FR2830370A1 - BREAKER - Google Patents

Abstract

Objective: to improve the assembled structure of a power interruption section, so that the power interruption section can be assembled more easily, provide improved interruption performance and serve to reduce the cost of a case Structure: in a circuit breaker comprising a current interruption section, an opening and closing mechanism and a tripping device in the event of overcurrent, all of which are arranged in a housing 1 of the main circuit breaker body, the current interruption section, consisting of pads 8, 9 of fixed contact, of a pad 10 of bridging mobile contact, of a spring 11 of contact pressure, of a push rod 12 which functions in unison with the opening and closing mechanism for opening or closing the movable contact pad, a lateral pair of arc extinguishing devices 13 and an arc guide 14, all the components 8 to 14 of the section inte current break for each phase being integrated into a single prismatic unit 17 to constitute a break unit 16 for a pole. This interrupt unit is integrated in a lower case of the main circuit breaker body case. Here, the unitary housing 17 has gas emission orifices 17c which open into its right and left end surfaces, respectively. Gas produced during the power outage is forced to pass through the arc extinguishers to expand and cause an arc.

Description

BREAKER

  The present invention relates to a circuit breaker which is

  _ works in an automatic cut-off device.

  Figure 3 illustrates the configuration of a conventional circuit breaker, using the example of an automatic cut-off device. The reference numeral 1 designates a box forming the main circuit breaker body (resin box) divided into three components: a lower box, an intermediate box and an upper cover. Numerical references 2 and 3

  designate a power terminal and a charging terminal, respectively.

  o The reference numeral 4 designates a current interruption section integrated in the lower casing. The reference numeral 5 designates an opening and closing mechanism of the toggle link type installed in the intermediate housing. The reference numeral 6 designates an opening and closing handle. The reference numeral 7 designates an overcurrent release device comprising a combination of an open phase / thermal overload device 7a and a

  electromagnetic instantaneous tripping device 7b.

  In this case, the section 4 of current interruption corresponds to a phase and consists of a lateral pair of pads 8 and 9 of fixed contact o, of a pad 10 of bridging mobile contact extending at the terminals of the contacts. fixed contact pads 8 and 9, a contact pressure spring 11 which presses and urges the movable contact pad 10 against the contacts of the fixed contact pads 8 and 9, a thrust rod 12 linked to a lever 5a of entranement of the mechanism 5 of opening and closing, so as to open or close the pad 10 of movable contact in unison with the operation of the mechanism 5 of opening and closing, of the arc extinguishing devices 13 arranged on the left and right sides, respectively, of the movable contact pad 10, and an arc guide 14 placed on a bottom surface of the housing, so as to extend across the terminals of the devices 13 right and o left d arc extinction (the arc guide switches and guides an arc towards the devices ifs 13 of arc extinction, the arc being produced between the fixed and movable contacts when the current is interrupted). These components are integrated in the lower housing of housing 1 forming the main body, so that their number corresponds to the number of phases in a main circuit (a single phase or three phases). The fixed contact pad 8 is integrated with a terminal; its contact shoe driver has power terminal 2 attached to it. The other fixed contact pad 9 is connected to the charging terminal 3 via the device 7 for triggering in the event of an overcurrent. In addition, each of the arc extinguishing devices 13 comprises an arc extinguishing grid consisting of a plurality of plates in the form of grids in

U shape stacked vertically.

  Circuit breaker opening and closing operations

  configured as described above are well known, and their description is

  thus omitted. If an overcurrent goes through the main circuit to cause the circuit breaker to carry out a tripping operation, an arc produced between the contacts of the pads 8 and 9 of fixed contact and the pad 10 of movable contact is subjected to electromagnetic forces and is extended towards the arc extinguishing devices 13. The arc is then extinguished at the level of arc extinguishing devices 13 to interrupt the current. In addition, hot gas produced in an arc interrupting space is diffused laterally from a central part of an arc extinguishing chamber. The gas is then emitted through open ventilation holes in the right and left end surface, respectively, of the lower housing of the box 1 tier 1

main body.

  In addition, an assembled structure known from section 4 of current interruption is described in Japanese patent application published n 668771. In this structure, the parts, including the movable contact pad 10, the contact pressure spring 11 and the push rod 12, are assembled in a fixed cage 15 as a unit, and this cage is o integrated in a lower housing 1a of the housing forming the main body, together with other parts (the fixed contact pads 8 and 9, the arc extinguishing devices 13 and the arc guide 14), as shown in the

Figure 4.

  The assembled structure of section 4 of current interruption of the conventional circuit breaker described above has the following drawbacks: (1) During a step in the process of assembling the circuit breaker, to integrate section 4 of current interruption in the bo ^ 'lower tier of bo ^' tier forming main body, the various parts 8 to 15 constituting the section 4 of current interruption must be assembled individually together on the same assembly line. The result

  that a large number of assembly steps is required.

