WO2025012562A1 - Multi-contact double-throw power switch - Google Patents

Abstract

A double-throw power switch (200) comprising: - a fixed part (210); - a mobile part able to come into contact with the fixed part and to move between a position in which the switch is open and a position in which the switch is closed, the mobile part comprising a switching contact (240) and at least one passing contact (230, 231, 232); - springs configured to apply a pressing force to the mobile part, pressing it towards the fixed part; - a pair of magnets (250) for generating a constant-direction magnetic field; - an interrupter chamber; characterized in that the distance (d1) between the fixed part and the switching contact is less than the distance (d2) between the fixed part and the passing contacts and in that the switching contact comprises a first portion (241) placed at a first end of the passing contacts, a second portion (242) placed at a second end of the passing contacts and a third portion (243) comprising one branch when there is one passing contact or (n-1) branches, where n is the number of passing contacts and n is strictly greater than 2, the passing contacts being parallel to one another and placed on either side of the branches of the third portion of the switching contact.

Description

Description

Title of the invention: Multi-contact bidirectional power contactor

Technical Domain

The present invention relates to the general field of electrical protection devices, such as electromechanical contactors and electrical contactors, more particularly to high voltage and direct current electromechanical contactors.

Previous technique

Power contactors are electrical protection devices generally made up of a fixed part and a moving part which may or may not be in contact with the fixed part.

To close a contactor, and therefore put the moving part in contact with the fixed part so that an electric current can flow between the two parts, the contactor motor is powered which will apply a pressure force to the moving part, and thus allow an electric current to flow between the two parts.

When the current flowing between the two parts exceeds a predefined threshold, for example in the event of a short circuit, electromagnetic repulsion forces will be applied to the moving part and compensate for, or even exceed, the force applied by the motor to the moving part. This causes levitation of the contactor, i.e. an unwanted opening of the contactor between the fixed and moving parts. In addition, during this phase, i.e. during the application of the repulsion forces before levitation, the contact resistance between the fixed part and the moving part of the contactor increases and creates local heating (proportional to the contact resistance squared multiplied by the current) which can lead to the destruction of the moving part, irreversible damage to the contactor and/or welding of the moving part on the fixed part when the moving part falls back on the fixed part after levitation.

Currently, to avoid damage to the contactors in the event of a short circuit, that is, to prevent the two parts of the contactor from welding together, to avoid using a more bulky actuator, the contact points between the fixed part and the moving part are multiplied. By multiplying the contact points between the two parts, the current flowing between the two is divided by the number of contact points, which reduces the pressure force exerted on each contact as well as the repulsion force.

However, for bidirectional high voltage direct current contactors 100, called bidirectional HVDC contactors, as shown in FIG. 1, this solution is not very satisfactory, because these contactors 100 use permanent magnets 150 to produce a magnetic field B and move the electric arcs using the Laplace force towards cut-off devices 120. Thus, by multiplying the contact points, as described in the prior art, the arc is just moved orthogonally to the magnetic field produced and is therefore sent to another contact point and not to the cut-off devices of the bidirectional HVDC contactors. For example, an electric arc appearing on the element 132 is moved either to the element 131 or to the element 133. By being sent to the element 131 or to the element 133, the arc will cause the welds of these elements, by welding them to the fixed part of the contactor 100.

It is therefore desirable to have a new bidirectional HVDC contactor with reduced risk of damage in the event of a short circuit.

Disclosure of the invention

The invention relates to a bidirectional power contactor comprising:

- a fixed part;

- a movable part capable of coming into contact with the fixed part and of moving between an open position and a closed position of the contactor, the moving part comprising a switching contact and at least one passing contact;

- two first springs configured to apply a pressure force on the switching contact towards the fixed part;

- at least one spring per passage contact configured to apply a pressure force on the associated passage contact in the direction of the fixed part and;

- a pair of magnets, capable of generating a magnetic field of constant direction;

- an extinguishing chamber comprising four fin blocks each having: o fins between a first and a second end of the corresponding fin block; and o arc guides, each arc guide extending from the movable part towards its respective fin block, characterized in that the distance between the fixed part and the switching contact is less than the distance between the fixed part and the passing contacts and in that the switching contact comprises a first portion placed at a first end of the passing contacts and opposite two first fin blocks, a second portion placed at a second end of the passing contacts and opposite the last two fin blocks and a third portion comprising a branch when there is a passing contact or (n-1) branches with n the number of passing contacts and n strictly greater than 2, the passing contacts being parallel to each other and placed on either side of the branches of the third portion of the switching contact, and the two first springs being placed opposite the first and second portions of the passing contact.

