RU2732797C1 - Method of calibration and verification of winding wires insulation defects measuring instruments - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: invention can be used in calibration and verification of winding insulation defection meters. Method consists in the fact that insulated wire section is placed on surface of dielectric cylindrical disc, ends of said wire section are brought to side surface of said disc and electrically connected to metal axis, on which disk is fixed, creating in the wire insulation one defect in form of point puncture of insulation to conductor of wire, to surface of the above wire spring-loaded metal disc-shaped electrode-defect sensor is pressed, on axis of which high constant voltage is supplied, leading the dielectric disc into rotation, measuring the wire movement speed and repeatedly drawing said defective wire insulation portion through the defect electrode, and at each passage of the defective area of the wire insulation through the electrode-sensor of defects, signals of defect pulses are picked up with the oscilloscope with the oscilloscope, with the help of which the defectiveness meters are calibrated and checked.

EFFECT: technical result consists in creation of possibility of calibration and verification of insulation defectiveness meters of winding wires using gas-discharge sensor of defects.

3 cl, 2 dwg

Description

The invention relates to control and measuring equipment, and can be used, for example, in the calibration and verification of meters of defectiveness of insulation of winding wires.

In the Russian Federation, during calibration, the actual metrological characteristics of measuring instruments are determined (see RMG 29-2013), and during verification, the characteristics obtained during calibration are compared with the specified ones (as a rule, the characteristics are given in the passport for the measuring instrument).

It is known that cables and insulated lines have a certain resistance to breakdown. For cables and insulated lines, spark control calibration and verification devices have long existed, by means of which, in accordance with various standards, using a test voltage, the insulation of lines is checked for defects. Also, for many years for this purpose, there has been the European standard EN 50356, which describes and specifies the design of devices of this type, as well as test voltages of various types, and, in addition, provides instructions on how to measure the sensitivity of the device when detecting insulation defects. The updated version of the European standard is named EN 62230: 2007. This standard is based on test voltages of various shapes: alternating voltages with a frequency of 40-62 Hz, alternating voltages with a virtually sinusoidal shape and a frequency of 500 Hz-1 MHz, or a pulse voltage with a steep rise and strong damping on the fall. The spark tester should also contain an indication system to indicate the presence of a defect, either by a light signal or an acoustic signal, when the insulation or sheath of the cable, due to a defect in insulation or a defect in coating, does not hold a certain test voltage and a breakdown occurs on a potential-free conductor. The defect detection device must run a digital counter to indicate each individual defect. The device should also summarize defects along the entire length of the cable to its end. The meter shall keep the indication result until the next defect is registered or the indicator is manually cleared.

To verify the sensitivity of a spark tester, it is required that the defect indicator is turned on when a defect condition is artificially created between a certain electrode and a zero potential conductor. It is known that for this purpose so-called defect simulators are created. The simulator must be configured so that for each simulated defect, the simulator generates a spark gap of 0.025 s for AC voltage and high frequency voltage and 0.0005 s for DC voltage. A sequence of at least 20 bits of this type must be triggered, with no time delay of more than 1 s. The sensitivity of the defect detection device is adjusted so that for each artificially generated discharge, no more than one and at least one counting pulse is recorded.

Known defect simulator, which meets the above requirements. The simulator contains a disc made of a dielectric material, which is driven into rotation by a motor through a transmission, and carries an electrode on itself, which is constantly at zero potential. A stationary needle electrode is installed opposite the specified electrode, to which a test voltage is applied. The distance between the needle electrode and the disc electrode is predetermined. The dimensions of the needle electrode are also specified (Appendix B to EN 62230: 2007). The operator of the cable factory using the spark test device is obliged to check the said device from time to time by means of a simulator. We recommend that you perform a sensitivity check at least once a year, and after initial installation, after every repair or major adjustment of the unit.

Closest to the claimed object is the method described in the patent (RF patent No. 2473920) [1].

The method for calibrating and checking insulation defectiveness meters consists in imitating defects using a spark control device, in which a test voltage from a high-voltage generator is applied through an electrode to a continuous cable, breakdown facts are recognized, displayed by means of a detection circuit and summed up by means of a defect counter, while for for verification of the reliability of defect recognition, a test voltage of a predetermined level, a predetermined duration and frequency is applied to a fixed discharge gap, while said impulse test voltages are generated by a high-voltage generator of the spark control device itself.

