CN204089152U - A kind of Zener type intrinsic safety electric source overload protecting circuit - Google Patents
A kind of Zener type intrinsic safety electric source overload protecting circuit Download PDFInfo
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- CN204089152U CN204089152U CN201420630759.3U CN201420630759U CN204089152U CN 204089152 U CN204089152 U CN 204089152U CN 201420630759 U CN201420630759 U CN 201420630759U CN 204089152 U CN204089152 U CN 204089152U
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- 230000000087 stabilizing effect Effects 0.000 claims abstract description 31
- 229910052571 earthenware Inorganic materials 0.000 claims description 3
- 230000004888 barrier function Effects 0.000 abstract description 9
- 231100001261 hazardous Toxicity 0.000 abstract description 8
- 238000012423 maintenance Methods 0.000 abstract description 6
- 230000007423 decrease Effects 0.000 abstract description 5
- 238000005303 weighing Methods 0.000 abstract description 2
- 230000009471 action Effects 0.000 description 4
- 230000000694 effects Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
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Abstract
The utility model discloses a kind of Zener type intrinsic safety electric source overload protecting circuit, it relates to the hazardous area power circuit design field of essential safe type weighing instrument.1 pin of first interface connects the first resistance successively, second fuse is to 2 pin of transformer primary side, 3 pin of transformer secondary connect 2 pin of resettable fuse to rectifier, 1 pin of rectifier, 4 pin connect 1 pin of three-terminal voltage-stabilizing chip respectively, 2 pin, 3 pin of three-terminal voltage-stabilizing chip connect the first fuse, 1 pin of the 3rd resistance to the second interface, 3 pin of the second interface connect 2 pin of three-terminal voltage-stabilizing chip, node between first fuse and the 3rd resistance and go back between 3 pin of the second interface and be connected to the series circuit of the first voltage stabilizing didoe and the second voltage stabilizing didoe, the series circuit of the 3rd voltage stabilizing didoe and the 4th voltage stabilizing didoe.The utility model avoids the fuse in zena's safety barrier circuit to damage, and decreases on-the-spot maintenance, improves the reliability of essential safety source.
Description
Technical field
The utility model relates to the hazardous area power circuit design field of essential safe type weighing instrument, be specifically related to a kind of Zener type intrinsic safety electric source overload protecting circuit.
Background technology
Guard grating is also known as safety holder, the safe interface in intrinsic safety loop, it can between place of safety (essential safety) and hazardous area (non-intrinsically safe safety) the bi-directional signal of telecommunication, and the place of safety caused because of fault can be limited pass on to the energy in hazardous area, Zener type guard grating is a kind of common guard grating structure, Zener type safety barrier circuit adopts fast acting fuse, current-limiting resistance or pressure limiting diode are to limit the electric flux of input, thus ensure the energy outputting to hazardous area, because its principle is simple, circuit easily realizes and is cheaply subject to extensive use, but the defect due to self principle makes its reliability in the application be greatly affected, and limit its range of application.
Zener type guard grating is larger on power supply impact, also the easy damage causing Zener type guard grating because of the fluctuation of power supply simultaneously, there is overload problem in traditional Zener type isolated gate circuit, the long fuse easily burning zena's safety barrier of overload time, in addition because essential safety source needs user from row wiring in installing and using, therefore be easy to cause the output short circuit of essential safety source to cause fuse F1 open circuit in installation wiring process, and this fuse device price is general higher, the fuse changing same specification model is not easily purchased, and due to embedding cause safeguard inconvenience, frequent replacing makes later maintenance cost very high.
In order to solve the problem, design a kind of novel Zener type intrinsic safety electric source overload protecting circuit still very with necessity.
Utility model content
For the deficiency that prior art exists, the utility model object is to provide a kind of Zener type intrinsic safety electric source overload protecting circuit, and structure is simple; reasonable in design; avoid the fuse in zena's safety barrier circuit to damage, decrease on-the-spot maintenance, improve the reliability of essential safety source.
