| 摘要 |
<p>A pulse generator for the spark-erosion cutting of workpieces by means of a liquid or solid electrode consists of a signal circuit and a main circuit. The signal circuit includes: a high-frequency oscillator (20); reduction stages (21, 22) to generate components of a pulse signal; a counter (24) for addressing the pulse signal components; a store (26) of a feedback circuit (27, 28, 29, 50, 51, 52, 53, 531) detecting the electrical states in the air-gap (13), said store addressing that state; a fixed value store (26) with programmed store areas which are controlled by the counter (24) depending on the addresses of the pulse signal components and by the store (25) depending on the addresses of the electrical states in the air-gap (13), whereby the contents of the controlled storages areas generate an output signal (261) or no output signal. The main circuit comprises: two electronic switches (34, 36) to generate a working pulse in the air-gap (13) when there is an output signal (261); a regulating circuit (41, 44, 45, 46, 47, 32) which, when a certain current level is exceeded in the air-gap (13) blocks only one (36) of the two electronic switches (34, 36), when the stray inductance of the circuit facilitates the flow of current in the new direction, which can occur several times during a working pulse; an array of power diodes (37, 38, 42) for a given direction of current flow into the d.c. source (40) to generate a steep rising edge in the working pulse.</p> |