The disadvantage of the prototype method is the inability to calibrate and verify the meters of defectiveness of the insulation of winding wires using a gas-discharge sensor of defects.

The technical problem posed within the framework of this invention is to create the possibility of calibrating and verifying the meters of defectiveness of the insulation of winding wires using a gas-discharge defect sensor.

The solution to this technical problem is achieved by the fact that in the method of calibrating and verifying the meters of defectiveness of insulation of winding wires, which consists in supplying voltage through the electrode to a continuous insulated wire, and in recognizing the fact of a defect by means of a detection circuit to simulate a continuous insulated wire, place a piece of insulated wire on the generatrix the surface of the dielectric cylindrical disk, and the laying of the wire in is carried out so that it forms a closed circle, the ends of the specified segment of the wire are brought out to the side surface of the specified dielectric disk and electrically connected to the metal axis on which the disk is fixed, the axis is grounded through a sliding contact, created in insulation wire one defect in the form of a point puncture of the insulation to the wire core, a spring-loaded metal disk-shaped electrode-sensor of defects freely rotating on the axis is pressed to the surface of the said wire, on the axis of which Cut the sliding contact, a high constant voltage is applied, a resistive voltage divider is connected to the axis, the low-voltage arm of which is connected to a defect detection circuit, which is an oscilloscope, the dielectric disk is rotated, the speed of the wire is measured, and the said defective section of the wire insulation is repeatedly pulled through electrode - defect sensor, and at each passage of the defective section of the wire insulation through the defect sensor electrode, defect pulse signals are removed from it with an oscilloscope, with the use of which the defectiveness meters are calibrated and verified.

2. To determine the operating voltage of the meter, according to claim 2 of the formula, in the process of repeatedly pulling the defective section of the wire through the electrode-sensor of defects, a constant voltage is applied to the said electrode, which, after each next pulling of the defective section through the electrode, is gradually increased until a defect pulse will not appear on the oscilloscope, while the voltage level at which the defect signal was received on the oscilloscope is taken as the control operating voltage U _p .

$${\displaystyle \sum _{i=1}^n{t}_{ci}}\times V_i$$

- среднее значение отрезка провода, прошедшего через электрод-датчик дефектов за время t_ci сигнального импульса дефекта; V_i-провода при i-м протягивании дефектного участка через электрод–датчик дефектов; σ= $$\sqrt{S^2}$$

- среднее квадратическое отклонение отрезка провода, прошедшего через электрод–датчик дефектов за время t_ci сигнального импульса дефекта; S²= $$\frac{1}{n}$$

$${\displaystyle \sum _{i=1}^n(t_{ci}\times V_i-l_{cp}}{)}^2$$

- дисперсия отрезка провода, прошедшего через электрод-датчик дефектов за время t_ci сигнального импульса дефекта.3. To determine the resolution of the meter, in accordance with claim 3 of the claims, when repeatedly pulling the defective section of the wire insulation through the electrode-sensor of defects, the operating voltage U _{p is} applied to the said sensor, and at each next pulling of the defective area through the sensor-electrode, oscillograms are taken defect signal, using which the resolution of the sensor electrode L _p is determined by the formula L _p = 2 (l _cp + 3σ), where l _cp = $$\frac{1}{n}$$

$${\displaystyle \sum _{i=1}^n{t}_{ci}}\times V_i$$

- the average value of a piece of wire that has passed through the defect sensor electrode during the time t _ci of the defect signal pulse; V _i -wire at the i-th pulling of the defective area through the electrode-sensor of defects; σ = $$\sqrt{{\mathrm{<figure-callout\; id="2"\; label="S"\; filenames="00000017.png"\; state="\{\{state\}\}">S</figure-callout>}}^2}$$

is the root-mean-square deviation of a piece of wire that has passed through the electrode-sensor of defects during the time t _{ci of the} signal pulse of the defect; S ² = $$\frac{1}{n}$$

$${\displaystyle \sum _{i=1}^n(t_{ci}\times V_i-l_{cp}}{)}^2$$

- dispersion of a piece of wire that has passed through the defect sensor electrode during the time t _ci of the defect signal pulse.

FIG. 1 shows a device that implements the inventive method. FIG. 2 shows a typical oscillogram of a signal from an electrode when a defective section of wire insulation passes through it.

