SU370001A1 - PULSE GENERATOR FOR ELECTROROSION - Google Patents

Description

one

The invention relates to the field of electrical discharge machining of metals and concerns generators for such processing.

Unipolar pulse generators are used for the EDM treatment of metals.

In conventional pulse-emitting pulse generators, an erosion gap circuit is connected to a power source via a controllable valve, which is turned off from the series inverter via a pulse transformer, the secondary winding of which is connected between the cathode of the controllable valve and the erosion gap.

This allows one to receive pulses of unipolar form with the same amplitude. However, igniting pulses and pulses of another form are difficult to obtain.

In the proposed generator, a single-phase rectifier is connected between the negative pole of the switching capacitance of the series inverter and the erosion gap through a current-limiting resistance, the cathode of the discharge thyristor of the serial inverter is connected via the current limiting resistance of the inverter to the anode of the erosion gap.

FIG. 1 shows a generator circuit; in fig. 2, 3, 4 - pulse shape.

The power source 1 (see Fig. 1) through controlled thyristor 2 and current-limiting resistance 3 is connected to the anode of the erosion runway 4. Serial inverter 5 is connected to the power source 6. The negative pole of the switching capacitor 7 of the serial inverter 5 is connected to the valves 8 and 9, forming a single phase rectifier. The cathode of the discharge thyristor 10 of the sequential inverter 5 is connected through the current limiting resistance 3 to the anode of the erosion gap 4, the cathode of which is connected to the negative poles of the power sources / and 5. Switching throttles are connected to the circuits of the charge thyristor // and the thyristor 10 of the serial inverter 5 12 and 13.

The device works as follows. The control electrodes of the thyristors 2, 11, 10 receive control pulses. In this case, in the sequence, the thyristor //, the thyristor 2, the thyristor 10 (see FIG. 2), along the circuit:

power source 6 (see Fig. 1), thyristor 11, switching throttle 12, switching capacitor 7, valve 9, current-limiting resistance 3, erosion gap 4, power supply 6 - breakdown occurs

of the erosion gap 4 and the charge of the capacitor 7. After the charge of the capacitor 7 has ended, the thyristor 11 is closed.

When the next control pulse arrives at the thyristor 2, it turns on, and a current impulse flows to the erosion gap 4.

Then the thyristor 10 is opened from the next control pulse.

The capacitor 7 is discharged along the circuit: switching choke 13, thyristor 10, erosion gap 4, valve 8.

At the time of discharge, a current limiting resistance — an erosion gap — is applied to a voltage, the amplitude of which exceeds the voltage of the power source 1, therefore the thyristor 2 is closed by the action of a counter voltage pulse.

Thus, a voltage pulse is generated, in which the current through the erosion gap has the shape shown in FIG. 2

When control pulses in the sequence arrive, the thyristor 2, the thyristor 11, the thyristor 2, the thyristor 10, a current flows through the erosion gap, the form of which is shown in FIG. 3

The alternate opening of the thyristors 11 10 allows to obtain the current form shown

in fig. 4. Consequently, changing the sequence of receipt of control pulses to the thyristors of the generator can be used to obtain a different form of current, which most closely matches the nature of the process of EDM processing.

The item is invented and 11

0 Pulse generator for electroerosive processing, in which the positive pole of the power source is connected to the anode of the erosion gap through a current limiting resistance through a controlled valve and the output of a serial single-phase inverter with switching throttles, characterized in that the negative pole of the switching capacitance of the series inverter and the current limiting resistance circuit - erosion gap is included dnofazny rectifier, the cathode discharge thyristor inverter is connected via a serial current-limiting resistor to the anode erosion period, the cathode of which is connected to the negative pole of the inverter power source sequentially.

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