EP0057452B1 - Vorrichtung zum Einschränken eines Lichtbogens in einem Schutzschalter - Google Patents

Vorrichtung zum Einschränken eines Lichtbogens in einem Schutzschalter Download PDF

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Publication number
EP0057452B1
EP0057452B1 EP19820100646 EP82100646A EP0057452B1 EP 0057452 B1 EP0057452 B1 EP 0057452B1 EP 19820100646 EP19820100646 EP 19820100646 EP 82100646 A EP82100646 A EP 82100646A EP 0057452 B1 EP0057452 B1 EP 0057452B1
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EP
European Patent Office
Prior art keywords
arc
contacts
stationary
contact
plan
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP19820100646
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English (en)
French (fr)
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EP0057452A3 (en
EP0057452A2 (de
Inventor
Hajimu Yoshiyasu
Yuichi Wada
Fumiyuki Hisatsune
Junichi Terachi
Shinji Yamagata
Kiyomi Yamamoto
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Mitsubishi Electric Corp
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Mitsubishi Electric Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP1333681A external-priority patent/JPS57126033A/ja
Priority claimed from JP1333781A external-priority patent/JPS57126034A/ja
Priority claimed from JP1245381A external-priority patent/JPS57126027A/ja
Priority claimed from JP1333581A external-priority patent/JPS57126032A/ja
Priority claimed from JP1333881A external-priority patent/JPS57126035A/ja
Priority claimed from JP1245281A external-priority patent/JPS57126026A/ja
Priority claimed from JP1245481A external-priority patent/JPS57126028A/ja
Priority claimed from JP1245581A external-priority patent/JPS57126029A/ja
Application filed by Mitsubishi Electric Corp filed Critical Mitsubishi Electric Corp
Publication of EP0057452A2 publication Critical patent/EP0057452A2/de
Publication of EP0057452A3 publication Critical patent/EP0057452A3/en
Application granted granted Critical
Publication of EP0057452B1 publication Critical patent/EP0057452B1/de
Expired legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H9/00—Details of switching devices, not covered by groups H01H1/00 - H01H7/00
    • H01H9/30—Means for extinguishing or preventing arc between current-carrying parts

Definitions

  • circuit breakers In prior-art circuit breakers, it has been common practice to shift the arc into an arc extinguisher or to raise the separating speed of the contacts in order to quickly extinguish an electric arc struck across the gap between a pair of contacts during the interrupting operation.
  • Such circuit breakers suffer from the disadvantage that the foot of the arc struck across the gap between the contacts expands to fall onto the contactor conductors on which the contacts are mounted, and metal particles produced from the contact surfaces are not effectively injected into the arc space, so that the arc voltage, which relates to the extinction of the arc, is lowered.
  • the document DE-A-1 765 999 describes the disposition of the contacts in a circuit breaker having the construction as defined above, and the arc foot surface is reduced in this circuit breaker in order to increase the arc voltage.
  • the means for attaining this aim consist in: contactors, conductors and contacts, an arc shield disposed on the fixed contactor, having a resistivity higher than that of the conductors and surrounding on three sides the associated contact piece.
  • the circuit breaker includes further arc driving means and an arc runway extending in a predetermined direction and adjoining the fixed contact.
  • the invention relates to an arc restricting device for a circuit breaker as defined above and having the features disclosed in the characterising part of claim 1.
  • An enclosure 1 is made of an insulating material, forming the housing for a switching device, and is provided with an exhaust port 101.
  • a stationary contactor 2 housed in the enclosure 1 comprises a stationary rigid conductor 201 which is rigidly fixed to the enclosure 1, and a stationary-side contact 202 which is mounted on one end of the stationary rigid conductor 201.
  • a movable contactor 3 which is adapted to engage the stationary contactor 2 comprises a movable rigid conductor 301 which makes or breaks contact with the stationary rigid conductor 201, and a movable-side contact 302 which is mounted on one end of the movable rigid conductor 301 in opposition to the stationary-side contact 202.
  • An operating mechanism 4 operates to move the movable contactor 3 in or out of contact with the stationary contactor 2.
  • the arc-extinguishing plates 501 are illustrated in numbers of two and four in Figures 1 (b) and 1(c), respectively, it is to be understood that actually the number of arc-extinguishing plates 501 in the arc-extinguishing plate assembly 5 may be as high as, for example, ten plates.