FIG. 1 introduced the following designations: 1 - dielectric cylindrical disc; 2 - insulated wire; 3 - electrode serving as a defect sensor; 4 - the axis of the dielectric disk; 5 - electrode axis; 6 - source of regulated constant voltage; 7, 8 - source terminals; 9 - double-beam oscilloscope serving as a defect detection circuit; 10 - calibrated defectiveness meter; R1 - discharge voltage; R2, R3 - voltage divider; R4 - current limiting resistance; C is the discharge capacity of the sensor; position l _d - denotes a defect in the insulation of the wire.

FIG. 2 introduced the following designations t _{p -} time from the moment of ignition of the corona discharge to the moment of extinction of the corona discharge during the passage of one defect in the area of the electrode-sensor of defects; t _s - the time of stable combustion of the corona discharge when a single defect passes under the electrode - the defect sensor.

The essence of the invention is as follows. In accordance with GOST R IEC 60851-5-2008 [2], the integrity of the insulation is expressed by the number of point faults on a wire of a certain length, recorded using an electrical test device. In this case, to monitor defects in the insulation of wires on the insulation of wires from 0.050 to 0.25 mm, the high-voltage electrode (sensor) used is made in the form of two. The rollers in the device must be made of stainless steel and ensure, each, contact with the wire over a length of (25 ± 2.5) mm.

When testing for point insulation of wires with a nominal wire core size of 0.250 to 1.600 mm, one high-voltage electrode in the form of a roller is used. The roller should be made of stainless steel and provide contact with the wire over a length of 25 ÷ 30 mm.

The disadvantage of this control is, firstly, the low versatility of the sensor, since for wires with a core diameter lying in the range from 0.050 to 0.25 mm, an electrode is used - a sensor made in the form of two rollers, and the controlled wire is pulled through 4 rollers, two of which are guides and the other two are sensor electrodes. For wires with a diameter ranging from 0.25 to 1.600 mm, this sensor is no longer applicable, and instead, one high-voltage electrode of a larger diameter is used.

Secondly, both when testing wires with a core diameter lying in the range from 0.050 to 0.25 mm, and when testing wires with a diameter lying in the range from 0.25 to 1.600 mm, the wire is repeatedly bent. This leads to high mechanical loads on the wire insulation from the side of the rollers, which leads not only to a weakening of the mechanical and electrical strength of the controlled wire insulation, but also causes additional defects in the wire insulation. Therefore, with the help of the mentioned control, only selective control is carried out, at a constant and relatively low speed of drawing the wire, equal to (275 ± 25) mm / s.

Some disadvantages of the specified control of defectiveness of the insulated wire are eliminated by the control set forth in [3]. A device for monitoring the defectiveness of wire insulation, contains a sensor-electrode, a high voltage source, the first output of which is connected to the first input of the defect pulse former, the output of the defect counter connected to the input, a speed pulse shaper and a speed sensor are introduced into it, and the second output of the high voltage is connected to the sensor-electrode, the speed sensor is connected through the speed former to the second input of the defect pulse former, the latter consisting of a reference voltage source, a shaper of the leading and trailing edges and a differential amplifier, the first, second inputs and outputs of which are connected respectively to the first input of the defect pulse former, to the output of the reference voltage source and to the first input of the leading and trailing edge shaper, the second input and output of which are respectively the second input and output of the defect pulse former.

The disadvantage of this control, as well as similar methods for monitoring the defectiveness of the insulation of winding wires [4, 5], is the absence of such metrological data as the control voltage, the sensitivity of the device to defects, the resolution of the gas-discharge electrode-sensor of defects and other important control characteristics. The lack of such data leads to unjustifiably high voltages applied to the electrode-sensor during testing, and to high errors in determining the number of defects in the insulation of the tested wire and their lengths.

To eliminate these shortcomings when monitoring the defectiveness of the insulation of the winding wires, it is necessary to calibrate the control means and their periodic verification.

In the Russian Federation, during calibration, the actual metrological characteristics of measuring instruments are determined (See RMG 29-2013 GSI. Metrology. Basic terms and definitions), and during verification, the characteristics obtained during calibration are compared with the specified ones (as a rule, the characteristics are given in the passport for the measuring instrument).

