Voice type current transformer polarity tester

Abstract

The utility model relates to the technical field of electric power measurement and test, in particular to a voice type current transformer polarity tester. According to the technical scheme of the utility model, the device mainly comprises a test terminal, a sampling circuit, an amplification comparison circuit, a voice execution circuit and a time-delay reset circuit, and the test terminal transmits the pulse voltage of the secondary side of the tested mutual inductor to the sampling circuit during the polarity test for positive polarity gating voltage division. After the signals are amplified and compared through the voltage amplification comparator circuit composed of the double operational amplifiers, the voice execution circuit is triggered to output voice measurement results, and then the delay reset circuit resets the working circuits in a delayed mode to prepare the next action. The beneficial effects of the utility model are that the circuit composed of the dual operational amplifiers amplifies and compares test signals, triggers the voice module to output measurement results in a voice manner, is accurate and clear, has high sensitivity and reliable action, reduces the labor intensity of repeated measurement caused by uncertain measurement result display of workers in the original measurement mode, and improves the work efficiency. And the test efficiency is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to power measurement test technical field, concretely relates to a voice formula current transformer polarity tester BACKGROUND

[0002] The principle of current transformer is based on electromagnetic induction principle, which is composed of closed core and winding. The primary winding of current transformer has few turns and is connected in series with the current line to be measured, so it often has the full current of the line flowing through it. The secondary winding has more turns and is connected in series with the measuring instrument and protection circuit. When the current transformer is working, its secondary circuit is always closed, so the impedance of the series coil of the measuring instrument and protection circuit is very small, and the working state of the current transformer is close to short circuit.

[0003] In the power generation, power transformation, power transmission, power distribution and power consumption lines, the current varies greatly, from a few amperes to tens of thousands of amperes. In order to facilitate measurement, protection and control, it is necessary to convert it into a relatively uniform current. In addition, the voltage on the line is generally high, so direct measurement is very dangerous. The current transformer plays a role in current conversion and electrical isolation.

[0004] In summary, the current transformer (CT) is an important electrical device in the power system. The correctness of its wiring is of great significance to the normal operation of the protection, measurement and metering devices of the system.

[0005] When installing a new CT and putting it into operation or replacing the secondary cable of the CT, it is necessary to determine the correctness of the polarity of the CT, which is an essential work procedure for relay protection personnel.

[0006] In addition, when the differential protection, power direction protection and other protections in operation malfunction or the electric meter reverses, the polarity of the CT should also be checked to prevent the current transformer from being connected incorrectly in polarity during wiring, causing misoperation or refusal of the relay protection device, and incorrect indication of the instrument and incorrect measurement of electric energy.

[0007] The polarity of the current transformer refers to the polarity of the primary side and the polarity of a certain end of the secondary side at a certain moment, that is, both are positive or both are negative at the same time. This polarity is called the same polarity end or the same name end.

[0008] In the actual operation and maintenance of the power system, it is necessary to determine the polarity of the current transformer, therefore, correctly determining the correctness of the polarity of the current transformer is a very important work.

[0009] At present, the test methods for measuring the polarity of the current transformer mainly include direct current method and instrument method.

[0010] Direct current method is to connect dry battery or battery to the primary winding of CT, the secondary winding of CT connects the pointer type milliammeter (or put the pointer type multimeter to milliammeter file), using the battery switch in the on, off moment, the deflection direction of milliammeter pointer to determine the polarity of current transformer.

[0011] This method is affected by different test equipment, transformer ratio capacity, sometimes the indication of milliammeter is very weak and transient, often mislead the test personnel who rely on naked eye observation, thus draw the wrong conclusion.

[0012] Instrument method is to use the transformer ratio polarity comprehensive tester to measure the polarity of CT, when testing the transformer, not only can display CT polarity, ratio value, but also can measure the direct resistance and excitation characteristic of CT, etc., but this transformer ratio polarity comprehensive tester is high in cost, complex in structure, bulky in size, and the polarity of transformer is only its additional function, its price is often more than 10,000 yuan, especially not suitable for single polarity measurement of single transformer.

[0013] For example, the patent number CN2013101166211 discloses a kind of current transformer ratio polarity fast tester and test method, and further discloses the following technical features:

[0014] A kind of current transformer ratio polarity fast tester, including current transformer ratio tester, the signal output end of the current transformer ratio tester is connected with the signal input end of excitation voltage display, the signal input end of ratio display, the signal input end of primary voltage display.