By having the passing contacts placed on either side of the legs of the third portion of the switching contact, this means that each passing contact is separated from another passing contact by the third portion or a leg of the third portion of the switching contact. The contactor comprises thus an alternation of the passing contact and branch of the third portion of the switching contact.

Thanks to the invention, when an electric arc appears on the switching contacts, it is sent directly to the breaking chamber.

Furthermore, by using several passing contacts, the intensity of the electric current flowing in each of the passing contacts is reduced, as explained previously, thus, for the same contact pressure force between the moving part and the fixed part, the electromagnetic forces and therefore the repulsion forces are reduced.

According to a particular characteristic of the invention, the contactor comprises two springs per passage contact, the springs being placed at the two ends of the associated passage contact.

According to another particular characteristic of the invention, the difference between the distance between the passing contacts and the fixed part and the distance between the switching contact and the fixed part is between 0.1 mm and 1 mm.

Another subject of the invention relates to a method of closing a power contactor in the open position according to the invention, comprising bringing the switching contact into contact with the fixed part and then bringing the passage contacts into contact with the fixed part.

By virtue of the closing method of the invention, since the switching contact closes before the passing contacts, electric arcs will occur on the switching contact. Furthermore, as explained above, by increasing the number of points of passage of the electric current between the moving part and the fixed part, the repulsion forces are reduced, which makes it possible to improve the resistance to high currents of the contactor.

Yet another object of the invention is a method of opening a power contactor in the closed position according to the invention, comprising opening the contact between the passing contacts and the fixed part and then opening the contact between the switching contact and the fixed part. When opening, since the passing contacts open first, only the switching contact can be subjected to electric arcs that appear during an electrical separation. Thus, the arcs can be sent to the interrupting chamber without damaging the contactor.

Brief description of the drawings

Other characteristics and advantages of the present invention will emerge from the description given below, with reference to the attached drawings which illustrate exemplary embodiments thereof which are not limiting in any way.

[Fig. 1] Figure 1 schematically and partially represents a bidirectional power contactor according to the prior art.

[Fig. 2] Figure 2 schematically and partially represents a bidirectional power contactor according to one embodiment of the invention.

[Fig. 3A] Figure 3A schematically and partially represents a bidirectional power contactor according to another embodiment of the invention.

[Fig. 3B] Figure 3B schematically represents the fixed and moving parts of the contactor of Figure 3A.

[Fig. 4] Figure 4 shows, schematically and partially, the closing of the contactor of Figure 2.

[Fig. 5] Figure 5 shows, schematically and partially, the opening of the contactor of Figure 2.

Description of the embodiments

Figure 2 schematically and partially represents a contactor 200 according to one embodiment of the invention.

The contactor 200 comprises a fixed part 210, and a switching contact 240 and passing contacts 230 capable of coming into contact with the fixed part 210, the switching contacts 240 and passing contacts forming the movable part of the contactor 200. In this embodiment, the contactor 200 comprises two passing contacts 231 and 232. The two passing contacts 231 and 232 are parallel to each other. In the open position of the contactor 200, the distance dl between the fixed part 210 and the switching contact 240 is less than the distance d2 between the fixed part 210 and the passing contacts 230. The difference between the distances dl and d2 is, for example, between 0.1 mm and 1 mm.

The contactor 200 also includes two springs configured to apply a pressure force on the switching contact 240 towards the fixed part 210, and at least one spring per passing contact configured to apply a pressure force on the associated passing contact towards the fixed part 210.

The contactor 200 also comprises a pair of magnets 250 configured to produce a magnetic field that will make it possible to move the electric arcs that may appear between the fixed part 210 and the moving part thanks to the Laplace force towards cut-off devices 221, 222, 223, 224 or more generally towards an arc chute. The arc chute makes it possible to extinguish these electric arcs. This is called arc blowing.

The cutting chamber comprises four fin blocks 221, 222, 223, 224 each having:

- fins comprised between a first and a second end of the corresponding fin block; and

- arc guides, each arc guide leading from the moving part to its respective fin block.

Arc guides direct electric arcs to their respective fin blocks, with the fin blocks serving as arc extinguishing or arc-breaking devices. Each block serves to split and extinguish an arc directed toward the block.

The switching contact 240 comprises: a first portion 241 placed at a first end of the passage contacts 231, 232 and opposite two first blocks of fins 221, 222; - a second portion 242 placed at a second end of the passage contacts 231, 232 and opposite the two other fin blocks 223, 224; and

- a third portion 243 placed between the first portion 241 and the second portion 242, so that the switching contact 240 forms a T.

