FR2957712A1 - Mobile contact device for electric switch i.e. AC3 switch, in wind turbine generators, has bar whose end parts are localized at level of zones and transmission units transmitting force of spring on central part of bar in juxtaposition - Google Patents

Abstract

The device (10) has contact bridges whose rigid wire (20) is provided on a face of two contact zones (22) separated by an external edge of central part (24). Locking units e.g. interface element (36), allow each contact bridge to be juxtaposed with the contact zones in a same plane orthogonal to a translation axis of a shaft (16). A flexible commutator bar (30) is associated with the bridge on a face of the wire opposite to the zones. End parts (32) of the bar are localized at the level of the zones. Transmission units (36) transmit force of a spring (18) on a support (34) of the bar. An independent claim is also included for an electric switch comprising a case.

Description

The invention relates to contact systems of electrical switching and switching devices, in particular contactors. BACKGROUND OF THE INVENTION The invention relates more particularly to the mobile contact device, forming a bridge which allows or not the current flow between two fixed contacts of such devices, especially in the case of use for resistive loads of high power.

STATE OF THE ART

A contactor is an electrically or pneumatically controlled switching device whose function is similar to that of an electromechanical relay, namely to establish or interrupt the current flow. This electrotechnical apparatus with high breaking capacity is used in particular to power industrial motors with power exceeding 0.5 kW, and supports a current greater than the relay. Standardized job categories, depending on the nature of the receiver and the conditions under which the closures and openings are made, set the current values that the contactor must withstand. For example, the AC3 category concerns high power consumers, including elevator-type cage motors, whose cut is engine launched. In particular, commercial contactors establish a starting current of five to seven times the rated current of the motor and cut at the opening the rated current absorbed by the motor; at this time, the voltage across the poles of the contactor is of the order of 20% of the network voltage and the cut remains easy.

Other devices have a different regime, less jerky, with for example higher opening / closing cycles, as for heating. In particular, the AC equipment whose power factor, or cos cp, is at least 0.95 is applied to the category called AC 1. The constraints on the contactors for these resistive uses are different: in particular for high powers, the heating 2724 LPu thermal can become important. In fact, the AC1 contactors beyond 1500 A are typically derived from the so-called "contactor on bar" technology, very bulky and made to measure, so expensive.

The development of certain areas, in particular the production of wind energy or the output of inverters, however, requires AC1 contactors of increasingly high power, up to 2500-2600 A, and of smaller size and cost, type "molded case". However, certain factors can not be ignored: the section and therefore the mass of the contacts thus depend directly on the current that must flow therein, and it is customary to multiply the number of connections for the same phase: see for example EP 2 124 238 which describes an increase in the number of fixed contacts. Another option is to increase the number of movable contacts, as described in FR 2 828 760, which may, however, lead to an increase in the contact resistance and therefore the dimensioning, due to the dispersion, which can reach 10% in the force exerted by the contact springs supports the actuation.

SUMMARY OF THE INVENTION

Among other advantages, the invention aims at overcoming the drawbacks of existing mobile contact devices, in particular for high power applications with resistive loads. In particular, contact bridges whose geometry is optimized to reduce overheating and costs have been developed to provide a range of contactors whose operating range is increased while maintaining an acceptable size. The invention finds a particularly advantageous application for contactors with a current greater than 1000 A or 1500 A in category AC1, particularly concerning resistive heating, lighting, wind turbine generators, etc.

In one aspect, the invention thus relates to an electric contactor comprising a housing in which at least one conduction circuit is provided; the conduction circuit comprises two external connection pads to the housing and each connected by a conductor to a fixed contact; the circuit is completed by a mobile contact device 2724 LPu according to the invention can connect the fixed contacts or take an open position. Advantageously, the contactor comprises three conduction circuits juxtaposed, said circuits being identical to each other.

