CN1805070A - PTC current limiting device having molding part made of insulating material - Google Patents
PTC current limiting device having molding part made of insulating material Download PDFInfo
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- CN1805070A CN1805070A CNA2006100005956A CN200610000595A CN1805070A CN 1805070 A CN1805070 A CN 1805070A CN A2006100005956 A CNA2006100005956 A CN A2006100005956A CN 200610000595 A CN200610000595 A CN 200610000595A CN 1805070 A CN1805070 A CN 1805070A
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- 238000000465 moulding Methods 0.000 title claims abstract description 57
- 239000011810 insulating material Substances 0.000 title claims abstract description 37
- 229920000642 polymer Polymers 0.000 claims description 29
- 238000007667 floating Methods 0.000 claims description 16
- 238000009413 insulation Methods 0.000 claims description 13
- 229920001903 high density polyethylene Polymers 0.000 claims description 10
- 239000004700 high-density polyethylene Substances 0.000 claims description 10
- 229920001684 low density polyethylene Polymers 0.000 claims description 10
- 239000004702 low-density polyethylene Substances 0.000 claims description 10
- 239000011248 coating agent Substances 0.000 claims description 8
- 238000000576 coating method Methods 0.000 claims description 8
- 239000002245 particle Substances 0.000 claims description 8
- 239000003822 epoxy resin Substances 0.000 claims description 6
- 229920000647 polyepoxide Polymers 0.000 claims description 6
- 239000002184 metal Substances 0.000 claims description 5
- 229910052751 metal Inorganic materials 0.000 claims description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 4
- 239000002033 PVDF binder Substances 0.000 claims description 4
- 239000003963 antioxidant agent Substances 0.000 claims description 4
- 230000003078 antioxidant effect Effects 0.000 claims description 4
- 229910052799 carbon Inorganic materials 0.000 claims description 4
- 238000001816 cooling Methods 0.000 claims description 4
- 229910044991 metal oxide Inorganic materials 0.000 claims description 4
- 150000004706 metal oxides Chemical class 0.000 claims description 4
- 229920001296 polysiloxane Polymers 0.000 claims description 4
- 229920002981 polyvinylidene fluoride Polymers 0.000 claims description 4
- 229920002050 silicone resin Polymers 0.000 claims description 4
- 239000003595 mist Substances 0.000 claims description 3
- 229920005749 polyurethane resin Polymers 0.000 claims description 3
- 229920005992 thermoplastic resin Polymers 0.000 claims description 3
- 229920001187 thermosetting polymer Polymers 0.000 claims description 3
- 239000007789 gas Substances 0.000 description 28
- 238000010891 electric arc Methods 0.000 description 25
- 238000012986 modification Methods 0.000 description 19
- 230000004048 modification Effects 0.000 description 19
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- 238000003763 carbonization Methods 0.000 description 3
- 230000015556 catabolic process Effects 0.000 description 3
- 238000002360 preparation method Methods 0.000 description 3
- 239000004698 Polyethylene Substances 0.000 description 2
- 239000004743 Polypropylene Substances 0.000 description 2
- 238000009835 boiling Methods 0.000 description 2
- 238000000748 compression moulding Methods 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000005611 electricity Effects 0.000 description 2
- 239000003344 environmental pollutant Substances 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 239000002923 metal particle Substances 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 231100000252 nontoxic Toxicity 0.000 description 2
- 230000003000 nontoxic effect Effects 0.000 description 2
- 229920001568 phenolic resin Polymers 0.000 description 2
- 231100000719 pollutant Toxicity 0.000 description 2
- 229920000573 polyethylene Polymers 0.000 description 2
- 229920001155 polypropylene Polymers 0.000 description 2
- 230000004224 protection Effects 0.000 description 2
- 230000000630 rising effect Effects 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 150000001335 aliphatic alkanes Chemical class 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 239000011889 copper foil Substances 0.000 description 1
- 150000001924 cycloalkanes Chemical class 0.000 description 1
- 230000008034 disappearance Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 238000003475 lamination Methods 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 239000002480 mineral oil Substances 0.000 description 1
- 235000010446 mineral oil Nutrition 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 125000001997 phenyl group Chemical class [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 description 1
- 229920002635 polyurethane Polymers 0.000 description 1
- 239000004814 polyurethane Substances 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 230000001846 repelling effect Effects 0.000 description 1
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- 230000008646 thermal stress Effects 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
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Classifications
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04F—FINISHING WORK ON BUILDINGS, e.g. STAIRS, FLOORS
- E04F13/00—Coverings or linings, e.g. for walls or ceilings
- E04F13/07—Coverings or linings, e.g. for walls or ceilings composed of covering or lining elements; Sub-structures therefor; Fastening means therefor
- E04F13/08—Coverings or linings, e.g. for walls or ceilings composed of covering or lining elements; Sub-structures therefor; Fastening means therefor composed of a plurality of similar covering or lining elements
- E04F13/0801—Separate fastening elements
- E04F13/0803—Separate fastening elements with load-supporting elongated furring elements between wall and covering elements
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- Engineering & Computer Science (AREA)
- Architecture (AREA)
- Civil Engineering (AREA)
- Structural Engineering (AREA)
- Thermistors And Varistors (AREA)
- Emergency Protection Circuit Devices (AREA)
Abstract
Disclosed is a PTC (Positive Temperature Coefficient) current limiting device for limiting a current by use of PTC characteristics, which includes a PTC element having the PTC characteristics; a pair of electrode units arranged on both sides to face each other with the PTC element being interposed therebetween; and a molding part prepared around the PTC element and the electrode units to surround at least an interface region between the PTC element and the electrode units, the molding part being made of elastic insulating material. The molding part is made of an elastic insulating material or any insulating materials selected from vacuum, gas and oil. Thus, this device may effectively restrain an arc generated while limiting overcurrent or short circuit current, and also prevent flashover between electrodes.