The two passing contacts 231, 232 being placed on either side of the third portion 243 of the switching contact 240 and surrounded by the first 241 and second 242 portions of the switching contact 240. There is therefore an alternation between passing contact 231, third portion 243 of the switching contact 240 and passing contact 232.

With this configuration, if an electric arc appears on the switching contact 240, the arc is sent directly to one of the fin blocks 221, 222, 223, 224 to be able to be extinguished thanks to the first and second portions 241, 242.

The two springs configured to apply a pressure force to the switching contact 240 are placed opposite the first 241 and second 242 portions of the switching contact 240.

The springs configured to apply a pressure force on the passage contacts 231, 232 are placed either at the center of each passage contact 230 and in this case, there is a single spring per passage contact 230; or at the ends of each passage contact 230 and in this case, there are two springs per passage contact 230. The advantage of having two springs per passage contact is to be able to better distribute the pressure force on the passage contact and thus improve the contact with the fixed part 210.

Figures 3A and 3B show a contactor 300 according to another embodiment of the invention.

The contactor 300 comprises a fixed part 310, and a switching contact 340 and passing contacts 330 capable of coming into contact with the fixed part 310, the switching contacts 340 and passing contacts forming the movable part of the contactor 300. In this embodiment, the contactor 300 comprises four passing contacts 331, 332, 333 and 334 parallel to each other. Like the contactor of Figure 2, in the open position of the contactor 300, the distance dl between the fixed part 310 and the switching contact 340 is less than the distance d2 between the fixed part 310 and the passing contacts 330. The difference between the distances dl and d2 is, for example, between 0.1 mm and 1 mm.

The contactor 300 also includes two springs configured to apply a pressure force on the switching contact 340 towards the fixed part 310, and at least one spring per passing contact configured to apply a pressure force on the associated passing contact towards the fixed part 310.

The contactor 300 also includes a pair of magnets 350 and an extinguishing chamber comprising four fin blocks 321, 322, 323 and 324 as described with reference to FIG. 2.

The 340 switching contact includes:

- a first portion 341 placed at a first end of the passage contacts 331, 332, 333, 334 and opposite two first fin blocks 321, 322;

- a second portion 342 placed at a second end of the passage contacts 331, 332, 333, 334 and opposite the two other fin blocks 323, 324; and

- a third portion 343 placed between the first portion 341 and the second portion 342, comprising three branches placed on either side of the passage contacts 331, 332, 333, 334 so that each passage contact 331, 332, 333, 334 is surrounded by a fin block and/or one or two branches of the third portion 343.

Thus, the passage contact 331 is surrounded by the fin blocks 321, 323 and a branch of the third portion 343; the passage contacts 332 and 333 are each surrounded by two branches of the third portion 343 and the passage contact 334 is surrounded by the fin blocks 322, 324 and a branch of the third portion 343. None of the passage contacts 320 is thus placed directly next to another passage contact 320. This alternates between passage contact 331, first branch of the third portion 343 of the passage contact 334 and second branch of the third portion 343. switching 340, passing contact 332, second leg of the third portion 343 of the switching contact 340, passing contact 333, third leg of the third portion 343 of the switching contact and passing contact 334. Thus, no passing contact 331, 332, 333, 334 is placed directly next to another passing contact. They are always separated by a leg of the switching contact 340.

With this configuration, if an electric arc appears on the switching contact 340, it is sent directly to the fin blocks 321, 322, 323, 324, as explained previously with reference to FIG. 2.

Figure 3B shows the springs configured to apply a pressure force to the switching contacts 340 and the passing contacts 331, 332, 333, 334.

As previously indicated, the contactor 300 comprises two springs 361 and 362 configured to apply a pressure force on the switching contact 340 and placed opposite the first 341 and second 342 portions of the switching contact 340.

In this embodiment of FIG. 3B, there are two springs per pass-through contact 330 that are configured to apply a pressing force to the associated pass-through contact. These springs are positioned at the ends of each pass-through contact 330. Thus, springs 3311 and 3312 are configured to apply a pressing force to the ends of pass-through contact 331; springs 3321 and 3322 are configured to apply a pressing force to the ends of pass-through contact 332; springs 3331 and 3332 are configured to apply a pressing force to the ends of pass-through contact 333; and springs 3341 and 3342 are configured to apply a pressing force to the ends of pass-through contact 334.

More generally, the third portion of the switch contact of the contactor comprises a branch if there are one or two passing contacts. Thus, the passing contact(s) are placed on either side of this branch.