In a more general aspect, the invention relates to a mobile contact device, adapted for the preceding contactor, comprising a contact-carrier shaft able to move in the contactor along a translation axis to transmit the movement of a actuator, preferably electromagnetic, to a contact bridge system which is integral therewith. The contact bridge system comprises a juxtaposition of a plurality of contact bridges, advantageously two symmetrical identical bridges, each formed of a rigid conductor provided on one face and at its ends with two contact zones, the contact zones of the system. formed by the set juxtaposed bridges being substantially in the same plane. Preferably, the conductors are such that the juxtaposition of the bridges is tight without play at a central portion of the conductors, and leaves gaps between their end portions which carry the contact areas.

The device according to the invention further comprises means for keeping the juxtaposed bridges tight, the clamping being exerted preferably at the central portion of the bridge conductors and in a direction orthogonal to the axis of translation of the door shaft. -Power jumper contacts. Preferably, the clamping means comprise branches biasing the outer edges of the contact bridge system, the spacing of which at the level of the bridge conductors is adjusted; in particular, the branches may be part of a metal U closed at the bridges by a holding pin, and / or inserted into holes adapted to the edge of the outer conductors of the juxtaposition.

The mobile contact device further comprises a contact spring housed in the contact-carrying shaft and adapted to exert a restoring force along the axis of translation of said shaft on the contact bridge system; the spring is associated with means for transmitting its restoring force to the bridges, in particular via the bridging means of the bridges. To allow an embodiment tolerance, the bridges are provided with flexible blades on the face opposite to the contact zones and on which the force of the contact spring is exerted, said blades comprising an end portion located at the level of the 2724 LPu zones. contact and a support portion, central, on which is exerted said force. Advantageously, the blades are independent of the bridges, which include rim-like arrangements for holding the blades in position; to simplify assembly, the blades can be coupled to each other at their central support portion, being for example unitary.

More generally, the invention relates to an electric contactor comprising a housing housing at least two fixed contacts connected to connection pads, and to a movable contact device for an electric contactor, said device comprising: a movable contact-carrying shaft along an axis of translation within the contactor and making it possible to transmit the force of an actuator in this axis of translation; a contact spring in the contact-carrying shaft for exerting a restoring force along the axis of translation of said shaft; a plurality of contact bridges, each bridge comprising a rigid conductor provided on one side with two contact zones separated by a central part of the clamping means making it possible to keep the plurality of contact bridges juxtaposed with their contact areas in the same plane substantially orthogonal to the axis of translation of the contact-carrying shaft; a flexible blade associated with each contact bridge on a face of the conductor opposite to the contact areas, the end portions of the blade being located at the contact areas; and means for transmitting the force of the spring on a central portion of the flexible blades of the juxtaposition.

BRIEF DESCRIPTION OF THE FIGURES Other advantages and features will become more clearly apparent from the following description of particular embodiments of the invention, given by way of illustration and in no way limiting, represented in the appended figures.

Figure 1 illustrates a section of a contactor in which the contact device according to the invention can be mounted. FIGS. 2A and 2B show an embodiment of a mobile contact device according to the invention. 2.24 LPu Figure 3 shows a movable contact device according to a preferred embodiment of the invention.

FIG. 4 shows a conduction circuit in the closed position according to one embodiment according to the invention.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

The invention finds particular and preferred application in a molded case contactor 1 used in three-phase power supply: for each of the phases, the contactor 1 comprises a conduction circuit as schematically illustrated in FIG. 1, the circuits being juxtaposed normally. in the drawing (of the sheet), for example within the same housing 2 arranged. In particular, according to a conventional construction, for each supply phase, two connection pads 4 project from the housing 2 of the contactor 1 and are intended to be connected to a power supply busbar; the connection pads 4 are extended inside the casing 2 by conductors 6 comprising two fixed contacts 8 separated from each other; the contacts 8 may, depending on the use, either be manufactured unitarily with the conductor 6 itself, which is conventionally made of raw copper, tinned or silver, or be reported, with for example a brazing pellets on a support arranged in 6. For electrodynamic reasons, it is also customary for the conductor 6 to form a U at the fixed contact 8: a first branch 6a of the conductor 6 carrying the contact 8 is substantially parallel to a second branch 6b, located at the bottom of the housing 2, which extends towards the beach 4.