Description
Technical field
The present invention relates to a kind of PTC (positive temperature coefficient) current-limiting apparatus, relate more specifically to a kind of like this PTC current-limiting apparatus, it can prevent to produce electric arc or produce flashover between PTC element and contact electrode between contact electrode.
Background technology
Usually, widely-used circuit breaker prevents high or low pressing system short circuit.Normally used power frequency is 60Hz, and an one phase place can become 16.7ms.If this phase place is defined as a circulation, then traditional circuit breaker needs the long period (promptly, at least several cycles) come open circuit, and do not have current-limiting function, so the moire effect of this fault continues the relative long period for the fault current value of estimating.In addition, there be not under the situation of interrupting short circuit power equipment and system around can having a strong impact on.Therefore, strongly need can be at short notice the current limiting technique of the short circuit current of restriction system effectively.
For current limiting technique, typically use a kind of like this current-limiting apparatus.This current-limiting apparatus is used for limiting or disconnecting overcurrent or the short circuit current that produces in electric power system, and it can realize its function by using PTC (positive temperature coefficient) element.
Material with ptc characteristics has relatively low resistance at normal temperatures, thereby electric current can pass through well.Yet if himself is heated owing to introduce the electric current that surpasses permissible value for the increase of the temperature of surrounding environment or this material, resistance increases hundred times or more suddenly, thereby can limit electric current.Therefore, if use above-mentioned material forming circuit element, then when raising, temperature can protect various circuit.
Based on this, the open H10-321413 of Japan Patent discloses the current-limiting apparatus of a kind of PTC of use.Reference and above-mentioned relevant Fig. 1, traditional PTC current-limiting apparatus comprises: PTC polymer element 1, it has ptc characteristics by being mixed with conductive particle therein; First electrode 2,3, it is arranged on two surfaces of PTC polymer element 1 by welding; And second electrode 4,5, be arranged on the surface of first electrode 2,3 to be electrically connected with it.
At this moment, this current-limiting apparatus has such condition, and promptly PTC polymer element 1 has the surface area bigger than first electrode 2,3, and first electrode 2,3 has the surface area bigger than second electrode 4,5.In this structure, can prevent from internal short-circuit to occur, and can reduce this current-limiting apparatus changes in resistance before or after its operation, thereby can apply electric current to it with heavy load at the place, two ends of first electrode 2,3.In addition, will be installed in by the framework 6,7 that insulating material is made PTC polymer element 1 around extending an insulation distance, thereby prevent the flashover between first electrode 2,3 and second electrode 4,5.
Yet, under this traditional current-limiting apparatus was used to limit situation above the short circuit current of 100V and 10kA basically, PTC polymer element 1 was showing time difference and non-linear because their thermal capacity is different aspect the resistance that produces with first electrode 2,3 that contacts with this PTC polymer element 1.Like this, before the resistance that produces by heating PTC polymer element 1, in the interface of the PTC polymer element 1 and first electrode 2,3, generate very big resistance.Therefore, thermal stress is concentrated, thereby produces electric arc and serious noise in the interface between the PTC polymer element 1 and first electrode 2,3.This electric arc decomposes and carbonization PTC polymer element 1, finally causes dielectric breakdown.In addition, ptc material melts owing to the heat of this electric arc and PTC polymer element 1 self and vaporizes, thus PTC polymer element 1 attenuation gradually, and first electrode 2,3 is immersed in the PTC polymer element 1.
Therefore, traditional current-limiting apparatus is intended to by using extrusion structure to increase contact pressure, to control the surface area of first electrode 2,3 and second electrode 4,5, but can not avoid owing to the interface of PTC polymer element 1 in the electric arc that causes of time difference of the electron repulsion energy that produces and resistance generate, and be not easy to avoid current limiting characteristic deterioration and the flashover between the electrode that cause owing to the electric arc that is produced.
In addition, the framework 6,7 that proposes in the prior art, made and be installed in the two ends of PTC polymer element 1 by insulating material is used to obtain insulation distance, but they can not eliminate in the PTC polymer element 1 and first electrode 2,3 electric arc that produces, and the noise that can not expect to reduce during open-circuit operation and produced.
In view of the foregoing, traditional current-limiting apparatus can be limited in the electric current in low current zone and not have noise and electric arc, but it can not avoid producing electric arc in high electric current or high capacitance system, thereby this electric arc also causes PTC element deterioration and makes its lost of life.
