SU1255328A1 - Method of adaptive protection from short-circuits in electric methods of machining - Google Patents

Abstract

The invention relates to the electrophysical and chemical processing of materials and makes it possible to increase the reliability of protection against short circuits. As an information parameter about the development of short circuits, the current values of the power of high-frequency signals are used and the current value of the power released in the interelectrode gap from the action of a current and voltage is measured. The signs of the derivatives of the measured power values are determined, and at the moments when the signs of the derivatives simultaneously take a positive value, the protection is triggered. The device contains a multiplying device 1, the input of which, together with the inputs of differentiating devices 2 and 3, is connected to the inter-electrode gap 4 by current and voltage. The differentiating device 2 by current through diode 5 is connected to the first input of the first coincidence circuit 6 , the second input of which through the first inverter 7 and the diode 8 inversely connected with respect to diode 5 is connected with the output of differentiating device 3 for voltage. The multiplying device 1 by one output through a differentiating device 9 and a second inverter K connected in parallel; and a key 11 connected to the output of the first coincidence circuit 6 is connected to one input of a first threshold device 12, the second input of which is connected to a driver 13. Another output of a multiplying device 1 through a high-pass filter 14 and a differentiating device 15 is connected to the first input of the first threshold device 16, the second input of which is connected to the second driver 17. The outputs of the threshold device roystv 12 and 16 are connected to the second coincidence skhe.me 18 connected with the output feed drive 19 and power source 20. 2 sec. n. f-ly, 3 ill. SS CO 1hE SP ate with rs5 00

Description

The invention relates to the field of electrophysical and chemical processing of materials and can be used based on the specifics of the methods used, processing to protect the electrodes and si. power supplies from the action of short circuit currents.

One of the inventions is a breach of the reliability of protection.

T.ch is achieved by the method of adaptive saturation from short circuits in electro-physicochemical processing methods, according to which current values of {d-1i and monichnosity released in the interelectrode gap from the action of a power current and voltage are measured, are derived from measured values and current;., their values of the high-frequency signals, and at the moments when the signs of argon-wave), m, take a positive value of time, produce a triggering response, ity.

The whole variety of the known electrophysical and chemical methods of the material strain mechanism can be divided into three small groups: electrochemical

(ECHO) e. 1electroerosio; 1e (EES)) and combined cherotroerosio11} 1o-cechrochemical {- cheskie (EECO) methods.

The principle of ada.ptivnosti is related to the specificity of each rpyii method. Conducted ex- emerial studies to determine the laws of the blackness of the measurements of the separated E.I. of the electrical parameters characterizing the development of short- and short circuits, which are common to all of the i pyiin methods mentioned.) C. It has been established that the power P, released in the electrode gap from the action of a current, a current / and a voltage U, / .l,

i o

increases before a short lock: in the case of an ECHO and decreases under those conditions (the magnitude and shape of the logo voltage, the power of the gingaia source, the load and the material of the workpiece in the cases of EEE and EECO.

The reduction of monosity in two noses. 1C-D1n-1x cases is explained by the fallaypchik xa1) actor of voltaic characteristics (I – V) of the sources of power (equivalent to current sources) used for the effects of 1E1H; to the EEO and EECO processes. Long E.H.I. isno. - isch students with a tough E.L.H.

If the inversion of the values of monogram in the case of EEO and EECHO, then one of the regularities for all rpviHi mslsm is an increase in MOHUIOCTH P before a short circuit. As the exernital examinations have been compressed, measuring the ria of the P parameter is a necessary, but not sufficient, condition. rea; | ia1i-1i and irin.iia adaggivnosti understate. Insufficient dependence is associated with the parasitic dependence of this parameter on the treatment area (ECHO) and the purity of the working fluid (EEE, EE.KO).

five

0

0

0

In order to fully implement the principle of adaptability of protection, it is necessary to measure the MOLUHOCTH of high-frequency signals / L., arising in the power circuit (voltage) in any of these methods, despite the different nature of occurrence in each of the processing methods. The general principle of high frequency signals is the increase in their power before a short circuit. In contrast to the power I, the power of Rach and. Has a parasitic dependence on the power voltage and pressure of the working fluid.

Thus, the simultaneous measurement of the parameters P and Rac makes it possible to compensate for the shortcomings that characterize each parameter separately and ensure the implementation of the principle of adaptability of protection.

