CN2175424Y

CN2175424Y - Isolation type high voltage microammeter

Info

Publication number: CN2175424Y
Application number: CN 93234563
Authority: CN
Inventors: 周志耘; 潘新辉
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-08-25
Filing date: 1993-08-25
Publication date: 1994-08-24
Anticipated expiration: 2003-08-25

Abstract

The utility model relates to an isolation type high voltage microammeter, comprising a sampling and transmitting part composed of a sampling and over current protecting element, a linearity integral element, a voltage frequency converting circuit, a reshaping element, an oscillating circuit, a power amplifying element, an outputting and transmitting element, a negative voltage producing element, a voltage-stabilizing circuit, a power supply indicating element, a high frequency filtering element, integration comparing element, a speech sound integrating sheet, a loudspeaker, etc. and a receiving and displaying part composed of an alternating current voltage reducing circuit, a digital and simulating part rectifying and voltage-stabilizing circuit, an infrared receiving demodulating circuit, a frequency overvoltage converting circuit, zeroing and enlarging circuit, a digital displaying circuit, etc. The isolation type high voltage microammeter is used for the direct current voltage withstanding tests of high voltage electric equipment. When the isolation type high voltage microammeter works, the isolation type high voltage microammeter isolates the high voltage from people and carries out speech sound alarm, which avoids the high voltage threat to people.

Description

Isolation type high voltage microammeter

The utility model relates to a kind of isolated high-voltage microampere meter of measuring size of current.

When high voltage electric equipment was carried out DC voltage withstand test, the size of the leakage current that produces when bearing high pressure of testing apparatus was the only resource of judging tested device insulation status quality exactly.And for the influence of getting rid of stray current so that accuracy of reading, the common practice is that common microampere gauge outfit directly is connected on the high-pressure side.But so, microampere high pressure that gauge outfit connects has constituted threat to operation reading personnel's safety, it is impossible particularly to want switching range just to become in the process of boosting, and must step-down and cut off the electricity supply after just can carry out range and switch, therefore bring great trouble to process of the test.

The purpose of this utility model is to carry out the isolated high-voltage microampere meter that DC voltage withstand test provides a kind of handling safety and conveniently saves trouble to high voltage electric equipment.

Referring to Fig. 1 the utility model electricity functional-block diagram, solution of the present utility model is as follows.Its circuit is made up of sampling radiating portion and reception display part, the sampling radiating portion has sampling and current foldback circuit (1), linear integration circuit (2), electric voltage frequency conversion and shaping circuit (3), oscillatory circuit (4) and power amplifier and output radiating circuit (5), the output terminal of preceding four circuit (1 to 4) joins with the input end of adjacent next circuit successively in these five circuit (1 to 5), the negative voltage power supply end of linear integration circuit (2) all links to each other with the negative voltage output terminal of negative voltage generation circuit (6) with reference voltage terminal, the positive voltage source end of conversion of the positive voltage source end of linear integration circuit (2) and electric voltage frequency and shaping circuit (3) all joins with the positive voltage output end of mu balanced circuit (7), the positive voltage output end of mu balanced circuit (7) also is connected to power indicating circuit (8), the sampling radiating portion also has a high-pass filtering and integration comparator circuit (9), its input end links to each other with an output terminal of electric voltage frequency conversion and shaping circuit (3), its output terminal links to each other with the input end of a speech IC (10), and the output terminal of speech IC (10) is connected to loudspeaker SP; Receive the display part and have ac buck circuit (11), its output terminal links to each other with the input end of numerical portion regulator rectifier circuit (12) and the input end of simulation part regulator rectifier circuit (13) respectively, receive the display part and also have infrared receiving demodulation circuit (14), frequency-voltage conversion circuit (15), zeroing amplifying circuit (16) and digital display circuit (17), the output terminal of first three circuit (14 to 16) joins with the input end of adjacent next circuit successively in these four circuit (14 to 17), the voltage output end of numerical portion regulator rectifier circuit (12) links to each other with the power input of infrared receiving demodulation circuit (14) with digital display circuit (17) respectively, and the voltage output end of simulation part regulator rectifier circuit (13) joins with the power input of the frequency-voltage conversion circuit (15) and the amplifying circuit (16) that returns to zero respectively.