Summary of the invention
Design the present invention is to solve the problems referred to above of prior art, therefore the purpose of this invention is to provide a kind of PTC current-limiting apparatus, because this device can suppress the electric arc that produced effectively in restriction overcurrent or short circuit current, with and can also prevent generation of flashover between electrodes, so it can be used in high-voltage system and the low-voltage system.
To achieve these goals, the invention provides a kind of PTC (positive temperature coefficient) current-limiting apparatus, it utilizes ptc characteristics to limit electric current, and this device comprises: the PTC element with ptc characteristics; The pair of electrodes unit, they are arranged in both sides facing with each other, and described PTC element is plugged between them; And the molding part of making by insulating material, its preparation around described PTC element and electrode unit to surround this PTC element and electrode unit at least in part.Here, described molding part can be elastic insulating material, or is selected from any insulating material in the group that comprises vacuum, gas and oil.
In another aspect of this invention, also provide a kind of PTC current-limiting apparatus, it utilizes ptc characteristics to limit electric current, and this device comprises: the PTC element with ptc characteristics; The pair of electrodes unit, they are arranged in both sides facing with each other, and described PTC element is plugged between them; And molding part, to surround the interface zone between this PTC element and the electrode unit at least in part, this molding part is made by elastic insulating material around described PTC element and electrode unit in its preparation.
Preferably, described molding part is by having 10
3To 10
20The insulation resistance of ohm and 5% or more the thermosetting or the thermoplastic resin of high elongation rate are made.
In addition, described elastic insulating material is preferably made by silicone resin or polyurethane resin.
In still another aspect of the invention, also provide a kind of PTC current-limiting apparatus, it utilizes ptc characteristics to limit electric current, and this device comprises: the PTC element with ptc characteristics; The pair of electrodes unit, they are arranged in both sides facing with each other, and described PTC element is plugged between them; And molding part, it comprises first insulating part and is prepared into second insulating part that surrounds this first insulating part that this first insulating part is made by floating insulating material, and is prepared to surround described PTC element and electrode unit at least in part contiguously.
Preferably, described floating insulating material is to be selected from a kind of in the group that comprises vacuum, gas and oil.
Under the situation that described floating insulating material is made of vacuum, described first insulating part preferably has 10
-3Holder or littler vacuum degree.Under the situation that described floating insulating material is made of gas, described first insulating part is preferably 1 crust or higher SF
6, N
2Or their mist.Under the situation that described floating insulating material is made of oil, described first insulating part is preferably the insulating oil with cooling capacity.
Also preferably, described electrode unit comprises: the contact electrode that contacts with described PTC element; And the electric wire that links to each other with this contact electrode, being used for applying the electric current of external circuit to described contact electrode, wherein said molding part surrounds whole PTC element, whole contact electrode and part electric wire.
In addition, described PTC element can comprise: be selected from down at least a polymer in the group, this group comprises HDPE (high density polyethylene (HDPE)), LDPE (low density polyethylene (LDPE)), epoxy resin, silicone and PVDF (poly-difluoroethylene); Be selected from down at least a conductive particle in the group, this group comprises carbon, metal and metal oxide; And antioxidant.
Simultaneously, can also comprise pressurizing unit, be used for pushing described electrode unit, and this pressurizing unit preferably applies and is equal to or greater than atmospheric extruding force towards described PTC element according to the PTC current-limiting apparatus of this embodiment.
At this moment, described pressurizing unit preferably includes: the housing that holds described molding part; And elastomeric element, its inner surface by described housing is elastically biased toward, to push at least one side of described molding part towards described PTC element.
Alternatively, described pressurizing unit can also comprise: a pair of plate, and they are arranged to described molding part is plugged between them; And link, be used to make described a pair of plate to interconnect and fix.
Description of drawings
From below in conjunction with the description of accompanying drawing to embodiment, will understand other purpose of the present invention and aspect, wherein:
Fig. 1 is the cutaway view of the traditional PTC current-limiting apparatus of expression;
Fig. 2 is the cutaway view of expression according to the PTC current-limiting apparatus of first embodiment of the invention;
Fig. 3 is the cutaway view of expression according to a modification of the PTC current-limiting apparatus of first embodiment of the invention;
Fig. 4 is the cutaway view of expression according to another modification of the PTC current-limiting apparatus of first embodiment of the invention;
Fig. 5 is the cutaway view of expression according to the another modification of the PTC current-limiting apparatus of first embodiment of the invention;
Fig. 6 is the cutaway view of expression according to the PTC current-limiting apparatus of second embodiment of the invention;
Fig. 7 is the cutaway view of expression according to a modification of the PTC current-limiting apparatus of second embodiment of the invention;
Fig. 8 is the cutaway view of expression according to the PTC current-limiting apparatus of third embodiment of the invention;
Fig. 9 is the cutaway view of expression according to a modification of the PTC current-limiting apparatus of third embodiment of the invention; And
Figure 10 is that expression is when applying overcurrent, according to the curve chart of the waveform during the open-circuit operation of PTC current-limiting apparatus of the present invention.