Let us consider in more detail what disadvantages are caused by the lack of calibration and verification of measuring devices for defectiveness of winding wires.

FIG. 2. shows a typical oscillogram of a signal from an electrode - a defect sensor, when a defective section of insulation passes through its zone of action. This oscillogram of the signal from the electrode-sensor of defects was taken at a negative potential at the said sensor equal to f = -2 kV.

In the known above-mentioned methods for monitoring the defectiveness of wire insulation to detect a defective section of wire insulation, the phenomenon of ignition of a corona discharge between the defect sensor and a grounded core wire is used when the defective section of insulation passes in the area of the defect sensor.

A corona discharge is a self-sustained discharge in a relatively dense gas. If an electric field is applied to two electrodes, between which there is a gas gap, then at a certain potential difference between the electrodes, which we call critical and denote by U ₀ , a corona discharge occurs. The value of U ₀ essentially depends on the configuration of the electrodes, the composition of the gaseous medium in the region of the electrodes and on the number of free electrons in the interelectrode region and a number of other factors. Direct visual observation of the corona discharge indicates a series of intermittent corona phenomena. The intermittent nature of the corona discharge was discovered by Trichel [5]. The corona current, as Trichel showed, is composed of periodic and regularly alternating pulses. As the voltage increases, the current in each pulse remains unchanged, while the total corona discharge current increases due to an increase in the pulse alternation frequency. Each regular pulse represents a series of avalanches developing in the usual way, accompanied by photoionization in the surrounding gas volume.

A typical signal from a defect sensor when a damaged section of wire insulation passes through it is shown in Fig. 2. In FIG. 2 shows an oscillogram of voltage (upper part of the oscillogram) and current (lower part of the oscillogram), taken using a two-beam oscilloscope. In zone A of the oscillogram, a section of the oscillogram is highlighted on an enlarged scale. It can be seen that the signal current has a pulsed form, which confirms the fact that the type of discharge is corona. Several voltage pulses sometimes appear in the signal from the defect sensor. FIG. 2 there are two of them: one is less, and the other is longer and more stable. The duration of a more stable section on the oscillogram is designated as t _n . The possibility of defects appearing in the signal from the sensor when only one defective section of several pulses passes through the sensor is due to the fact that when the wire moves and the front boundary of the insulation defect approaches the defect sensor, the corona discharge can ignite, then go out, and after a while re-ignite.

This process of ignition and extinction of the discharge depends on a number of reasons, such as the voltage level at the defect sensor electrode, the degree of contamination of the wire, lateral vibrations of the wire, etc.

Determination of the number of defects in the insulation of the monitored wire in methods and devices using a gas-discharge sensor of defects is carried out by the number of signal voltage pulses that have come to the counter of the number of defects from the sensor of defects. There can be several such unstable zones when one defective area passes under the sensor; in the oscillogram in Fig. 2 there are two of them. In this case, each voltage pulse in the signal from the sensor can be mistakenly counted as a defect. A decrease in the control voltage at the defect sensor electrode leads to a decrease in the probability of several voltage pulses in the signal from the defect sensor electrode. Therefore, the voltage level at the electrode - sensor is a very important control parameter. The sensitivity of the sensor to defects depends on the level of this voltage, as well as the magnitude of the systematic error that the sensor introduces into determining the number of defects and their length during the inspection process. Under the sensitivity to a defect, we mean such a minimum voltage level at the defect sensor electrode, at which any point defect in the form of an insulation puncture will be detected with 100% probability. Let us designate this voltage through U _p and call it the operating voltage of the defect sensor.

The magnitude of the absolute systematic error in monitoring the length of defects depends on the sensor resolution zone, which should be understood as the length of the path traversed by a point defect of negligible length in the sensor zone during the time interval from the moment of ignition to the moment of extinction of the corona discharge between the sensor and the core wire in the place of the defect.

The magnitude of the mentioned systematic error is determined by the resolving power of the electrode - the defect sensor. By the resolving power of an electrode - a defect sensor, we will agree to understand the minimum distance between the boundaries of two adjacent defects, at which these defects are recorded separately.

The smallest linear distance between two point defects in wire insulation, from which their images merge and cease to be distinguishable, is called the linear resolution limit.

To determine the operating voltage and resolution, it is necessary to calibrate the defect sensor electrode, which is reflected in the claimed method.

