EP0322321B1 - High caliber multipole breaker with mould case - Google Patents

Description

The invention relates to a low voltage multipolar circuit breaker, for high currents, comprising a plurality of poles juxtaposed inside an insulating molded case, each pole comprising a pair of separable contacts, an arc extinguishing chamber, a pair of contact pads connected to the separable contacts and projecting towards the outside of the housing, and a current transformer arranged around one of the contact pads and the output of which is connected to a trigger common to the different poles, the pads contacts being connected to terminal blocks intended to be connected respectively to the phases of a network to be protected.

The size of a circuit breaker of this type is, for a housing of predetermined size, determined by the choice of poles, that is to say essentially by the dimensions of the copperware associated with the pole.

The subject of the invention is the extension of a range of circuit breakers comprising a certain number of standard poles, so as to form, in a standard molded case, a circuit breaker of greater caliber than that of the individual standard poles which compose it, this goal to be achieved with a minimum number of modifications.

The document EP-A-117.094 describes a single-pole circuit breaker constituted by the parallel connection of elementary single-pole electromagnetic circuit breakers.

The circuit breaker according to the invention is characterized in that at least one of the connection bars, intended to be connected to one of the phases of the network, is connected to at least two adjacent twin poles, electrically arranged in parallel, at least one of the connection bars associated with another pole of the circuit breaker having a width such that it laterally protrudes from said pole and partially overlaps the immediately adjacent pole, so that the circuit breaker can be used for a rating greater than that of the individual standard poles that compose it.

According to a preferred embodiment, the connection bars projecting laterally from the associated pole have a flared shape, their smallest face being in contact with the rear face of the associated contact pad and the connection bar associated with the twin poles only covers 'A part of the associated contact pads, an isolation screen being arranged on the free part of the contact pads of the twin poles so as to ensure isolation between said pads and the adjacent connection bars.

In the case where the circuit breaker is of the plug-in type in a fixed frame carrying fixed connection pads intended to be connected by means of connection clamps to the circuit breaker connection strips, the width of the fixed pads and connection clamps is substantially equal to that of the corresponding bar, so as to form connection zones, at least one of which is wider than the associated pole and at least one of which, associated with the twin poles, has a width less than the previous one .

• la figure 1 est une vue éclatée, en perspective, d'un disjoncteur multipolaire, de type connu;
• la figure 2 est une vue en perspective du boîtier intermédiaire du disjoncteur selon la figure 1;
• la figure 3 est une vue en coupe longitudinale d'un pôle du disjoncteur selon la figure 1, représenté en position d'ouverture des contacts;
• la figure 4 est une vue de dessus schématique partielle, représentant les éléments de raccordement entre les plages de contact faisant saillie de la face arrière d'un disjoncteur à pôles jumelés selon l'invention et des plages fixes de raccordement solidaires d'un châssis, en coupe, dans lequel vient s'embrocher le disjoncteur;
• les figures 5 et 6 représentent en vue arrière,en perspective, la partie supérieure de deux modes de réalisation d'un disjoncteur à pôles jumelés selon l'invention;
• la figure 7 représente en perspective, un élément isolant appartenant aux éléments de raccordement représentés sur les figures 4, 5 et 6;
• la figure 8 illustre un ensemble capteur de courant utilisé dans un disjoncteur à pôles jumelés selon l'invention.

Other advantages and characteristics will emerge more clearly from the description which follows of different embodiments of the invention, given by way of nonlimiting examples and represented in the appended drawings, in which:

• Figure 1 is an exploded perspective view of a multipole circuit breaker of known type;
• Figure 2 is a perspective view of the intermediate case of the circuit breaker according to Figure 1;
• Figure 3 is a longitudinal sectional view of a pole of the circuit breaker according to Figure 1, shown in the open position of the contacts;
• Figure 4 is a partial schematic top view showing the connecting elements between the ranges of contact protruding from the rear face of a circuit breaker with twin poles according to the invention and fixed connection pads secured to a chassis, in section, in which the circuit breaker is connected;
• Figures 5 and 6 show a rear perspective view of the upper part of two embodiments of a twin pole circuit breaker according to the invention;
• 7 shows in perspective, an insulating element belonging to the connecting elements shown in Figures 4, 5 and 6;
• FIG. 8 illustrates a current sensor assembly used in a circuit breaker with twin poles according to the invention.

