EP0018553A1 - Modular circuit breaker - Google Patents

Abstract

1. A modular circuit breaker comprising in a box of essentially rectangular cross-section, means for manual and automatic release, the automatic release means being controlled at low overload intensities by the deflection of a bimetal strip (8) and at the higher intensities by an electromagnetic device (13) placed in series with desionization plates (17-21), the manual release means being controlled by a handle which displaces a movable contact (6) serving for the disconnection and supported by a contact-carrier (37), the automatic release means further comprising a hooking cylinder (40) revolving under the effect of said bimetal strip (8) or said electromagnetic device (13) and thus releasing said contact-carrier (37) in order to displace said movable contact (6), said desionization plates (17-21) and said contact-carrier (37) being disposed essentially along the direction of the diagonal line of the cross-section of said box, characterized in that said bimetal strip (8) is further disposed along said direction and that a rounded end (75) of said bimetal strip (8) cooperates with a cam (76) of said hooking cylinder (40) which cam further comprises a flat part (78) permitting, by a continuous displacement of the end (75) on this flat part, the disengagement of said bimetal strip (8) during the operation at said high intensities.

Description

The present invention relates to a modular circuit breaker, in particular a low voltage circuit breaker, the wheelbase characteristics of which are standardized in order to accommodate them in suitable cabinets arranged in the walls of the dwellings.

Some modular circuit breakers made up to now have included manual disjunction means by a joystick and automatic disjunction means by a bimetallic strip at intensities slightly exceeding the nominal currents and by an electromagnetic device associated with deionization plates at high short currents -circuit. Previous circuit breakers were expensive, had a large number of parts and because of their arrangement it was not possible to maintain in a standardized volume a bimetal of the greatest possible length, a breaking chamber and a very large electromagnetic device in order to make them perform.

The circuit breaker according to the invention overcomes these drawbacks. In this one indeed the number of parts is reduced as well as the cost price for improved technical characteristics.

The present invention relates to a modular circuit breaker comprising in a substantially rectangular box manual and automatic tripping means, the automatic tripping means being controlled at low overload intensities by the deflection of a bimetallic strip and at higher intensities by a device electromagnetic arranged in series with deionization plates, the manual tripping means being controlled by a lever moving a movable contact serving for the disjunction and supported by a contact holder, the automatic tripping means further comprising a rotating latching cylinder under the action of said bimetallic strip or of said electromagnetic device and thus releasing said contact holder in order to move said movable contact, said deionization plates and said contact holder being arranged substantially in the direction of the diagonal of said box, characterized in that said bimetallic strip is arranged in addition according to ladi direction.

With reference to the attached diagrammatic figures 1 to 7, an example of implementation of the present invention will be described below, an example given purely by way of illustration and in no way limiting.

• La figure 1 représente une vue de côté du disjoncteur selon l'invention, couvercle enlevé, avec des parties partiellement coupées, le disjoncteur étant dans la position enclenché.
• La figure 2 représente la même vue dans la même position que celle de la figure 1 avec une représentation des forces mécaniques agissant sur les organes de la manette.
• La figure 3 représente la même vue que celle de la figure 1 dans la position ouvert prêt à être réarmé.
• La figure 4 représente la même vue que celle de la figure 1 dans la position en cours de déclenchement du basculeur de la commande multipolaire.
• La figure 5 représente la même vue que celle de la figure 1 dans la position enclenché.
• La figure 6 représente une vue de dessus d'une plaque de désionisation utilisée dans le dispositif selon les figures précédentes.
• La figure 7 représente une vue de côté partielle du disjoncteur selon les figures précédentes avec le dispositif électromagnétique.
• La figure 8 représente un schéma de principe de l'interaction entre le dispositif électromagnétique selon la figure 7 et un cylindre d'accrochage.

The same elements shown in several of these figures bear the same references on all of them.

• Figure 1 shows a side view of the circuit breaker according to the invention, cover removed, with parts partially cut, the circuit breaker being in the engaged position.
• FIG. 2 represents the same view in the same position as that of FIG. 1 with a representation of the mechanical forces acting on the organs of the lever.
• Figure 3 shows the same view as that of Figure 1 in the open position ready to be reset.
• FIG. 4 represents the same view as that of FIG. 1 in the position during tripping of the rocker of the multipolar control.
• Figure 5 shows the same view as that of Figure 1 in the engaged position.
• FIG. 6 represents a top view of a deionization plate used in the device according to the preceding figures.
• Figure 7 shows a partial side view of the circuit breaker according to the previous figures with the electromagnetic device.
• Figure 8 shows a block diagram of the interaction between the electromagnetic device according to Figure 7 and a latching cylinder.

