CN201392367Y - Tracking instrument for micro current contact resistance variation trend - Google Patents
Tracking instrument for micro current contact resistance variation trend Download PDFInfo
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- CN201392367Y CN201392367Y CN200920141692U CN200920141692U CN201392367Y CN 201392367 Y CN201392367 Y CN 201392367Y CN 200920141692 U CN200920141692 U CN 200920141692U CN 200920141692 U CN200920141692 U CN 200920141692U CN 201392367 Y CN201392367 Y CN 201392367Y
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Abstract
The utility model provides a tracking instrument for micro current contact resistance variation trend. The tracking instrument adopts an intelligent-type multifunctional digital-analog and analog-digital conversion unit, a voltage following unit, a sampling unit, and a voltage signal magnifying unit of which gears are adjustable, and can autotrack the variation trend of contact resistance along with current increase through data exchange between a computer and a USB interface as well as matched programming software; and the tracking instrument also can automatically measure contact resistance under different current, display the contact resistance through a chart, and save the contact resistance. Compared with the prior art, the utility model can not only measure contact resistance under micro current 10 mA so as to facilitate exact contact point aging condition judgment, but also track the variation trend of contact resistance under current ranging in a large range from 10 mA to 1A so as to be suitable for judging application occasions of different contact points and facilitating switch device lectotype under a specific occasion.
Description
Technical field
The utility model relates to a kind of little electric current measuring contact resistance device, particularly a kind of can be when flowing through contact current and change from the device of motion tracking contact resistance variation tendency.
Background technology
For low-voltage equipments such as relay, instrument control switches, the contact resistance of contact should keep within the acceptable range, and is good to guarantee contact.If the contact occurs aging, its contact resistance can increase, even the loose contact phenomenon occurs.Generally require contact resistance below 10-20mohm, according to the regulation among the GBT 15078, contact resistance should be not more than 0.1 Ω, and measuring current should be less than 100mA.
In fact contact resistance because rete is difficult for puncturing, can present high-impedance state when electric current is less.The thicknesses of layers difference, its electrical conduction mechanism difference, thereby shown film resistance is also inevitable different.(0.5～2nm), general tunnel current is main when rete is thin; And rete is when thicker (about 5nm), and flow of emitted electrons then is main; After thickness＞5nm, the intrinsic resistance of rete increases thereupon, and at this moment the conduction of rete is a semiconductor property, and effect is received in the main snap of its electrical conduction mechanism.
Thicker rete can appear in its surface, aging contact, and it is more obvious that rete resistance shows under little current condition.When electric current was very little, rete was difficult for breakdown, presented high-impedance state this moment; When electric current was big, rete was breakdown, shows the contact resistance of normality.The contact degree of aging is obvious more, and rete is thick more, it is breakdown to be difficult for more, when the running current deficiency so that the phenomenon of poor contact of contacts when breakdown, promptly appears in rete.
Little electric current measuring contact resistance device can be measured the contact resistance of microampere order electric current lower contact, and can dynamically follow the tracks of the variation tendency of contact at little electric current contact resistance to the ampere level current condition.According to variation tendency, can judge that under given electric current, can this contact normally use.
In the prior art, contact resistance is to test under the condition of given voltage or electric current substantially, and what obtain is the contact resistance value of a static state, and Shang Wuke is from the equipment of motion tracking contact resistance with the variation tendency of electric current increase.Original method of testing exists following defective and deficiency:
1, existing instrument is just measured contact resistance under given voltage or current condition, and measurement result can not reflect the gamut variation tendency of contact resistance, is unfavorable for the occasion of judging that the contact is suitable being unfavorable for the switchgear type selecting under the specific occasion.
2, existing apparatus measures contact resistance is by bigger electric current, as the electric current of 100mA, 10A and even 100A, under this condition, rete resistance is easily breakdown, can't describe the characteristic of the contact resistance under little current condition, be unfavorable for judging the ageing state of contact.