  • the operating mechanism 4 and the arc-extinguishing plate assembly 5 are well known in the art, and are described, for example, in US-A-3,599,130. As is apparent from this patent, the operating mechanism includes a reset mechanism.
  • the arc voltage rises as the distance of separation of the movable-side contact 302 from the stationary-side contact 202 increases.
  • the arc-extinguishing plates 501 are made of a magnetic material and have a reluctivity much lower than that of the surrounding space, a magnetic flux induced by the current of the arc A is attracted in the direction V ( Figure 1(b)) of the arc-extinguishing plates 501. Accordingly, the arc A is drawn toward the arc-extinguishing plates 5 and is stretched, whereby the arc voltage rises even further.
  • a method utilizing an air current is also well known, in addition to the above method utilizing a magnetic field. More specifically, the arc is driven by the air current which is created when the air in the enclosure 1 is raised in temperature and pressure by the energy of the arc A and is discharged through the exhaust port 101.
  • a means for driving the arc utilizing a magnetic field in addition to the above described method employing arc-extinguishing plates 501, also well known are a method employing a blowout coil, a blowout magnet, or a permanent magnet; a method utilizing a parallel current which flows in the reverse direction across the stationary rigid conductor 201 and the movable rigid conductor 301, etc.
  • the arc current reaches the current zero point to extinguish the arc A, so that the interruption is completed.
  • the power supply is a D.C. power supply
  • an arc voltage greater than the supply voltage is generated, whereby a current limiting action is effected and the current zero point is forcibly established.
  • a D.C. power supply accordingly, a phenomenon similar to that in the case of the foregoing A.C. current zero point occurs.
  • large quantities of energy are generated by the arc A across the gap between the movable-side contact 302 and the stationary-side contact 202 in a short period of time of the order of several milliseconds. In consequence, the temperature of the gas within the enclosure 1 rises abruptly, as does the pressure thereof, and the high temperature and pressure gas is emitted into the atmosphere through the exhaust port 101.
  • the operations of the stationary-side contact 202 and the movable-side contact 302 can be analyzed as follows.
  • the arc resistance R(Q) is given by the following expression:
  • the arc space is occupied by particles of metal from the rigid conductors on which the arc has its foot.
  • the emission of metal particles from the rigid conductors occurs orthogonally to the rigid conductor surfaces.
  • the emitted metal particles have a temperature close to the boiling point of the metal used in the rigid conductors.
  • the metal particles possess a conductivity due to the electrical energy of the arc and they are also further raised in temperature by the arc, and flow away from the rigid conductors at high speed while expanding in a direction conforming with the pressure distribution in the arc space.
  • the arc resistivity p and the arc sectional area S in the arc space are determined by the quantity of metal particles produced and the direction of emission thereof. Accordingly, the arc voltage is determined by the behaviour of such metal particles.
  • the contour Z indicated by a dot-and-dash line in the figure is the envelope of the arc A struck across the gap between the rigid conductors 6 and 7.
  • metal particles b are typically representative of the metal particles which are respectively emitted from the surfaces X and Y of the conductors 6 and 7 by vaporization, etc.
  • the directions of emission of the metal particles a and b are the directions of the flow lines indicated by arrows m, m' and n, n', respectively.
  • Such metal particles a and b emitted from the rigid conductors 6 and 7 have their temperature raised by the energy of the arc space from approximately 3,000°C, the boiling point of the metal of the rigid conductors, to a temperature at which the metal particles bear conductivity, i.e., at least 8,000°C, or up to an even higher temperature of approximately 20,000°C.
  • the metal particles take energy out of the arc space and thus lower the temperature of the arc space, resulting in increased arc resistance R.
  • the quantity of energy taken from the arc space by the metal particles a and b increases with the rise in the temperature of the metal particles.
  • the unidirectional blowing from the rigid conductor 7 heats the rigid conductor 6 on the blown side and expands the foot (anode spot in some cases, and cathode spot in others) of the arc on the surface of the rigid conductor 6 from the front surface X thereof to the other surface thereof.
  • the current density on the surface of the conductor 6 lowers, as does the pressure of the arc.
  • the unidirectional blowing from the rigid conductor 7 is increasingly intensified.
  • the discrepancy in the flight paths of the metal particles a emitted from the respective rigid conductors 6 and 7 as has thus occurred results in a discrepancy in the quantities of energy that the particles of both the conductors take from the arc space.