The utility model with foregoing circuit structure, because of the sampling radiating portion of circuit is in high-pressure side, for preventing the influence of high pressure to measured value, thus should adopt the can encapsulation, electromagnetic-field-shielded to carry out.Receive the display part and isolate with high pressure, for making support easy, direction is regulated easily, can adopt tripod to support, and is convenient to practical operation.When concrete the use, add the E+ power supply should for circuit (4) to the circuit (16) of sampling radiating portion, can adopt nickel-cadmium battery such as this power supply.Receive the display part and then give ac buck circuit (11) input 220V electric main, will sample then and the input end of current foldback circuit (1) is serially connected in the high-pressure side of carrying out DC voltage withstand test equipment and introduces the high-tension current signal.

During work; the high-tension current signal becomes sampling voltage through sampling and current foldback circuit (1); flow to linear integration circuit (2) then and carry out line integral; voltage behind linear integration is delivered to electric voltage frequency conversion and shaping circuit (3); after μ A/f conversion and shaping; the square-wave signal of output and the symmetry of the corresponding frequency of line integral voltage; again through oscillatory circuit (4); become the sample conversion signal of making carrier frequency with certain frequency; send into power amplifier and output radiating circuit (5), be modulated into infrared beam to spatial emission.Place the infrared receiving demodulation circuit (14) of the low-pressure side of keeping apart, after will carrying out infrared reception and demodulation from transmitting of receiving of space, send frequency-voltage conversion circuit (15) to carry out f/ μ A conversion, be reduced into current signal, amplify through zeroing amplifying circuit (16) zeroing again, send digital display circuit (17) to carry out analog to digital conversion at last, convert numeral to, show the microampere value of tested equipment leakage current through digital watch.In process of the test, high-pass filtering and integration comparator circuit (9) are accepted the square-wave signal of electric voltage frequency conversion and shaping circuit (3), through high-pass filtering, integration and comparison, output signal removes to control speech IC (10), make loudspeaker SP send the chimes of doom that " have electricity dangerous " and so on pre-sets, with reminds people not near high pressure.After test finished, speech IC (10) quit work, and SP stops to report to the police, and can carry out on high-tension side thread-changing, has effectively guaranteed personal safety.The effect of power indicating circuit (8) is, when the E+ supply voltage is higher or lower than setting, makes corresponding indication respectively, takes measures when supply voltage is lower than setting to remind the user, guarantees the normal of sampling radiating portion operating voltage.

The utility model is transferred to the safety area of low-pressure side with the microampere value that the high-pressure side records by opto-electronic conversion, makes operating personnel clearly reading, gearshift, thus effectively with people's isolation, avoided the threat of high pressure to the person.And, can carry out audio alert to the unrelated person that when pressurizeing, enters the explosive area, so safety coefficient improves more owing to the phonetic alarm that is provided with when high-pressure work.

Below in conjunction with drawings and Examples the utility model is further specified.

Fig. 1 is the utility model electricity functional-block diagram;

Fig. 2 is a kind of physical circuit schematic diagram of Fig. 1 sampling radiating portion of the present utility model;

Fig. 3 is a kind of physical circuit schematic diagram of Fig. 1 reception of the present utility model display part.