The utility model content
In order to overcome the deficiencies in the prior art, the purpose of this utility model provides a kind of little electric current contact resistance variation tendency tracker, it not only can be implemented in and measure contact resistance, the variation tendency that can also follow the tracks of contact resistance with electric current in a big way under the Weak current.
The utility model can be implemented by the following technical programs:
A kind of little electric current contact resistance variation tendency tracker, it comprise the measuring resistance that is in series with tested contact and:
Sampling unit, described sampling unit and described measuring resistance are electrically connected, and are used for the voltage of described standard resistor at two terminals is taken a sample;
Signal amplification unit, described signal amplification unit and described tested contact are electrically connected, and are used for the touch voltage signal at two ends, described tested contact is amplified, and described signal amplification unit has the gear of a plurality of scalable enlargement factors;
Multi-functional D/A, A/D converter, described multi-functional D/A, the input end of A/D converter is electrically connected with the output terminal of described sampling unit and the output terminal of signal amplification unit respectively, the touch voltage conversion of signals that A/D converter wherein is used for the sampling voltage signal of described sampling unit output and the output of described signal amplification unit is a digital signal, by computing machine this digital signal is carried out calculation process and obtain the resistance of contact resistance and the voltage digital signal that output is used for the little electric current of variation in control survey loop, described multi-functional D/A, D/A switch unit in the A/D converter is converted to voltage analog signal with the voltage digital signal of described computing machine output;
The voltage follow unit, the input signal of described voltage follow unit is the voltage analog signal of described multi-functional D/A, A/D converter output, the output voltage signal of described voltage follow unit forms the closed-loop path as the input signal of described sampling unit, and described voltage follow unit is used in the driving force that keeps enhancing output current under its output voltage and the situation that input voltage equates.
Described computing machine adopts PID link control output voltage to measure the controllable micro current in loop with accurate generation.
Described measuring resistance and the tested contact measurement current in loop variation range that forms that is in series is 10 μ A～1A.
Compared with the prior art the utility model has following advantage:
The utility model has been used the voltage signal amplifying unit of intelligent D/A conversion unit, voltage follow unit, sampling unit and scalable gear, exchanges data by USB interface and computing machine also cooperates programming software, has realized the variation tendency that increases with electric current from the motion tracking contact resistance.By two inputs of the feedback voltage signal on sampling unit and the tested contact as D/A conversion unit, measure the controllable micro current in loop by PID link control output voltage with accurate generation after being converted to digital signal, thereby realize measuring the control that increases gradually of loop current.Because the voltage follow unit can be in the driving force that keeps enhancing output current under its output voltage and the situation that input voltage equates, thereby enlarged the scope that electric current changes in the measuring contact resistance loop, made the utility model can realize wide region, high-acruracy survey.
Signal amplification unit is the amplifier with many gear gains, can guarantee the measuring accuracy of touch voltage at relative broad range, can select suitable gear automatically according to the preliminary survey magnitude of voltage.
The utility model combines with PC, can export various electric currents in an orderly manner under software control, can also measure the contact resistance value under the different electric currents simultaneously automatically, shows and preservation by chart.Compared with prior art, it not only can be implemented in the Weak current of 10 μ A and measure contact resistance down, help accurately judging the contact ageing state, can also with electric current 10 μ A～1A in a big way in follow the tracks of contact resistance variation tendency, help judging the applicable situation of different contacts and the switchgear type selecting under the specific occasion.
Description of drawings
Accompanying drawing 1 is a principle schematic of the present utility model;
Accompanying drawing 2 is circuit theory diagrams of the present utility model;
Accompanying drawing 3 is the measurement resistance chart of inefficacy sample resistance;
Accompanying drawing 4 is the measurement resistance chart of non-defective unit resistance;
Wherein:
2, tested contact; 3, sampling unit; 4, signal amplification unit; 5, multi-functional D/A, A/D converter; 6, computing machine; 7, voltage follow unit.