In FIGS. 1 to 3, a low-voltage multipolar circuit breaker, of known type, comprises a plurality of juxtaposed poles disposed inside a molded case made of insulating material. The parallelepiped housing consists of an intermediate housing 10 (FIG. 2), a cover 12 and a rear housing 14. The front face 16 of the intermediate housing 10 divides the housing into an anterior compartment 18, delimited by this face and by the cover 12, and in a rear compartment 20 intended for housing the poles and electrically isolated from the front compartment.

The front compartment 18 contains a control mechanism (not shown) acting on a transverse switching bar 22, common to all the poles. A lever 24 for arming the control mechanism, an electronic trip device (not shown) causing an automatic trip upon the occurrence of a fault current, and electrical measurement, signaling and control auxiliaries (not shown) are also housed in the front compartment 18.

The rear compartment 20 is subdivided longitudinally into elementary pole accommodation compartments by insulating walls 26 for separating the poles. Each pole of the rear compartment has a pair of separable contacts 28,30 and a removable arc extinguishing chamber 32. The fixed contact 28 is carried directly by a first contact pad 34 projecting slightly outward from the rear face of the rear housing 14. The movable contact 30 is connected by a flexible conductor 36 (braid) to a second contact pad 38, also projecting outwards from the rear face of the rear housing 14. A current transformer 40 is arranged around one of the contact pads, so as to provide the trigger with a current measurement passing through the corresponding pole.

The internal arrangement and operation of a circuit breaker of this type is known and reference will advantageously be made to French patents No. 2589624 and 2589625 (= EP-A- 0 225 207) for a more detailed description.

Such a circuit breaker is preferably designed so as to be withdrawable, that is to say intended to be plugged into a fixed frame 42 (Figure 4) carrying, on its rear face, two superimposed rows of fixed connection pads 44 intended to be connected respectively to the two superimposed rows of contact pads 34, 38 by means of connection clamps 46 each constituted by a plurality of fingers 48 of juxtaposed elementary contacts. French patents 2583217 and 2594265 respectively describe particular embodiments of connection clamps and of a racking-in and racking-out mechanism of a withdrawable circuit breaker of this type.

A range of known circuit breakers of this type includes two standard models of molded boxes, three-pole and four-pole, the size of which, from 800A to 3200A, is determined by the choice of poles housed in the elementary compartments, i.e. essentially by the dimensions of the contact pads 34, 38 secured to the housing, the clamps 46 and the pads 44 of connection secured to the chassis in the case of a withdrawable circuit breaker. The current transformers 40 also have a rating adapted to the rating of the circuit breaker.

According to the invention, it is possible to use the standard elements of known circuit breakers to form, in a molded case of standard dimension, a circuit breaker of greater caliber than that of the individual poles which compose it.

By way of nonlimiting example, FIGS. 4 and 5 illustrate, respectively in top view and in partial rear view, a three-pole circuit breaker of 4000A caliber constituted by a standard four-pole molded case in which four individual standard poles A, B are mounted. , C and D with a rating of 3200A. In FIG. 4, the circuit breaker is shown in the plugged-in position in a chassis 42.

The two adjacent central poles B and C are paired, that is to say electrically parallel, to form one of the poles of the three-pole circuit breaker of higher rating, the two side poles A and D constituting the other two poles of the circuit breaker respectively. tripolar.

The contact pads 34, 38, of the different poles are fixed to connection bars 50 intended to be plugged into the connection clamps 46, themselves connected to the fixed connection pads 44, during racking-in of the circuit breaker in its chassis 42.

In known manner, a connection strip 50 is fixed to each contact pad 34, 38 of a lateral pole. Each contact pad has tapped holes, only the axes of which are shown in FIG. 4, opening out on its rear face and coming opposite orifices 52 passing through the associated bar so as to allow the bar to be fixed on the bar. contact by means of screws 54.

The connection bars 50 associated with the side poles A and D have a flared shape from front to rear, so that their front face, in contact with the corresponding contact pad 34, 38 having the same width that this range, the entire bar has a width greater than this, the rear part of the bar projecting laterally from the pole, A or D, corresponding in the direction of the pole, B or C, adjacent.

The central connection bar 50 is common to the twin central poles B and C and therefore fixed to the contact pads 34 of these two poles. This central bar is narrower than the previous ones and can be parallelepipedal as shown in the figures. It only covers part of the associated contact areas.

On the rear face of the circuit breaker, the space is thus divided into three connection zones, the two lateral connection zones having a width greater than that of the pole, A or D, associated, the central connection zone having a width less than the sum of the widths of the two twin poles, B and C, associated, and preferably less than the width of the lateral connection zones. Thus a lateral connection zone partially overlaps the adjacent central pole.