Referring to Fig. 2, sampling and current foldback circuit (1) are by stabilivolt DW ₁, voltage dependent resistor (VDR) R _VTC, resistance R ₁To R ₄, resistance R _QAnd capacitor C ₁Form, linear integration circuit (2) is by operational amplifier IC ₁, resistance R ₁₂And capacitor C ₂Form, electric voltage frequency conversion and shaping circuit (3) are by electric voltage frequency converter ic IC ₃, Schmidt trigger IC ₄, triode BG ₁, diode B ₁, resistance R ₁₃To R ₁₉, resistance R ₃₄And capacitor C ₇With C ₉Form, oscillatory circuit (4) is by four Sheffer stroke gate IC ₅, resistance R ₂₀With R ₂₁And capacitor C ₉Form, power amplifier and output radiating circuit (5) are by triode BG ₂, high energy infrared-emitting diode D ₅To D ₇And resistance R ₂₂With R ₂₃Form, negative voltage generation circuit (6) is by time-base integrated circuit IC ₂, diode D ₂With D ₃, stabilivolt DW ₂With DW ₃, resistance R ₅To R ₁₁And capacitor C ₃To C ₆Form, mu balanced circuit (7) is by stabilivolt DW ₄, resistance R ₃₀To R ₃₂And capacitor C ₁₀With C ₁₁Form, power indicating circuit (8) is by dual operational amplifier IC ₆, two-color diode D ₄, resistance R ₂₄To R ₂₉And resistance R ₃₃Form, high-pass filtering and integration comparator circuit (9) are by operational amplifier IC ₇With IC ₈, resistance R ₃₅With R ₃₆And capacitor C ₁₂With C ₃₁Form, speech IC (10) is by the voice ic chip ₉Constitute, ac buck circuit (11) is by transformer 8, K switch with two secondary winding ₁And fuse BX composition, numerical portion regulator rectifier circuit (12) is by rectifier bridge D ₁, three end integrated voltage stabilizer IC ₁₀And capacitor C ₁₃To C ₁₆Form, simulation part regulator rectifier circuit (13) is by rectifier bridge Q ₂, three end integrated voltage stabilizer IC ₁₁With IC ₁₂And capacitor C ₁₇To C ₂₄Form, infrared receiving demodulation circuit (14) is made of infrared remote receiver YH, and frequency-voltage conversion circuit (15) is by electric voltage frequency converter ic IC ₁₃, operational amplifier IC ₁₄, resistance R ₃₇To R ₄₃, capacitor C ₂₅To C ₂₇And capacitor C ₃₀Form, zeroing amplifying circuit (16) is by operational amplifier IC ₁₅, stabilivolt DW ₅, potentiometer W ₁With W ₂, resistance R ₄₄To R ₄₇And capacitor C ₂₈With C ₂₉Form, digital display circuit (17) is by digital wash head DVM, single-pole double-throw switch (SPDT) K ₂And resistance R ₄₈With R ₄₉Form.

Referring to Fig. 2.In normal sampling process, by R ₁, R ₂, R _QForm through-flow loop, R _QBe sample resistance, R _VTC, DW ₁, C ₁Be in cut-off state, all electric current is from R _QOn flow through, at R _QThe pressure drop of last generation is sampling voltage.When the input overcurrent, at R ₂On can produce bigger pressure drop, when voltage surpasses 100V, R _VTCBy by becoming conducting, guarantee R ₂, R _QThe voltage of last generation no longer raises, simultaneously at R _QIf last pressure drop is during greater than 6V, DW ₁Puncture, make input voltage be lower than 6V.When signal is zero, inverting integrator IC ₁6 pin produce a fundamental frequency, improve gradually with reduction (sampling voltage the is a negative value) output frequency of sampling voltage, in full width of cloth input-500mV scope, constitute line integral and export.IC ₃The 2nd pin is a bandgap voltage reference, is used for controlling the size of output frequency, uses BG ₁Do temperature compensation, be used for stabilized frequency, IC ₃The 6th, 7 pin constitute comparer, trigger timing circuit, IC ₃The 3rd pin be output pin, export the frequency signal corresponding with input voltage, this signal is asymmetric square wave, through IC ₄After the shaping, its 14 pin is output as the square wave of symmetry, is convenient to the vibration emission.Work as IC ₄Signal is sent into IC ₅Behind the 6th pin, just export the unscented transformation signal of making carrier frequency with 40KHZ, send into the BG of power amplifier level at the 10th, 11 pin ₂Amplify, make collector current be about 100mA, through D ₅To D ₇Signal is exported.Regulate easily for reliability and direction that assurance connects, three infrared transmitting tubes are formed director spheres, increased emission space.IC ₂Form no steady oscillatory circuit, by the coupling of the 3rd foot meridian capacitor, the output negative voltage is for IC ₁The 4th pin, again with negative voltage through DW ₃Voltage stabilizing provides IC ₁The input reference voltage of the 2nd pin.When E+ is higher than 6V, D ₄Give a green light, when E+ is lower than 6V, D then ₄Send out a warning, pilot cell voltage is not enough, needs battery charge.IC ₇Constitute Hi-pass filter, eliminate the frequency that is lower than 200HZ, pass through IC again ₈The integration comparer that constitutes removes to control music integrated block IC ₉

