CN104952640B

CN104952640B - Device for controlling the bounce of a mobile contact of a medium-voltage electrical protection apparatus and apparatus thereof

Info

Publication number: CN104952640B
Application number: CN201510148199.7A
Authority: CN
Inventors: P.查夫
Original assignee: Schneider Electric SE
Current assignee: Schneider Electric SE
Priority date: 2014-03-31
Filing date: 2015-03-31
Publication date: 2019-12-20
Anticipated expiration: 2035-03-31
Also published as: CN104952640A; ES2602968T3; FR3019386A1; EP2927921A1; EP2927921B1

Abstract

The invention relates to a bounce prevention device for controlling the bounce of at least one moving contact (1, 2, 3) in an electrical protection apparatus, said moving contact being adapted to be displaced between a so-called closed position, in which said moving contact is in electrical contact with a fixed contact (4, 5, 6) of the apparatus, thereby allowing current to flow between the two contacts, and a second position, in which the two contacts are separated, said device comprising a damping member adapted to limit the bounce of said moving contact at the closed end of the moving contact. The device comprises a spring (13) mounted on one of the two contacts (1, 2, 3), called first contact, and adapted to cooperate, at the closed end, with the other of the two contacts (4, 5, 6), called second contact, to ensure damping of the displacement of the first contact and to index the moving contact with respect to the fixed contact.

Description

Device for controlling the bounce of a mobile contact of a medium-voltage electrical protection apparatus and apparatus thereof

Technical Field

The present invention relates to a bounce prevention device for controlling the bounce of at least one moving contact in an electrical protection apparatus, said moving contact being adapted to be displaced between a so-called closed position, in which said moving contact is in electrical contact with a fixed contact of the apparatus, thereby allowing a current to flow between the two contacts, and a second position, in which the two contacts are separated, said device comprising a damping member adapted to limit the bounce of said moving contact at the end of the closing of the moving contact, and to an electrical protection apparatus comprising such a device.

Background

When the contacts in the medium voltage pneumatic protection device are closed, the moving contact (usually in the form of a blade) engages on the fixed contact and strikes the abutment surface at the end of the stroke. Then, a spring-up phenomenon equivalent to the behavior of the drumstick falling on the anvil occurs.

As a result of this phenomenon, the final position of the moving contact is random. In fact, the latter depends on the geometrical dispersion, the energy variation of the control, the pressure exerted on the contacts, and the quality of the lubrication and mounting gaps. Therefore, it is not ensured that all the contact surface area necessary for the current flow is present.

It is therefore known to use hard abutments to ensure that the moving contacts are stopped. In this case, the bounce is uncontrolled and the blade can move away from its theoretical position resulting in a loss of contact surface area below the level required for current flow.

Furthermore, it is also known that abutments of rubber, or even elastomers, are present, exhibiting damping qualities. In this case, the bounce still exists due to the high energy.

In fact, the physical and chemical properties of the damper deteriorate when the device is used at extreme temperatures (-40 ℃/+70 ℃). The elastomeric material interacts with the SF6 gas used in the switch housing and loses its properties.

Disclosure of Invention

The present invention solves these problems and proposes a device for controlling the bounce of at least one moving contact, in particular in a medium-voltage electrical protection apparatus, which makes it possible to eliminate the angular displacement of the moving contact when it bounces, in order to obtain a strict and repeatable position of the contact, regardless of its environment, thus ensuring an optimal contact surface area for the flow of electric current.

To this end, the subject of the invention is a device for preventing bounce of the aforementioned kind, characterized in that it comprises a spring mounted on one of the two contacts, called first contact, and adapted to cooperate, at the closed end, with the other of the two contacts, called second contact, to ensure the damping of the displacement of the first contact and the indexing of the first contact with respect to said second contact.

According to a particular feature of the invention, the aforementioned spring is mounted so as to be telescopic with respect to the first contact and cooperates with a connection member carried by the second contact, which is adapted to produce the connection of the two contacts in the closed position of the contacts, while allowing the opening of the first contact.

According to another feature, the connection part comprises a notch provided in said second contact.

According to another feature, the first contact is the moving contact and the second contact is the fixed contact.

According to another feature, the mobile contact is of the rotary type.