  • a metal particle a blown from the contact surface X of the rigid conductor 7 is able to absorb substantial energy from the positive column, whereas a metal particle a blown from the contact surface X of the rigid conductor 6 is not, and so it is ejected out of the system without effectively cooling the arc A.
  • metal particles b emitted from the surfaces Y of the respective rigid conductors 6 and 7 spread transversely as indicated by the flow lines of the arrows n and n' in Figure 2. Therefore, they do not deprive the arc A of substantial heat. Moreover, they increase the arc sectional area S, resulting in lowered resistance R of the arc A.
  • the efficiency of the cooling of the positive column by the metal particles a from the other rigid conductor 6 is reduced.
  • the metal particles b emitted from the surfaces Y of both the rigid conductors 6 and 7, being those surfaces other than the opposing contact surfaces do not contribute to the cooling of the positive column at all and may even lower the arc resistance R by increasing the arc sectional area S. Accordingly, the presence of the unidirectional blowing of the metal particles from one rigid conductor to the other is impedimental to raising the arc voltage and renders it impossible to enhance the current-limiting performance during tripping.
  • the stationary contactor and the movable contactor used in conventional circuit breakers have large opposing surface areas, similar to the conductors of the model of Figure 2, making it impossible to limit the size of the foot of the struck arc.
  • the contactors have exposed surfaces such as peripheral surfaces in addition to the opposing surfaces, so that, as explained with reference to Figure 2, the position and size of the foot (anode spot or cathode spot) of the arc appearing on the surfaces of the two conductors cannot be limited.
  • the unidirectional blowing of the metal particles a from one contactor to the other occurs, with the result that the arc sectional area increases as explained with reference to Figure 2, such that the current-limiting performance during tripping cannot be enhanced, as stated above.
  • the arc voltage has to be raised, and to this end, the metal particles appearing in the foot of the arc need to be effectively injected into the positive column from both electrodes.
  • the force which injects the metal particles into the positive column is the pressure based on the pinch force arising in the foot of the arc.
  • the pinch force changes greatly in accordance with the size of the foot of the arc oh the contactors, or with the current density. It is accordingly possible to control the pinch force.
  • the area of the surfaces X of the conductors is large, which fact effectively prevents a limitation of the size of the foot of the arc.
  • the spread of the foot of the arc to the surface Y leads to the disadvantage that the foot of the arc is liable to spread directly to the interfacing point between the contact and the conductor which is often set on the surface Y, and a joint member of a low fusing point may be melted by the heat of the arc making the contact liable to fall off.
  • the invention relates to a circuit breaker which provides good current-limiting performance in the interruption of excess currents such as accompany electric faults, and which also has a high arc voltage, and yet in which the problem of the contacts falling off is eliminated.
  • the above and other objects can be achieved by covering and concealing the portions of the rigid conductors in the vicinity of the contacts behind arc shields of a high resistivity material with a higher resistivity than the material forming the rigid conductors (hereinbelow simply called high resistivity material), leaving a portion of the electrical contact surface of the contacts of the circuit breaker, whereby the metal particles will be forcibly injected into the arc space, and wherein the arc shields are of a predetermined form.
  • a high resistivity material with a higher resistivity than the material forming the rigid conductors
  • organic or inorganic insulators as well as high resistivity alloys or metals, such as copper- nickel, copper-manganese, manganin, iron- carbon, iron-nickel and iron-chromium, may be used. It is also possible to use iron the resistivity of which increases abruptly with temperature.
  • Figures 3(a) and 3(b) are respectively a sectional plan view and a sectional side view of an embodiment showing the basic construction of this invention.
  • Parts of the circuit breaker other than the stationary contactor 2 and the movable contactor 3 are constructed similarly to the corresponding parts of the circuit breaker of the prior art shown in Figures 1(a), 1(b) and 1(c), and so description thereof will not be repeated.
  • the dimensions to be mentioned hereinbelow relate to a circuit breaker in which the rated current is 100 A.
  • the stationary contactor 2 is constructed with a stationary rigid conductor 201, an arc shield 8 and a stationary-side contact 202.
  • the plate-form stationary rigid conductor 201 is made of an electrically conductive material, such as copper, and in the described embodiment it is formed with a width of 8 mm, while the thickness is 3,2 mm.
  • the lower surface of the stationary rigid conductor 201 is fastened to the enclosure 1.