Embodiment
As shown in Figure 1, a kind of little electric current contact resistance variation tendency tracker, it comprise the measuring resistance that is in series with tested contact 2 and:
Signal amplification unit 4, described signal amplification unit 4 is electrically connected with described tested contact 2, is used for the touch voltage signal at 2 two ends, described tested contact is amplified, and described signal amplification unit 4 has the gear of a plurality of scalable enlargement factors; Can guarantee the measuring accuracy of touch voltage, and can select suitable gear automatically according to the preliminary survey magnitude of voltage at relative broad range.
Multi-functional D/A, A/D converter 5, described multi-functional D/A, the input end of A/D converter 5 is electrically connected with the output terminal of described sampling unit 3 and the output terminal of signal amplification unit 4 respectively, the touch voltage conversion of signals that A/D converter wherein is used for the sampling voltage signal of described sampling unit 3 outputs and 4 outputs of described signal amplification unit is a digital signal, carry out calculation process by 6 pairs of these digital signals of computing machine and obtain the resistance of contact resistance and the voltage digital signal that output is used for the little electric current of variation in control survey loop, the resistance of measuring is shown by chart by computing machine 6 and preserves test result, as shown in accompanying drawing 3 and accompanying drawing 4.
D/A switch unit in described multi-functional D/A, the A/D converter 5 is converted to voltage analog signal with the voltage digital signal of described computing machine 6 outputs; This voltage digital signal of computing machine 6 outputs is the output voltage signal of PID link.
Voltage follow unit 7, the input signal of described voltage follow unit 7 is the voltage analog signal of described multi-functional D/A, A/D converter 5 outputs, and the output voltage signal of described voltage follow unit 7 forms the closed-loop path as the input signal of described sampling unit 3.Described voltage follow unit 7 is used in the driving force that keeps enhancing output current under its output voltage and the situation that input voltage equates, thereby enlarged the scope that electric current changes in the measuring contact resistance loop, made the utility model can realize wide region, high-acruracy survey.
The characteristics of closed-loop control system are that the output that influences controller can be instead sent back in the output of system's controlled device, and PID control is meant the error according to system, and proportion of utilization, integration, difference gauge calculate that controlled quentity controlled variable controls.Two inputs of the PID link in described computing machine 6 software programs are respectively the feedback voltage digital signal on sampling unit 3 and the tested contact 2, the voltage signal of output is used for the size of current in control survey loop as the input of voltage follow unit 7 behind D/A switch, thereby realize following the tracks of the trend that contact resistance changes with electric current.
As shown in Figure 2, described measuring resistance R
SWith tested contact R
CThe measurement current in loop variation range that forms that is in series is 10 μ A～1A, and the size of measuring electric current in the loop is by sampling voltage U
SDraw divided by measuring resistance, the resistance of contact resistance is by touch voltage U
CObtain divided by this electric current, it can realize the measurement of contact resistance and the tracking of variation tendency in bigger electric current variation range.
The utility model has been used the voltage signal amplifying unit 4 of intelligent multifunction D/A, A/D converter 5, voltage follow unit 7, sampling unit 3 and scalable gear, exchanges data by USB interface and computing machine 6 also cooperates programming software, realized from the variation tendency of motion tracking contact resistance with the electric current increase, can also measure simultaneously the contact resistance value under the different electric currents automatically, can measure the equivalent resistance that tunnel effect, heat of emission electron stream effect and zener effect form, show and preservation by chart.
Compared with prior art, it not only can be implemented under the Weak current of 10 μ A and measure contact resistance, Be conducive to accurately judge the contact ageing state, can also with electric current 10 μ A～1A in a big way in follow The variation tendency of track contact resistance is conducive to judge that the applicable situation of different contacts reaches opening under the specific occasion Close lectotype selection.