Referring to Fig. 3, transformer B adopts two two secondary winding of 12V, single 9V, will simulate part and numerical portion isolated from power, to reduce interference.Numerical portion power supply output+5V voltage, simulation part independent power source output+8V voltage.Infrared remote receiver YW can adopt commercially available CX20106.IC ₁₃The signal that the 6th pin reception YH sends here carries out the f-V conversion, by IC ₁₃IC is sent in output of the 1st pin and the corresponding electric current of frequency ₈, IC ₈Export the voltage corresponding, finish the f-V conversion with electric current.DW ₅The 2.5V reference voltage that produces passes through V ₁After the dividing potential drop, the bias voltage of radiating portion neutral line amplifying circuit setting and offset voltage etc. are compensated, when making sampling voltage be omv, be output as omv.IC ₉Voltage after the f-V conversion and zeroing voltage are carried out anti-phase summation amplification, make the measurement electric current press corresponding with output.DVN is commercially available, and it constitutes with 3 1/2 A/D sheets 7107, and 4 LED show, make clear reading.Divide 200mV and 2000mV shelves to measure input voltage, promptly, input voltage is directly shown, when input voltage during, by by R greater than 200mV when input voltage during less than 200mV ₄₈And R ₄₉The voltage divider input of forming.

If with sampling resistor R of the present utility model _QResistance reduce and change standard shunt (100A/75mV, 300A/75mV etc. are arranged) into, then the utility model can be transferred to and isolate transmission kilo-ampere table usefulness, to be used for measuring the exciting current of generator, make the loop produce the measuring error that pressure drop caused thereby reduce to use long line transmission because of classic method.

Claims

1, a kind of isolated high-voltage microampere meter is characterized in that, circuit is made up of sampling radiating portion and reception display part:

A) the sampling radiating portion has sampling and current foldback circuit (1); linear integration circuit (2); electric voltage frequency conversion and shaping circuit (3); oscillatory circuit (4) and power amplifier and output radiating circuit (5); the output terminal of preceding four circuit (1 to 4) joins with the input end of adjacent next circuit successively in these five circuit (1 to 5); the negative voltage power supply end of linear integration circuit (2) all links to each other with the negative voltage output terminal of negative voltage generation circuit (6) with reference voltage terminal; the positive voltage source end of conversion of the positive voltage source end of linear integration circuit (2) and electric voltage frequency and shaping circuit (3) all joins with the positive voltage output end of mu balanced circuit (7); the positive voltage output end of mu balanced circuit (7) also is connected to power indicating circuit (8); the sampling radiating portion also has a high-pass filtering and integration comparator circuit (9); its input end links to each other with an output terminal of electric voltage frequency conversion and shaping circuit (3); its output terminal links to each other with the input end of a speech IC (10); the output terminal of speech IC (10) is connected to loudspeaker SP