  • the stationary-side contact 202 is made of a silver alloy contact material, and is formed in the shape of a rectangular block with a square base of 4,5 mm sides and a height of 3,5 mm.
  • the bottom surface of the stationary-side contact 202 is fastened to the top surface of the stationary rigid conductor 201 near the fore end thereof.
  • the silver alloy contact material may contain tungsten carbide (WC) or iridium.
  • the arc shield 8 is made of a high resistivity material as above described, or an insulating material such as a phenol resin or a ceramic. It is formed in a plate form of regular square plan with sides of 12 mm, while the thickness is 2 mm. Centrally of the arc shield 8 is provided a square through-hole of sides of approximately 4,5 mm, in length, corresponding to the stationary-side contact 202, and the stationary-side contact 202 projects through this hole. In this way, the arc shield 8' not only covers the upper surface of the stationary rigid conductor 201 in the vicinity of the stationary-side contact 202, but it also substantially projects horizontally beyond the sides or edges of the stationary rigid conductor 7.
  • the movable contactor 3. is constructed with a movable rigid conductor 301, a movable-side contact 302, and an arc shield 9, each of which is respectively constructed of the same materials as the corresponding portions of the stationary contactor 2.
  • the movable rigid conductor 301 is formed in a rod shape of 3,2 mm thickness and 3,2 mm width, and to its lower surface near the fore end thereof is affixed the upper surface of the movable-side contact 302.
  • the movable side contact is formed in the shape of a rectangular block with a square base of 3,2 mm sides, and a height of 3,5 mm.
  • the arc shield 9 is formed in a plate form of regular square plan with sides of 7,5 mm, while the thickness is.2 mm. Centrally of the arc shield 9 is provided a square through-hole of sides of approximately 3,2 mm length, corresponding to the movable-side contact 302 which projects therethrough. In a manner similar to the arc shield 8 on the side of the stationary contactor 2, the arc shield 9 substantially projects horizontally beyond the sides or edges of the movable rigid conductor 301.
  • Figure 4 is a model diagram showing the behaviour of the metal particles in the circuit breaker of Figures 3(a) and 3(b).
  • the metal particle behaviour to be described may also be regarded as being substantially identical in an instance where the surfaces X are constructed of the contact material.
  • a pair of rigid conductors 6 and 7 are constructed in the same form as those of Figure 2, and the arc shields 8 and 9 respectively project beyond the surfaces X, the opposing surfaces of the respective rigid conductors 6 and 7, and are affixed to the respective rigid conductors 6 and 7.
  • the pressure values in the spaces Q cannot exceed the pressure value of the space of the arc A itself. However, much higher values are exhibited, at least in comparison with the values attained without the arc shields 8 and 9.
  • the peripheral spaces Q which have the relatively high pressures caused by the arc shields 8 and 9 generate forces that suppress the spread of the space of the arc A and confine the arc A to a small area.
  • the arc shields 8 and 9 as shown, for example, in Figures 3(a) and 3(b) are disposed near and around the contact surfaces of the stationary-side contact 202 and the movable-side contact 302, namely the opposing surfaces X shown in Figure 4, the arc A-is prevented from moving to the other surfaces Y of the rigid conductors, and also the size of the foot of the arc A is limited.
  • the emission of metal particles a and c is concentrated on the surfaces X, and the arc sectional area S is contracted, so that the effective injection of the metal particles a and c into the arc space is further promoted. Accordingly, the cooling of the arc space, and the rise of the arc resistivity and of the arc resistance R are further improved, and the arc voltage can be further raised.
  • Figures 5(a) and (b) to Figures 12(a) and (b) relate to various embodiments of a contactor of a circuit breaker according to the present invention.
  • the illustration is restricted for simplicity to the stationary contactor side as exemplary of the embodiment as a whole. That is to say, the arc shield or contact on the movable contactor side in each embodied case may be regarded as being provided similarly and with a similar configuration to the corresponding stationary contactor side arc shield or contact, and so illustration is omitted.
  • Figures 5(a) and (b) illustrate an embodiment wherein the arc shield 8 and the contact 202 have substantially the same form in plan view, and they are respectively affixed to the rigid conductor 201 of the stationary contactor 2 such that their planar centers substantially coincide.
  • Figure 5(a) is a plan view of the contact portion of the stationary contactor 2 of the embodiment
  • Figure 5(b) is a side view of the same.