[0015] A kind of current transformer ratio polarity fast tester test method, voltage output by volt-ampere tester is input to the volt-ampere voltage input end of the tester, excitation voltage U2 is output by S1, S2 to the secondary coil of current transformer, the primary side of current transformer is input to the primary voltage U1 input end of the tester, volt-ampere is input to excitation voltage U2 output end and is connected with a small current transformer, for monitoring volt-ampere current I;U2, I and U1 are respectively through corresponding range switching circuit, buffer amplification circuit and AD sampling, are sent to CPU through photoelectric isolation, CPU measures the amplitude of 3-way signal, U2 and U1 are also respectively through waveform conversion circuit into square wave, are sent to CPU after photoelectric isolation, for measuring the phase difference of U2 and U1, to determine the polarity of current transformer.

[0016] The above scheme is that the voltage output by the volt-ampere tester is input to the volt-ampere voltage input end of the tester, the excitation voltage U2 output by S1 and S2 is output to the secondary coil of the current transformer, the primary side of the current transformer is input to the primary voltage U1 input end of the tester, and the volt-ampere is input to the excitation voltage U2 output end in series with a small current transformer for monitoring the volt-ampere current I; U2, I and U1 are respectively sampled through the corresponding range switching circuit, buffer amplification circuit and AD, and are sent to the CPU through photoelectric isolation, the CPU measures the amplitudes of the three signals, U2 and U1 are respectively converted into square waves through the waveform conversion circuit, and are sent to the CPU through photoelectric isolation, and the phase difference of U2 and U1 is measured, so that the polarity of the current transformer is judged.

[0017] Although the product has the advantages of small size, convenient carrying, high measurement precision and safety and reliability, the above scheme has complex structure and principle and high manufacturing cost after application.

[0018] CN102780234A, entitled "Power generation engineering high-voltage electrical debugging method", the debugging method includes debugging preparation, high-voltage equipment static test and debugging, generator static test and debugging, PT nuclear phase, starting test, dynamic orientation and power generation and grid connection, the wiring, polarity check and ratio measurement test of the voltage transformer, when the wiring, polarity check and ratio measurement test of the voltage transformer measurement winding are performed, the primary and secondary side fuses of the transformer are disconnected before measurement, the measurement lines of the full-automatic ratio tester are connected to the measurement winding terminals of the primary side and the secondary side of the voltage transformer, and then the measurement is started; when the measurement result is that the three-phase ratio is 100 and the wiring mode is Y, y0, the ratio, polarity and wiring are correct; when the wiring, polarity check and ratio measurement test of the voltage transformer protection winding are performed, the open short circuit is formed to form a triangular wiring, and then the measurement lines of the full-automatic ratio tester are connected to the three da terminals of the protection winding of the primary side and the secondary side of the voltage transformer, and when the measurement result is that the three-phase ratio is 300 and the wiring mode is Y, d, the ratio, polarity and wiring are correct.

[0019] Disadvantages: first, the test equipment is heavy and the process is complex; second, when the current is increased, sometimes it needs to reach thousands of amperes, and if the wiring is not reliable, it will cause serious arc, which will damage the equipment and the person; third, the moment when the direct current voltage is added during the test will cause burn on the rheological wiring busbar.

[0020] At present, there is no voltage transformer polarity tester with simple principle, low cost, convenient carrying and use, high accuracy and voice type output measurement result in the domestic power industry, and such products are not found on the market. Content of the utility model

[0021] The utility model discloses a purpose at present technical deficiency existing in the prior art provides a kind of voice type current transformer polarity tester, overcome the above-mentioned shortcomings in prior art testing process, make it convenient to carry, test accuracy is high, low in price, and it has the function of voice type output measurement result.

[0022] Its technical scheme is as follows:

[0023] A kind of voice type current transformer polarity tester, including test terminal, sampling circuit and amplification comparison circuit, the test terminal is set to the input of sampling circuit, the output of sampling circuit is connected amplification comparison circuit, the output of amplification comparison circuit is connected voice execution circuit, the output of voice execution circuit is connected with loudspeaker.