Embodiment
The preferred embodiment of the present invention will be described in detail below with reference to accompanying drawings.Before describing, should understand, the term that uses in specification and claims should not be regarded as being limited to usually and lexical meaning, and should allow the inventor suitably limit term with the basis that this principle is described best on, based on making an explanation with corresponding meaning of technical elements of the present invention and notion.Therefore, the description of being done here only is the preferred exemplary for illustration purpose, and is not intended to limit the scope of the invention, and therefore should understand under the situation that does not break away from the spirit and scope of the present invention and can make other substitutions and modifications of equal value to it.
Fig. 2 is the cutaway view of expression according to PTC (positive temperature coefficient) current-limiting apparatus of first embodiment of the invention.
With reference to Fig. 2, the PTC current-limiting apparatus of this embodiment comprises: PTC element 110; Pair of electrodes unit 120,130, they are arranged to make PTC element 110 to be plugged between them; And molding part 140, it prepares around PTC element 110 and electrode unit 120,130.
Along with the temperature rising of surrounding environment, PTC element 110 is used for by making resistance increase the overcurrent that suppresses electric power system suddenly under particular temperature value.
Preferably, PTC element 110 has plate structure, and it can have circle, ellipse or polygonal shape.In addition, consider that preferably service condition (that is, for example normal current, overcurrent to be limited and the various factors of operating time) designs its area and thickness.
Described polymer can be at least a polymer that is selected from down in the group, and this group comprises HDPE (high density polyethylene (HDPE)), LDPE (low density polyethylene (LDPE)), epoxy resin, silicone and PVDF (poly-difluoroethylene).In addition, described conductive particle can have at least a conductive particle in the group of being selected from down, and this group comprises carbon, metal and metal oxide (TiB
2).
In addition, can also add antioxidant to prevent the oxidation of PTC polymer.In addition, can also add inorganic additive, to improve low resistance characteristic when the normal temperature and the high-ohmic during at high temperature to the PTC polymer.
Electrode unit 120,130 comprises contact electrode 121,131 that contacts with PTC element 110 and the electric wire 122,132 that is used for applying to contact electrode 121,131 electric current of external circuit.
Contact electrode 121,131 can be made of Copper Foil or other hardware.In addition, contact electrode 121,131 for example by using lamination or free contact so that contact resistance reduces to minimum mode, be installed in the both sides of PTC element 110.
Preferably, consider the area of PTC element 110 and the contact area that thickness is determined contact electrode 121,131, so that in 110 operations of PTC element, between contact electrode 121,131, flashover can not occur.
Electric wire 122,132 is connected to contact electrode 121,131, so that contact electrode 121,131 is electrically connected with electric power system.In more detail, electric wire 122,132 extends so that their end is electrically connected to contact electrode, and the other end is connected to external circuit.In addition, electric wire 122,132 is preferably made by metal material, and has the sectional area and the thickness of the current capacity that is fit to described system.
More specifically, described current-limiting apparatus can also comprise the connection electrode (not shown) that is plugged between contact electrode 121,131 and the electric wire 122,132.This connection electrode is made by metal (for example, having the Jin Heyin of relatively low resistance), thereby electric current can more easily impose on this current-limiting apparatus from electric power system.
If PTC element 110 owing to overcurrent is operated, then can produce electric arc immediately in the interface of contact electrode 121,131, and this electric arc can make the deterioration in characteristics and the damage of PTC element 110.In addition, if repeatedly produce electric arc, the performance of PTC element 110 deterioration and can not re-using greatly then.Yet, in the present invention, when PTC element 110 carries out current limliting when operation, the molding part 140 that directly surrounds PTC element 110 is absorbed in temporary impact energy and the initial arc that produces in the interface between PTC element 110 and the contact electrode 121,131 immediately, and makes it disappearance.
In addition, when PTC element 110 operation during with the restriction electric current, the electric arc that produces in the interface between PTC element 110 and contact electrode 121,131 may be skipped PTC element 110 at the place, two ends, and causes the flashover located at two ends between the contact electrode 121,131.Therefore, importantly guarantee insulation distance and can not cause flashover.In the present invention, because molding part 140 is configured to surround whole PTC element 110, whole contact electrode 121,131 and part electric wire 122,132, it is hereby ensured sufficient insulation distance between the two ends of PTC element 110.That is to say, guaranteed the effective dielectric strength around contact electrode 121,131, thereby can prevent flashover.
In addition, molding part 140 has sealed owing to the incomplete space that causes that contacts between PTC element 110 and the contact electrode 121,131, thereby can improve contact resistance behavior.
Preferably, the PTC current-limiting apparatus of present embodiment also comprises the coating 150 that is plugged between PTC element 110 or electrode unit 120,130 and the molding part 140.Increase coating 150 to improve between molding part 140 and the PTC element 110 and molding part 140 is connected with interface between the electrode unit 120,130.For example, silicone resin, polyurethane resin or epoxy resin can be used for coating 150.Yet the present invention is not limited to this.
