CN101246206A

CN101246206A - Bleeder current measurer checking device

Info

Publication number: CN101246206A
Application number: CNA2008100151557A
Authority: CN
Inventors: 谭国强
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-03-13
Filing date: 2008-03-13
Publication date: 2008-08-20

Abstract

The invention discloses a leak current measure instrument check device, including check device with source and check device without source, the check device with source includes signal source providing standard check current or voltage signal; the check device without source includes load resistance box, the load resistance box includes the load resistance connected with wave band switch, the load resistance is connected in series with standard ammeter; the invention can measure existing every leak current measure instrument, can make the leak current measure instrument measure result accurate, stable, and is convenient for extended application in a large scale.

Description

Bleeder current measurer checking device

Technical field

The present invention relates to a kind of electronics calibration equipment, relate in particular to a kind of electronic installation that is used for the verification bleeder current measurer.

Background technology

Because the design concept difference of at present common bleeder current measurer, its method of calibration are also different, mainly are divided into following two kinds:

First kind: bleeder current measurer only has measurement function, and the no-output function.Used multifunctional signal source (or common current source) to detect for such bleeder current measurer, because such signal source function is more, range is bigger, so stability is lower aspect little electric current in the past.Simultaneously, can't satisfy the detection requirement of most of bleeder current measurer, thereby cause phenomenons such as the complete and error of sensing range is bigger, influence accuracy in detection because such signal source common design power is less.

Second kind: bleeder current measurer is measured tested product leakage current by output voltage.Can use megger and digital watch to detect for such bleeder current measurer.During detection, because the power bracket of different meggers is all different with range ability, misoperation is easy to damage megger and digital watch.Megohm box and digital watch all are the standard metrology appliances of measurement unit or metrological service, effect is big, precision is high, price is expensive, in case damage inconvenience and the bigger economic loss that to bring work, and because megger and digital watch range is different, the instrument range is idle in the time of certainly will causing detection, thereby causes personnel's muscle power and the waste of instrument resource or the deficiency of detectability.

Summary of the invention

Technical matters to be solved by this invention provides a kind of accuracy height, stable performance, be convenient to operate, bleeder current measurer checking device easy to carry.

For solving the problems of the technologies described above, technical scheme of the present invention is: bleeder current measurer checking device, comprise active calibration equipment and passive calibration equipment, and described active calibration equipment comprises the signal source that standard verification curtage signal is provided;

Described passive calibration equipment comprises the pull-up resistor case, and described pull-up resistor case is the pull-up resistor that is connected by waver, and described pull-up resistor is in series with standard amperemeters.

As a kind of improvement, described signal source comprises the oscillating unit that oscillator signal is provided, described oscillating unit output terminal is electrically connected the amplifying unit input end, the output terminal of described amplifying unit is electrically connected by verification bleeder current measurer and range unit, described range unit output terminal is electrically connected the AC/DC converting unit, described AC/DC converting unit is electrically connected the A/D converting unit, and described A/D converting unit is electrically connected display unit.

As further improvement, also be electrically connected with the overload protection unit between described oscillating unit and the described amplifying unit.

Owing to adopted technique scheme, bleeder current measurer checking device comprises active calibration equipment and passive calibration equipment, and described active calibration equipment comprises the signal source that standard verification curtage signal is provided; Described passive calibration equipment comprises the pull-up resistor case, and described pull-up resistor case is the pull-up resistor that is connected by waver, and described pull-up resistor is in series with standard amperemeters; The invention has the beneficial effects as follows: can detect existing various bleeder current measurers, the detection that can make bleeder current measurer accurately, stable, convenient, fill up the blank that China's bleeder current measurer detects.Metrology and measurement departments at different levels and other applying units cut payroll to improve efficiency has positive effect, and the raising of China's metrology and measurement level is had certain impetus.

