SU727977A1 - Device for testing the wearout of contact wire - Google Patents

Description

The invention relates to the field of measuring equipment and can be used to control the wear of the wires of the contact network in electric vehicles.

Known devices for determining the amount of wear of the wires of contact networks — ⁵ , which are hand-held measuring instruments, for example micrometers or measuring brackets, with the help of which measurements of wire sizes are carried out manually in the intervals between the following composition® [£ 1].

The disadvantage of these devices is the complexity of the manual measurement process.

The closest technical solution to the invention is a device for measuring the wear of a contact wire containing a primary transducer, an excitation source and a measuring circuit [2]. The converter is a runner made in the form of a capacitive sensor, and the measuring circuit measures the capacitance between the runner and the contact wire.

A disadvantage of the known device is the low accuracy of monitoring the wear of the contact wire, determined by the low noise immunity of the converter and the influence of measuring the gap between the runner and the drive.

The aim of the invention is to improve the accuracy of the device.

To do this, in the proposed device, the primary converter is made in the form of an electrode placed in a dielectric housing filled with gas, the excitation source is made pulsed, and the measuring circuit is made in the form of a temporary gating unit, a delay measuring unit, a key, an adjustable amplifier, a control voltage driver, a matching element , two formers and a pulse amplitude meter, the output of the converter through a matching element is connected to the information input of the key, the output of which a connected to the input of the controlled amplifier, the excitation source output

3 .......... 727977

connected to the input of the first driver, the outputs of which are connected to the first input of the delay measurement unit and through the time gating unit to the control input of the key, the output of the adjustable _5th amplifier is connected through the second driver to the second input of the delay measurement unit, the output of which is connected through the driver of the control voltage with a control input of an adjustable 10 amplifier, the second input of which is connected to a pulse amplitude meter. .

In FIG. 1 shows a block diagram of the proposed device; in FIG. 2 - design of the primary converter} in FIG. 3 is a typical waveform.

A device for monitoring the wear of the contact wire contains a master oscillator '1 and a generator 2 of probing pulses 20, which form the source of excitation, the first driver. 3, primary converter 4, matching element 5, key 6, delay measurement unit 7, temporary gating unit 8, adjustable amplifier 9, second driver 10, driver 1? unitary enterprise ”” of leveling voltage and pulse amplitude meter 12.

The primary transducer 4 (see ^{30 of} Fig. 2) contains a dielectric housing

13, inside which the electrode is placed

14. Kopnvc 13 is filled with an inert gas. The Converter 4 is adjacent to the lower part of the contact wire 15 with ³⁵ some clearance.

The device operates as follows.

When a probing pulse is supplied from generator 2) with an amplitude of several ⁴⁰ eV volts between the electrode 14 and the contact wire 15 in the gas medium of the primary transducer 4, a dark current arises. When the voltage reaches a certain probe pulse ⁴⁵ of Great masks, in a gas avalanche ionization occurs and the current increases abruptly. Electrons moving in the direction of the contact wire 15 are deposited on the dielectric casing 13 and shield ^{50 the} field inside the transducer 4, as a result of which the current through the transducer ceases. The width of the discharge column in a gaseous medium determined by the width converter flat portion of the contact wires ⁵⁵ Foot 15 (region 16 in FIG. 2), so that current pulse magnitude depends on the area of the flat portion and the wire, with "is responsible, in pulse amplitude with rreobrazovatelya 4 can be determined degree of wear of the contact wire 15.

A useful signal from the converter 4 occurs both at the leading and trailing edges of the probe pulse.

In FIG. Figure 3 shows a typical waveform: Ϊ is the trailing edge of the probe pulse} Q is the useful signal from transducer 4, ill is the interference signal without correction at the initial moment, the front of the probe pulse, | y is the interference signal after correction. The duration of the useful signal is a few microseconds.

The signal from the Converter 4 is removed using the matching element 5, which provides isolation of subsequent blocks from the high-voltage probing pulses. * It provides accuracy of measurements. the influence of the interfering signal that occurs at the initial moment of the front of the probe pulse A, and also affects the change in the distance from the transducer 4 to the contact wire 15, which inevitably takes place when the transducer moves along the wire.

To eliminate this influence, the signal from its matching element 5 is passed through the key 6, and the signal from the down-dropping generator 1, formed by the first driver 3, triggers a temporary gating block 8. The latter generates an inhibitory signal of a given duration, which is fed to the control input of the key 6 and closes the key to ground, preventing the interference signal from passing to the adjustable amplifier 9. As a result, the interfering signal turns into a short pulse (pulse IV in Fig. 3), which does not overlap the useful signal. At the end of the inhibitory pulse, the key 6 opens and allows the passage of the useful signal.

The signal from the output of the first driver 3, marking the beginning of the front of the probe pulse, and the signal from the output of the adjustable amplifier 9, generated by the second driver 10 and marking the moment of appearance of the useful signal from the converter 4, is sent to block 7, which measures the amount of delay between these pulses. With changes in the distance between the converter 4 and the contact wire of 15 amp5, the useful signal changes there, but the voltage at which the useful signal also changes, that is, the delay time between the moment of the beginning of the front of the probing pulse and the moment of the appearance of the useful signal changes . In accordance with the magnitude of this delay, the driver 11 generates a control voltage that is supplied to the control input of the adjustable amplifier 9 and changes its transmission coefficient, compensating for the change in the amplitude of the useful signal when the distance between the converter 4 and the contact wire 15 is changed. ¹⁵

The amplitude of the useful signal is measured by a meter 12 of amplitude, momentum and the degree of wear of the wire is determined from the results of its readings.