The PTC current-limiting apparatus of this embodiment can be revised the shape of molding part within the scope of the invention in every way, for example as shown in Figure 3.With reference to Fig. 3, can be configured to surround PTC current-limiting apparatus 110 according to the molding part 141 of the PTC current-limiting apparatus of this modification, and make it surround the surface to expose.
In addition, Fig. 4 and Fig. 5 are the cutaway views of other modification of the PTC current-limiting apparatus of expression present embodiment.In Fig. 4 and Fig. 5, represent to have the same parts of identical function with Reference numeral identical in the former accompanying drawing, therefore be not described in detail.
At first with reference to Fig. 4, has steam vent 161,162 according to the molding part 142 of the PTC current-limiting apparatus of this modification.When this PTC current-limiting apparatus carried out the current limliting action, PTC element 110 can decompose to produce gas.This decomposition gas includes the conducting metal particles of carbonization, and if this conducting metal particles be attracted to PTC element 110, thereby the conductive path that then can form carbonization has a negative impact to insulation.In addition, occur under the situation of decomposition gas in current limliting moment operating period, interior pressure is owing to decomposition gas raises, and this can make 140 excessive expansions of rubber-like molding part.At this moment, the steam vent 161,162 that is formed in the molding part 142 can be discharged into the outside with the decomposition gas of PTC element 110, thereby addresses the above problem.
At least one steam vent 161,162 can be prepared, thereby the decomposition gas of PTC element can be more effectively discharged.
Simultaneously, with reference to Fig. 5, the PTC current-limiting apparatus of this modification also comprises and is prepared into the housing 170 that holds molding part 140.Housing 170 supports the structure of molding parts 140, and suppresses the excessive expansion of molding part 140 in current limliting operating period.In addition, housing 170 protection molding parts 140 are avoided the infringement of external environment condition (for example, light, moisture and pollutant sources).
This housing 170 can be made by the material with insulation characterisitic (for example, polyethylene, polypropylene or phenolic plastics).Yet the present invention is not limited to above-mentioned, can make various modifications within the scope of the invention for those of ordinary skills.
Fig. 6 represents the PTC current-limiting apparatus according to second embodiment of the invention.In Fig. 6, represent to have the same parts of identical function with Reference numeral identical in the former accompanying drawing, therefore be not described in detail.
With reference to Fig. 6, the PTC current-limiting apparatus of this embodiment also comprises pressurizing unit, is used for towards PTC element 110 extruding electrode units 120,130.This pressurizing unit comprises housing 610 and elastomeric element 620,630.
Elastomeric element 620,630 supported inner surfaces that abut against housing 610, and they are configured to surround the periphery of electric wire 122,132, thereby and compression moulding part 140 make electric wire 122,132 be extruded towards contact electrode 121,131.Like this, contact electrode 121,131 is extruded towards PTC element 110.Preferably, can prepare elastomeric element 620,630 for any or both in the electric wire 122,132.
Simultaneously, preferably the extruding force of elastomeric element 620,630 is set at least 1 crust, thus overcome since the electron repelling power that when short trouble, produces cause, the separating of the interface between PTC element 110 and contact electrode 121,131.In addition, also preferably, even, also keep 1 crust or bigger extruding force when owing to the current limliting operation that repeats makes the thickness of PTC element 110 be reduced to a half.
Elastomeric element 620,630 can for example be made of the helical spring that is prepared into the periphery of surrounding electric wire 122 and/or 132.Yet the present invention is not limited to above-mentioned, but can make various modifications within the scope of the invention by those skilled in the art.
Fig. 7 represents the modification according to the PTC current-limiting apparatus of this embodiment.In Fig. 7, represent to have the same parts of identical function with Reference numeral identical in the former accompanying drawing, therefore be not described in detail.
With reference to Fig. 7, the pressurizing unit of the PTC current-limiting apparatus of this modification comprises that top board 710 is with base plate 720 and the link that is used to be connected top board 710 and base plate 720.
Preferably, described pressurizing unit also comprises the elastomeric element 620,630 that is prepared into encirclement electric wire 122,132.Elastomeric element 620, the 630 supported inboards that abut against plate 710,720, and they are compressed and resiliently biased then along the periphery of electric wire 122,132.Therefore, elastomeric element 620,630 compression moulding parts 140, thereby contact electrode 121,131 extruding PTC elements 110.The extruding force of elastomeric element 620,630 equates substantially with last embodiment's.
Simultaneously, in Fig. 7, elastomeric element 620,630 is arranged to be used for two wires 122,132, but they can be arranged to be used for wherein any if desired.
In addition, be applied to as shown in Figure 2 the PTC current-limiting apparatus with molding part 140 although demonstrate described pressurizing unit in Fig. 6 and Fig. 7, this pressurizing unit also can be applied to the PTC current-limiting apparatus of the molding part with different structure shown in Fig. 3 to Fig. 5 equally.
Although the detailed structure of pressurizing unit has been described in the above-described embodiments, the present invention is not limited to this, should understand that can adopt can be towards any distortion of the pressurizing unit of PTC element 110 extruding electrode units 120,130.