Referring to Figure 1 we can see the path of the electric current through the circuit breaker.

The cable or the current arrival bar not shown is tightened by a screw 1 and a cable clamp plate 2 on an input terminal 3 whose curved part 4 forming the plate at the higher potential comprises a contact pad 5.

A movable contact 6 conducts the current via a braid 7 to the end of a bimetallic strip 8, the other end 9 of which is fixed on a bimetallic strip support 10 itself fixed on a plate at lower potential 11.

One end 81 of the bimetal support is connected to the input of a magnetic coil 13, the output of which is connected to an output terminal 14, also comprising a cable clamp plate 15 and a clamping screw 16 allowing connection to the cable or to the current output strip.

Plates 17, 18, 19, 20 and 21 are so-called deionization plates intended to break up the arc at the time of cutting.

The electrical path diagram is modified at the time of opening on a short circuit.

At the opening under the effect of a strong current during a tripping on a short circuit, the contact 6 moves away enough from the pad 5 the arc stretches between the contact and the pad and it is expelled in the deionization chamber by the field generated by the passage of current in the curved part 4 of the input terminal and the movable contact 6.

At this time, the arc leaves the movable contact and springs between the part 4 forming a plate with higher potential and the plate with lower potential 11. The electronic flux then no longer crosses the bimetallic strip 8 _" ; the current flows directly from the plate 4 to the plate 11 connected to the magnetic coil 13 and to the output terminal 14, until the arc is extinguished.

This provision was adopted to protect the bimetallic strip. In particular, it limits the thermal stress borne by the latter during cuts under heavy load. This arrangement significantly increases the breaking capacity of the circuit breaker. Of course during manual opening, this arrangement has practically no effect.

The mechanical operation is as follows:

Referring to Figure 2 showing the circuit breaker in the engaged state with the cover removed we see a lever 31 of the circuit breaker in the engaged position causing an axis 32 whose ends are guided in a light in the form of a ramp 33 practiced in two insulating half-shells forming the housing and the cover enclosing and positioning all of the members.

This axis 32 drives a connecting rod 34 which pulls on an axis 35 also moving in a slot 36 formed in each of the shells.

On the axis 35 is articulated a contact carrier 37 whose end 38 is supported on the latching cylinder 40. The other end of the contact carrier 37 supports the movable contact 6 whose tail 42 receives the thrust of the spring 43.

The spring 43 performs a triple role. it allows both to ensure the contact pressure, to push the contact carrier 37 / contact 6 assembly upon opening, and finally its force causes the lever 31 to lock in the engaged position.

The result of the force of the spring 43 generates a vector F1 forming an angle A with the axis of rotation of the lever 31, which causes the appearance of a torque F2 greater than the force of the return spring 44 of lever 31.

the circuit breaker operation in manual tripping is as follows:

By operating the lever 31 in the opposite direction to the representation (FIG. 2) along arrow 0, the contact 6 / contact carrier 37 assembly descends (see FIG. 3) until the domed part 51 of the contact carrier 37 touches a fixed stop 52 of the housing. The length of the connecting rod 34 is such that the lever 31 is in abutment on the part 55 of the housing and maintained in this position by a torsion spring (44) having the mission of returning the lever 31 in the direction of the arrow F , a day appears between the end 38 of the contact carrier 37 and the cylinder exhaust 40. This day is necessary to release the cylinder 40 after an automatic triggering by rotation of the latter in order to allow a rearming.

The operation of the automatic tripping circuit breaker is as follows:

Referring to FIG. 4, the attachment cylinder having, under the effect of an impulse from the movable core 100 of the electromagnetic device or a thrust from the bimetallic strip 8, turned in the direction of the arrow C, the end 38 of the contact carrier, 37 is released and under the pressure of the spring 43 the contact carrier 37 / contact 6 assembly pivots about the axis 35 until the convex part 51 of the contact carrier 37 comes to bear on the fixed stop 52. At this time, the traction on the connecting rod 34 having ceased, the lever 31 is driven in the direction of the arrow F by the return spring 44 whose tail can be seen on the view (torsion spring). The lever returning completely back the end 38 of the contact carrier returns to be housed under the latching cylinder 40 and the device is ready again to be engaged (identical to FIG. 3).