[0024] Further, the voice execution circuit includes triode BG1, BG2, base resistance R11, R12, collector resistance R13, R14, VM voice module, loudspeaker SP, the high level of amplification comparison circuit output is triggered triode BG1 or BG2 conduction after base resistance R11 or R12, VM voice module trigger end K1 or VM voice module trigger end K2 changes from previous high level to low level, to trigger voice module to play voice by loudspeaker SP.

[0025] Further, the output of amplification comparison circuit is also connected with delay reset circuit, for controlling the on-off of voice execution circuit.

[0026] Further, the delay reset circuit includes time base integrated circuit U3, diode D3, D4, D5, resistance R15, RC1, RC2, capacitor C3, C4, wherein time base integrated circuit U3, diode D3, D4, D5, resistance R15, capacitor C3, C4 constitute trigger timer circuit, while the triode BG1 or BG2 of voice execution circuit conduction output low level, diode D3 or D4 conduction, trigger timer circuit starts to work, +12 volts power supply is charged to capacitor C4 through resistance R15, after charging reaches condition, time base integrated circuit U3 output end 3 foot outputs high level, relay is attracted, and its two pairs of normally open nodes J1, J2 are closed respectively, capacitor C1 passes through resistance RC1 and J1 normally open node and forms discharge circuit, capacitor C2 passes through resistance RC2 and J2 normally open node and forms discharge circuit, C1 or C2 instantaneous discharge is completed, BG1 or BG2 is cut off, D3 or D4 is cut off, J returns, at this time, each circuit discharge reset is completed, and waits for next action.

[0027] Further, the sampling circuit is composed of resistors R1, R2, capacitors C1, C2 and diodes D1, D2, wherein D1 and D2 form a positive polarity gating circuit, the pulse voltage Es obtained by the test terminals S1 and S2 is positively gated, and then the capacitors C1 or C2 are charged and filtered; the resistors R1 and R2 divide the voltage across the capacitors C1 or C2 and limit the voltage to Es / 2, and then the voltage is sent to the amplification and comparison circuit.

[0028] Further, the amplification and comparison circuit comprises double operational amplifiers U1 and U2, in-phase input resistors R3 and R4, inverse-phase input resistors R5 and R6, voltage dividing resistors R9 and R10, coupling resistors R7 and R8, amplifier gain adjusting potentiometers W1 and W2, voltage threshold adjusting potentiometers W3 and W4, and the voltage obtained by the sampling circuit is input to the in-phase input end of the operational amplifier 3 through the input resistors R3 or R4, and then the voltage is amplified and output from the 1st pin, and then the voltage is sent to the 5th pin through the coupling resistors R7 or R8 to complete voltage comparison, and when the comparison value is greater than the threshold value, the 7th pin outputs high level.

[0029] Further, the relay coil J is connected with the diode D5 in reverse-parallel connection to prevent the damage of the reverse electromotive force generated in the instant of power-off to the coil J and the insulation of the time base integrated circuit U3.

[0030] Further, the VM voice module trigger end K1 is connected with the negative electrode of the diode D3, the VM voice module trigger end K2 is connected with the negative electrode of the diode D4, and the positive electrodes of D3 and D4 are connected in parallel with the low level working circuit of the time base integrated circuit U3, and the purpose is to trigger D3 or D4 to conduct when any of the VM voice module trigger end K1 or the VM voice module trigger end K2 obtains low level, so as to meet the low level potential required by the trigger timer circuit with U3 as the core.

[0031] Further, the VM voice module trigger end K1 is connected with the triode BG1 and the front double operational amplifier U1, and the VM voice module trigger end K2 is connected with the triode BG2 and the front double operational amplifier U2, and the function is to change the high level output by the double operational amplifiers U1 and U2 into the low level required by the voice module through the triodes BG1 and BG2 respectively.

[0032] Further, the resistors RC1 and J1 are connected in series and then connected in parallel with the capacitors C1, and the resistors RC2 and J2 are connected in series and then connected in parallel with the capacitors C2, and the resistors RC1 and J1 and the capacitors C1 form an independent discharge circuit, and the resistors RC2 and J2 and the capacitors C2 form an independent discharge circuit.

