SU772781A1 - Short-circuiting protection for electrodes in dimensional electrochemical working - Google Patents

Description

one

The invention relates to electrophysical and electrochemical processing methods and, in particular, to a device; protection of electrodes from short circuits during dimensional electro- 5 chemical processing.

Protective devices against short jaws are known, made in the form of serially connected operating current sensor, bandpass amplifier 10 and detector, which is connected through a control circuit to the blocking source of the power source l.

The disadvantage of the known device is the lack of reliability in 5 work and limited technological capabilities.

The purpose of the invention is to increase the reliability of the security device.

This goal is achieved by the fact that the control circuit contains two analog memory cells; A comparison circuit, a control circuit and a pulse counter, the first inputs of the analog memory cells are connected to the detector output 25, and the second to the two outputs of the compensation circuit connected to the second input of the pulse counter, the first input of which is connected to the outputs through a comparison circuit cells 30

analog pichi tee, and the output - to the input of the blocking body.

FIG. 1 shows a block diagram of the device} in FIG. 2 is a timing diagram of the operation of the control circuit.

A device for protecting electrodes from short circuits during dimensional electrochemical processing contains a current sensor 1, the input of which is connected to a current-carrying bus connecting the interelectrode gap 2 with the power source 3, connected to the output of the blocking organ 4, a band-pass amplifier 5, the input of which is connected to the output of the sensor current 1, and the output to the input of the detector 6, two analog memory cells 7 and 8, the first inputs of which are connected to the output of the detector 6, and the second with two outputs of the control circuit 9, the outputs of the analog memory 7, and 8 are connected through a comparison circuit 10 to the first input of the pulse counter 11, the second input of which is connected to the third output cxei "i of control 9, and the output to the input of the blocking organ 4.

The device works as follows.

In the process of dimensional electrochemical processing from the output of sensor 1 (Fig. 1), the input of the bandwidth gain 5 receives a variable component of the process current, from which the bandwidth amplifier 5 extracts the high-frequency signals converted by the detector 6 into unipolar ones. The latter arrive at the inputs of the analog memory cells 7 and 3, the operation of which is controlled by the control circuit 9.

Control pulses CD, and (figure 2). Produced by the control circuit 9, alternately include analog memory cells 7 and 8, which are stored for equal periods of time (0.1-1 s) of the amplitude of the signals from the output of the detector 6. On the falling edge of the Ug pulse, the control circuit 9 also generates pulses ir, which synchronize the operation of the pulse counter 11.

The comparison circuit 10 subtracts the signals from the outputs of the cells of the analog memory 7 and 8, and when the signal from the output of cell 8 exceeds the signal from the output of cell 1, which indicates an increase in the intensity of high-frequency signals, the signal from the output of the comparison circuit 10 is positive, The signal from the output of cell 7 above the signal from the output of cell 8, which indicates the intensity, is negative.

When the intensity of high-frequency signals is constant, the signal from the output of the comparison circuit Yu is zero. The signals produced by the comparison circuit 10 are fed to one of the inputs of the counter 11, to the other input of which the clock pulses and are received. In the case of t, when the polarity of the signals from the output of the comparison circuit 10 is positive, the synchronizing pulses Up successively fill the registers of the counter 11. With a negative or zero signal from the output of the comparison circuit 10, the counter 11 is zeroed. With continuous and sequential filling of all registers of counter 11, it generates a signal for the block 4, which turns off the power source 3. The number of registers of counter 11 is selected so that the device operation time is 1.5-2 times less than the process development time preceding a short circuit, which is characterized by an increase in the intensity of high-frequency signals.

Thus, the principle of operation of the proposed device is based on recording a continuous increase in the intensity of high-quality signals for a certain predetermined time. This is due to the fact that common to high-frequency signals before a short circuit is an increase in their intensity (an increase in the level and frequency of the signals), while the instantaneous value of the level is random and will be different for different processing modes.

The increase in reliability occurs due to the fact that the proposed device continuously detects the growth of the intensity of high-frequency signals over time and does not respond to random short-term changes in their intensity or to interference pulses from the power source, such as switching.

Expansion of functionality occurs because the proposed device does not contain a selective element, characterized by a response threshold and, therefore, can be used in any processing modes without much reconfiguration.

Claims (1)

Invention Formula The device for protection of electrodes from short circuits during dimensional electrochemical processing, made in the form of serially connected operating current sensor, bandpass amplifier and detector, which is connected via a control circuit to a blocking power source, 0c is distinguished by the fact that, in order to ensure the reliability of the protection device, the control circuit contains two angled memory cells, comparison circuits, control circuits and a pulse counter, the first inputs of the analog memory cells being connected to the detector output, and the second to the two inputs a control circuit connected to the second input of the pulse counter, the first input of which is connected through the comparison circuit to the outputs of the analog memory cells, and the output to the input of the blocking source of the power supply. Sources of information taken into account in the examination of 5 1. USSR Copyright Certificate 528165, cl. B 23 P 1/02, 1975.