Fig. 8 represents the PTC current-limiting apparatus according to third embodiment of the invention.In Fig. 8, represent to have the same parts of identical function with Reference numeral identical in the former accompanying drawing, therefore be not described in detail.
With reference to Fig. 8, the PTC current-limiting apparatus of this embodiment has the molding part of the structure different with the PTC current-limiting apparatus of first embodiment.That is to say that the molding part of this embodiment comprises first insulating part of being made by floating insulating material 180 and is prepared into second insulating part 190 that surrounds first insulating part 180.
First insulating part 180 can be configured to surround whole PTC element 110, whole contact electrode 121,131 and part or all of electric wire 122,132.Therefore, first insulating part 180 can provide the function that more effectively prevents to produce electric arc or flashover.
First insulating part 180 is configured to directly surround PTC element 110, thereby can remove electric arc and the noise that produces between PTC element 110 and contact electrode 121,131.That is to say that first insulating part 180 is absorbed in temporary impact energy and the initial arc that produces in the PTC element interface of 110 operating periods between PTC element 110 and contact electrode 121,131 immediately, and they are disappeared.Therefore, can produce electric arc and noise hardly.In addition,, therefore can seal because the incomplete space that produces that contacts between PTC element 110 and the contact electrode 121,131 because first insulating part 180 made by floating insulating material, thus the generation of minimizing electric arc.
In addition, first insulating part 180 can be guaranteed between contact electrode 121,131 insulation distance at the place, two ends.As mentioned above, when PTC element 110 is operated with the restriction electric current, moment produce electric arc at the place, two ends in the interface between PTC element 110 and contact electrode 121,131.If do not suppress this electric arc, then locate this electric arc and may skip PTC element 110 and between contact electrode 121,131, produce flashover at two ends.Therefore, importantly guarantee insulation distance and do not cause flashover.In the present embodiment, because first insulating part 180 is configured to surround whole PTC element 110, whole contact electrode 121,131 and part or all of electric wire 122,132, it is hereby ensured insulation distance enough between the two ends of PTC element 110.That is to say, guaranteed the effective dielectric strength around contact electrode 121,131, thereby can prevent flashover.
In addition, in the superheat state after the current limliting operation, PTC element 110 can be cooled at short notice by first insulating part 180 and be in the normal temperature state.
Particularly, the floating insulating material that is used for first insulating part 180 can be made of vacuum.More specifically, this vacuum is to have 10
-3The vacuum layer of holder or littler vacuum degree.This vacuum has the dielectric strength bigger at least 10 times than normal air.In addition, owing to be not used in the medium of transmission energy at vacuum state, so can prevent any further progress of dielectric breakdown.Like this, if first insulating part 180 is made of vacuum, then can be implemented in the very big dielectric strength under the vacuum.In addition, by utilizing electric arc this fact in a vacuum that disappears apace, electric arc is disappeared, and can make this insulating part be constructed with less weight.
As a possibility, the floating insulating material that is used for first insulating part 180 can be made of gas.Preferably, this gas can be 1 crust or higher SF
6Gas or N
2Gas.
SF
6Gas is tasteless, harmless, nontoxic, not flammable and unexplosive inert gas, and it produces less medium or leakage loss, and is heat-staple.The dielectric strength of this gas is 89kV/cm, and this is the atmosphere of 30kV/cm much larger than dielectric strength.In addition, the dielectric constant of this gas is littler than the solid insulating material, thereby needs less charging current, and can more freely select the shape of insulating material than solid insulating material.
N
2Gas is the main component of air, and itself and SF
6Gas is similar, also is non-combustible gas.In addition, N
2Gas is cheap because it is easy to obtain.
More preferably, this gas can be 1 crust or higher SF
6-N
2Mist.This gas is by to SF
6Gas adds N
2Gas obtains, N
2Gas is the main component of air and (for example shows excellent chemical stability, nontoxic and incombustibility) and low boiling and be cheap, there is impurity in this gas or coarsely shows less dielectric strength deterioration owing to electrode surface, and because low boiling and cheapness, this gas can also be used as more economical insulating gas.
As another possibility, the floating insulating material that is used for first insulating part 180 can be made of oil.
Preferably, described oil can be the insulating oil that does not comprise impurity and have cooling capacity, and it can also be to comprise the mineral oil of the hydrocarbon of cycloalkanes, alkane or benzene class as main component.Described cooling capacity is defined as, and PTC element 110 can recover its normal condition in 3 minutes after its operation.
Although disclose the concrete example of floating insulating material in the above, it should be understood that the present invention is not limited to this, and can adopt many changes.
Second insulating part 190 plays the effect of housing, is used to support and remain on the shape of dilatable first insulating part 180 of current limliting operating period possibility.In addition, second insulating part, 190 protections, first insulating part 180 is avoided the infringement of external environment condition (for example, light, moisture and pollutant sources).Like this, second insulating part 190 preferably is configured to make first insulating part 180 to seal fully with the outside.
Second insulating part 190 can be made of the material with insulation characterisitic (as polyethylene, polypropylene or phenolic plastics).Yet the present invention is not limited to above-mentioned, and can make various modifications within the scope of the invention by those skilled in the art.