According to another feature, the above-mentioned moving contact comprises two blades mechanically connected to each other by a shaft, and the above-mentioned spring comprises two windings connected by a so-called horizontal chain, the spring comprising two free ends respectively fixed to the two blades, the two windings being respectively mounted around the two ends of the above-mentioned shaft, the ends of the shaft being located outside the blades, the two blades also respectively comprising a groove extending substantially parallel to the longitudinal axis of the blades and intended to slidingly receive the above-mentioned chain, the horizontal chain of springs cooperating with the fixed contacts when the moving contact is closed, so that when the moving contact comes into contact with the fixed contacts through its entry radius, this causes compression of the spring and therefore sliding of the chain within the groove, after which the chain engages in the recess of the fixed contacts, creating damping and the above-mentioned guidance.

According to another feature, the aforementioned recess comprises an inlet radius and an outlet radius, and the compression ratio of the spring and the aforementioned inlet and outlet radii are chosen so as to obtain the connection of the mobile contact on the fixed contact in the closing direction of the mobile contact, while allowing it to open on the opposite command.

According to another feature, the above-mentioned moving contact is a so-called main contact intended to carry the rated current, or a grounding contact belonging to a grounding circuit breaker.

Yet another subject of the present invention is a medium voltage electrical protection device comprising an anti-bounce device considering the above features, alone or in combination.

According to a particular feature, each pair formed by a fixed contact and a mobile contact belonging to the device comprises anti-bounce means considering the above features, alone or in combination.

According to another feature, the device is a switch or a medium voltage circuit breaker.

Drawings

Other features and advantages of the invention will, however, become more apparent from the following detailed description, given by way of example only, with reference to the accompanying drawings, in which:

figure 1 is a perspective view of an indexing spring belonging to the anti-bounce device according to a particular embodiment of the present invention,

figure 2 is a partial perspective view of a mobile contact belonging to a medium voltage electrical protection apparatus according to a particular embodiment of the invention,

figure 3 is the same view as figure 2 after the indexing spring according to the invention has been mounted on the moving contact,

figure 4 is a partial perspective view, more particularly showing the three moving contacts of the medium voltage switch according to the invention and the support in which they are mounted,

FIG. 5 is a partial perspective view, more particularly showing one of the moving contacts and one of the fixed contacts of the device equipped with a bouncing apparatus according to the invention,

FIG. 6 is the same view as FIG. 4, but also showing the fixed contacts of the device in the closed position of the device, an

Figures 7 and 8 are two partial perspective views, showing, on a larger scale and according to two different directions respectively, a plurality of mobile contacts in a closed position.

Detailed Description

Fig. 6 shows, in part, a medium voltage switch I according to a particularly preferred embodiment of the invention.

In the figure, this switch I is in the closed position, comprising three moving contacts 1, 2, 3 in electrical contact with three main fixed contacts 4, 5, 6, respectively, in order to close the circuit in which this switch I is placed.

More specifically, these moving contacts 1, 2, 3 are shown in fig. 2, 3 and 5, it being seen that each fixed contact 4, 5, 6 comprises a single blade, while the moving contacts comprise two blades. The two blades 1a, 1b of each moving contact are mechanically connected to each other at each end by a shaft 25 passing through the two end parts of the two blades 1a, 1b, respectively. The spacer 7 ensures the spacing between the two blades. The shaft 25 includes a shouldered head at one of the ends, which is visible in fig. 4. The opposite end comprises a spring 10 and a cup 11 ensuring the necessary pressure for the electrical contact, as shown in fig. 3.

The two blades 1a, 1b (each constituting a moving contact 1) comprise, from their free ends, grooves 14, 15 extending substantially parallel to the longitudinal direction of the blade in an axial plane passing through the central axis of the shaft, which plane passes through the middle of the width of the blade. These recesses 14, 15 are intended to also receive a portion of the above-mentioned indexing spring 13, called chain 19, as will be explained below.

According to a particularly preferred embodiment of the invention shown in fig. 1, this indexing spring 13 comprises a rigid wire 16 comprising two windings 17, 18, the two windings 17, 18 being connected to each other by one of their ends (called first) by a chain wire 19 (called horizontal) which extends substantially at right angles to the plane of the two windings 17, 18 and which comprises at its other end (called second) a portion 20, 21 which is folded substantially at right angles.

