SU1317509A1 - Device for measuring time of firing arc on contacts of switching device - Google Patents

Abstract

The invention relates to electrical engineering and can be used when testing electrical apparatus for critical switching capacity. The aim of the invention is to improve the accuracy and automate the measurement of arc time by automatically measuring the voltage drop on the closed contacts of the device and maintaining the voltage threshold automatically during the test for limiting (or critical) switching capacity taking into account the change in current of the test circuit and contact wear in order to expand the limits of measurement and accuracy. The element And the interrupter with the blocking circuit is made on high-speed optocouplers. 1 hp ff. 2 Il. with SP

Description

The invention relates to electrical engineering, in part to the technique of measuring the arc time at the contacts of switching devices, electrical switches.

The aim of the invention is to improve the accuracy and automation of measurements of arc time.

FIG. 1 is a block diagram of an apparatus for measuring arc time; in fig. 2 shows time diagrams of voltages at various points in the block diagram of the device.

The device contains a voltage sensor 1, the output of which is connected to the input of the full-wave rectifier 2 and through a resistor 3 to the anode of the thyristor optron 4, and to the cathode of the thyristor optron 5 and the input of the interrupter 6, and the output of the rectifier 2 is connected to the measuring input the comparator 7, and the output of the chopper 6 is connected to the input of the amplitude detector 8 of the signal module, the output of which is connected to the reference input of the comparator 7, the output of which is connected to the first input of the AND 9 element loaded on the registration block 10, and to the second input of the And 9 pr element The output of the full-wave detector - amplifier 11 is connected, the input of which is connected to the output of current sensor 12, the output of amplifier 11 of which is connected to the anode of breaker b, and the output of element I with the anodes of optron LEDs 4, 5, and the cathode of the thyristor the optocoupler 4, the anode of the thyristor optron 5 and the cathodes of all the LEDs are connected to the common wire. The "Reset Amplitude Detector 8 and Recording Unit 10 are connected to a common wire through a twin button 13. Element I consists of two transistor optocouplers 14, 15 whose transistors are connected in series to a common load — a resistor 16. The LED anodes are inputs e; 1 , and the cathodes are connected to an openable wire. Curve 17 in FIG. 2 indicates the voltage dependence of the output of the rectifier 2 in time. Curve 18 denotes the dependence of the change in the output signal of current sensor 12 over time. Curve 19 shows the time dependence of the output voltage of the comparator 7. Curve 20 denotes the dependence of the output voltage of the rectifier-amplifier 11 in time. Curve 21 denotes the time dependence of the output voltage of the amplitude detector 8. Curve 22 denotes the dependence of the output voltage of the element And 9 over time.

The device works as follows.

To prepare for work, press button 13 "Reset. At the same time, the readings of the registration and voltage unit 10 on the memory capacitance of the amplitude detector 8 are zeroed. The contacts of the apparatus under test are open, the current in the circuit does not leak. At the output of voltage sensor 1, there is a voltage proportional to the voltage of the energy source. This voltage is rectified.

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It is a full-wave rectifier 2 (curve 17 in Fig. 2) and is fed to the input of the substation 7, the output of which is voltage (curve 19 in Fig. 2), since the voltage at its reference input, i.e. the output of the amplitude detector 8 is zero. At the output of the element And 9, the voltage is zero, the optocoupler 14 is open, and the optocoupler 15 is still closed, since the current in the circuit does not flow. When the contacts of the test apparatus are closed, a current begins to flow in the circuit, a voltage appears at the output of current sensor 12 (curve 18 by 2), and a voltage drop appears at the output of the rectifier — amplification (curve 20 in FIG. 2). ). The interrupt-6 LED lights up, the interrupter passes the signal, the input of the amplitude detector 8 receives a voltage proportional to the voltage drop on the contacts of the test apparatus, which is stored on the capacitor of the amplitude detector 8 and supplied to the reference input of the comparator 7. The measuring input of the comparator 7 has voltage less by the amount of voltage drop on open diodes of rectifier 2, and the comparator 7 is closed (curve 19 in Fig. 2). The optocoupler 14 of the element And 9 is closed, and the optocoupler 15 is opened. There is no signal at the Velokhod element I 9 - the mode of closed contacts. When the contacts open, an arc appears on them (curve 17 in Fig. 2). The voltage at the measurement input of the comparator 7 becomes greater than that at the reference input. The co.parator opens by opening the optocoupler 14 of the element I 9, at the output of which a signal appears corresponding to I1, the moment of arc firing (curve 22 in Fig. 2). In this case, the thyristors of the optocouplers 4, 5 are opened, by shunting the input of the interrupter 6, the measured value of the voltage drop on the contacts of the test apparatus is stored at the E output of the amplitude detector 8. After the arc extinguishes, the current in the 0 circuit stops, the optocoupler 15 closes. Block 10 registration shows the measured value of the arc time.

After zeroing the readings with button 13, the measurement process can be repeated. The device automatically sets the response threshold for voltage, which improves measurement accuracy and automates the measurement process.

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Claims (2)

1. A device for measuring the arc time at the contacts of a switching device, containing voltage and current sensors, a full-wave rectifier, a full-wave rectifier-amplifier, 55 comparator, a coincidence circuit and a recording unit, the voltage sensor being connected through a full-wave rectifier connected to the measuring input of the comparator, and its output is connected to the end input of the element I, and the current sensor through the full-wave rectifier-amplifier is connected to the second input of the element AND loaded on the unit register In order to increase accuracy and automate measurements, an amplitude detector of the signal module, a resistor, two thyristor optocouplers, an optoelectroin interrupter, and the anode of the thyristor of the first optocoupler, the cathode of the second optocoupler - dinene to the output of the voltage sensor, the cathode of the thyristor of the first optocoupler and the anode of the thyristor of the second optocoupler connected to the common wire, and the output of the chopper is connected to the input of the amplitude detector, the output of which is connected to the reference th input of the comparator, the anodes optocoupler LEDs connected to the output element and the anode of the LED connected to an output chopper rectifier amps and cathodes of the LEDs connected to a common wire. 2. The device according to claim 1, characterized in that, in order to expand the measurement limits and reduce the error, the element And is made of transistor optocouplers, the anodes of the LEDs are the inputs of the element And, the cathodes of the LEDs are connected to the common wire, the emitter of one of the optocouplers is connected to the collector of the other, the emitter of which is connected to the load resistor and is the output of the element I, and the second end of the resistor is connected to the common wire, and the collector of the first optocoupler is connected to the "plus power supply. + i / smtuu l