To achieve these goals, the utility model realizes by the following technical solutions: a kind of Zener type intrinsic safety electric source overload protecting circuit, comprises first interface, second interface, first fuse, second fuse, resettable fuse, three-terminal voltage-stabilizing chip, first voltage stabilizing didoe-four voltage stabilizing didoe, first resistance-three resistance and transformer, 1 pin of first interface connects the first resistance successively, second fuse is to 2 pin of transformer primary side, and 2 pin of first interface connect 1 pin of transformer primary side, and 3 pin of transformer secondary connect 2 pin of resettable fuse to rectifier, and 4 pin of transformer secondary connect 3 pin of rectifier, 1 pin of rectifier, 4 pin connect 1 pin of three-terminal voltage-stabilizing chip respectively, 2 pin, are connected to electric capacity between 1 pin of three-terminal voltage-stabilizing chip and 2 pin, 2 pin ground connection of three-terminal voltage-stabilizing chip, and 3 pin of three-terminal voltage-stabilizing chip connect the first fuse, 1 pin of the 3rd resistance to the second interface, 3 pin of the second interface connect 2 pin of three-terminal voltage-stabilizing chip, the node between the first fuse and the 3rd resistance and go back between 3 pin of the second interface and be connected to the series circuit of the second resistance and light-emitting diode, the series circuit of the first voltage stabilizing didoe and the second voltage stabilizing didoe, the series circuit of the 3rd voltage stabilizing didoe and the 4th voltage stabilizing didoe, the first described fuse adopts the earthenware package lead formula fusing type soon fuse of litterfuse company of the U.S., first voltage stabilizing didoe-four voltage stabilizing didoe adopts model to be the voltage stabilizing didoe of 1N5338B, and the 3rd resistance adopts domestic noninductive wirewound power resistance.
As preferably, described first interface, the second interface all adopt model to be the interface of Connect J5.08-3.
As preferably, described three-terminal voltage-stabilizing chip adopts model to be the three-terminal voltage-stabilizing chip of LM7809.
The beneficial effects of the utility model: can automatic cut-off power when transshipping and occurring; protection device is not damaged; improve the overload protection of zena's safety barrier; prevent the frequent replacing of fuse; the F1 fuse in zena's safety barrier circuit is avoided to damage; decrease on-the-spot maintenance, improve the reliability of essential safety source.
Accompanying drawing explanation
The utility model is described in detail below in conjunction with the drawings and specific embodiments;
Fig. 1 is circuit theory diagrams of the present utility model;
Fig. 2 is fusing time and the blowout current curve chart of the utility model first fuse;
Fig. 3 is the typical action time current curve chart of the utility model resettable fuse.
Embodiment
The technological means realized for making the utility model, creation characteristic, reaching object and effect is easy to understand, below in conjunction with embodiment, setting forth the utility model further.
With reference to Fig. 1-3, this embodiment is by the following technical solutions: a kind of Zener type intrinsic safety electric source overload protecting circuit, comprise first interface J1, second interface J2, first fuse F1, second fuse F2, resettable fuse TF1, three-terminal voltage-stabilizing chip U1, first voltage stabilizing didoe D1-the 4th voltage stabilizing didoe D4, first resistance R1-the 3rd resistance R3 and transformer T1, 1 pin of first interface J1 meets the first resistance R1 successively, 2 pin on the former limit of the second fuse F2 to transformer T1, 2 pin of first interface J1 connect 1 pin on the former limit of transformer T1, 3 pin of transformer T1 secondary connect 2 pin of resettable fuse TF1 to rectifier DB1, 4 pin of transformer T1 secondary connect 3 pin of rectifier DB1, 1 pin of rectifier DB1, 4 pin connect 1 pin of three-terminal voltage-stabilizing chip U1 respectively, 2 pin, electric capacity C1 is connected between 1 pin of three-terminal voltage-stabilizing chip U1 and 2 pin, the 2 pin ground connection of three-terminal voltage-stabilizing chip U1, 3 pin of three-terminal voltage-stabilizing chip U1 meet the first fuse F1, 1 pin of the 3rd resistance R3 to the second interface J2, 3 pin of the second interface J2 connect 2 pin of three-terminal voltage-stabilizing chip U1, go back between 3 pin of the node between the first fuse F1 and the 3rd resistance R3 and the second interface J2 and be connected to the series circuit of the second resistance R2 and light-emitting diode D6, the series circuit of the first voltage stabilizing didoe D1 and the second voltage stabilizing didoe D2, the series circuit of the 3rd voltage stabilizing didoe D3 and the 4th voltage stabilizing didoe D4.
It should be noted that described first interface J1, the second interface J2 all adopts model to be the interface of ConnectJ5.08-3.