The method is implemented by a device containing two differing-route devices connected to the inputs back on qeHfibLx diodes, a high-pass filter, a data supply device connected to the same inputs of two threshold devices, a switch, a conditioment circuit, a feed drive and a power source. . sci; 1 s to the interelectrode gap. It introduced the third and fourth supplements; | Loop differentiating devices, two inverters and a second connection scheme, with inputs multiplying its devices and the first two differentiating devices connected in parallel by the output of one of the diodes to one input of the first soviade, and the output of the second diode through the first inverter to the second input of the first circuit We are coincidentally connected to the interelectrode gap, one output of the multiplying device is connected to the input of the high-pass filter, and the other output is through the third differentiating device, the second inverter is switched on. A parallel KJIIOM connected to it, connected to the output of the first coincidence circuit, is connected to another input of the first threshold device, the output of which is connected to one input of the second coincidence circuit, the other input of which is through the second threshold device li It is connected with the output of the high-pass filter, the output of the second combination circuit is connected to the feed drive and the gp-1 tani source.

FIG. timing diagrams, gy-sleeping principle of the method are shown; in fig. 2 is a block diagram of the device; in fig. 3 - characteristic (d) scilograms of currents i and voltages and.

Example. Depending on the method of electrophysical and chemical treatment used (ECHO, EEO, EEHO), the prod.d. mye (case of ECHO) or the opposite (EEO and EEHO case) measurement of the current I emitted in the interelectrode from the action of the power current / ia

For ECHO P - W-iat,

 about

where T is the period of power tension. For EEO and EEHO I 4-U

A derivative sign is then determined.

Р - (or Р) from measured power

nosti. A positive sign of P (P) corresponds to a decrease in the interelectrode gap, a negative sign to an increase. J3 due to the fact that the establishment of the P (P) sign is also influenced by a change in the treatment area (ECM) and the purity of the working fluid (EEE, EECO), while measuring the P (P) power measurement of high-frequency signals

. IDS

RVCH ij {/ vh gvcha /,

.184

where 7HF is the period of oscillation of high-frequency signals, and 7Wh (2-5) 10 s;

(Bc, UB - current AND voltage of high-frequency signals (measured by filtering, respectively, for power current and voltage purposes),

and the derivative sign is determined.

at

A positive sign of the RWh corresponds to a decrease in the interelectrode gap, a negative sign to an increase. Tripping is performed at times (e.g., may be 4 of FIG. 1), when the signs of the derivatives P (P) and RVC simultaneously take a positive value. It was experimentally established that the positive signs of the derivatives of P (P) and RF, if they are not installed simultaneously, are not associated with the development of short circuits in the treatment area. Thus, a positive sign P (moment) may occur with an increase in the processing area (ECHO). Accordingly, the positive sign P can be established when the working fluid is contaminated when the probability of breakdown of a liquid column through particles (EEE, EECO) is high. In this case, the RVC, if the gap does not change, will have a zero value. (Interval / i- / 5) - The positive sign of the RF (interval O-1) can be set due to an increase in the voltage across the gap, as well as a decrease in the pressure of the working fluid in him. At the same time, the derivative P (P), if the gap does not decrease, will have a zero value (intervals and). Obviously, only the simultaneous installation of positive signs of the derivatives P (P) and Rfc uniquely characterizes the decrease in the interelectrode gap, i.e. short circuit development in the processing area.

Simultaneous measurement of the parameters P (P) and RVC increases the reliability of protection not less than 4 eiM by a factor of 2, since parasitic connections affecting each parameter separately are excluded. In addition, the one-time use of the P (P) and RVC parameters extends the protection functionality, since it can be used for any of the electrophysicochemical processing methods without reconfiguring the hardware (without changing the principle of operation).

Thus, the simultaneous registration of the signs of the parameters P (P) and Rwh ensures the adaptability of the protection to the specifics of the processing methods used and thereby provides an excessive sum effect on their use.

A device that implements an adaptive short-circuit protection method for electrophysical and chemical processing methods contains a multiplying device 1, whose input, together with the inputs of differentiating devices for current 2 and voltage 3, is connected to the interelectrode gap 4. Differentiating device for current 2 through diode 5 It is connected with the first input of the first circuit. We have 6 coincidences, the second input of which through the first inverter 7 and the diode 8 connected back to diode 5 is connected to the output of the differentiating device on the voltage 3. Multiplying device 1 by one output through the third differentiating device 9 and the second inverter 10 connected in parallel and the key 11 connected to the output of the first circuit. We used coincidences connected to one input of the first threshold device 12, the second input of which is connected to the driver 13. The second output multiplying device 1 through the filter 14 high frequencies and the fourth differentiating device 15 is connected to one input of the second threshold device 16, the second input of which is connected to the second driver 17. Outputs p squamous devices 12 and 16 are connected to the second coincidence circuit 18 connected with the output feed drive 19 and power source 20.

The device works as follows.