The operation of the multipole circuit breaker is as follows:

The operating descriptions have been made for a single assembly enclosed in a housing and a cover.

It is possible to build multipoles by associating several unipoles and by synchronizing the exhausts.

Still referring to FIG. 4, at the time of its pivoting around the axis 35, the end 38 of the contact carrier 37 strikes the end 61 of a rocker 62 which is an optional part which lion puts in place when you want to make multipoles.

This rocker 62 has a square recess 63 which makes it possible to synchronize the rockers of the neighboring poles by introducing between two poles a small square rod, each end of which is housed in the rockers of the contiguous poles, thus making them integral in rotation. Under the effect of the shock generated by the contact carrier 37 and the force exerted by the spring 43, the rocker-r of the pole just opened pivots, thus causing the rocker of the neighboring pole. The protrusion 64 of the rocker 62 of the neighboring pole strikes a tooth 65 of the attachment cylinder 40 of the neighboring pole, which causes its rotation and thereby the opening of the pole.

By this arrangement, we obtain a multipolar operation without it being necessary to increase the force generated by the detectors which remain identical. The poles are opened with recovered energy.

If, on the contrary, for example, its synchronization was carried out at the level of the exhausts, it would be necessary for the bimetallic strip 8 and the core. 100 of the electromagnetic device generate a force four times greater in tetrapolar than in unipolar to be able to overcome the forces necessary for the four exhausts.

The reduction in dimensions generally goes against the reduction in price.

For example, at the level of the mechanism, if one is not limited by the space, one can obtain a desired reduction by a single lever. In the case where space is limited, it will be necessary to use a multiplier with several stages less bulky but more expensive.

ou D : la déflexion en mm. L = longueur en mm

• F = la déflexion spécifique (₁₀ ^-6/C°)
• T = écart de température t - to
• e = épaisseur en mm

où l'on voit que la longueur conditionne grandement la déflexion. Cependant c'est de la grande déflexion que découlent la facilité et la rapidité du réglage et la stabilité du réglage. Si la déflexion est importante, les variations dues à la déformation des matériaux (climat - dilatation) ou les jeux parasites indispensables au touril- lonnement des pièces présentent une valeur en pour cent négligeable ; il en résulte une moins grande précision nécessaire pour le réglage, une moins grande habileté des opératrices et un temps réduit d'exécution. La réduction des dimensions des dijoncteurs actuels a eu tendance par manque de place de réduire les bilames. L'architecture du disjoncteur faisant l'objet de l'invention permet au contraire paradoxalement de l'augmenter.For the operation of the thermal device, it is even. If we examine the formula for the deflection of a bimetallic blade embedded at one end, we have:

or D: the deflection in mm. L = length in mm

• F = the specific deflection ( ₁₀ ^-6 / C °)
• T = temperature difference t - to
• e = thickness in mm

where we see that length greatly conditions deflection. However, it is from the great deflection that the ease and speed of the adjustment and the stability of the adjustment arise. If the deflection is significant, the variations due to the deformation of the materials (climate - expansion) or the parasitic clearances essential for the swirling of the parts have a negligible percentage value; this results in less precision required for the adjustment, less skill of the operators and a reduced execution time. The reduction in the dimensions of current circuit breakers has tended, due to lack of space, to reduce bimetallic strips. Paradoxically, the architecture of the circuit breaker which is the subject of the invention makes it possible to increase it.

Referring to FIGS. 5 and 6, the contact assembly 6, the contact carrier 37, the deionization plates 17 to 21, the bimetallic strip 8 and its support 10 are inclined, thus making it possible to benefit from maximum length for the format. The deionization plates 17 to 21, all identical, are housed under the input terminal 3. They each have a V-shaped notch such as 170. An electrode 110 coming from the middle of the plate at lower potential 11 penetrates into the notch in V of the plate 21. The purpose of the electrode 110 is to promote the passage of the arc coming from the plate of higher potential 4 and passing through the movable contact 6 when the latter is open, to lead to the plate of lower potential 11. 'The gases generated during a cut-off escape into an expansion chamber 71 where they must bypass or pass under a deflector 72 to finally escape through a vent 73.

The bimetallic strip 8 fixed at 74 on the bimetallic strip support 10 itself fixed under the deionization plates 17 to 21 has a length of 40 to 50% higher than the models currently known for the format considered.

The bimetallic strip deflects in the direction of arrow D. Its rounded end 75 pushes on the part 76 of the latching cylinder 40, causes its rotation and the opening of the circuit breaker.