  • the plan form of the arc shield 8 affixed to the stationary rigid conductor 201 of the stationary contactor 2 is substantially the same as that of the stationary-side contact 202, and the planar centers of the arc shield 8 and the stationary-side contact 202 are arranged so as to substantially coincide.
  • the contact and the arc shield each have a shape which in plan view is substantially trapezoidal.
  • the periphery of the arc is subject to an equal compressive force from the anode or cathode spots in the vicinity of the contacts, to the positive column in the center of the arc, by the arc shields 8 and 9 which are similar in plan form to the respective contacts 202 and 302, and so efficient confining of the arc A is achieved from the moment that the arc is produced.
  • the potential inclination of the anode and cathode and the positive column can be effectively raised from the moment of arc generation, and the arc voltage between the contacts can be further increased.
  • the stationary-side contact 202 and the arc shield 8 are shown as having a trapezoidal shape in plan view, but, of course, they may have any suitable shape, such as round, rectangular, elliptical, polygonal, etc.
  • the dimensions of the stationary contactor 2 of Figures 5(a) and 5(b) are fundamentally the same as the corresponding dimensions in the embodiment of Figures 3(a) and 3(b), but the stationary-side contact 202 is a trapezoid of parallel sides of 3 mm and 6 mm length, and of a height of 5 mm.
  • the height of the contact 202 itself is 3,5 mm, and the lower surface of the contact 202 is affixed to the upper surface of the stationary rigid conductor 201.
  • the arc shield 8 is 2 mm thick, and is formed as a trapezoid in plan view, with parallel sides of 9 mm and 20 mm length and a height of 20 mm. Centrally of the arc shield 8 is provided a through-hole of trapezoidal plan, substantially corresponding in size and shape to the stationary-side contact 202 which projects therethrough.
  • Figures 6(a) and 6(b) illustrate an embodiment wherein the contact 202 is rectangular in plan and the arc shield 8 is circular in plan.
  • Figure 6(a) is a plan view of the contact portion of the stationary contactor 2 of the embodiment
  • Figure 6(b) is a side view of the same.
  • the peripheral shape of the arc A produced between the stationary-side contact 202 and the movable-side contact 302 as shown in Figure 3(b), in the vicinity of the rectangular stationary-side contact 202 and the movable-side contact 302 is rectangular, closely resembling the shape of the contacts 202 and 302.
  • the sectional shape of the arc A is made circular by the pinch effect of the arc A itself.
  • the round portion of the section of the arc A i.e. the outer periphery of the central portion of the arc positive column, is evenly subjected to a confining force as hereinabove described, and the potential inclination of the positive column is effectively raised, while the arc voltage between the contacts is further increased.
  • the dimensions of this embodiment are the same as the dimensions of corresponding portions in the embodiment of Figures 3(a) and 3(b).
  • the arc shield 8 is 2 mm thick, and is circular in plan with a 25 mm diameter, and a rectangular through-hole is provided centrally thereof with a shape and size substantially corresponding to the stationary-side contact 202 which projects therethrough.
  • Figures 7(a) and 7(b) illustrate an embodiment wherein the contact 202 is circular in plan and the arc shield 8 is rectangular in plan.
  • Figure 7(a) is a plan view of the contact portion of the stationary contactor 2 of the embodiment
  • Figure 6(b) is a side view of the same.
  • the peripheral shape of the arc A produced between the stationary-side contact 202 and the movable-side contact 302 as shown in Figure 3(b), in the vicinity of the circular stationary-side contact 202 and movable-side contact 302 is circular, closely resembling the shape of the contacts 202 and 302.
  • the dimensions of this embodiment are basically the same as the corresponding dimensions in the embodiment of Figures 3(a) and 3(b), except that the stationary-side contact 202 is of circular plan with a 6 mm diameter.
  • the height of the contact is 3,5 mm.
  • the arc shield 8 is rectangular in plan, being 20 mm wide and 25 mm long, and has a plate-like configuration.
  • the arc shield 8 is 2 mm thick.
  • a circular through-hole is provided centrally of the arc shield 8 with a shape and size substantially correspoinding to the stationary-side contact 202 which projects therethrough.
  • Figures 9(a), 9(b), 9(c) and 9(d) illustrate an embodiment wherein the stationary contactor 2 and the movable contactor 3 have the planar center points of their respective arc shields 8 and 9 located further from the arc-extinguishing plate assembly than the respective planar center points of the contacts 202 and 302.