If there are at least three passing contacts, the third portion of the switching contact comprises (n-1) branches (with n the number of passing contacts). The passing contacts are placed on either side of the (n-1) branches, such that the passing contacts are placed between two branches of the switching contact or between a fin block and a branch of the switching contact.

Regardless of the embodiment, the third portion of the switching contact may be perpendicular to the first and second portions of the switching contact.

Regardless of the embodiment, the first and second portions of the switching contact may be parallel to each other.

Figure 4 represents a method 400 for closing the contactor of the invention, and more particularly the steps for closing the contactor 200 described with reference to Figure 2.

The contactor 200 is initially in the open position 410, so the fixed parts 210 and the switching contacts 240 and passage 230 of the moving part are not in contact and no electric current flows between these two parts.

In order for the contactor 200 to move to the closed position, the motor is powered so as to apply a pressure force via the springs to the movable part of the contactor, and the switching contacts 240 are first brought into contact with the fixed part 210 (step 420), then the passing contacts 230 are brought into contact with the fixed part 210 (step 430). Thus, in step 420, the electric current represented by the arrows flows only between the fixed part 210 and the switching contacts 240, whereas in step 430, the contactor is completely closed and the electric current flows both between the fixed part 210 and the switching contact 240 and between the fixed part 210 and the passing contacts 230. Thus, if electric arcs appear when the contactor is closed, they are present only on the switching contact 240.

Figure 5 represents a method of opening the contactor of the invention, and more particularly the steps of opening the contactor 200 described with reference to Figure 2. The contactor is initially in the closed position 510, so the fixed part 210 is in contact with the switching contact 240 and the passing contacts 230 of the moving part and an electric current flows between these contacts 240, 230 and the fixed part 210. For the contactor to switch to the open position 530, the power supply to the motor is cut off and the passing contacts 230 open first (step 520). So they are no longer in contact with the fixed part of the contactor and the current continues to flow in the switching contact 240. Then, the switching elements 240 open (step 530). Thus, when the contactor opens, as the switching contact 240 is the last to open, if electric arcs appear, they will be sent to the breaking chambers to protect the contactor.

The opening and closing methods described above also apply to the contactor 300 described with reference to FIGS. 3A and 3B.

Claims

Claims [Claim 1] Bidirectional power contactor (200, 300) comprising: - a fixed part (210, 310); - a movable part capable of coming into contact with the fixed part and of moving between an open position (410, 530) and a closed position (430, 510) of the contactor, the movable part comprising a switching contact (240, 340) and at least one passing contact (230, 231, 232, 330, 331, 332, 333, 334); - two first springs (361, 362) configured to apply a pressure force on the switching contact towards the fixed part; - at least one spring (3311, 3312, 3321, 3322, 3331, 3332, 3341, 3342) per passage contact configured to apply a pressure force on the associated passage contact in the direction of the fixed part and; - a pair of magnets (250, 350), capable of generating a magnetic field of constant direction; - a breaking chamber comprising four fin blocks (221, 222, 223, 224, 321, 322, 323, 324) each having: o fins between a first and a second end of the corresponding fin block; and o arc guides, each arc guide leading from the movable part towards its respective fin block, characterized in that the distance (dl) between the fixed part and the switching contact is less than the distance (d2) between the fixed part and the passing contacts and in that the switching contact comprises a first portion (241, 341) placed at a first end of the passing contacts and facing two first (221, 222, 321, 322) fin blocks, a second portion (242, 342) placed at a second end of the passing contacts and facing the last two (223, 224, 323, 324) fin blocks and a third portion (243, 343) comprising a branch when there is a passing contact or (n-1) branches with n the number of passing contacts and n strictly greater than 2, the passing contacts being parallel to each other and placed on either side of the branches of the third portion of the switching contact, and the first two springs being placed opposite the first and second portions of the passing contact. [Claim 2] A power contactor according to claim 1, comprising two springs per passing contact, the springs being placed at both ends of the associated passing contact. [Claim 3] A power contactor according to any one of claims 1 or 2, wherein the difference between the distance between the passing contacts and the fixed part and the distance between the switching contact and the fixed part is between 0.1 mm and 1 mm. [Claim 4] Method (400) of closing a power contactor in the open position (410) according to any one of claims 1 to 3, comprising bringing the switching contact into contact with the fixed part (420) then bringing the passage contacts into contact with the fixed part (430). [Claim 5] Method (500) of opening a power contactor in the closed position (510) according to any one of claims 1 to 3, comprising opening the contact between the passage contacts and the fixed part (520) then opening the contact between the switching contact and the fixed part (530).