SU624757A1 - Low-frequency pulse generator for electro-erosion working - Google Patents

Description

(54) LOW-FREQUENCY GENERATOR OF IMMEDIATES FOR ELECTUEROSION

PROCESSING

This invention relates to electrophysical metal processing methods.

Generators of pulses for electrical discharge machining are known, consisting of a semi controlled bridge rectifier with thyristors in the cathode group and a block of high voltage pulses 1 parallel to the erosive gap.

Known generators are not reliable enough and have low efficiency,

The aim of the invention is to ensure the reliability of the generator and to increase its efficiency.

It is achieved by connecting the positive pole of the block of overvoltage pulses through dividing diodes, connected, in turn, with ballast resistance, to the anodes of the thyristors of the bridge rectifier.

The drawing is an electrical circuit of the proposed generator,

A three-phase rectifier 3 with thyristors in the cathode group is fed from three-phase transformer 1 through chokes 2. The positive pole of the block 4 of overvoltage pulses is connected to the anodes of the thyristors of the bridge rectifier 3 through separator diodes 5, connected in series with the ballast resistance 6, the pulse generator is connected to the erosion gap 7.

Simultaneously with the switching on of one of the thyristors of the semi-controlled bridge rectifier 3, a pulse is energized in the high voltage block 4, the sum of the voltage of the bridge rectifier 3 and block 4 is applied to the erosion gap 7.

Breakdown of the erosion gap 7 causes current to flow from the block 4 of overvoltage pulses through one chain of ballast resistance 6 and diode 5, through chokes 2 and secondary windings of transformer 1 in two phases and through the open thyristor of bridge rectifier 3. At this stage the current rise erosion occurs quickly due to the active nature of the resistance of the chain and the voltage applied to it.

Claims (1)

With the end of the pulse generated by block 4, the increase in current in the erosion gap slows down due to a decrease in the applied voltage and a change in the nature of the co-flow control of the circuit. Subsequently, the erosion gap current flows through the elements of the bridge rectifier 3, the chokes 2 and the secondary windings of the transformer 1, and the current current is determined by the voltage between the respective phases of the transformer 1. As the potential difference between the operating phases of the transformer JTOK decreases in the erosion gap, it decreases current off the thyristor of bridge bridge 3. The process is repeated every time the respective thyristors of grid 3 are switched on next time. The circuit parameters and duration and pulse unit 4 the Enhance eg zhe1sh selected from conditions maintaining reliable shower ero sec tor interval rectifier bridge 3 at the moment of turn-off unit povyshe1shogo voltage. The generator reduces the power of the overvoltage unit and ensures high reliability of the passage of a current pulse after the breakdown of the erosion gap. Claims of the Invention A low-frequency pulse generator for the electrical erosion treatment of metals, consisting of a semi-controlled bridge gate with thyristors in the cathode group and a block of high-voltage pulses. active ballast resistors. effects, the negative pole of which is connected to the anodes of the diodes of the anode group of the top of the target, characterized in that, in order to increase the reliability of the generator and increase its efficiency, the positive pole of the upstream voltage pulse block is connected through separation diodes connected in series with ballast resistances to the anodes of the thyristors of the bridge top Sources of information taken into account in the examination: 1. Livshits, AL, and others. Pulse generators, M., Energo, 1970, p. 159, 187.