  (2) Gas pressure produced in the interrupting section at the same time as an arc during the current interruption is applied directly to the bottom 1a (Figure 4a) of the circuit breaker box. Consequently, the casing forming the main body of the circuit breaker must have a

  robust structure and, thus, increased pressure resistance.

  (3) In addition, in the assembled structure shown in FIG. 4, upper surfaces of the cage 15, which surround peripheral zones of the movable contact pad 10, and arc extinguishing devices 13 open in the interior space of the lower casing 1a of the main circuit breaker body. Consequently, gas produced when an interruption operation has been carried out as a result of an overcurrent which partially propagates on the arc extinguishing devices 13 and is then emitted towards the outside without passing through the devices d arc extinction. Thus, the force o of gas flow drive, which otherwise pushes an arc in the direction of the arc extinguishing device, does not work effectively. The arc driving force of the gas flow can be effectively applied by allowing all the gas produced to pass through the devices 13

arc extinction.

  The present invention is achieved by taking into account the various points above. An object of the present invention is to provide a circuit breaker in which the assembled structure of a current interruption section is improved to solve the problems mentioned above, can be assembled more easily, has so high performance. improved interruption and serves to reduce the cost of a circuit breaker box. To obtain the above-mentioned objective, the present invention aims at a circuit breaker comprising a current interruption section, an opening and closing mechanism, and a tripping device in the event of an overcurrent, all of which are arranged in a main body housing divided into an upper part and a lower part, the current interruption section consisting of a lateral pair of fixed contact pads, of a movable bridging contact pad located opposite the contact pads fixed and extending on both sides of the contaGts of the fixed contact pads, of a coritact pressure spring which presses and biases the loose contact pads against the fixed contact pads, of a push rod which works in unison with the opening and closing mechanism to open or close the movable contact pad, and a pair of arc quenching devices arranged on the left right side, respectively, of the movable contact pad, the circuit breaker being characterized in that: all the constituents of the current interruption section for each phase are integrated in a single unitary casing to constitute an interruption unit for a pole, and interpretation units, in number equal to the number of main circuit phases, are installed in a box

  lower part of the box forming the main body in juxtaposition.

  s In addition, on the basis of the configuration mentioned above, the interrupt unit can be constructed as follows: (1) The unitary casing of the interrupt unit is made of resin and shaped like a prism, and has gas emission ports formed in the right and left end surfaces, respectively,

  o located opposite the respective arc extinguishing devices in the housing.

  (2) The unitary housing has an arc guide installed on its bottom surface and extending across the terminals of arc extinguishing devices

right and left.

  With the above mentioned configuration, interrupt units for the respective poles are assembled on an assembly line which differs from that for the main body of the circuit breaker. A complete assembly is provided to the assembly line for the main circuit breaker body. Then, the assembly is integrated in the lower casing of the casing forming the main body. Thus, compared to the conventional assembled structure in which parts are integrated individually into the housing, the number of assembly steps required for the main body

  circuit breaker is decreased, increasing the flow of the assembly process.

  In addition, a gas pressure produced while an overcurrent is interrupted is not applied directly to the casing forming the main body of the circuit breaker. All the gas produced is forced to pass through the arc extinguishing devices in the unitary casing and is then emitted outwards through the gas emission orifices, which open into the end surfaces unit casing, and through ventilation holes in the main body casing. Thus, the pressure resistance required for the lower casing of the main circuit breaker body is reduced. In addition, s the gas flow produced during the power interruption allows an arc to be effectively drawn towards the extinguishing devices

  arc, improving interrupt output.

  An embodiment of the present invention is described on the basis of the example shown in Figures 1 and 2. In the figures of this example, the elements which correspond to Figures 3 and 4 are designated by

  the same reference numbers and their description is omitted.

  Figure 1 is a diagram of an interrupt unit, in accordance with an example of the present invention, in which Figures 1a and 1b are plan and front views respectively, and Figure s 1c is a view in vertical section of Figure 1 (b) showing its internal structure. Figure 2 is a diagram of an assembled structure in which interrupt units such as that shown in Figure 1 have been installed in a lower casing of a main circuit breaker body, Figure 2 (a ) being a plan view of a lower casing alone, Figure 2 (b) being a plan view showing that interrupt units have been integrated into the lower casing, and Figure 2 ( c) is a vertical sectional view of the

Figure 2 (b).

  Figure 3 is a sectional view showing the configuration of the complete conventional circuit breaker, using the example of an automatic breaking device. Figure 4 is an exploded perspective view of an example of the structure of a current interruption section of the conventional circuit breaker of

Figure 3.

  o First, the assembled structure of an interrupt unit

  according to the present invention is described with reference to Figures 1a to 1c.

  That is to say parts constituting a current interruption section - that is to say the pads 8 and 9 of fixed contact, a pad 10 of movable contact, a spring 11 of pressure of contact, a push rod 12, arc extinguishing devices 13 and an arc guide 14 are integrated into a housing 17

  unitary to constitute a unit 16 of interruption for a pole.