Description of drawings

Fig. 1 is the structured flowchart of the active calibration equipment of the embodiment of the invention;

Fig. 2 is the circuit theory diagrams of the active calibration equipment oscillating unit of the embodiment of the invention;

Fig. 3 is the circuit theory diagrams of active calibration equipment power supply unit of the embodiment of the invention and overload protection unit;

Fig. 4 is the circuit theory diagrams of the active calibration equipment AC/DC of embodiment of the invention converting unit;

Fig. 5 is the circuit theory diagrams of the active calibration equipment A/D of embodiment of the invention converting unit;

Fig. 6 is the circuit theory diagrams of the active calibration equipment display unit of the embodiment of the invention;

Fig. 7 is the circuit theory diagrams of the active calibration equipment of the embodiment of the invention;

Fig. 8 is the structured flowchart of the passive calibration equipment of the embodiment of the invention.

Embodiment

Be illustrated in figure 1 as the structured flowchart of the active bleeder current measurer checking device of the embodiment of the invention, described active calibration equipment comprises the signal source that standard verification curtage signal is provided; Described signal source comprises provides the oscillating unit AP1 that the power supply unit of working power AP3 is electrically connected provides oscillator signal, described oscillating unit AP1 output terminal is electrically connected amplifying unit AP4 input end, the output terminal of described amplifying unit AP4 is electrically connected by verification bleeder current measurer A and range unit AP 6, described range unit AP 6 output terminals are electrically connected AC/DC converting unit AP5, described AC/DC converting unit AP5 is electrically connected A/D converting unit AP2, and described A/D converting unit AP2 is electrically connected display unit AP7.

Also be electrically connected with overload protection unit AP 8 between described oscillating unit AP1 and the described amplifying unit AP4.

Be illustrated in figure 2 as the circuit theory diagrams of the active calibration equipment oscillating unit of the embodiment of the invention, described oscillating unit AP1 is mainly by two Analogous Integrated Electronic Circuits N21, N22, and digital integrated circuit T063,2 field effect transistor 3DJ6F and 3 elements such as triode composition venturi bridge oscillator circuits, select different arm resistances with frequency selective switch, form frequency selection network in conjunction with capacitor C 21, C22, produce the oscillation frequency of 50Hz/60Hz/400Hz, also can adopt crystal oscillation and digital oscillatory circuit.The in-phase input end 2 that feeds back to it by the first Analogous Integrated Electronic Circuits 1/2N211 output terminal 12 forms positive feedback, and to produce frequency be the oscillating voltage of 50Hz/60Hz/400Hz, stablizing of oscillating voltage amplitude by the first Analogous Integrated Electronic Circuits 1/2N212 and field effect transistor VT21, diode VD21, VD22 finishes, regulate the feedback quantity that trimmer potentiometer RP21 changes it, make the waveform that obtains the distortion minimum; Stabilivolt VD23 provides a stable negative reference voltage, be added to first Analogous Integrated Electronic Circuits, 1/2 N212 inverting input 7 as start bias, when oscillating voltage is zero, positive voltage of 10 ends output of first Analogous Integrated Electronic Circuits, 1/2 N212, make conducting resistance minimum between VT1DS, reduced feedback quantity like this and helped starting of oscillation.Diode VD21, VD22 is in addition rectification and be added to the

input end

6,7 of first Analogous Integrated Electronic Circuits, 1/2 N212 respectively of oscillating voltage, enhancing along with oscillation amplitude, the positive voltage of the 10 ends output of first Analogous Integrated Electronic Circuits, 1/2 N212 descends gradually, the conducting resistance of VT21 also increases gradually, promptly increase feedback quantity, oscillation amplitude is descended, obtained the oscillating voltage of a stabilized amplitude; The second Analogous Integrated Electronic Circuits N22 forms buffer amplifier 1/2 N221 and output amplifier 1/2 N222, and its gain is regulated with RP22, serves as no node on-off switch to reduce the back load to the VT22 that influences of oscillator, controls the output of oscillating voltage; Integrated circuit D1, triode VT23, VT24, VT25, diode VD24, VD25, VD26, VD27, photocoupler VT26 forms an on-off control circuit, finish the operation that output detects power supply, integrated circuit D1 forms a bistable circuit, and its 5V power supply has triode VD24 to provide, and its input signal has manual make-break operation; The break signal input, the input of overload signal is owing to the reason of capacitor C 211, integrated circuit D1 is high level output at ordinary times, so diode VD26 ends, diode VD25 conducting, triode VT25 conducting simultaneously, because the dividing potential drop effect of resistance R 221, R219, the negative voltage of a 7.5V of triode VT23 output is closed triode VT22, makes not output of oscillating voltage, triode VT24 is ended, and " leading to " pilot lamp does not show; When pressing " leading to " button, make low-voltage of integrated circuit D1 upset output, at this moment diode VD26 conducting, triode VT25 base stage is a low level, so triode VT25 ends, at this moment because the dividing potential drop effect of resistance R 221, R219, R217, the current potential of a 7.5V of triode VT23 output, be added to triode VT22, make it open oscillating voltage output, make triode VT24 conducting simultaneously, logical pilot lamp is bright, expression has the output of the power supply of detection, thereby reaches the purpose of break-make control oscillating voltage output.