The resolution range of the electrode of the defect sensor depends in particular on the voltage at the sensor. Therefore, to determine the resolution zone (sensor resolution), it is first necessary to calibrate the defect sensor and determine at what voltage the control will be carried out. The optimal control voltage U _p will be such a voltage at which a point defect in the form of a puncture of insulation is guaranteed, with 100% probability will be registered by the defect sensor. To determine the value of the mentioned voltage, a defect-free section of the wire is selected and a point defect is applied in its insulation, in the form of a puncture of the insulation with a needle to the conductive core of the wire.

On the electrode - the sensor of defects 5 (Fig. 1) voltage is supplied from the power source 6 of such a value, at which the corona discharge during the passage of the mentioned defective section of the wire insulation is guaranteed not to ignite. In the process of sensor calibration, the mentioned defective section of insulation 2 is repeatedly pulled through the electrode-sensor of defects 5 and with each subsequent pulling the voltage on the sensor 5 is increased. This procedure is repeated until the specified point defect is guaranteed to be registered by the electrode-sensor of defects 5. By evidence such a defect detection is the appearance of a pulse signal on the oscilloscope 9. The voltage at which this occurs and will be the operating voltage U _p of the defect sensor. Since a point defect is made in the form of an insulation puncture, then, in the first approximation, we can assume that this defect has a negligible length, i.e. l _d ≈ 0. However, when the aforementioned negligible defect passes through the defect sensor, a pulse of duration t _s will appear on the latter _. The distance the wire will move in time t _s. will depend on the resolution of the sensor electrode. To determine the resolution of the electrode of the sensor of defects, select a defect-free section of the insulation of the wire 2 (Fig. 1) and in its insulation make a point puncture of the insulation to the core of the wire. After that, the prepared piece of wire, with a defect applied to it, is repeatedly pulled through the defect sensor electrode, to which the voltage U _{p is} applied _. With each next pulling of the wire, the speed of its movement relative to the electrode-sensor of defects is measured, and using the oscilloscope 9 (Fig. 1), the time t _ci (see Fig. 2) is determined at each next i-th pulling.

$${\displaystyle \sum _{i=1}^n{t}_{ci}}\times V_i$$

- среднее значение отрезка провода, прошедшего через электрод-датчик дефектов за время t_ci сигнального импульса дефекта; V_i-провода при i-ом протягивании дефектного участка через электрод-датчик дефектов; n - количество протягиваний дефектного участка провода через электрод-датчик дефектов; σ= $$\sqrt{S^2}$$

- среднее квадратическое отклонение отрезка провода, прошедшего через электрод–датчик дефектов за время t_ci сигнального импульса дефекта; S²= $$\frac{1}{n}$$

$${\displaystyle \sum _{i=1}^n(t_{ci}\times V_i-l_{cp}}{)}^2$$

- дисперсия отрезка провода, прошедшего через электрод-датчик дефектов за время t_ci сигнального импульса дефекта.Then the resolution of the sensor electrode L _p is determined by the formula L _p = 2 (l _cp + 3σ), where l _cp = $$\frac{1}{n}$$

$${\displaystyle \sum _{i=1}^n{t}_{ci}}\times V_i$$

- the average value of a piece of wire that has passed through the defect sensor electrode during the time t _ci of the defect signal pulse; V _i -wire with the i-th pulling the defective area through the electrode-sensor of defects; n is the number of pulling the defective section of the wire through the defect sensor electrode; σ = $$\sqrt{{\mathrm{<figure-callout\; id="2"\; label="S"\; filenames="00000017.png"\; state="\{\{state\}\}">S</figure-callout>}}^2}$$

is the root-mean-square deviation of a piece of wire that has passed through the electrode-sensor of defects during the time t _{ci of the} signal pulse of the defect; S ² = $$\frac{1}{n}$$

$${\displaystyle \sum _{i=1}^n(t_{ci}\times V_i-l_{cp}}{)}^2$$

- dispersion of a piece of wire that has passed through the defect sensor electrode during the time t _ci of the defect signal pulse.

An example of a specific implementation. According to the claimed method, the electrode was calibrated - the sensor of defects, in the meter for the defectiveness of the insulation of the PETV wire with a diameter of 0.8 mm, on the installation shown in FIG. 1.