  • Figure 9(a) is a plan view of the contact portion of a stationary contactor of this embodiment, and Figure 9(b) is a side view of the same.
  • Figure 9(c) is a plan view of the contact portion of a movable contactor of this embodiment, and Figure 9(d) is a side view of the same.
  • the arc shield 8 affixed to the rigid conductor 201 of the stationary contactor 2 has its planar central point located more remote from the arc-extinguishing plate assembly than the planar central point of the stationary-side contact 202, and similarly the arc shield 9 on the side of the movable contactor 3 has its planar central point located more remote from the arc-extinguishing plate assembly than the planar central point of the movable-side contact 302.
  • the arc A generated across the gap between the stationary-side contact 202 and the movable-side contact 302 is distorted towards the side of the arc-extinguishing plate assembly.5 and the exhaust port 101 in Figure 3(b), and cooling of the arc A by the arc-extinguishing plate assembly 5, or the exhausting of hot gas from the exhaust port 101 are carried out with good effect.
  • the potential inclination of the positive column is effectively raised, and the arc voltage between the contacts is further increased.
  • each of the arc shields 8 and 9 is provided with a through-hole of dimensions and configuration substantially corresponding to the respective contacts 202 and 302 which respectively project therethrough.
  • Figures 10(a) and 10(b) illustrate an embodiment wherein the arc shield 8 is formed with a concave surface.
  • Figure 10(a) is a plan view of the contact portion of a stationary contactor of this embodiment
  • Figure 10(b) is a side view of the same.
  • the surface of the arc shield 8 is concave in form, and so when an arc A is produced between the stationary-side contact 202 and the movable-side contact 302 at the moment of the tripping operation of the circuit breaker, as shown in Figure 3(b) the arc A is even more strongly confined, and the cross-sectional diameter of the arc column becomes even smaller than in the case with a flat plate arc shield. Accordingly, the potential inclination of the anode and cathode and the positive column are effectively raised from the moment of generation of the arc A, and the arc voltage between the contacts can be further increased.
  • the dimensions of this embodiment are substantially the same as the corresponding dimensions of the embodiment of Figures 6(a) and6(b), except that the arc shield 8 is provided substantially centrally on the surface which opposes the arc A, with a spherical concavity with a surface radius of curvature of approximately 50 mm, and the thickness of the arc shield 8 at its thinnest point, i.e. in the vicinity of the central point, is approximately'2 mm.
  • the concave depression is formed substantially concentrically with the arc shield 8, but does not extend fully to the outer circumference of the latter, leaving a flat circular band of 3 mm width around the concave depression.
  • Figures 11(a) and T1(b) illustrate an embodiment wherein the arc shield-8 is formed with a convex surface.
  • Figure 11 (a) is a plan view of the contact portion of a stationary contactor of this embodiment, and
  • Figure 11(b) is a side view of the same.
  • the surface of the arc shield 8 is convex in form, and so the force confining the arc A at the time of the tripping operation of the circuit breaker, 'as shown in Figure 3(b), is inferior in its positive column potential inclination raising power as compared to the concave arc shield shown in Figures 10(a) and 10(b), but it does have the advantage that even where repeated switching of the contact causes wear of the contacts, the arc shields themselves will not make physical contact.
  • the dimensions of this embodiment are substantially the same as the corresponding dimensions of the embodiment of Figures 6(a) and 6(b), except that the surface of the arc shield 8 which opposes the arc A is formed with a spherical convexity of a radius of curvature of approximately 50 mm.
  • the convexity extends fully to the outer circumference of the circular arc shield 8, and the thickness of the arc shield 8 at its thickest point, i.e. in the vicinity of its central point, is approximately 2 mm.
  • Figures 12(a) and 12(b) illustrate an embodiment wherein the surface of the arc shield 8 has an inclination.
  • Figure 12(a) is a plan view of the contact portion of a stationary contactor of this embodiment
  • Figure 12(b) is a side view of the same.
  • the flat top surface of the arc shield 8 is inclined downwards in the direction in which the arc A bows towards the arc-extinguishing plate assembly, and so directionality is imparted to the force that confines the arc A at the time of the tripping operation of the circuit breaker, as shown in Figure 3(b), and the arc length, i.e. the length of the current path, tends to increase.