[0033] Compared with the prior art, the utility model has the beneficial effects as follows:

[0034] The utility model discloses a voltage amplification comparator circuit that is composed of double operational amplifiers, triggers a voice module to simulate a real person's voice to broadcast measurement results, has a simple circuit structure principle, high sensitivity, reliable operation, and is easy to implement, and can output measurement results accurately and clearly in a voice mode, reduce the labor intensity of repeated measurement of original measurement mode measurement results of a staff, and improve test efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 It is a circuit principle schematic diagram of the utility model;

[0036] Figure 2 It is an internal principle block diagram of NE555 chip;

[0037] Figure 3 It is a pin arrangement diagram of (U3) NE555 time base circuit. DETAILED DESCRIPTION

[0038] The preferred embodiments of the utility model are described below in combination with the drawings, and it should be understood that the preferred embodiments described here are only used for describing and explaining the utility model and are not used for limiting the utility model.

[0039] Embodiment 1

[0040] A voice type current transformer polarity tester, comprising a test terminal, a sampling circuit, an amplification comparison circuit and a voice execution circuit.

[0041] The test terminal is arranged at the input end of the sampling circuit and is used for connecting a measured current transformer and collecting current transformer test signals.

[0042] The output end of the sampling circuit is connected with the amplification comparison circuit, and the collected and processed electric signals are transmitted to the amplification comparison circuit, which is composed of resistors R1 and R2, capacitors C1 and C2, and diodes D1 and D2, wherein, D1 and D2 constitute a positive polarity gating circuit, the pulse voltage Es obtained by the test terminal S1 and S2 is positively gated, and then the capacitor C1 or C2 is charged and filtered, the voltage across the capacitor C1 or C2 is divided by the resistors R1 and R2 and limited to Es / 2, and the voltage is sent to the amplification comparison circuit.

[0043] The output end of the amplification comparison circuit is connected with a voice execution circuit, which is used for outputting the comparison result electric signal and transmitting the electric signal to the voice execution circuit, and the voice execution circuit comprises two operational amplifiers U1 and U2, input resistors R3 and R4 in phase, input resistors R5 and R6 in reverse phase, coupling resistors R7 and R8, voltage threshold adjustment potentiometers W3 and W4, and a sampling circuit, and the voltage obtained by the sampling circuit enters the operational amplifier 3 in phase through the input resistor R3 or R4, is amplified and outputted from the 1 pin, is sent to the 5 pin through the coupling resistor R7 or R8 to complete voltage comparison, and when the comparison value is greater than the threshold value, the 7 pin outputs a high level.

[0044] The output end of the voice execution circuit is connected with a loudspeaker, which is used for driving the loudspeaker according to the electric signal outputted by the amplification comparison circuit, and mainly comprises a triode BG1, a triode BG2, base resistors R11 and R12, collector resistors R13 and R14, and a VM voice module, and after the high level outputted by the amplification comparison circuit triggers the triode BG1 or BG2 to conduct through the base resistor R11 or R12, the K1 or K2 trigger end of the VM voice module changes from a high level to a low level, so as to trigger the voice module to play voice through the loudspeaker SP.

[0045] Embodiment 2

[0046] A voice type current transformer polarity tester, comprising a test terminal, a sampling circuit, an amplification comparison circuit, a voice execution circuit and a delay reset circuit.

[0047] The test terminal, the sampling circuit, the amplification comparison circuit and the voice execution circuit in the embodiment are the same as those in the embodiment one, and the delay reset circuit is connected to the output end of the amplification comparison circuit and is connected in parallel with the voice execution circuit in the embodiment one.

[0048] The delay reset circuit comprises a time base integrated circuit U3, diodes D3, D4 and D5, resistors R15, RC1 and RC2, and capacitors C3 and C4, wherein the time base integrated circuit U3, the diodes D3, D4 and D5, the resistor R15 and the capacitors C3 and C4 constitute a trigger timer circuit, when the triode BG1 or BG2 of the voice execution circuit conducts and outputs a low level, the diode D3 or D4 conducts and triggers the trigger timer circuit to work, the +12-volt power supply charges the capacitor C4 through the resistor R15, when the charging reaches a condition, the time base integrated circuit U3 outputs a high level from the 3 pin, the relay J is attracted, the two pairs of normally open nodes J1 and J2 of the relay J are closed respectively, the capacitor C1 forms a discharge circuit through the resistor RC1 and the normally open node J1, the capacitor C2 forms a discharge circuit through the resistor RC2 and the normally open node J2, the C1 or C2 is discharged instantly, the BG1 or BG2 is cut off, the D3 or D4 is cut off, and the J returns, at this time, the discharge reset of each circuit is completed and waits for the next action.