A movable contact device 10 completes the conduction circuit; it can take a closed position in which a conductive bridge system 12 provides the electrical connection between the fixed contacts 8, and an open position in which the current does not flow between the connection pads 4. The actuation of the device movable contact 10 is conventionally made by an electromagnetic actuator 14 housed in the 2724 LPu housing 2 of the contactor 1. The movable contact device 10 comprises a contact-carrying shaft 16 transmitting the movement of the actuator 14 to the conductive bridge system 12 ; spring means 18 provide the contact pressure by biasing the bridge system 12 towards the fixed contacts 8.

In addition to the juxtaposition of the conduction circuits 6, 8, 12 within the housing 2 for the contactors 1 operating in multi-phase power supply, for optimization purposes, it is conventional for high power applications that the conduction between the ranges. 4 is simultaneously provided by a plurality of lines: the contact resistance is reduced by the same, and therefore the limited heating. According to the invention, the bridge system 12 of the mobile contact device 10 thus comprises a plurality n of bridges 12i, coupled to the same shaft 16 and actuated jointly by the same actuator 14, which provide the connection between two fixed contacts 8. Tel 2, each bridge 12 comprises a rigid conductor 20, in particular made of copper, the cross section of which is adapted to the circulating current, provided on one surface with two contact zones 22 which face the fixed contacts 8. The surface contact areas 22 of the set 12 of the bridges of the movable contact device 10 are sized for the current to flow between the corresponding fixed contacts 8; as for the fixed contacts 8, the contact zones 22 of each bridge 12i may comprise a brazed pellet or be formed directly by the conductive copper.

The set of bridges 121 to 12 ,, juxtaposed in a plane parallel to the contact zones 22, thus completes the conduction circuit 6, 8, 12. According to the invention, the juxtaposition of the bridges 12i within the contact device mobile 10 is provided by direct clamping of the conductors 20 against each other; the clamping force is located substantially in the middle of the conductors 20, on the outer edges 24 of the two bridges 121, 12 end of the juxtaposition, and orthogonal to the direction defined by their two contact zones 22. The clamping can be realized by any appropriate means associated with the contact-carrying shaft 16, in particular means springing or screwing around the bridges 12i. In order to keep in place any bridges 12i which are not directly stressed by the clamping means, that is to say the bridges 12i located between two other bridges 12i4, 12i + 1 when the number n of bridges 12i exceeds two , arrangements 26 on the edges of the central 2724 LPu bridges 12i, as well as possibly on the inner edges of the end bridges 121, 12 ,,, are provided, for example complementary cuts, so that the clamping on the edges external 24 forms a substantially stable interlocking.

In order to avoid possible welding of the contact zones 22 of two bridges 12; adjacent, it is advantageous that the clamping of the bridges 12i against each other and their contacting is limited to a central portion of the conductors 20, facing the clamping edges 24, and to provide a spacing of the conductors 20 to their end, at the contact areas 22. In particular, a recess 28 (see Figure 3) on the inner edges of the end conductors 201, 20n and / or a dimensioning of stabilization arrangements 26 of the conductors 20i, allows for have a functional clearance between the bridges 12i, which also contributes to avoid, during a break, welding due to the electric arc bridges 12i them.

