Patent ID: 7045735

Claim:
A machining electrical power supply device for a wire electrical discharge machining apparatus that supplies machining electrical power to a wire electrode and a workpiece as electrodes, and machines the workpiece by electrical discharge, the device comprising: an electrical discharge state distinguishing circuit for distinguishing at least two inter-electrode states including electrical shorting and normal electrical discharge; and an inter-electrode current waveform control means for supplying, and for switching between supply of, a triangular wave and a trapezoidal wave current to the electrodes; wherein according to the inter-electrode state distinguished by the electrical discharge state distinguishing circuit, in cases where the inter-electrode state is that of the electrical shorting, the inter-electrode current waveform control means supplies the triangular wave current to the electrodes; and in cases where the inter-electrode state is that of the normal electrical discharge, the inter-electrode current waveform control means supplies the trapezoidal wave current to the electrodes.