[0049] Embodiment 3

[0050] With reference to the accompanying drawings Figure 1 A voice type current transformer polarity tester, mainly composed of test terminals, sampling circuit, amplification comparison circuit, voice execution circuit, delay reset circuit, wherein when the polarity test of the transformer is carried out, the S1, S2 terminal of the device is connected to the S1, S2 of any group of coils on the secondary side of the transformer.

[0051] The sampling circuit is composed of resistors R1, R2, capacitors C1, C2, and diodes D1, D2. When the polarity test of the transformer is carried out by using the direct current method, the primary coil L1 of the transformer is connected to the positive pole of the battery, L2 is connected to the negative pole of the battery, and the switch K is connected to the battery. At the moment when the switch K is connected to the battery, the secondary coil will induce a pulse voltage Es. As shown in the accompanying drawings, this voltage is obtained from the test terminals S1, S2 connected to the secondary coil of the transformer, and the pulse voltage Es connected to the S1 terminal side is positive and the S2 terminal side is negative. Therefore, after the pulse voltage Es passes through the positive polarity gating circuit of the diodes D1, D2, only the diode D1 through which the positive pulse flows is turned on, and the capacitor C1 is charged and filtered. Due to the voltage division of the resistors R1, R2, the voltage of the capacitor C1 is limited to Es / 2, and this voltage is sent to the amplification comparison circuit. Similarly, as described above, at the moment when the switch K is disconnected from the battery, the secondary coil will induce a pulse voltage Es with opposite polarity. At this time, the pulse voltage Es connected to the S1 terminal side is negative and the S2 terminal side is positive. Therefore, after the pulse voltage Es passes through the positive polarity gating circuit of the diodes D1, D2, only the diode D2 through which the positive pulse flows is turned on, and the capacitor C2 is charged and filtered. After the voltage of the capacitor C2 is limited to Es / 2 due to the voltage division of the resistors R1, R2, it is sent to the next stage of the amplification comparison circuit. Figure 1 The amplification comparison circuit is a voltage amplification comparator circuit composed of two groups of identical double operational amplifiers, including double operational amplifiers U1, U2, non-inverting input resistors R3, R4, inverting input resistors R5, R6, voltage division resistors R9, R10, coupling resistors R7, R8, amplifier gain adjustment potentiometers W1, W2, and voltage threshold adjustment potentiometers W3, W4. As shown in the accompanying drawings, the voltage amplification comparator circuit composed of two groups of operational amplifiers U1a and U1b inside U1 and the voltage amplification comparator circuit composed of two groups of operational amplifiers U2a and U2b inside U2 work when the polarities of the pulse voltages induced at the S1, S2 terminals of the measured transformer secondary side are opposite, i.e. the U1 amplifier circuit works at the moment when the battery switch K of the primary coil of the transformer is connected, and the U2 amplifier circuit works at the moment when the battery switch K is disconnected.

[0052] Figure 1

[0053] ​​The voltage obtained by the sampling circuit enters the same-phase input end of the 3-pin operational amplifier of U1a or U2a through input resistor R3 or R4, is amplified and output from the 1-pin, and is sent to the 5-pin to complete voltage comparison through coupling resistor R7 or R8, and the 7-pin outputs high level when the comparison value is greater than the threshold value. Since the CT transformation ratio range is large, from 50:5 to 3000:5, various specifications are available, in order to make the utility model have high sensitivity to collect the instantaneous pulse signal of the secondary side of the CT, the amplifier must have sufficient amplification factor to achieve, the increase of the gain makes the interference pulse also be amplified, when the interference pulse is amplified to a certain extent, the false triggering occurs, in order to ensure that the test accuracy is 100%, the utility model introduces the voltage comparator, only when the amplified voltage is greater than the preset threshold value, the comparator outputs high level, so that the false triggering phenomenon can be effectively eliminated. The amplification factor of the amplifier is determined by the ratio of W1 or W2 to resistor R5 or R6, therefore, the resistance of W1 and W2 can be changed to change the amplification factor of the amplifier. Adjusting W3 and W4 can change the reference potential of resistor R9 and R10, therefore, adjusting W3 and W4 can change the threshold reference voltage of the preset threshold value of the comparator.