After the start of the processing process, the process current / and voltage U (Fig. 2) are fed to the inputs of multiplying device 1 and, accordingly, differentiating devices according to current 2 and voltage 3.

If the processing is carried out by the ECM method (Fig. 3), which is characterized by synchronous current. The change in current i with respect to voltage and, the output of differentiating devices 2 and 3 will always contain signals of the same sign. Unipolar signals from one of the reversely connected diodes 5 or 8 will not be passed through to one

five

from the inputs of the circuit 6 matches. As a result, the And key will remain on for the entire processing period. Signals proportional to the power P released in the interelectrode gap 4 are output from the multiplying device 1 to the inputs of the differentiating device 9 and the high-pass filter 14. Due to the fact that the key 11 when processing by the ECHO method remains included in the processing, the signals P from the output of the differentiating device 9 bypass the inverter 10 and through the key 11 enter the input of the threshold device 12. IF the signal level P exceeds the value of the reference voltage If the signal is generated by driver 13, then signal A is generated at the output of threshold device 12 (FIG. 1).

The level of Rsad is chosen from the conditions of compensation and weak parasitic oscillations of the signal P, initiated by the instability of the electronic components of the protection device. A signal proportional to the power of the high-frequency oscillations Rwh from the output of the high-pass filter 14 through the differentiating device 15 enters the input of the threshold device 16. If the signal level of the Rvh signal exceeds the value of the reference voltage Rcv back generated by the master device 17, then the output of the threshold device 16 is generated In (Fig. 1). The level Rhv butt is chosen from the same condition as the Rzad level. Signals A and B, if they arrive simultaneously, actuate the coincidence circuit 18, Last generates signal D (Fig. 1) and stops (reverses) the feed drive 19 and turns off the power supply 20.

If the processing is carried out by the EEE or EECO method, which are characterized by points in time (Fig. 3), when a synchronous change in current (relative to U) breaks (voltage drop U corresponds to growth /, moments 1, t-2, 1h, etc.) , on the E output of differentiating devices 2 and 3, opposite-polar signals will appear. They are transmitted back by the included diodes 5 and 8, and after the inverter 7 inverts one of the signals of the same polarity (positive) at the same time to the input of the coincidence circuit 6. The last key is activated and turns off the key 11, after which the signal P from the output of the differentiator 9 enters to the input of the threshold device 12 through the inverter 0. The inverted signal P will be positive if there is a decrease in the interelectrode gap in the treatment area. In the rest, the operation of the device is completely similar to the operation of the device in the considered example, when the processing was performed by the ECM method.

6

Thus, G1), the proposed device allows, without changing the hardware, to automatically adapt (adapt) to the specifics of any of the electrophysical and chemical methods of processing, which significantly expands its functional capabilities.

Q 5

0 o

Q

five

Claims (2)

Invention Formula . The method of short circuit short-circuit protection with electrical processing methods, according to which the current values of high-frequency signal power, which is different from the current value of 1%, is used as an information parameter on the development of short circuits The current values of the power released in the inter-elec- tive range from the action of si are efficiently measured. ovo1 current and voltage, determine the signs of 1% of the measured signs of the device 1 sy and at the moments when the signs of derivatives are positively charged, they trigger the protection. 2. An adaptive protection device against short closures in electrical processing methods, containing a multiplying and two differentiated devices, a high-pass filter, devices connected to the inputs of the UR.OX threshold devices, a key, the first c. Coincidences, and also a co. l innings; and 1-: power supply source, connected to me-kele -: to native nro.meshutku, different, (; if, for the purpose of newer reliability, for 1G,) 1 it additionally introduced ret ret and fourth differentiator, two In this case, the first two differentiating devices are connected in parallel with the inputs of the first coincidence circuit through the diode and through the diode and the first inverter, respectively, and the inputs of these differentiating devices and the inputs of the multiplying device are connected to the interelectrode gap, one multiplication input The device is connected to the input of a high-pass filter, its other output is through a third differentiating device, a second inverter and a key connected in parallel with it connected to the output of the first coincidence circuit are connected to the free E; the course of the first prison device whose output is connected to one input of the second the coincidence circuit, the other input of which is; through the second threshold and fourth differential device, is connected to the output of the high-pass filter, and the output of the second coincidence circuit is connected to the drive of the hclatch and the source Itani. Р {Р) /.V chzad AT and 3X0 I Compiled by I. Komarova Editor N. EgorovaTehred I. VeresKorrektor T. Kolb Order 4756/13 Circulation 1001Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab. 4/5 Branch PPP "Patent, Uzhgorod, st. Project, 4 2T-3 FIG 3