In addition, described three-terminal voltage-stabilizing chip U1 employing model is the three-terminal voltage-stabilizing chip of LM7809.
This embodiment first fuse F1 adopts the earthenware package lead formula fusing type soon fuse of litterfuse company of the U.S., specifications and models are 0.315A/250V, first voltage stabilizing didoe D1-the 4th voltage stabilizing didoe D4 adopts the voltage stabilizing didoe 1N5338B of motorola company, specifications and models are 5.1V/5W, 3rd resistance R3 adopts domestic noninductive wirewound power resistance, specifications and models are 10 Ω/6W, this part circuit constitutes the safety barrier circuit of Zener structure, energy after pressure-limit current-limit is connected to hazardous area by the second interface J2, meet hazardous area electricity consumption requirement.
When the power consumption equipment in hazardous area is short-circuited fault in case of a fault, be equivalent to 1, the 3 pin short circuits of the second interface J2, the electric current now having short circuit current Is=Uo/ (R3+F1 [fuse cold-state resistance]) ≈ 0.793A flows through the first fuse F1 of the safety barrier circuit of this Zener structure, by searching the fusing time that handbook provided and the blowout current curve chart (Fig. 2) of the first fuse F1, we can learn that the first fuse F1 will fusing in about 100 seconds.
Therefore; in order to prevent frequent breakage and the replacing of the first fuse F1; connect a resettable fuse TF1 between the secondary of power transformer T1 and the input circuit of rectifier bridge; these resettable fuse specifications and models are 0.5A/60V; its objective is leading action before the first fuse F1 fuses, thus protection the first fuse F1 avoids frequent replacing.
The operation principle of this embodiment is as follows: by the output of essential safety source, i.e. the second interface J2 short circuit, analog output be short-circuited overload situation.
Can learn by calculating us, the effective value electric current flowing through resettable fuse TF1 is greater than short circuit current Is, according to the typical action time current curve chart (Fig. 3) of this model resettable fuse, we can check in, avalanche effect cutoff circuit electric current can be there is in this resettable fuse about 20 seconds, this 20 second operate time much smaller than the operate time (100 second) of the first fuse F1 when the second interface J2 short circuit, therefore resettable fuse TF1 will in the first action of the first fuse F1, thus cutoff circuit, protect the first fuse F1 and avoid fusing, after the short trouble of the second interface J2 is eliminated, the junction temperature of resettable fuse TF1 drops to normal value, will recover conducting again, thus avoids the first fuse F1 in zena's safety barrier circuit to damage, decrease on-the-spot maintenance, improve the reliability of essential safety source.
In addition; resettable fuse TF1 is positioned between transformer secondary output and the AC of rectifier diode; the protection range of resettable fuse TF1 can also be maximized; both the first fuse F1 had been protected; also can protect transformer and rectifier diode simultaneously, thus reach good service efficiency.
This embodiment provides a kind of overload protecting circuit, can automatic cut-off power when transshipping and occurring, and protection device is not damaged; after overload situations is cancelled; can resume work voluntarily, structure is simple, reasonable in design; protective circuit prototype part; effectively avoid fuse to damage, decrease maintenance, reduce cost; reliability is high, has market application foreground widely.
The above is preferred implementation of the present utility model; should be understood that; for those skilled in the art; under the prerequisite not departing from principle described in the utility model; can also make some improvements and modifications, these improvements and modifications also should be considered as protection range of the present utility model.