The installation (Fig. 1) included a dielectric disk 1 with a diameter of D = 600 mm, rotated through a gearbox by a DC motor. A groove with a depth of h = 0.3 mm was cut along the generatrix of the disk surface, into which a piece of controlled wire 2 with a diameter of d = 0.8 mm with a point defect applied in its insulation in the form of a puncture of the insulation to the wire core was laid. The ends of the wire were brought out to the side surface of the disk and electrically connected to the metal shaft 4, to which the disk 1 was fixed. The axis was grounded through a sliding contact, the resistor R ₄ , which is a current sensor. The disk rotation speed was controlled by changing the motor supply voltage. The disk rotation frequency υ was controlled by a TEMP-4 tachometer. The speed of the wire V relative to the sensor of defects was determined using the readings of the tachometer according to the formula V = υ × (Ddh).

$${\displaystyle \sum _{i=1}^n{t}_{ci}}\times V_i$$

= $$\frac{350}{100}=\mathrm{3,5}мм$$

- среднее значение отрезка провода, прошедшего через электрод–датчик дефектов за время t_ci сигнального импульса дефекта; V_i-провода при i-ом протягивании дефектного участка через электрод-датчик дефектов; n - количество протягиваний дефектного участка провода через электрод-датчик дефектов; σ= $$\sqrt{S^2}$$

= $$\sqrt{\mathrm{0,0225}}$$

=0,15 мм,A spring-loaded rotating electrode-sensor of defects, made in the form of a stainless steel roller, 13 mm in diameter, was pressed against the surface of the wire being tested. On the axis 5 of the electrode-sensor of defects through the sliding contact was supplied from the source 6 from terminal 8 high voltage control. A capacitance C = 90 pF was connected in parallel to the discharge gap. From a high-voltage source, a voltage of negative polarity was fed through a current-limiting resistance R ₁ = 500 kΩ to an electrode-sensor of defects. On the electrode - the sensor of defects 3 (Fig. 1), a voltage was supplied from the power source 6 of such a value, at which the corona discharge during the passage of the mentioned defective section of the wire insulation is guaranteed not to ignite. This voltage started from 100 V. With each subsequent pulling, the voltage at the electrode-sensor 3 was increased by 50 V. This procedure was repeated until the indicated point defect was guaranteed to be registered by the electrode-defect sensor 3. This defect detection is evidenced by the appearance of a pulse signal on the oscilloscope 9. The voltage at which this happened was equal to 450 V. At the specified voltage, the pre-pulse disappeared from the defect oscillogram, and the time t _c became equal to the time t _p (figure 2). At this voltage, the defective area was pulled 100 times through the defect sensor electrode and 100 times it was guaranteed to be recorded by the oscilloscope. After this procedure, the value of U _p was taken as the operating voltage of the defect sensor electrode. At each pulling out of the 100 indicated above, the wire speed Vi was measured, the oscillogram of the defect signal was taken, which was used to determine the time t _ci (see Fig. 2). Based on the results obtained, the resolution of the electrode-sensor of defects was determined by the formula L _p = 2 (l _cp + 3σ) = 2 (3.5 + 3 × 0.15) = 7.9 mm, where l _cp = $$\frac{1}{n}$$

$${\displaystyle \sum _{i=1}^n{t}_{ci}}\times V_i$$

= $$\frac{350}{100}=3.5mm$$

- the average value of a piece of wire that has passed through the electrode-sensor of defects during the time t _{ci of the} signal pulse of the defect; V _i -wire with the i-th pulling the defective area through the electrode-sensor of defects; n is the number of pulling the defective section of the wire through the defect sensor electrode; σ = $$\sqrt{{\mathrm{<figure-callout\; id="2"\; label="S"\; filenames="00000017.png"\; state="\{\{state\}\}">S</figure-callout>}}^2}$$

= $$\sqrt{0.0225}$$

= 0.15 mm,

$${\displaystyle \sum _{i=1}^n(t_{ci}\times V_i-l_{cp}}{)}^2$$

=0,0225 мм² дисперсия отрезка провода, прошедшего через электрод-датчик дефектов за время t_ci сигнального импульса дефекта.is the root-mean-square deviation of a piece of wire that has passed through the electrode-sensor of defects during the time t _{ci of the} signal pulse of the defect; S ² = $$\frac{1}{n}$$

$${\displaystyle \sum _{i=1}^n(t_{ci}\times V_i-l_{cp}}{)}^2$$

= 0.0225 mm ² dispersion of a piece of wire that has passed through the defect sensor electrode during the time t _ci of the defect signal pulse.

