SU1403344A1 - Pulse generator for electric-erosion working of materials - Google Patents

Abstract

The invention can be used as a source of technological flow for powering EDM cutting machines. The pulse generator for the EDM of materials contains a source of constant voltage 1, transistor amplifiers (TU) 2-5, the master oscillator 6. TU 2-5 consists of transistors 7-10, pulse transformers 11-14 and resistors 15-17. The generator has an erosion gap 18, diodes 19-24. The pulse generator has an increased efficiency due to an increase in the amplitude of the voltage and the current of the discharge pulses and the elimination of the distortion of the pulse shape, 1 sludge.

Description

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The invention relates to electrical discharge machining in a conductive medium and can be used as a source of technological current for powering EDM cut-out machines.

The aim of the invention is to increase the efficiency by increasing the amplitude of the voltage and the current of the discharge pulses and eliminating the distortion of the pulse shape.

The drawing shows the scheme of the proposed pulse generator for electrical discharge machining of materials for four transistor amplifiers ().

The generator contains a constant voltage source 1 to which transistor amplifiers 2-5 with a transformer output are connected in parallel, controlled from a common master oscillator 6. Amplifiers consist of transistors 7-10 in whose collectors primary windings of pulse transformers and - 14, The secondary windings of these transformers are connected to each other by means of resistors 15 - 17 so that one output of the resistor is connected to the end of the previous winding, and: the other to the beginning of the next. Start- The secondary winding of the transformer 11 is connected to the positive terminal of the erosion gap 18 and from the cathode: mi diodes 19-21.

The anodes of the diodes are connected to the beginning of the secondary windings of the transformers. The end of the secondary winding of the transformer 14 is connected to the negative terminal of the erosion gap 18 and to the anodes of the diodes 22-24. The cathodes of the diodes are connected to the ends of the secondary windings.

The generator works as follows.

The control pulse from the master oscillator 6 includes transistors 7-10, the collector circuits of which include the primary windings of the pulse transformers 11-14. The parameters of the transformer windings and the source voltage 1 are selected so that the collector currents of the transistors and the back surge voltage are MO below the maximum permissible values for you (5ran transistors. On the secondary windings of pulse transformers induced emf with more than

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soky potential on the upper according to the scheme conclusions windings. Until the breakdown of the erosion gap 18 occurred, the potentials of the cathodes of the diodes 19-2 are higher than the potentials of their anodes, and the potentials of the anodes of the diodes 22 - 24 are lower than the potentials of their cathodes. Therefore, all the diodes are locked and do not affect the operation of the generator. The secondary windings are connected in series through the resistors 15-17, and the resulting idling voltage on the erosion gap 18 is equal to the sum of the voltages of all the secondary windings.

The presence of the inductance of magnetization of the output pulse transformers causes the formation of a reverse surge voltage on the erosion gap, with the result that the average voltage over a period is zero. This makes it possible to conduct processing in a conductive medium. The presence of resistors 15–17 limits the amplitude of the backward ejection, which eliminates the possibility of erosion gap breakdowns by negative pulses.

As soon as a breakdown of the eroded and zionic gap 18 occurs with a positive voltage pulse, a current begins to flow in the secondary windings, creating a voltage drop across the resistors 15-17, the magnitude and polarity of which are sufficient to open the diodes. Through the erosion gap 18 current begins to flow through the circuit: the upper circuit output of the secondary winding of the transformer 11 (12,13,14), the diode 19 (20, 21) erosion gap 18, the diode 22 (23,24), the lower output winding of the transformer 11 (12,13,14). As a result, all secondary windings of the transformers are connected in parallel to the erosion gap. The resulting operating current through the erosion gap is equal to the sum of the currents of all windings.

Each amplifier is connected to the erosion gap by means of an independent coaxial line. Thus, only a portion of the operating current flows in each line. This reduces mutual interference between amplifiers, losses and distortion of the output pulse.

Claims (1)

1. A pulse generator for electrical discharge machining of materials, containing N transistor amplifiers with transformer output and controlled from a single master oscillator, characterized in that, in order to increase efficiency and eliminate distortion of the output pulse, the secondary windings of transformers are connected in series in parallel, for which the end the secondary winding of the transformer is connected through a resistor to the beginning of the secondary winding of the next transformer, and the positive terminal of the erosion gap is connected to The secondary transformer windings, and starting from the second, through the diodes anodes connected to the windings, the negative lead of the erosion gap is connected to the end of the secondary winding of the last transformer, and to the ends of the secondary windings of the rest through the diodes anodes connected to the erosion gap, 2, Pop-1 generator, characterized in that, for the purpose of loss reduction, the erosion gap is connected to each amplifier by an independent coaxial line.