Claims (5)
1. a Zener type intrinsic safety electric source overload protecting circuit, it is characterized in that, comprise first interface (J1), second interface (J2), first fuse (F1), second fuse (F2), resettable fuse (TF1), three-terminal voltage-stabilizing chip (U1), first voltage stabilizing didoe (D1)-four voltage stabilizing didoe (D4), first resistance (R1)-three resistance (R3) and transformer (T1), 1 pin of first interface (J1) connects the first resistance (R1) successively, second fuse (F2) is to 2 pin on transformer (T1) former limit, 2 pin of first interface (J1) connect 1 pin on transformer (T1) former limit, 3 pin of transformer (T1) secondary connect 2 pin of resettable fuse (TF1) to rectifier (DB1), 4 pin of transformer (T1) secondary connect 3 pin of rectifier (DB1), 1 pin of rectifier (DB1), 4 pin connect 1 pin of three-terminal voltage-stabilizing chip (U1) respectively, 2 pin, electric capacity (C1) is connected between 1 pin of three-terminal voltage-stabilizing chip (U1) and 2 pin, 2 pin ground connection of three-terminal voltage-stabilizing chip (U1), 3 pin of three-terminal voltage-stabilizing chip (U1) connect the first fuse (F1), 3rd resistance (R3) is to 1 pin of the second interface (J2), 3 pin of the second interface (J2) connect 2 pin of three-terminal voltage-stabilizing chip (U1), node between first fuse (F1) and the 3rd resistance (R3) and go back between 3 pin of the second interface (J2) and be connected to the series circuit of the second resistance (R2) and light-emitting diode (D6), the series circuit of the first voltage stabilizing didoe (D1) and the second voltage stabilizing didoe (D2), the series circuit of the 3rd voltage stabilizing didoe (D3) and the 4th voltage stabilizing didoe (D4), described the first fuse (F1) adopts earthenware package lead formula fusing type soon fuse.
2. a kind of Zener type intrinsic safety electric source overload protecting circuit according to claim 1, is characterized in that, described the first voltage stabilizing didoe (D1)-four voltage stabilizing didoe (D4) adopts model to be the voltage stabilizing didoe of 1N5338B.
3. a kind of Zener type intrinsic safety electric source overload protecting circuit according to claim 1, is characterized in that, the 3rd described resistance (R3) adopts domestic noninductive wirewound power resistance.
4. a kind of Zener type intrinsic safety electric source overload protecting circuit according to claim 1, is characterized in that, described first interface (J1), the second interface (J2) all adopt model to be the interface of Connect J5.08-3.
5. a kind of Zener type intrinsic safety electric source overload protecting circuit according to claim 1, is characterized in that, described three-terminal voltage-stabilizing chip (U1) adopts model to be the three-terminal voltage-stabilizing chip of LM7809.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420630759.3U CN204089152U (en) | 2014-10-28 | 2014-10-28 | A kind of Zener type intrinsic safety electric source overload protecting circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420630759.3U CN204089152U (en) | 2014-10-28 | 2014-10-28 | A kind of Zener type intrinsic safety electric source overload protecting circuit |
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| CN204089152U true CN204089152U (en) | 2015-01-07 |
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| CN201420630759.3U Expired - Lifetime CN204089152U (en) | 2014-10-28 | 2014-10-28 | A kind of Zener type intrinsic safety electric source overload protecting circuit |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105207144A (en) * | 2015-09-29 | 2015-12-30 | 哈尔滨东方报警设备开发有限公司 | Plugging type intrinsic safety wiring module |
| CN105634490A (en) * | 2015-12-28 | 2016-06-01 | 上海耀华称重系统有限公司 | Zener type intrinsically safe analog-to-digital signal conversion circuit |
| CN105836624A (en) * | 2016-05-31 | 2016-08-10 | 河南卫华机械工程研究院有限公司 | Control circuit for explosion-proof place |
| CN107041050A (en) * | 2017-04-11 | 2017-08-11 | 长兴肖达科技有限公司 | The power circuit of neon light |
| CN108111001A (en) * | 2017-12-27 | 2018-06-01 | 恒安科技（中山）有限公司 | A kind of intrinsically safe power supply |
-
2014
- 2014-10-28 CN CN201420630759.3U patent/CN204089152U/en not_active Expired - Lifetime
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105207144A (en) * | 2015-09-29 | 2015-12-30 | 哈尔滨东方报警设备开发有限公司 | Plugging type intrinsic safety wiring module |
| CN105634490A (en) * | 2015-12-28 | 2016-06-01 | 上海耀华称重系统有限公司 | Zener type intrinsically safe analog-to-digital signal conversion circuit |
| CN105634490B (en) * | 2015-12-28 | 2019-01-08 | 上海耀华称重系统有限公司 | Zener type essential safe type analog signal conversion digital signal circuit |
| CN105836624A (en) * | 2016-05-31 | 2016-08-10 | 河南卫华机械工程研究院有限公司 | Control circuit for explosion-proof place |
| CN107041050A (en) * | 2017-04-11 | 2017-08-11 | 长兴肖达科技有限公司 | The power circuit of neon light |
| CN108111001A (en) * | 2017-12-27 | 2018-06-01 | 恒安科技（中山）有限公司 | A kind of intrinsically safe power supply |
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