Claims (2)

(54) A DEVICE FOR THE WEIGHT-WRITTEN CYTROL 3 7 is connected to the input 7 of the first driver whose output is connected to the first input of the delay measuring unit and through the temporary gate to the second input of the key amplifier, the output of the adjustable amplifier is connected through the second driver to the second input measurement of the delay, the output of which is connected to the control input of the adjustable amplifier through the control voltage driver, the second input of which is connected to the pulse amplitude meter,. Fig. 1 shows a block diagram of the proposed device in Fig. 2, the structure of the primary converter in Fig. 3 is a typical form of signals. A device for monitoring the end wire contains a master oscillator 1 and a generator 2 probe pulses that form the excitation source. first shaper. 3, primary converter 4, matching element 5, key 6, delay measurement unit 7, temporary gating unit 8, adjustable amplifier 9, second shaper 1O, shaper 1 control voltage and pulse amplitude meter 12, -primary converter 4 (see , Fig, 2) contains a dielectric body 13, inside which is placed the electrode 14, the housing 13 is filled with an inert gas. Converter 4 is adjacent to the bottom of the contact wire 15 with a certain gap. The device works as follows. When supplied from generator 2, the probe I of its impulse with amplitude in several sbt volts between electrode 14 and contact wire 15 in the gaseous medium of the primary transducer 4 warms a dark current. When the voltage of the probe pulse reaches an unbroken wave, the avalanche ionization rises sharply in the gas, the electrons, dyhgapies towards the contact wire 15 are deposited on the dielectric case 13 and this "wound" field inside the converter 4, resulting in the current through the transformer is discontinued. The width of the discharge column in the gas medium of the converter is determined by the width of the flat part of the contact wire 15 (region 16 in Fig. 2). The current of the first current pulse depends on the flat part of the wire n, respectively, the degree of wear of the converter 4 can determine the degree of wear contact wire 15, the useful signal from the transducer 4 arises both on the front 5 and on the falling front of the probe pulse. FIG. 3 shows a typical waveform: T is the falling front of the probe pulse; - is the useful signal from converter 4, Ш is the interfering signal without correction at the initial moment of the front of the probe pulse, IV is the interfering signal after correction. The duration of the useful signal is several microseconds. The signal from converter 4 is removed by means of a matching element 5, which provides isolation of subsequent blocks from high-voltage sounding pulses. It has a measurement accuracy. the influence of the interfering signal that occurs at the initial moment of the probe pulse front, and also affects the change in the distance from the transducer to the contact wire 15, which inevitably occurs, when the transducer moves along the wire. To eliminate this effect, the signal from matching element 5 is passed through key 6, and the signal from target generator 1, generated by the first driver 3, starts the time gate 8 bliy. The latter operates a prohibiting signal of a predetermined duration, which is fed to the control input key 1a 6 and closes the key to the ground, preventing the interfering signal from passing to the adjustable amplifier 9. As a result, the interfering signal turns into a short pulse (Y in FIG. 3 ), which does not override the useful signal. At the end of the inhibit pulse, key 6 opens and enables the passage of the useful signal. The signal from the output of the first driver 3, which marks the beginning of the front of the probe pulse, and the signal from the output of the adjustable amplifier 9, formed by the second driver 10 and from the marking moment of the appearance of the useful signal c. converter 4 is fed to block 7, which measures the magnitude of the electric wave between these pulses. With changes in the distance between the transducer and the contact wire 15 fl f, the useful signal changes, but also the voltage at which the useful signal is generated, i.e. the delay time between the beginning of the sounding signal momentum and moment of appearance of the useful signal. In accordance with the magnitude of this delay, the shaper 11 forms a control voltage, which is fed to the control input of the adjustable amplifier 9 and changes its transmission coefficient, to compensate for the change in the amplitude of the useful signal when the distance between the converter 4 and the contact wire 15 changes. Amplitude The useful signal is measured by an amplitude meter 12 pulse. The degree of wear of the wire is determined from the results of its reading. Claims An apparatus for monitoring the wear of a contact wire containing a primary transducer, a source of excitation and a measuring circuit, which is so that, in order to verify ACCURACY, the primary transducer is filled in the form of an electrode placed in a dielectric case filled with gas, the excitation source is pulsed, and the measuring circuit is made in the form of a time gate unit, a delay measurement unit, a key, an adjustable force; l, a control generator a matching element, two drivers and an impulse amplitude measurer; the output of the converter is connected to the information input of a switch, the output of which is connected to the input of an adjustable amplifier; through the temporary rhythm block - with the control input of the key, the output of the adjustable amplifier is connected via the second driver to the second input of the measuring unit Support, the output of which is connected via a control voltage driver to a control input of an adjustable amplifier, the second input of which is connected to a pulse amplitude meter. Sources of information taken into account in the examination 1. The author's certificate of the USSR Mo 142438, cl. G01 7/08, 1961. 2. Authors certificate of the USSR 9 503164, class, Q 01 N3 / 56, 1973 (prototype). IG P