According to the invention, in order to eliminate the dispersions in the force occasioned by the use of several contact springs, the pressure on each bridge 12i of the mobile contact device 10 is exerted by a single spring 18 located in the shaft contact carrier 16. In order to accept the construction and operating clearances, in particular any misalignment in the plane of the contacts 8, 22 so as to guarantee the best electrical contact each bridge 12i is coupled to a flexible blade 30 making it possible to distribute the force of the actuator 14 and the contact spring 18 at best. In particular, to balance the forces within the same bridge 12i, the ends 32 of the flexible blade 30 are located at the contacts 22, and a central bearing portion 34 of the blade 30 is biased perpendicularly to the plane of the contacts 22 by the contact spring 18 and the actuator 14. An interface 36 integral with the contact-carrying shaft 16 may be provided for each blade 30 but, in order to balance the forces, the interface 36 is advantageously common to all 30i blades and allows a distributed joint action on the central portions 34 bearing the blades 30 of the assembly.

Advantageously, the flexible blades 30 spring and are independent of the conductors 20, which preferably comprise housing in which the blades 30 are just positioned. In a preferred embodiment (Figure 3), the blades 30i of the various bridges 12i are coupled together, and in particular unitary, at the support portion 2724 LPu central 34 so as to simplify the mounting of the contact device 10 Preferably, on their side opposite to the contact zones 22, the conductors 20 comprise flanges 38 forming housings where the ends 32 of the blades 30 are blocked. The flanges 38 may also be configured so as to form a horn. arc, that is to say an extension in the direction of the blast fins 39 accelerating the movement of the electric arc of the contact 8, 22 to the fins 39, and thus to facilitate the cutting of the electric arc during the separation of the contacts 8, 22.

Thus, according to the invention, it is possible to multiply the number of contacts per phase in a small footprint, and by minimizing the number of additional parts required for clamping, thus further simplifying assembly: the contact device 10 is presented as a conventional bridge 12 "cut" into slices 12; which are interconnected by simple orthogonal clamping. It is preferred, as illustrated in a preferred embodiment 100 of FIG. 3, to have two bridges 121, 122 of contact per phase: this configuration makes it possible to simplify the shapes and cuts of the parts, and to preserve the configuration general contactors 1 existing, particularly at their actuation.

Thus, the contact device 100 is put in place at one end of a contact-carrying shaft 16 housing a contact spring 18; the contact zones 22 are located on the same side of the conductors 20 as the contact spring 18, below in the illustrated example. On the upper face, each of the two bridges 12; comprises arc-horn flanges 38 and slots for spring strips 30, blocking their end portions 32 at the contact areas 22; the spring strips 30 are symmetrical and interconnected at their central portion 34 serving as a support zone. The bridges 121, 122 are juxtaposed along their inner edge, opposite the clamping edge 24; to maintain a spacing at the ends of the conductors 20, the cutting of each inner edge may comprise three parallel parts, the two end portions being further aligned, with a recess 28 for the central part, so as to leave no contact that the central portions of each conductor 20. An element 40 serves as a clamping and transmission interface between the contact-holder shaft 16, the contact spring 18, the bridges 12 and the strips 30. 2724 LPu The element d interface 40 comprises a U, preferably a metal, housed in the contact-holder shaft 16 and in which the contact spring 18 is put in place; the branches 42 of the U protrude from the contact-carrying shaft 16, by two orifices, being put in place at the level of the conductors 20 to maintain the clamping pressure between the two bridges 121, 122. Advantageously, each of the conductors 20 comprises on its central outer edge 24 clamping, an orifice 44 adapted to pass a branch 42, and the free ends of the legs 42 are interconnected by a screwed or riveted pin which holds the assembly in place. Preferably, the holding pin 36 is also used to transmit the force of the contact spring 18 to the spring-loaded sipes 30, being located at the central support portion 34 of the set of sipes 30. Thus, as shown in FIG. 4, in the closed position, the contact spring 18 is compressed and exerts downward pressure on the holding pin 36 which compresses the lamellae 30; the pressure increases the contact force between the movable contacts 22 and fixed 8 of the contactor 1.