[0054] The voice execution circuit comprises triode BG1, BG2, base resistor R11, R12, collector resistor R13, R14, VM voice module, and speaker SP. The high level output by the amplification comparison circuit triggers the triode BG1 or BG2 to conduct through the base resistor R11 or R12, the trigger end K1 or K2 of the VM voice module changes from high level to low level, thereby triggering the voice module to play voice through the speaker SP. The voice triggered by the K1 end of the VM voice module can record the voice content of the analog human being with minus polarity, and the voice triggered by the K2 end can record the voice content of the analog human being with plus polarity. The trigger end K1 or K2 of the VM voice module can only meet the instantaneous low level pulse trigger to broadcast the voice of the corresponding port, and is not affected by the level change of K1 or K2 during the broadcasting process, and the K1 or K2 is invalid again, and is effective until the broadcasting is completed.

[0055] In the figure, the trigger end K1 of the VM voice module is connected with the previous-stage double operational amplifier U1 through triode BG1, and the trigger end K2 of the voice module is connected with the previous-stage double operational amplifier U2 through triode BG2, which changes the high level output by the double operational amplifier U1, U2 into low level required by the voice module through triode BG1, BG2 respectively.

[0056] The delay reset circuit comprises a time base integrated circuit U3, diodes D3, D4 and D5, resistors R15, RC1 and RC2, and capacitors C3 and C4, wherein the time base integrated circuit U3, the diodes D3, D4 and D5, the resistor R15, and the capacitors C3 and C4 form a trigger timer circuit with the time base integrated circuit U3 as the core. Figure 2 、 Figure 3 The internal principle diagram and pin arrangement of the NE555 chip are shown in Figs. 1 and 2, and the functions of the pins of the chip are shown in the description. The NE555 time base circuit has multiple functions, and a typical application is a monostable mode, that is, when the trigger end obtains a valid negative pulse signal, the output end immediately jumps to a high potential and remains until the time constant ends and then jumps back to a low level. A typical application of the monostable mode of the NE555 is a start-up delay output high potential circuit. After the power supply is turned on each time, the voltage across the capacitor C is 0V due to the insufficient charging of the capacitor C, the pins ② and ⑥ of the NE555 time base circuit are at a high level, and the pin ③ outputs a low level. With the charging of the capacitor C, the potentials of the pins ② and ⑥ of the 555 time base circuit decrease. Until the potential of the pin ② is lower than 1 / 3Vcc, the state of the circuit is reversed, the pin ③ changes from a low level to a high level and remains. The start-up delay time Tw=1.1 RC, and the diode VD in the circuit is arranged for discharging the capacitor C after the power supply is turned off. This circuit is generally used to control the delayed turn-on of a high-voltage power supply or to control the delayed turn-on of other power supply circuits.

[0057] The delay reset circuit of the utility model is a start-up delay output high potential circuit of the typical application of the NE555, but the No. 1 ground pin GND end of the NE555 chip in the circuit is not directly connected to the negative pole of the power supply or the ground wire, but is connected with the diodes D3 and D4, and the purpose is to form a loop through the ground end of the voice execution circuit after the diode D3 or D4 is turned on.