An insulation screen 56, made of plastic, covers the parts of the contact pads of the twin poles, B and C, which are not in contact with the associated bar 50, so as to insulate between the exposed parts of the contact pads and the connection bars 50 of the adjacent poles which come into the zone arranged opposite the central poles B and C.

According to a preferred embodiment, represented in FIG. 7, the isolation screen 56 comprises an orifice 58 for the introduction of the connection strip 50, a part central unit 60, the rear face of which is arranged substantially in the plane of the front face of the rest of the isolation screen 56, serving to hold the screen when the connection strip is fixed on the contact pads of the twin poles . In fact, this central part 60 is then held in place, towards the front by the rear face of the rear housing 14, towards the rear by the central part of the bar 50 which is not in contact with the contact pads, and laterally by the side walls, arranged face to face, of the contact pads of the twin poles.

In each connection zone, the connection clamp 46 and the connection pad 44 associated with a connection strip 50 have a width corresponding to the largest width of the latter.

Thus, for the lateral connection zones, the clamps and the connection pads are wider than the associated pole, A or D, and protrude laterally in the direction of the adjacent central pole, B or C. The chassis 42 has insulating walls 62, perpendicular to its rear face, laterally delimiting the connection zones when the circuit breaker is in the plugged-in position, and defining a minimum isolation distance between phases.

By way of nonlimiting example, for a three-pole circuit breaker of caliber 4000A, formed from a four-pole case comprising four standard poles of caliber 3200A, the central connection clamp 46, associated with the twin poles is a standard clamp, comprising 56 contact fingers 48, suitable for a rating of 3200A, while the lateral connection clamps each have 96 contact fingers.

Thus, in each of the parts associated with a phase of the circuit breaker of higher rating, one of the elements is oversized. For the phase corresponding to the twin poles, the contact pads, constituted by the paralleling of two contact pads are oversized, while for the other two phases, it is the elements for connecting the contact pads to the phases that are oversized. An optimal distribution of heating is thus obtained, allowing the use for a given rating of a circuit breaker whose individual poles are provided for a rating smaller than the aforementioned rating.

The current transformers 40 are also adapted to the rating of the circuit breaker. By way of example, for a three-pole circuit breaker of 4000A rating, shown in FIGS. 4 and 5, the current transformers of the side poles A and D are each provided for a nominal current of 4000A. On the other hand, each of the current transformers 40 of the twin poles, B and C, is provided for a nominal current corresponding to half the size of the circuit breaker, i.e. 2000A, a transformer-summator 64 (FIG. 8) receiving the output signals from the two transformers and supplying the trigger the sum of these signals.

In a preferred embodiment, a transformer-reducer is interposed between each of the current transformers and the trip device, the transformer-summator 64 also serving as a reducer for the two current transformers of the twin poles. While the output signals of the current transformers are of the order of 1A, the output signals of the transformer-reducers applied to the trip unit are of the order of 100mA. The transformer-reducers and the transformer-summator-reducer are preferably arranged in the front compartment 18, in cells 66 provided in the front face 16 of the intermediate housing 10 (Figures 1 and 2).

Obviously, the present invention is not limited to the use of a four-pole case to form a three-pole circuit breaker of higher rating.

By way of nonlimiting example, FIG. 6 represents a four-pole circuit breaker formed from two adjoining three-pole boxes. The axis of the poles (not shown) is extended so as to be common to all the poles and the release (not shown) is common to the two housings. A particular embodiment of a box formed by the joining of two boxes is described in French patent application No. 8717447, filed on 10.12.1987. The circuit breaker shown in Figure 6 is made from 6 elementary compartments E, F, G, H, I and J. As in the embodiment of Figure 5, the three network phases are respectively associated with a first pole lateral, E, with enlarged connection bar 50, with two twin poles F and G, and at a second pole H, with enlarged connection bar. As for the neutral, it is associated with the other lateral pole J and separated from the other poles by an unused elementary compartment I. Each of the poles E, F, G, H and J being provided for a rating of 3200A, it is thus possible build a 4000A four-pole circuit breaker. Since the current normally flowing through the neutral is lower than that flowing through the other phases of the network, there is no need to provide an extended connection area for the neutral. On the other hand, for reasons of insulation, it is preferable to separate the pole associated with the neutral from the other poles and to insert the unused elementary compartment I between them.