  Here, the unitary unit 17 is shaped like a prism (made of resin) and is divided into two parts - that is to say the housings 17a and 17b divided, as shown in FIG. 2b - which are integrated . The unitary housing 17 has an opening in the form of an outwardly-opening slot in the center of one of its upper surfaces, by which the pads 8 and 9 of fixed contact and the thrust rod 12 are pulled towards the outside. The unitary housing 17 also comprises emission orifices 17c which open in its right and left end surfaces, opposite the rear surface of the respective arc extinguishing devices 13. The divided boxes 17a and 17b are

  o coupled by snap-fastening or with screws.

  On the other hand, the main body of the circuit breaker (three phases) has #U sections. #V and #W of interruption unit insertion corresponding to the respective phases (U. V and W) defined inside a lower casing 1a by means of separation walls 1a-1 , as shown in Figure 2a. The interrupting units 16 such as those described above are installed in the respective insertion sections in juxtaposition, as shown in Figures 2b and 2c. The reference numeral 1 a-2 designates an air hole opening into

  each of the right and left end surfaces of the lower handpiece 1a.

  o In an assembled state of the circuit breaker in which the current interruption section is combined with an opening and closing mechanism and others, a lever 5a for driving an opening and closing mechanism 5, shown in Figure 3, is located opposite the rod 12 pushed upwardly projecting from the housing 17 unit of the unit 16 of interruption. The drive lever 5a operates in unison with an operation of the opening and closing mechanism for

  open or close the movable contact pad 10.

  With this configuration, when an arc is produced between movable / fixed contacts during a current interruption, hot gas is also produced in the casing of the interruption unit 16 around the arc and

  is diffused laterally from the center of the housing under arc pressure.

  The hot gas passes through the arc extinguishing devices 13 and is then emitted into the interior of the lower casing 1a of the main circuit breaker body passing through the gas emission orifices 17c which open into the surfaces right and left end of the unitary unit 17. The gas is then emitted to the outside through air holes 1a-2 which open into the respective end surfaces of the lower housing 1a. During this process, the gas flow effectively operates to entrain and

  push the arc towards the arc extinguishing devices 13. - -

  As described above, in accordance with the configuration of the present invention, all the components of the current interruption section to be integrated in a housing of a main circuit breaker body are integrated in a single unit housing for each phase to constitute a unit. of interruption for a pole, and interruption units of this gerre c

  installed in a lower case of the main body case. Through--

  o Consequently, the interrupting units assembled on a certain assembly line can be introduced into another assembly line for the main circuit breaker body. This significantly decreases the number of assembly steps required for the main circuit breaker body compared to the conventional structure. In addition, the gas pressure s produced during the power outage is not applied directly to the main circuit breaker body. Therefore, resistance to

  pressure required for the main body housing is decreased.

  Furthermore, in accordance with a configuration according to the invention, the unit housing of the interrupting unit is shaped in the form of a prism, and o has emission orifices formed in its right and left end surfaces, respectively, located opposite the respective arc extinguishing devices in the housing. With this configuration, all the gases produced in the unitary casing during the interruption of current at the same time as an arc pass through the arc extinguishing devices. This gas flow can effectively draw the arc towards the extinguishing devices

  arc to improve interrupt performance.

Claims (3)

CLAIMS - _   1. Circuit breaker comprising a section (4) for interrupting the current, a mechanism (5) for opening and closing, and a device (7) for tripping in the event of an overcurrent, all of which are arranged in a housing. (1) main body divided into an upper part and a lower part, the current interruption section (4) consisting of a lateral pair of fixed contact pads (8 and 9), a pad (10 ) of a bridging mobile contact situated opposite the fixed contact pads (8, 9) and extending on either side of the contacts of the fixed contact pads (8, 9), of a contact pressure spring o which presses and urges the movable contact pad (10) against the fixed contact pads (8, 9), a push rod (12) which functions in unison with the mechanism (5) for opening and closure to open or close the movable contact pad (10), and a pair of arc extinguishing devices (13) arranged on the right and left sides, respectively ement, of the shoe (10) of movable contact, the circuit breaker being characterized in that: all the components of the section (4) of current interruption for each phase are integrated into a single unit (17) for constitute an interrupt unit for a pole, and interrupt units in number equal to the number of main circuit phases are installed in a   o lower box of the main body box in juxtaposition.   2. Circuit breaker according to claim 1, characterized in that the unitary unit ^ of the interrupting unit is shaped like a prism, and comprises orifices (17a) for emitting gas formed in its end surfaces right and left, respectively, located opposite the devices   (13) respective arc extinction in the housing.   3. Circuit breaker according to claim 1 or 2, characterized in that the bo ^ 'tier (17) unit includes a guide (14) of arc installed on its bottom surface and extending on either side of the devices (13) arc extinction