  • the length of the arc grows orthogonally to the contact surfaces of the stationary-side contact 202 and the movable-side contact 302, and due to the spaces Q, as shown in Figure 4, produced by the arc shield 8 with an inclined surface, the length of the arc varies in a direction orthogonal to the arc shield 8. As a result, the length of the arc increases and the arc voltage between the contacts is further increased.
  • the dimensions of the embodiment are substantially the same as the corresponding dimensions of the embodiment of Figures 3(a) and 3(b), except that the surface of the arc shield 8 which opposes the arc A is formed with an inclination downwards in the direction of the arc-extinguishing plate assembly or the exhaust port, whereby the thickness of the arc shield 8 decreases gradually and evenly from its thickest point, the edge farthest from the arc-extinguishing plate assembly or exhaust port, where it is substantially 3 mm thick, to its thinnest point, the edge nearest the arc-extinguishing plate assembly or exhaust port, where it is substantially 1 mm thick.
  • Figures 13(a) and 13(b) illustrate an embodiment wherein the width of the contact decreases as it approaches' the circuit breaker's arc-extinguishing plate assembly or gas exhaust port.
  • Figure 13(a) is a plan view of the contact portion of a stationary contactor of this embodiment, and
  • Figure 13(b) is a side view of the same.
  • the arc A generated between the stationary-side contact 202 and the movable-side contact 302 during the tripping operation of the circuit breaker, as shown in Figure 3(b), is drawn by the arc-extinguishing plate assembly 5 which is made of a magnetic material, and it moves in the direction of the exhaust port 101 due to the flow of the arc A, which has a high pressure, and so as the arc A moves, the width of its foot on the contact narrows.
  • the arc voltage can be even further raised.
  • the arc shield is circular in form, but as the cross-sectional shape of the arc column comes to resemble the shape of the stationary-side contact 202 and the movable-side contact 302, having the shape of the arc shields 8 and 9 resemble the shape of the stationary-side contact 202 and the movable-side contact 302 further raises the effectiveness.
  • the stationary-side contact 202 has a substantially triangular plan, the base of the triangle being 5 mm and the height of the triangle being 8 mm.
  • the height of the contact is 3,5 mm, and the contact is affixed on its lower surface to the upper surface of the stationary rigid conductor 201.
  • the arc shield 8 is a circular plate in form, 25 mm in diameter and 2 mm thick, and is provided at its central portion with a through-hole of a size and configuration substantially the same as the stationary-side contact 202 which projects therethrough.

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  • Arc-Extinguishing Devices That Are Switches (AREA)

Claims (10)

1. Lichtbogen begrenzende Vorrichtung für Schalter mit einem Paar von Kontaktgebern (2, 3), die jeweils einen starren verlängerten Leiter (201, 301) umfassen, an dem an einem Ende ein Kontakt (202, 302) befestigt ist, wobei die Kontaktgeber (2, 3) derart funktionieren, daß sie den Stromkreis öffnen oder schließen, und mit Lichtbogenblenden (8, 9), welche auf den Leitern (201, 301) angeordnet sind, dadurch gekennzeichnet, daß diese Lichtbogenblenden (8, 9) die Kontakte (202, 302) umgeben und dahinter die starren Leiter (201, 301) in der Umgebung der Kontakte (202, 302) bedecken bzw. verdecken, wobei die Lichtbogenblenden (8, 9) über die Seiten am Ende der verlängerten festen Leiter (201, 301) sich hinaus erstrecken und einen Widerstand haben, der höher ist als der der festen Leiter (201, 301) der Kontaktgeber (2, 3).
2. Lichtbogen begrenzende Vorrichtung gemäß Anspruch 1, in der die Lichtbogenblenden (8, 9) die auf den starren Leitern (201, 301) befestigt sind, in der Planfläche eine der Kontakte (202, 302) ähnliche Form haben, und die Lichtbogenblenden (8, 9) auf den starren Leitern (201, 301) derart befestigt sind, daß ihre planare Zentren im wesentlichen jeweils mit den planaren Zentren der Kontakte (202, 302) übersteinstimmen.
3. Lichtbogen begrenzende Vorrichtung nach Anspruch 1, worin die Formen der Lichtbogenblenden (8, 9) und der Kontakte (202, 302) im wesentlichen voreinander unterschiedlich sind.