Claims (3)
1, a kind of little electric current contact resistance variation tendency tracker is characterized in that: it comprise the measuring resistance that is in series with tested contact (2) and:
Sampling unit (3), described sampling unit (3) is electrically connected with described measuring resistance, is used for the voltage of described standard resistor at two terminals is taken a sample;
Signal amplification unit (4), described signal amplification unit (4) is electrically connected with described tested contact (2), be used for the touch voltage signal at two ends, described tested contact (2) being amplified the gear that described signal amplification unit (4) has a plurality of scalable enlargement factors;
Multi-functional D/A, A/D converter (5), described multi-functional D/A, the input end of A/D converter (5) is electrically connected with the output terminal of described sampling unit (3) and the output terminal of signal amplification unit (4) respectively, the touch voltage conversion of signals that A/D converter wherein is used for the sampling voltage signal of described sampling unit (3) output and described signal amplification unit (4) output is a digital signal, by computing machine (6) this digital signal is carried out calculation process and obtain the resistance of contact resistance and the voltage digital signal that output is used for the little electric current of variation in control survey loop, described multi-functional D/A, D/A switch unit in the A/D converter (5) is converted to voltage analog signal with the voltage digital signal of described computing machine (6) output;
Voltage follow unit (7), the input signal of described voltage follow unit (7) is the voltage analog signal of described multi-functional D/A, A/D converter (5) output, the output voltage signal of described voltage follow unit (7) forms the closed-loop path as the input signal of described sampling unit (3), and described voltage follow unit (7) is used in the driving force that keeps enhancing output current under its output voltage and the situation that input voltage equates.
2, a kind of little electric current contact resistance variation tendency tracker according to claim 1 is characterized in that: described computing machine (6) adopts PID link control output voltage to measure the controllable micro current in loop with accurate generation.
3, a kind of little electric current contact resistance variation tendency tracker according to claim 1 and 2 is characterized in that: described measuring resistance and tested contact (2) the measurement current in loop variation range that forms that is in series is 10 μ A～1A.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200920141692U CN201392367Y (en) | 2009-02-13 | 2009-02-13 | Tracking instrument for micro current contact resistance variation trend |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200920141692U CN201392367Y (en) | 2009-02-13 | 2009-02-13 | Tracking instrument for micro current contact resistance variation trend |
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| CN201392367Y true CN201392367Y (en) | 2010-01-27 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN200920141692U Expired - Lifetime CN201392367Y (en) | 2009-02-13 | 2009-02-13 | Tracking instrument for micro current contact resistance variation trend |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102818946A (en) * | 2012-06-05 | 2012-12-12 | 苏州热工研究院有限公司 | Method for diagnosing aging state of electric touch spot |
| CN105242104A (en) * | 2015-10-13 | 2016-01-13 | 欣旺达电子股份有限公司 | Current detection method, current detection device, and current detector |
| CN106415295A (en) * | 2014-10-06 | 2017-02-15 | 株式会社Lg 化学 | Switch deterioration detection device and method |
| CN110806532A (en) * | 2019-11-25 | 2020-02-18 | 昆明理工大学 | Pre-amplifier detection system of EH4 |
-
2009
- 2009-02-13 CN CN200920141692U patent/CN201392367Y/en not_active Expired - Lifetime
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102818946A (en) * | 2012-06-05 | 2012-12-12 | 苏州热工研究院有限公司 | Method for diagnosing aging state of electric touch spot |
| CN106415295A (en) * | 2014-10-06 | 2017-02-15 | 株式会社Lg 化学 | Switch deterioration detection device and method |
| CN105242104A (en) * | 2015-10-13 | 2016-01-13 | 欣旺达电子股份有限公司 | Current detection method, current detection device, and current detector |
| CN110806532A (en) * | 2019-11-25 | 2020-02-18 | 昆明理工大学 | Pre-amplifier detection system of EH4 |
| CN110806532B (en) * | 2019-11-25 | 2021-01-08 | 昆明理工大学 | Pre-amplifier detection system of EH4 |
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Legal Events
| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CX01 | Expiry of patent term |
Granted publication date: 20100127 |
|
| CX01 | Expiry of patent term |