Be illustrated in figure 3 as the circuit theory diagrams of active calibration equipment power supply unit of the embodiment of the invention and overload protection unit, power supply unit AP3 is by rectifier bridge U1, electric capacity and integrated package of pressure-stabilizing N31, N32 composition ± 15V power supply; Rectifier bridge U2, electric capacity and integrated package of pressure-stabilizing N33, N34 composition ± 5V power supply; Commutation diode VD31 formation+6V power supply; Overload protection unit AP 8 circuit are by Analogous Integrated Electronic Circuits N35; five transistors are formed; N35 constitutes overvoltage protection amplifier 1/2 N351 and overcurrent protection amplifier 1/2 N352, and triode VT31, VT32 constitute Schmidt circuit, as the overload signal generator.Usually triode VT31 ends, triode VT32 conducting, and output low level, triode VT33 is a phase inverter, the output high level, at this moment diode VD35 ends, diode VD36 conducting, triode VT34 conducting, triode VT35 ends, and the super pilot lamp that cuts does not show, the expression operate as normal; To measure electric current excessive for too high or output when the output measuring voltage, by sample circuit sampling output amplifier, after amplifying, send into Schmidt circuit, make the Schmidt circuit upset, then output surpasses a section signal high level, through triode VT33 paraphase is low level, sends a super signal negative pulse of cutting and gives oscillator, closes oscillator output automatically, diode VD35 conducting simultaneously, VD36 ends, triode VT35 conducting, and the overload pilot lamp is bright.Because oscillator output is closed, the overload disappearance, the overload pilot lamp also extinguishes immediately, and overload is described, must reduce the unreasonable load of output or eliminating output terminal, restarts to get final product operate as normal.

Be illustrated in figure 4 as the circuit theory diagrams of the active calibration equipment AC/DC of embodiment of the invention converting unit AP5, the AC/DC converting unit by field effect to pipe VT41, differential pair tube VT42, operational amplifier N41 and diode VD45, VD46 form.Field effect is a preamplifier state to pipe VT41, differential pair tube VT42 is a constant current source, obtain the input stage of a high impedance high stable, operational amplifier N41 is main amplifier stage, and direct current is a closed loop, exchanges to be open loop, because operational amplifier N41 has very big enlargement factor, make commutation diode be operated in linear zone, guarantee the linear transformation precision, conversion coefficient is 1: 1.

Be illustrated in figure 5 as the circuit theory diagrams of the active calibration equipment A/D of embodiment of the invention converting unit, A/D converting unit AP2 has large scale integrated circuit 7135, phase inverter CC4069 and take advantage of 2 circuit to form.Large scale integrated circuit 7135 is double integrator self-correcting zero an A/D change-over circuit, and changing voltage is 0 ~ 1.9999 volt, and conversion accuracy is ± 0.025% ± 2 words, after taking advantage of 2 circuit, is 0 ~ 3.9998 volt with Range Extension, and it forms digital voltmeter with display unit.The A/D conversion accuracy is just examined by proofreading and correct resistor, and 7135 each measuring period of large scale integrated circuit are 40002 clock period, divide three phases to carry out; A, school zeroth order section T0 took for 10001 clock period; B, signal integration stage T1 take 10000 clock period; C, reference source integration phase T2 take 20001 clock period.There is a return-to-zero stage T3 to take 100 ~ 200 clock period after measurement finishes, is extended down to 6200 clock period during as if outrange.