4. Lichtbogen begrenzende Vorrichtung gemäß Anspruch 3, worin die Kontakte (202, 302) in der Planfläche rechteckig und die Lichtbogenblenden (8, 9) in der Planfläche kreisförmig sind, und die Lichtbogenblenden (8, 9) auf den starren Leitern (201,301) derart befestigt sind, daß ihre planaren Zentren im wesentlichen jeweils mit den planaren Zentren der Kontakte (202, 302) übereinstimmen.
5. Lichtbogen begrenzende Vorrichtung gemäß Anspruch 3, worin die Kontakte (202, 302) in ihrer Planfläche kreisförmig und die Lichtbogenblenden in ihrer Planfläche rechteckig sind und die Lichtbogenblenden (8, 9) auf den starren Leitern (201, 301) derart befestigt sind, daß ihre planaren Zentren im wesentlichen jeweils mit den planaren Zentren der Kontakte (202,302) übereinstimmen.
6. Lichtbogen begrenzende Vorrichtung gemäß Anspruch 1, worin die Lichtbogenblenden (8, 9) derart auf den starren Leitern (201, 301) befestigt sind, daß ihre planaren Zentren jeweils in eine vorbestimmte Richtung versetzt von den planaren Zentren der Kontakte (202, 302) befestigt sind.
7. Lichtbogen begrenzende Vorrichtung nach Anspruch 1, worin die Oberflächen der Lichtbogenblenden (8, 9), die die Kontakte (202, 302) umgeben, konkav ausgebildet sind.
8. Lichtbogen begrenzende Vorrichtung nach Anspruch 1, worin die Oberflächen der Lichtbogenblenden (8, 9), die die Kontakte (202, 302) umgeben, konvex ausgebildet sind.
9. Lichtbogen begrenzende Vorrichtung nach Anspruch 1, worin die Oberflächen der Lichtbogenblenden (8, 9), die die Kontakte (202, 302) umgeben, mit einer Neigung in eine vorbestimmte Richtung versehen sind.
10 Lichtbogen begrenzende Vorrichtung nach Anspruch 1, worin die Breite der Kontakte (202, 302) in einer Richtung schrittweise (nach und nach) abnimmt.
EP19820100646 1981-01-29 1982-01-29 Vorrichtung zum Einschränken eines Lichtbogens in einem Schutzschalter Expired EP0057452B1 (de)

Applications Claiming Priority (16)

Application Number Priority Date Filing Date Title
JP13335/81 1981-01-29
JP1245281A JPS57126026A (en) 1981-01-29 1981-01-29 Circuit breaker
JP13336/81 1981-01-29
JP13337/81 1981-01-29
JP12452/81 1981-01-29
JP1245581A JPS57126029A (en) 1981-01-29 1981-01-29 Circuit breaker
JP12455/81 1981-01-29
JP12453/81 1981-01-29
JP1333881A JPS57126035A (en) 1981-01-29 1981-01-29 Circuit breaker
JP12454/81 1981-01-29
JP13338/81 1981-01-29
JP1333781A JPS57126034A (en) 1981-01-29 1981-01-29 Circuit breaker
JP1333681A JPS57126033A (en) 1981-01-29 1981-01-29 Circuit breaker
JP1245481A JPS57126028A (en) 1981-01-29 1981-01-29 Circuit breaker
JP1333581A JPS57126032A (en) 1981-01-29 1981-01-29 Circuit breaker
JP1245381A JPS57126027A (en) 1981-01-29 1981-01-29 Circuit breaker

Publications (3)

Publication Number Publication Date
EP0057452A2 EP0057452A2 (de) 1982-08-11
EP0057452A3 EP0057452A3 (en) 1982-09-01
EP0057452B1 true EP0057452B1 (de) 1985-07-03

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Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1008383B (de) * 1953-01-21 1957-05-16 Siemens Ag Schaltstueck
US3166660A (en) * 1960-05-09 1965-01-19 Square D Co Contact construction with metallic contact members and auxiliary metallic arc suppressant conducting members
US3310649A (en) * 1964-10-21 1967-03-21 Greber Henry Electrical switch with electrostatic prevention of arc formation
FR1544754A (fr) * 1967-09-22 1968-11-08 Merlin Gerin Dispositif de contact à pression directe

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DE3264469D1 (en) 1985-08-08
EP0057452A2 (de) 1982-08-11

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