[0058] Further as described above, while the triode BG1 or BG2 of the voice execution circuit outputs low level, the diode D3 or D4 is momentarily turned on, providing the low level potential required for the working of the NE555 timer circuit, triggering the timer circuit to start working, the power supply loop is momentarily formed, because the voltage across the capacitor C4 cannot be abruptly changed, the voltage across C4 is 0V, the ② and ⑥ pins of the time base circuit U3 are at high level, the ③ pin outputs low level, and the relay J is not actuated, at this time, the capacitor C4 starts to be charged through the resistor R15, with the charging of C4, the voltage across C4 gradually rises, the potential of the ② and ⑥ pins of the time base circuit U3 gradually decreases, until the potential of the ② pin is lower than 1 / 3Vcc, the state of the U3 circuit is reversed, the ③ pin changes from low level to high level and remains so, at this time, the relay J is attracted, and its two pairs of normally open nodes J1 and J2 are closed, the capacitor C1 forms a discharge loop through the resistor RC1 and the normally open node J1, and the capacitor C2 forms a discharge loop through the resistor RC2 and the normally open node J2, C1 or C2 is momentarily discharged, BG1 or BG2 is cut off, D3 or D4 is cut off, and J returns, at this time, the discharge and reset of each circuit are completed, and the next time the secondary winding S1 and S2 of the transformer generates a pulse, the utility model will output the "de-polarity" or "add polarity" real voice measurement result. The delay time of triggering the timer circuit is determined by R15 and C4, Tw=1.1 R15*C4, in the utility model, R15=1MΩ, C4=2Uf, so the delay time of the reset action is 2.2 seconds; the charging time can be changed by changing the parameters of R15 and C4, and the delay time of the action is determined by the length of time required for the voice module to play voice. The relay J coil is connected with the diode D5 in reverse parallel connection to prevent the reverse electromotive force generated in the instant of power failure from damaging the insulation of the relay coil and the time base integrated circuit U3.

[0059] In the figure, the negative pole of the diode D3 is connected with the trigger end K1 of the VM voice module, the negative pole of the diode D4 is connected with the trigger end K2 of the VM voice module, and the positive poles of D3 and D4 are connected in parallel and connected with the low level working loop of the time base integrated circuit U3, the purpose is to trigger D3 or D4 to turn on when any of the trigger ends K1 or K2 of the VM voice module obtains low level, so as to meet the low level potential required for the working of the trigger timer circuit with U3 as the core, and here the fast switching diode is selected for D3 and D4 to play the role of controlling the low level power switch of the trigger timer circuit of U3.

[0060] In summary, when the polarity test of the transformer is performed by using the DC method, the S1 and S2 terminals of the utility model are connected to the S1 and S2 of any group of coils on the secondary side of the transformer, and in the operation test, only the time difference between the on and off of the battery switch K of the primary coil of the transformer needs to be mastered, and the on and off of the switch K should not be too fast (the time difference between the on and off of the switch K is mainly to meet the output of the voice module), and then the utility model will output the "de-polarity" or "add polarity" real voice measurement result in the instant of the on and off of the battery switch K.

[0061] The utility model discloses a voltage amplification comparator circuit that is composed of double operational amplifiers, triggers a voice module to simulate real human voice to broadcast measurement results, and has simple circuit structure principle, high sensitivity, reliable action and easy realization.

[0062] NE555 pin function explanation: NE555 is a bipolar 555 time base circuit, and its working voltage range is 4.5-16V. The maximum output current of the output end ③ pin can reach 200mA, and can directly drive a small power electromagnetic relay. The NE555 chip generally has 8 pins, and the functions of each pin are as follows: 1. GND: the ground pin of the chip, used for connecting the negative pole of the power supply or the ground wire. Ensure that this pin is connected to the negative pole of the power supply to ensure normal work.

[0063] 2. TR: trigger pin, used for receiving a trigger signal. In the pulse generating circuit, an external trigger signal can be provided through this pin. When this pin is pulled low, the chip will enter the working state.

[0064] 3. V0: output pin, used for outputting the working result of the 555 chip. In the timer application, this pin can output a pulse signal or a square wave signal. In the pulse width modulation (PWM) application, this pin can output a square wave signal with adjustable width.

[0065] 4. MR: reset pin, used for clearing the internal state of the 555 chip. When this pin is pulled low, the internal counter and other states of the chip will be cleared to zero and restored to the initial state.

[0066] 5. VC: control voltage pin, used for controlling the comparator threshold of the 555 chip. By applying different voltages to this pin, the working frequency and duty cycle of the 555 chip can be adjusted.

[0067] 6. TH: threshold input end pin, which determines the comparator threshold of the 555 chip together with the control voltage pin. By applying different voltages to these two pins, the threshold level of the 555 chip can be adjusted.

[0068] 7. DIS: discharge tube pin, used for controlling the discharge operation of the output pin. When the voltage of this pin is higher than 2 / 3 of VCC, the output pin is open; when the voltage of this pin is lower than 1 / 3 of VCC, the output pin is closed.