Similarly, by joining two four-pole boxes comprising eight elementary compartments K, L, M, N, O, P, Q, R intended for the accommodation of 7 individual standard poles each designed for a rating of 3200A, it is possible to achieve, in accordance to the invention, a three-pole circuit breaker of caliber 8000A (not shown). For this, two adjacent lateral poles K and L are twinned and include an enlarged connection strip, that is to say one whose width is greater than the width of the two twinned poles. It is the same for the two adjacent opposite side poles Q and R. Three of the central poles, for example M, N and O are connected in parallel, the compartment elementary P remaining unused. The size of this circuit breaker is then greater than the size of 2 standard poles placed in parallel.

Claims (10)

1. A low-voltage multipole circuit breaker, for high current intensities, comprising a plurality of poles juxtaposed inside an insulating moulded case (10, 12, 14), each pole comprising a pair of separable contacts (28, 30), an arc extinguishing chamber (32), a pair of contact terminal pads (34, 38) connected to the separable contacts and protruding outwards from the case, and a current transformer (40) disposed around one of the contact terminal pads (38) and whose output is connected to a trip device common to the different poles, the contact terminal pads (34, 38) being connected to connecting strips (50) designed to be connected respectively to the phases of a power system to be protected, a circuit breaker characterized in that at least one of the connecting strips (50), designed to be connected to one of the phases of the power system, is connected to at least two adjacent twinned poles (B, C ; F, G), electrically arranged in parallel, at least one of the connecting strips (50) connected to another pole of the circuit breaker having a width such that it extends laterally beyond said pole and partially overlaps the immediately adjacent pole, so that the circuit breaker can be used for a higher rating than that of the individual standard poles which make it up.
2. The circuit breaker according to claim 1, characterized in that the connecting strips (50) extending laterally beyond the associated pole are of flared shape, their smallest face being in contact with the rear face of the associated contact terminal pad (34, 38).
3. The circuit breaker according to either of the claims 1 or 2, characterized in that the connecting strip associated with the twinned poles (B, C ; F, G) covers only a part of the associated contact terminal pads, an insulating shield (56) being fitted on the free part of the contact terminal pads of the twinned poles in such a way as to provide insulation between said terminal pads and the adjacent connecting strips.
4. The circuit breaker according to any one of the claims 1 to 3, characterized in that, the circuit breaker being of the draw-in type in a fixed frame (42) bearing fixed connecting terminal pads (44) designed to be connected by means of connecting grips (46) to the circuit breaker connecting strips (50), the width of the fixed terminal pads and of the connecting grips is appreciably equal to that of the corresponding strip, so as to form connecting zones at least one (A, D, E, H) of which is wider than the associated pole and at least one of which, associated with the twinned poles, has a smaller width than the previous one.
5. The circuit breaker according to any one of the claims 1 to 4, characterized in that the outputs of the current transformers (40) of the twinned poles are connected to the input of a summing transformer (64) whose output is applied to the trip device.
6. The circuit breaker according to any one of the claims 1 to 5, characterized in that it comprises four standard poles (A, B, C, D) juxtaposed in a single case, the two centre poles (B, C) being twinned and the connecting strips of the two lateral poles (A, D) laterally overlapping in the direction of the centre poles, so as to form a three-pole circuit breaker of a higher rating than the rating of each of its individual poles.
7. The circuit breaker according to claim 6, characterized in that the four poles being standard poles of 3200A rating, the circuit breaker is a three-pole circuit breaker of 4000A rating.
8. The circuit breaker according to any one of the claims 1 to 5, comprising six elementary compartments (E, F, G, H, I, J) juxtaposed in a single case and designed to house standard poles, two of the centre poles (F, G) being twinned and the connecting strips of the poles (E, H) adjacent to the twinned poles laterally overlapping in the direction of these poles, one of the elementary compartments (I) being unused, so as to form a four-pole circuit breaker of a higher rating than the rating of each of its individual poles.
9. The circuit breaker according to any one of the claims 1 to 5, comprising eight elementary compartments juxtaposed in a single case and designed to house standard poles, the end poles being twinned two by two and associated with connecting strips laterally overlapping in the direction of the adjacent poles, three of the centre poles being twinned and one of the elementary compartments remaining unused, so as to form a three-pole circuit breaker of a higher rating than the rating of two of its individual poles mounted in parallel.
10. The circuit breaker according to claim 8 or 9, characterized in that it is formed by adjoining two three-pole or four-pole circuit moulded case circuit breakers whose pole operating axis is common and comprising a common trip device.

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