During an opening on short circuit despite the shunting of the bimetallic strip 8 by the deionization plates 17 to 21 as we have described, the bimetallic strip supports a significant thermal stress causing its sudden displacement. If the bimetallic strip encounters an obstacle during its displacement, it results in an irreversible deformation of said bimetallic strip.

To remedy this drawback, the rounded end 75 of the bimetallic strip 8 having pushed the part 76 of the cylinder, the part 75 continues its movement on the part 78 of the cylinder thus forming a sort of disengagement. Bimetallic strip 8 continues its stroke without load.

The attachment cylinder 40 is made of a material which promotes operation.

During standardized tests which simulate actual operation, the devices must not trip for a current flow of approximately 10% greater than their nominal rating, then after one hour the current is increased up to 1.4 or 1.5 times the nominal current which should cause tripping.

During operation, the bimetallic strip 8 must overcome the forces essentially due to friction between the part 38 of the contact carrier 37 and the attachment cylinder 40 and also between the end 75 of the bimetallic strip and the part 76 of the cylinder.

During the 10% test, it is advantageous for the friction to be high to avoid tripping and, on the contrary, low for the test at 1.4 or 1.5 times the nominal current which should generate the tripping.

The condition is fulfilled if one uses for the realization of the attachment cylinder, a material whose coefficient of friction is variable according to the temperature.

The temperature of the bimetallic strip increases as a function of the through current and therefore 1.1 of the nominal current the temperature is lower than 1.4 or 1.5 times the nominal current. If a partially thermoplastic polyester is used as a non-limiting example lens based on POLYBUTYLENETEREPHTHALATE (PBT) also designated by polytetramethylene terephthalate (PTMT) of formula C ₆ H ₄ [C 0 0 (CH); the desired effect is obtained. The figures below indicate the coefficients of friction on a steel plate of the material indicated above as a function of the different temperatures t.

It can be seen that the static and dynamic coefficients practically halve between 23 ° and 120 ° C.

The distance between the end 75 and the part 76 is adjusted by acting on a screw 79 whose head is trapped and which causes the support 10 to rise or fall. The support has a weakness at 80 to favor the displacement of all.

It should be noted that the end 81 of the support 10 is connected to rigid wire forming the coil 13. It is the coil which allows the movement of the support 10 without disadvantage, the winding behaving like a spring, it allows the small displacement required for adjustment.

This arrangement is very advantageous in conjunction with the interior organization. It makes it possible to reduce the requirements for manufacturing the circuit breaker to a single flexible braid and to the corresponding welds.

• a/ le contact mobile 6
• b/ 1 extrémité 75 du bilame 8
• c/ le réglage du pied du bilame 8

Indeed in a circuit breaker, there is for a pole three points which move at least

• a / mobile contact 6
• b / 1 end 75 of bimetallic strip 8
• c / the adjustment of the foot of the bimetallic strip 8

In the circuit breaker which is the subject of the invention, the contact 6 is connected by a single braid 7 to the end 75 of the bimetallic strip 8 and the displacement of the bimetallic strip support 10 is collected by the turns of the magnetic coil 13.

• le porte-contact 37 permet à lui seul par sa relative grande longueur d'effectuer la démultiplication nécessaire. Son extrémité 38 horizontale délimite un plan aligné suivant la ligne 86. Cette ligne passe largement au-dessus des ailes 87 du support de contact 37 ; ce qui permet la rectification et le polissage sans problème. Pour faciliter la compréhension la ligne en arc de cercle 88 figure une portion de meule ou de tampon à polir.

On the mechanical level, the following advantages emerge from the inclination:

• the contact carrier 37 alone allows for its relative great length to carry out the necessary reduction. Its horizontal end 38 delimits a plane aligned along the line 86. This line passes largely above the wings 87 of the contact support 37; which allows grinding and polishing without problem. To facilitate understanding, the line in an arc 88 shows a portion of a grinding wheel or a polishing pad.

• a/ embectage constant entre le porte-contact 37 et le cylindre 40
• b/ rattrapage automatique des jeux du dispositif électromagnétique.

An advantageous arrangement has been implemented to obtain the following arrangements without adjustment:

• a / constant connection between the contact carrier 37 and the cylinder 40
• b / automatic adjustment of the games of the electromagnetic device.

Referring to Figures 7 and 8, the view of Figure 7 shows the actual shape of the elements of the electromagnetic device.

The view of FIG. 8 is a schematic representation intended to make the operation understand.