Fig. 9 is the cutaway view of schematically representing according to the modification of the PTC current-limiting apparatus of this embodiment.In Fig. 9, represent to have the same parts of identical function with Reference numeral identical in the former accompanying drawing, therefore be not described in detail.
With reference to Fig. 9, the PTC current-limiting apparatus of this modification also comprises coating 150, and it is plugged between PTC element 110 or the electrode unit 120,130 and first insulating part 180.
When first insulating part 180 surrounds PTC element 110, in their interface, can produce bubble.Then, dielectric breakdown can make progress along bubble when 110 operations of PTC element, and this is tending towards making first insulating part 180 not work well.At this moment, if preparation has coating 150 on described interface, then first insulating part 180 can easier mode closely be installed on the surface of PTC element 110, thereby this PTC current-limiting apparatus can more effectively be operated.
Preferably, coating 150 can be made by applying epoxy resin or silicon rubber.Yet the present invention is not limited to above-mentioned, and can make various modifications within the scope of the invention by those skilled in the art.
Figure 10 be expression when being applied with overcurrent, according to the curve chart of the waveform of the open-circuit operation of PTC current-limiting apparatus of the present invention, and make this PTC current-limiting apparatus according to the embodiment shown in Fig. 2.In this test, apply 400V voltage to the two ends of PTC element, and check current limiting characteristic by the fault current that changes in the scope that is applied to 2kV to 30kV.With reference to Figure 10, can find not only under the situation that the low current at 2kA flows, and under the situation of the high current flow of 10kA, 15kA, 20kA and 30kA, fast and accurately carry out the current limliting action, thus opens overcurrent effectively.
Described the present invention in detail.Yet, should understand because those skilled in the art can understand within the spirit and scope of the present invention various changes and modification from this detailed description, therefore only provided the detailed description and the concrete example of the expression preferred embodiment of the present invention in the mode of explanation.
Industrial applicibility
As mentioned above, PTC current-limiting apparatus of the present invention can be when restriction overcurrent or short circuit current, Effectively suppress and remove the electric arc that between PTC element and contact electrode, produces, thereby prevent electricity Flashover between the utmost point. Like this, can prevent the wearing and tearing of PTC element, thereby prolong this PTC current limliting The life-span of device. In addition, PTC current-limiting apparatus of the present invention not only for low-pressure system and also for High-pressure system can be carried out reliable current limliting action.
Claims (22)
1, a kind of PTC (positive temperature coefficient) current-limiting apparatus, it utilizes ptc characteristics to limit electric current, and this device comprises:
PTC element with ptc characteristics;
The pair of electrodes unit, they are arranged in both sides facing with each other, and described PTC element is plugged between them; And
Molding part, it prepares around described PTC element and electrode unit, and to surround the interface zone between described PTC element and the electrode unit at least, this molding part is made by elastic insulating material.
2, PTC current-limiting apparatus according to claim 1 is characterized in that,
Described elastic insulating material is to have 10
3To 10
20The insulation resistance of ohm and 5% or the thermosetting or the thermoplastic resin of higher percentage elongation.
3, PTC current-limiting apparatus according to claim 2 is characterized in that, described elastic insulating material is made by silicone resin or polyurethane resin.
4, PTC current-limiting apparatus according to claim 1 is characterized in that, described electrode unit comprises:
The contact electrode that contacts with described PTC element; And
With the electric wire that this contact electrode links to each other, be used for applying the electric current of external circuit to described contact electrode,
Wherein said molding part surrounds whole contact electrode and part electric wire.
5, PTC current-limiting apparatus according to claim 1 is characterized in that, described PTC element comprises:
Be selected from down at least a polymer in the group, this group comprises HDPE (high density polyethylene (HDPE)), LDPE (low density polyethylene (LDPE)), epoxy resin, silicone and PVDF (poly-difluoroethylene);
Be selected from down at least a conductive particle in the group, this group comprises carbon, metal and metal oxide; And
Antioxidant.
6, PTC current-limiting apparatus according to claim 1 is characterized in that, also comprises the coating in the interface that is plugged between described PTC element or electrode unit and the described molding part.
7, PTC current-limiting apparatus according to claim 1 is characterized in that, is formed with steam vent in described molding part, so that described PTC element and external communications.
8, PTC current-limiting apparatus according to claim 1 is characterized in that, also comprises the housing of the outer surface that surrounds described molding part.
9, PTC current-limiting apparatus according to claim 1 is characterized in that, also comprises the pressurizing unit that is used for pushing towards described PTC element described electrode unit.
10, PTC current-limiting apparatus according to claim 9 is characterized in that, described pressurizing unit applies and is equal to or greater than atmospheric extruding force.
11, PTC current-limiting apparatus according to claim 9 is characterized in that, described pressurizing unit comprises:
The housing that holds described molding part; And
Elastomeric element, its inner surface by described housing is elastically biased toward, to push at least one side of described molding part towards described PTC element.
12, PTC current-limiting apparatus according to claim 9 is characterized in that, described pressurizing unit comprises:
A pair of plate, they are arranged to make described molding part to be plugged between them; And
Link is used to make described a pair of plate to interconnect and fix.