After calibrating the defect sensor electrode, the defect meter 10 was checked (Fig. 1). The verification was carried out according to the method described in the claimed method, only as a defect detection scheme was used not an oscilloscope, but a defect meter. The verification showed that the metrological characteristics established using the proposed method fully corresponded to the characteristics of the meter.

Compared with the analogs [3,4], where the control voltage was (1.5-2) kV, the calibration according to the claimed method made it possible to reduce the control voltage by 3.3 - 4.4 times.

Thus, the developed calibration method makes it possible to calibrate and calibrate the meters of defectiveness of the insulation of winding wires, which cannot be done using the prototype method.

Sources used:

1. RF patent No. 2011112057. A method for imitating defects using a spark control device and a spark control device. Published on 2012.10.10 (Prototype).

2.GOST R IEC 60851-5-2008. Winding wires. Test methods. Part 5. Electrical properties.

3. USSR author's certificate No. 364885, class. G01N27 / 00, 1971.

4. RF patent No. 2506601. // Method of control and repair of wire insulation // G.V. Smirnov, D.G. Smirnov. Published on February 10, 2014 Byull. No. 4.

5. Raizer Yu.P. Gas discharge physics. - Moscow: Nauka, 1987 .-- 592 p.

Claims (3)

1. A method of calibrating and verifying meters for defectiveness of insulation of winding wires, which consists in supplying voltage through an electrode to a continuous insulated wire and in recognizing the fact of a defect by means of a detection circuit, characterized in that to simulate a continuous insulated wire, a piece of insulated wire is placed on the generating surface of a dielectric cylindrical disk, and the laying of the wire is carried out so that it forms a closed circle, the ends of the specified section of the wire are brought out to the side surface of the specified dielectric disk and electrically connected to the metal axis on which the disk is fixed, the axis is grounded through the sliding contact, one defect is created in the wire insulation in in the form of a point puncture of the insulation to the wire core, a spring-loaded metal disc-shaped electrode-sensor of defects freely rotating on the axis is pressed to the surface of the said wire, on the axis of which a high position is fed through a sliding contact DC voltage, a resistive voltage divider is connected to the axis, the low-voltage arm of which is connected to a defect detection circuit, which is an oscilloscope, the dielectric disk is rotated, the speed of the wire is measured, and the said defective section of the wire insulation is repeatedly pulled through the defect sensor electrode, and at each passage of the defective section of the wire insulation through the electrode-sensor of defects, the signals of the defect pulses are removed from it with an oscilloscope, with the use of which the defectiveness meters are calibrated and verified. 2. The method according to claim 1, characterized in that in the process of repeatedly pulling the defective section of the wire through the defect sensor electrode, a constant voltage is applied to said electrode, which, after each next pulling of the defect through the electrode, is stepwise increased until the oscilloscope shows a defect pulse will appear, while the voltage level at which the defect signal was received on the oscilloscope is taken as the control operating voltage U _p . 3. The method according to PP. 1, 2, characterized in that repeated pulling of the defective section of the wire insulation through the defect sensor electrode, the detected operating voltage is supplied to said sensor U_R, and at each next pulling of the defective area through the sensor-electrode, the oscillograms of the defect signal are taken, using which the resolution of the electrode-sensor L_p by the formula L_p =2 (l_cp +3σ)where l_cp = $$\frac{1}{n}$$

$${\displaystyle \sum _{i=1}^n{t}_{ci}}\times V_i$$

is the average value of a piece of wire that has passed through the defect sensor electrode during time t_cisignal pulse of the defect; V_i- wires at the i-th pulling of the defective area through the electrode-sensor of defects; σ= $$\sqrt{S^2}$$

is the root-mean-square deviation of a piece of wire that has passed through the defect sensor electrode during time t_{c i} signal pulse of the defect; S² = $$\frac{1}{n}$$

$${\displaystyle \sum _{i=1}^n(t_{ci}\times V_i-l_{cp}}{)}^2$$

is the dispersion of a piece of wire that has passed through the defect sensor electrode during time t_cisignal pulse of the defect.

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