Be illustrated in figure 6 as the circuit theory diagrams of the active calibration equipment display unit of the embodiment of the invention, display unit AP7 display unit is by decoder driver 74LS247, and the elements such as code translator that luminous digital pipe and diode are formed are formed.Diode matrix shows that for the conversion character radix point is provided with, and five triodes are the gating switch of position signal; Open the demonstration of every nixie tube, 74LS247 is seven sections decoder drivers; The binary-coded decimal that the analog-to-digital conversion unit is transported is translated into seven piece of digital pipe signals, and promotes corresponding stroke demonstration.

Be illustrated in figure 7 as the circuit theory diagrams of the embodiment of the invention, also show the partial circuit schematic diagram in the active bleeder current measurer checking device range unit AP 6, current sampling is formed current sampling resistor by R715, R716, R717, R718, R719, R720, R721, R722, constitute by accurate wire-wound resistor, full accuracy is 0.01%, voltage sampling is by resistance in series R723, R724, R727, R728, R729, R725, the sampling of R726 dividing potential drop, and its fundamental quantity threshold currents is 0.8mA.

Its principle of work of active bleeder current measurer checking device is as described below:

Active bleeder current measurer checking device is for only being used for the bleeder current measurer that verification has measurement function, signal source produces that standard signal is transported to the range unit simultaneously by oscillating unit and amplifying unit and by in the bleeder current measurer of verification, standard signal through overrange unit sampling after the AC/DC converting unit is transformed into direct current signal with AC signal is transported to the A/D converting unit and converts simulation value to digital value by the A/D converting unit and directly shown by display unit, the standard figures that display unit is shown with compared by the shown actual numerical value of the bleeder current measurer of verification, resulting difference is exactly by the error of indication of the bleeder current measurer of verification.

Be illustrated in figure 8 as the structured flowchart of the passive calibration equipment of the embodiment of the invention, described passive calibration equipment comprises pull-up resistor case B, described pull-up resistor case B is the pull-up resistor D that is connected by toggle switch C, described pull-up resistor D directly is electrically connected standard amperemeters E, and described pull-up resistor case B input end is electrically connected tested bleeder current measurer A; Passive calibration equipment generally is used for the bleeder current measurer that verification has the leakage current of output, the concrete course of work is: directly be added on 220V (or 380V) voltage of tested bleeder current measurer output on the load box, regulating load case resistance, make the demonstration of reometer on the load box identical with the output gear value of tested bleeder current measurer, the shown electric current indicating value of electric current indicating value that tested bleeder current measurer is shown and standard amperemeters is compared, and the difference that obtains is exactly by the error of indication of verification bleeder current measurer.

The present invention as a kind of accuracy height, stable performance, be convenient to operate, the specialized equipment that is applicable to that various bleeder current measurers detect easy to carry, the invention of bleeder current measurer checking device, can detect existing various bleeder current measurers, the detection that can make bleeder current measurer accurately, stable, convenient, fill up the blank that China's bleeder current measurer detects, metrology and measurement departments at different levels and other applying units cut payroll to improve efficiency has positive effect, for the raising of China's metrology and measurement level has certain impetus.

Claims

1. bleeder current measurer checking device, it is characterized in that: comprise active calibration equipment and passive calibration equipment, described active calibration equipment comprises the signal source that standard verification curtage signal is provided;

2. bleeder current measurer checking device as claimed in claim 1, it is characterized in that: described signal source comprises the oscillating unit that oscillator signal is provided, described oscillating unit output terminal is electrically connected the amplifying unit input end, the output terminal of described amplifying unit is electrically connected by verification bleeder current measurer and range unit, described range unit output terminal is electrically connected the AC/DC converting unit, described AC/DC converting unit is electrically connected the A/D converting unit, and described A/D converting unit is electrically connected display unit.

3. bleeder current measurer checking device as claimed in claim 2 is characterized in that: also be electrically connected with the overload protection unit between described oscillating unit and the described amplifying unit.