13, PTC current-limiting apparatus according to claim 12 is characterized in that, also comprises an elastomeric element, and it is by the inner surface fexible bias pressure of described plate, to push at least one side of described molding part towards described PTC element.
14, a kind of PTC current-limiting apparatus, it utilizes ptc characteristics to limit electric current, and this device comprises:
PTC element with ptc characteristics;
The pair of electrodes unit, they are arranged in both sides facing with each other, and described PTC element is plugged between them; And
Molding part, it comprises first insulating part and is prepared into second insulating part that surrounds this first insulating part that this first insulating part is made by floating insulating material, and is prepared to surround described electrode unit and PTC element at least in part contiguously.
15, PTC current-limiting apparatus according to claim 14 is characterized in that, described floating insulating material is to be selected from a kind of in the group that comprises vacuum, gas and oil.
16, PTC current-limiting apparatus according to claim 15 is characterized in that,
Under the situation that described floating insulating material is made of vacuum, described first insulating part has 10
-3Holder or littler vacuum degree.
17, PTC current-limiting apparatus according to claim 15 is characterized in that,
Under the situation that described floating insulating material is made of gas, described first insulating part is 1 crust or higher SF
6, N
2Or their mist.
18, PTC current-limiting apparatus according to claim 15 is characterized in that,
Under the situation that described floating insulating material is made of oil, described first insulating part is the insulating oil with cooling capacity.
19, PTC current-limiting apparatus according to claim 14 is characterized in that, described electrode unit comprises:
The contact electrode that contacts with described PTC element; And
With the electric wire that this contact electrode links to each other, be used for applying the electric current of external circuit to described contact electrode,
Wherein said molding part surrounds whole PTC element, whole contact electrode and part electric wire.
20, PTC current-limiting apparatus according to claim 14 is characterized in that, described PTC element comprises:
Be selected from down at least a polymer in the group, this group comprises HDPE, LDPE, epoxy resin, silicone and PVDF;
Be selected from down at least a conductive particle in the group, this group comprises carbon, metal and metal oxide; And
Antioxidant.
21, PTC current-limiting apparatus according to claim 14 is characterized in that, also comprises the coating in the interface that is plugged between described PTC element or electrode unit and described first insulating part.
22, a kind of PTC current-limiting apparatus, it utilizes ptc characteristics to limit electric current, and this device comprises:
PTC element with ptc characteristics;
The pair of electrodes unit, they are arranged in both sides facing with each other, and described PTC element is plugged between them; And
Molding part, it is prepared surrounding described electrode unit and PTC element at least in part contiguously, and this molding part by elastic insulating material or any insulating material that is selected from the group that comprises vacuum, gas and oil make.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020050003047 | 2005-01-12 | ||
| KR1020050003045 | 2005-01-12 | ||
| KR1020050003047A KR100697919B1 (en) | 2005-01-12 | 2005-01-12 | PTC current limiting device having multi insulator |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1805070A true CN1805070A (en) | 2006-07-19 |
| CN100538922C CN100538922C (en) | 2009-09-09 |
Family
ID=36867023
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2006100005956A Expired - Fee Related CN100538922C (en) | 2005-01-12 | 2006-01-11 | PTC current-limiting apparatus with molding part of making by insulating material |
Country Status (2)
| Country | Link |
|---|---|
| KR (1) | KR100697919B1 (en) |
| CN (1) | CN100538922C (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104350553A (en) * | 2012-05-30 | 2015-02-11 | 西门子公司 | Encapsulated surge protector having central duct |
| CN104681219A (en) * | 2013-11-29 | 2015-06-03 | 聚鼎科技股份有限公司 | Plug-in type overcurrent protection element |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8716633B2 (en) | 2009-10-13 | 2014-05-06 | Uniplatek Co., Ltd. | Method for manufacturing PTC device and system for preventing overheating of planar heaters using the same |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7475744B2 (en) * | 2005-01-17 | 2009-01-13 | Us Synthetic Corporation | Superabrasive inserts including an arcuate peripheral surface |
-
2005
- 2005-01-12 KR KR1020050003047A patent/KR100697919B1/en active IP Right Grant
-
2006
- 2006-01-11 CN CNB2006100005956A patent/CN100538922C/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104350553A (en) * | 2012-05-30 | 2015-02-11 | 西门子公司 | Encapsulated surge protector having central duct |
| CN104350553B (en) * | 2012-05-30 | 2017-09-29 | 西门子公司 | Packaged type discharge device for overvoltage protection with center sleeve |
| CN104681219A (en) * | 2013-11-29 | 2015-06-03 | 聚鼎科技股份有限公司 | Plug-in type overcurrent protection element |
| CN104681219B (en) * | 2013-11-29 | 2017-11-10 | 聚鼎科技股份有限公司 | Plug-in type overcurrent protection element |
Also Published As
| Publication number | Publication date |
|---|---|
| CN100538922C (en) | 2009-09-09 |
| KR20060082363A (en) | 2006-07-18 |
| KR100697919B1 (en) | 2007-03-20 |
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