The preferred embodiment thus greatly simplifies the manufacture of the components of the device 10, 100 according to the invention and their assembly. The cost is lower as the number of additional components compared to a single bridge is reduced, it is possible to size the components to the fair, thus achieving further savings of copper. Although of compact and encapsulated structure, the device 10, 100 according to the invention allows a homogeneous distribution of the pressure force on each contact pad 8, 22, and a rebalancing of the electrodynamic forces on the strong current repulsion effects . Thus, the architecture according to the invention significantly impacts the performance of the contactor 1 at the level of the heating (by division of the contact resistance), on the cut / repulsion (by multiplication of the lines of necking), while limiting dispersions (by balancing pressures).

Although the invention has been described with reference to a three-phase contactor with high power double contacts for resistive load, it is not limited thereto and can be used on devices intended for AC3 or other uses. Similarly, if the design of the mobile contact devices according to the invention finds major advantages for contactors of more than 1000 or 1300 A, in particular 1700, 2100 or 2500 A, in particular downstream of 2724 LPu wind generators, the solution according to the invention can be adopted for lower powers. Finally, the characteristics of the various embodiments described can be combined with each other in different ways.

2724 LPu

Claims (10)

REVENDICATIONS1. Mobile contact device (10, 100) for an electric contactor (1) comprising: a contact-carrying shaft (16), movable along an axis of translation within the contactor (1) and making it possible to transmit the force of a actuator (14) in this translation axis; a contact spring (18) in the contact-carrying shaft (16) for exerting a restoring force along the axis of translation of said shaft (16); a plurality (n) of contact bridges, each bridge (12i) comprising a rigid conductor (20) provided on one side with two contact zones (22) separated by a central portion (24, 26); clamping means (36, 40) for keeping the plurality of contact bridges (12i) juxtaposed with their contact areas (22) in the same plane substantially orthogonal to the axis of translation of the contact-carrying shaft ( 16); a flexible blade (30i) associated with each contact bridge (12i) on a face of the conductor (20) opposite the contact areas (22), the end portions (32) of the blade (30) being located at the contact areas (22); transmission means (36) of the spring force (18) on a central portion (34) of the flexible blades (30) of the juxtaposition. 2. Mobile contact device according to claim 1 wherein the central portions (26) of the conductors (20) internal to the juxtaposition are complementary shapes so that orthogonal clamping bridges (12i) at the central portions (24). ) external to the juxtaposition keeps said central portions tight and leaves a spacing between the conductors (20) at the contact areas (22). 3. A movable contact device according to one of claims 1 or 2 wherein each bridge (12i) comprises on its face opposite the contact areas (22) flanges (38) forming a housing for the flexible blades (30). 4. A movable contact device according to one of claims 1 to 3 wherein the clamping means (36, 40) comprise two branches (42) which can be inserted in 11 2 724 LPules external bridges of the juxtaposition (121, 122 ) and a holding pin (36) connecting the branches (42) to each other by exerting an orthogonal force at the bridges. 5. A movable contact device according to claim 4 wherein the legs (42) form a metal U in which is placed the contact spring (18) and housed in the contact shaft (16). 6. Mobile contact device according to one of claims 4 or 5 wherein the holding pin (36) is adapted to exert pressure on the central portion (34) of the 10 blades (30). 7. Mobile contact device according to one of claims 1 to 6 wherein the flexible blades (30) are coupled together at their central portion (34). 15 8. Mobile contact device according to one of claims 1 to 7 wherein the plurality (n) of bridges comprises two bridges (121, 122) identical, placed in symmetry with respect to each other. 9. Electrical contactor (1) comprising a housing (2) housing at least two fixed contacts (8) connected to connection pads (4) and a movable contact device (10, 100) according to one of claims 1 to 8 whose contact areas (22) are located facing the fixed contacts (8), the movable contact device (10, 100) being able to assume a first contact position and a second open position. 25 10. Electrical contactor according to claim 9 comprising three movable contact devices (10, 100) similar to each other, juxtaposed and facing three pairs of fixed contacts (8). 2724 LPu