B) receive the display part and have ac buck circuit (11), its output terminal links to each other with the input end of numerical portion regulator rectifier circuit (12) and the input end of simulation part regulator rectifier circuit (13) respectively, receive the display part and also have infrared receiving demodulation circuit (14), frequency-voltage conversion circuit (15), zeroing amplifying circuit (16) and digital display circuit (17), the output terminal of first three circuit (14 to 16) joins with the input end of adjacent next circuit successively in these four circuit (14 to 17), the voltage output end of numerical portion regulator rectifier circuit (12) links to each other with the power input of infrared receiving demodulation circuit (14) with digital display circuit (17) respectively, and the voltage output end of simulation part regulator rectifier circuit (13) joins with the power input of the frequency-voltage conversion circuit (15) and the amplifying circuit (16) that returns to zero respectively.

2, isolated high-voltage microampere meter as claimed in claim 1 is characterized in that, sampling and current foldback circuit (1) are by stabilivolt DW ₁, voltage dependent resistor (VDR) R _VTC, resistance R ₁To R ₄, resistance R _QAnd capacitor C ₁Form, linear integration circuit (2) is by operational amplifier IC ₁, resistance R ₁₂And capacitor C ₂Form, electric voltage frequency conversion and shaping circuit (3) are by electric voltage frequency converter ic IC ₃, Schmidt trigger IC ₄, triode BG ₁, diode B ₁, resistance R ₁₃To R ₁₉, resistance R ₃₄And capacitor C ₇With C ₈Form, oscillatory circuit (4) is by four Sheffer stroke gate IC ₅, resistance R ₂₀With R ₂₁And capacitor C ₉Form, power amplifier and output radiating circuit (5) are by triode BG ₂, high energy infrared-emitting diode D ₅To D ₇And resistance R ₂₂With R ₂₃Form, negative voltage generation circuit (6) is by time-base integrated circuit IC ₂, diode D ₂With D ₃, stabilivolt DW ₂With DW ₃, resistance R ₅To R ₁₁And capacitor C ₃To C ₆Form, mu balanced circuit (7) is by stabilivolt DW ₄, resistance R ₃₀To R ₃₂And capacitor C ₁₀With C ₁₁Form, power indicating circuit (8) is by dual operational amplifier IC ₆, two-color diode D ₄, resistance R ₂₄To R ₂₉And resistance R ₃₃Form, high-pass filtering and integration comparator circuit (9) are by operational amplifier IC ₇With IC ₈, resistance R ₃₅With R ₃₆And capacitor C ₁₂With C ₃₁Form, speech IC (10) is by the voice ic chip ₉Constitute.

3, as claim 1,2 described isolated high-voltage microampere meters, it is characterized in that ac buck circuit (11) is by transformer B, K switch with two secondary winding ₁And fuse BX composition, numerical portion regulator rectifier circuit (12) is by rectifier bridge D ₁, three end integrated voltage stabilizer IC ₁₀And capacitor C ₁₃To C ₁₆Form, simulation part regulator rectifier circuit (13) is by rectifier bridge D ₂, three end integrated voltage stabilizer IC ₁₁With IC ₁₂And capacitor C ₁₇To C ₂₄Form, infrared receiving demodulation circuit (14) is made of infrared remote receiver YH, and frequency-voltage conversion circuit (15) is by electric voltage frequency converter ic IC ₁₃, operational amplifier IC ₁₄, resistance R ₃₇To R ₄₃, capacitor C ₂₅To C ₂₇And capacitor C ₃₀Form, zeroing amplifying circuit (16) is by operational amplifier IC ₁₅, stabilivolt DW ₅, potentiometer W ₁With W ₂, resistance R ₄₄To R ₄₇And capacitor C ₂₈With C ₂₉Form, digital display circuit (17) is by digital wash head DVM, single-pole double-throw switch (SPDT) K ₂And resistance R ₄₈With R ₄₉Form.