CN204575747U - Equipment ground impedance self-checking circuit - Google Patents
Equipment ground impedance self-checking circuit Download PDFInfo
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- CN204575747U CN204575747U CN201520196818.5U CN201520196818U CN204575747U CN 204575747 U CN204575747 U CN 204575747U CN 201520196818 U CN201520196818 U CN 201520196818U CN 204575747 U CN204575747 U CN 204575747U
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Abstract
The utility model discloses equipment ground impedance self-checking circuit, comprise power positive end, power supply negative terminal, electrical network zero line side, device housings link, first resistance, second resistance, 3rd resistance and operational amplifier, one end of first resistance connects electrical network zero line side, the other end of the first resistance connects power positive end, one end connection device shell link of the second resistance, the other end of the second resistance connects power supply negative terminal, 3rd resistance is connected between device housings link and the in-phase input end of operational amplifier, power positive end and voltage negative terminal are also for providing power supply for operational amplifier.The earth impedance of the utility model energy automatic checkout equipment shell, avoids equipment personnel to be caused to the Danger Electric shock risk caused because of electric leakage.
Description
Technical field
The utility model relates to self-checking circuit, is specifically related to equipment ground impedance self-checking circuit.
Background technology
Relating in the nonisulated shell electric equipment that human body may touch, often have grounding requirement to shell, in the use procedure of equipment, the effective earthing of casing, can avoid equipment personnel to be caused to the Danger Electric shock risk caused because of electric leakage.At present, determine that whether the mode of device housings ground connection is generally manual detection, still there is Danger Electric shock risk, and whether impedance ground meets the demands and also have no way of learning.
Utility model content
Technical problem to be solved in the utility model, is just to provide equipment ground impedance self-checking circuit, the earth impedance of automatic checkout equipment shell, avoids equipment personnel to be caused to the Danger Electric shock risk caused because of electric leakage.
For solving the problems of the technologies described above, the technical scheme that the utility model is taked is as follows:
Equipment ground impedance self-checking circuit, comprise power positive end, power supply negative terminal, electrical network zero line side, device housings link, the first resistance, the second resistance, the 3rd resistance and operational amplifier, one end of first resistance connects electrical network zero line side, the other end of the first resistance connects power positive end, one end connection device shell link of the second resistance, the other end of the second resistance connects power supply negative terminal, 3rd resistance is connected between device housings link and the in-phase input end of operational amplifier, and power positive end and voltage negative terminal are also for providing power supply for operational amplifier.
Further, described power positive end provides+15V power supply, and described power supply negative terminal provides-15V power supply.
The utility model is compared to the beneficial effect of prior art:
The utility model is made up of three resistance and an operational amplifier, automatically the resistance value between device housings and the earth can be detected, exactly, judge that whether equipment ground is good, if resistance value has exceeded the value of setting, the external control system of output by operational amplifier sends warning, and other function of closing device is until the effective earthing of casing detected, guarantee equipment comes into operation when the earthing of casing is good, avoids equipment personnel to be caused to the Danger Electric shock risk caused because of electric leakage.And the utility model three resistance and an operational amplifier composition, structure is simple, and reliable in function is with low cost, has very high practical value.
Accompanying drawing explanation
The connection diagram of Fig. 1 the utility model equipment ground impedance self-checking circuit.
Embodiment
Equipment ground impedance self-checking circuit as shown in Figure 1, comprise power positive end, power supply negative terminal, electrical network zero line side P1, device housings link P2, first resistance R1, second resistance R2, 3rd resistance R3 and operational amplifier U1A, one end of first resistance R1 connects electrical network zero line side P1, the other end of the first resistance R1 connects power positive end, one end connection device shell link P2 of the second resistance R2, the other end of the second resistance R2 connects power supply negative terminal, 3rd resistance R3 is connected between the in-phase input end of device housings link P2 and operational amplifier U1A, power positive end and voltage negative terminal are also for providing power supply for operational amplifier U1A.Wherein, power positive end provides+15V power supply, and power supply negative terminal provides-15V power supply, to provide a safe voltage, and just supplies as the power supply of operational amplifier U1A.
Due in electric power system, the zero line of electrical network is at generating set end and each power distribution room all reliable ground, and therefore, circuit of the present invention, by the impedance between checkout equipment shell and electrical network zero line, obtains the impedance ground value of device housings.In this example, the first resistance R1, the second resistance R2, the 3rd resistance R3 are comparatively large by value, to meet the resistance requirements between control system and the earth proposed in some specific occasion.By by the resistance value of device housings with the earth, convert voltage V0 to, be supplied to control system and carry out AD conversion or carry out voltage compare, carry out judgment device shell whether reliable ground.Relation between the impedance ground of device housings and output voltage, can calculate with the following methods:
Suppose that the impedance ground of device housings is Rgnd, then
30/(R1+Rgnd+R2)＝V0-(-15))/R2
Calculate:
Rgnd＝(30·R2)/(V0+15)-R1-R2
Above-described embodiment is only preferred embodiment of the present utility model, is not used for limiting practical range of the present utility model; I.e. all changes of doing according to the utility model content and modification, all by the utility model claim scope required for protection is contained.
Claims (2)
1. equipment ground impedance self-checking circuit, it is characterized in that: comprise power positive end, power supply negative terminal, electrical network zero line side, device housings link, first resistance, second resistance, 3rd resistance and operational amplifier, one end of first resistance connects electrical network zero line side, the other end of the first resistance connects power positive end, one end connection device shell link of the second resistance, the other end of the second resistance connects power supply negative terminal, 3rd resistance is connected between device housings link and the in-phase input end of operational amplifier, power positive end and voltage negative terminal are also for providing power supply for operational amplifier.
2. equipment ground impedance self-checking circuit according to claim 1, it is characterized in that: described power positive end provides+15V power supply, described power supply negative terminal provides-15V power supply.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520196818.5U CN204575747U (en) | 2015-04-02 | 2015-04-02 | Equipment ground impedance self-checking circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520196818.5U CN204575747U (en) | 2015-04-02 | 2015-04-02 | Equipment ground impedance self-checking circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN204575747U true CN204575747U (en) | 2015-08-19 |
Family
ID=53868366
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201520196818.5U Active CN204575747U (en) | 2015-04-02 | 2015-04-02 | Equipment ground impedance self-checking circuit |
Country Status (1)
| Country | Link |
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| CN (1) | CN204575747U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105301364A (en) * | 2015-11-12 | 2016-02-03 | 天津市百利电气有限公司 | Power supply plant grounding resistance measuring device and control method |
| CN106885947A (en) * | 2017-03-06 | 2017-06-23 | 营口康辉石化有限公司 | A kind of resistance meter |
-
2015
- 2015-04-02 CN CN201520196818.5U patent/CN204575747U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105301364A (en) * | 2015-11-12 | 2016-02-03 | 天津市百利电气有限公司 | Power supply plant grounding resistance measuring device and control method |
| CN106885947A (en) * | 2017-03-06 | 2017-06-23 | 营口康辉石化有限公司 | A kind of resistance meter |
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Legal Events
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |