit is interrupted, thereby indicating breakage of the wire electrode.