[0069] 8. VCC: chip power supply pin, usually connected to the positive power supply, and the voltage is generally 5V or 12V

[0070] The above merely describes preferred embodiments of the present application, and any modification or equivalent substitution of the technical solutions described above can be made by those skilled in the art. Therefore, any simple modification or equivalent substitution made according to the technical solutions of the present application is within the scope of the present application.

Claims

1. A voice type current transformer polarity tester comprising a test terminal, a sampling circuit and an amplification comparison circuit, the test terminal is arranged at the input end of the sampling circuit, the output end of the sampling circuit is connected to the amplification comparison circuit, characterized in that, The output end of the amplification comparison circuit is connected with a voice execution circuit, and the output end of the voice execution circuit is connected with a loudspeaker; the sampling circuit is composed of resistors R1 and R2, capacitors C1 and C2, and diodes D1 and D2, wherein the diodes D1 and D2 constitute a positive polarity gating circuit, the pulse voltage Es obtained by the test terminals S1 and S2 is positively gated, and then the capacitors C1 or C2 are charged and filtered, the voltage across the capacitors C1 or C2 is divided by the resistors R1 and R2 and limited to Es / 2, and the voltage is sent to the amplification comparison circuit; the amplification comparison circuit comprises double operational amplifiers U1 and U2, in-phase input resistors R3 and R4, inverse-phase input resistors R5 and R6, voltage dividing resistors R9 and R10, coupling resistors R7 and R8, amplifier gain adjusting potentiometers W1 and W2, voltage threshold adjusting potentiometers W3 and W4, the voltage obtained by the sampling circuit is input to the in-phase input end of the operational amplifier 3 through the input resistors R3 or R4, and then output by the 1st pin after amplification, and then sent to the 5th pin through the coupling resistors R7 or R8 to complete voltage comparison, and when the comparison value is greater than the threshold, the 7th pin outputs a high level; the voice execution circuit comprises transistors BG1 and BG2, base resistors R11 and R12, collector resistors R13 and R14, a VM voice module, and a loudspeaker SP, after the high level output by the amplification comparison circuit triggers the transistors BG1 or BG2 to conduct through the base resistors R11 or R12, the VM voice module trigger end K1 or the VM voice module trigger end K2 changes from a high level to a low level, so as to trigger the voice module to play voice through the loudspeaker SP; the output end of the amplification comparison circuit is also connected with a delay reset circuit for controlling the on-off of the voice execution circuit; the delay reset circuit comprises a time base integrated circuit U3, diodes D3, D4 and D5, resistors R15, RC1 and RC2, and capacitors C3 and C4, wherein the time base integrated circuit U3, the diodes D3, D4 and D5, the resistor R15, and the capacitors C3 and C4 constitute a trigger timer circuit with the time base integrated circuit U3 as the core.

2. A voice type current transformer polarity tester according to claim 1, characterized in that, A relay is further included, and the coil J of the relay is reversely connected in parallel with a diode D5 to prevent the damage of the reverse electromotive force generated at the moment of power failure to the insulation of the coil J and the time base integrated circuit U3.

3. A voice type current transformer polarity tester according to claim 2, characterized in that, The negative pole of diode D3 connected with the trigger end K1 of the VM voice module, the negative pole of diode D4 connected with the trigger end K2 of the VM voice module, the positive poles of diode D3 and diode D4 connected with the low level working circuit of time base integrated circuit U3 in parallel, the purpose is to trigger diode D3 or diode D4 to conduct when any trigger end of the trigger end K1 or trigger end K2 of the VM voice module obtains low level, to meet the low level potential required by the trigger timer circuit working with time base integrated circuit U3 as the core.

4. A voice type current transformer polarity tester according to claim 3, wherein, The trigger end K1 of the VM voice module is connected with the former double operational amplifier U1 through triode BG1, the trigger end K2 of the VM voice module is connected with the former double operational amplifier U2 through triode BG2, the function is to change the high level outputted by double operational amplifier U1 and double operational amplifier U2 into low level required by the voice module through triode BG1 and triode BG2 respectively.

5. A voice type current transformer polarity tester according to claim 4, wherein, The series connection of resistance RC1 and always-on node J1 is connected with the parallel connection of the two ends of capacitor C1, the series connection of resistance RC2 and always-on node J2 is connected with the parallel connection of the two ends of capacitor C2, which respectively constitute the independent discharge circuit of capacitor C1 and capacitor C2.

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