The attachment cylinder 40 comprises under a tooth 92 a non-visible stop which comes to bear downwards in an excavation made in the housing. This stop has been shown in Figure 7 by the tip 93 and the bearing triangle 94. Under the effect of the thrust of the spring 95 the control rod 96 presses on the latching cylinder 40 via a finger 97.

By this arrangement, the inclination 98 of the cutaway of the cylinder 40 is very reproducible, which generates a quantity 99 of constant plugging.

The magnetic core 100 is constantly held in abutment against the control rod 96 by a small steel wire 101 reinforced on two spans. The force of the wire is just sufficient to be substantially equal to the weight of the core.

By this arrangement, the only parasitic clearance f causing a delay in the control by the magnetic core is the clearance between the difference in the diameter of the pin 97 and the width of the notch E.

This jea can be minimized to the strict necessary by construction.

A great advantage emerges from these provisions. The packaging and them no longer being dependent on a knack, reproauetibility sought after in series production is greatly increased and the execution time reduced.

It should be noted the obvious economy of means and in particular the fact that the magnetic core is a simply cut cylinder without further machining.

The setting of the electromagnetic device is as follows:

According to the standards, the electromagnetic device must cause the tripping of the circuit breaker for currents which can vary between 2.5 and 10 times the nominal current of the circuit breaker.

There is great interest in a circuit breaker being able to adapt to different settings in order to be able to respond to demanded markets.

Referring to Figure 6, the operating threshold of the magnetic device is conditioned by the relative arrangement of the parts.

, Let L be the length of the magnetic coil, L2 the middle of L and SG the center of gravity of the mobile magnetic core. The operation varies as a function of the distances d1, d2, d3 which are respectively the distance between L2 and the upper end of the core, the gap distance, the distance between L2 and SG. Operation at different thresholds can be obtained simply by varying the length of the magnetic core 100 possibly in combination with the length of the collar 102 which forms the fixed magnetic core.

These two parts being simply turned, it results in great ease of adjustment without expensive tools; the most expensive operation being the appropriate length of the rod 96.

It is understood that, in addition to these measurements, the number of turns of the coil can be modified.

Claims (9)

1 / Modular circuit breaker comprising in a substantially rectangular box manual and automatic tripping means, the automatic tripping means being controlled at low overload intensities by the deflection of a bimetallic strip (8) and at higher intensities by an electromagnetic device ( 13) arranged in series with deionization plates (17 - 21), the manual tripping means being controlled by a lever moving a movable contact (6) serving for the disjunction and supported by a contact carrier (37), the means automatic release further comprising a latching cylinder (40) rotating under the action of said bimetallic strip (8) or of said electromagnetic device (13) and thus releasing said contact carrier (37) in order to move said movable contact (6) , said deionization plates (17 - 21) and said contact carrier (37) being arranged substantially in the direction of the diagonal of said box, characterized in that said bimetallic strip 8 e st further arranged in said direction. 2 / A circuit breaker according to claim 1, characterized in that said latching cylinder (40) comprises a cam (76) of a shape such that it allows the disengagement of the end (75) of said bimetallic strip (8) during operation at said high intensities. 3 / Circuit breaker according to claim 1, characterized in that said latching cylinder (40) is made of a material whose coefficient of friction varies in inverse function to the temperature. 4 / A circuit breaker according to claim 3, characterized in that said material is polybutylene terephthalate. 5 / A circuit breaker according to claim 1, said bimetallic strip (8) comprising at one end, a braid (7) for connection with said movable contact (6), characterized in that a support (10) of said bimetallic strip (8) arranged at the other end is able to move as a function of the mechanical elasticity of the turns of said electromagnetic device (13). 6 / A circuit breaker according to claim 1, characterized in that said contact carrier (37) has a horizontal end (38) resting on said latching cylinder _. (40). 7 / A circuit breaker according to claim 1, characterized in that the adjustment of the said electromagnetic device (13) is carried out by the balance of a spring (95) and a wire (101) which support the core (100) and the control rod (96) of said electromagnetic device (13), said control rod (96) pressing the intermediary of a finger (97) on said attachment cylinder (40), a point (93) of which rests on a fixed bearing (94). 8 / A circuit breaker according to claim 7, characterized in that said magnetic core (100) is a mild steel cylinder cut at its two ends. 9 / A circuit breaker according to claim 8, characterized in that the operating threshold of the circuit breaker at high intensities is variable and can be adjusted according to the length of said magnetic core (100).

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