The indexing spring 13 is mounted on the moving contact 1 as follows.

First, the horizontal chain 19 of springs 13 is introduced into the grooves 14, 15 of the two blades forming the moving contact. Winding 17 then covers the shouldered head of shaft 25 at end 8, and winding 18 covers spring 10 and cup 11 at end 9.

The fixing of the spring 13 with respect to the blade is performed by inserting the two free ends 20, 21 of the indexing spring 13 into two holes respectively belonging to the two blades. Thus, the spring 13 is mounted by covering the already pre-assembled elements. Its curved rear ends 20, 21 hold it in place. The three phase moving contacts 1, 2, 3 of the switch are equipped with such indexing springs 13.

More specifically, as shown in fig. 5, each fixed contact 4, 5, 6 comprises a single blade comprising, at the free end, a solid portion 22 of substantially parallelepiped form comprising, on its surface 23 intended to come into contact with the mobile contact 1, a cut 24 or notch extending in a direction substantially parallel to the longitudinal direction of the horizontal chain 19 of springs 13 and to the alignment direction of the device, over a certain width of the fixed contact defined in the plane of the fixed blade 4, 5, 6 and at right angles to the longitudinal direction of the fixed blade 4, 5, 6.

This solid portion 22 of the fixed contacts 4, 5, 6 is dimensioned so that the fixed contacts can be slidingly introduced between the two blades 1a, 1b of the moving contacts 1, 2, 3 when the moving contacts are placed in contact on the fixed contacts (once these contacts are closed).

In operation, once switch I is closed, horizontal chain 19 of indexing springs 13 strikes fixed contact 4 at its entry radius R1. As a result, the spring 13 is compressed by means of the vertical grooves 14, 15 present on the blade. When it comes to coincide with the fixed blade 4, the spring 13 engages in a notch 24 located below the fixed contact. Bounce occurs but the spring 13 resists the backward movement of the moving contact 1 and is vertically strengthened against the blades 1a, 1b of the moving contacts 1, 2, 3, as in the position shown in fig. 6, 7 and 8.

The energy present upon springing is thus guided by the spring 13, which serves to dampen the movement of the moving contact and to direct the moving contact with respect to the fixed contact.

During this closing, the moving blades move apart and cover the fixed contacts against the action of the contact pressure springs.

When the moving contact of the device is open, the chain 19 of springs comes into contact with the wall of the solid portion 22 of the fixed contact 4 defining the notch 24 by the exit radius R2, and the spring 13 is easily retracted, because its compression force is weak (40N) with respect to the torque delivered by the control means (95 n.m).

It should be noted that in the durability test, the constant bounce obtained was ± 0.3mm, whereas the average bounce of the non-indexed system was about 9 mm.

The invention is therefore advantageously applicable to any type of medium voltage electrical protection equipment, such as switches or circuit breakers, which comprise a rotating moving contact at the point of connection of the electrical contacts.

By means of the invention, a device is thus obtained which aims to limit the bounce of at least one moving contact in a medium voltage electrical protection apparatus, which is simple in design and enables precise repetitive positions of the contacts to be obtained, regardless of their environment, to ensure an optimal contact surface area, which is obtained by adding an indexing spring mounted on one of the contacts and a notch provided in the other contact, in which notch a horizontal chain of springs retracts when closed and will be accommodated, preventing bounce.

It is obvious that the invention is not limited to the described and illustrated embodiments, which are given by way of example only.

The system can therefore be used in practice also when the moving contact is closed on a blade belonging to the fixed earthing contact of the earthing circuit breaker, the blade comprising the same notch.

The invention therefore includes all the technical equivalents of the means described and their combinations, provided that the latter are made in accordance with the spirit of the invention.

Claims

1. A bounce prevention device for controlling the bounce of at least one moving contact in an electrical protection apparatus, said moving contact being adapted to be displaced between a so-called closed position, in which said moving contact is in electrical contact with a fixed contact of the apparatus, thereby allowing a current to flow between the moving contact and the fixed contact, and a second position, in which the moving contact is separated from the fixed contact, said device comprising a damping member adapted to limit the bounce of said moving contact at the end of the closing of the moving contact,

characterized in that it comprises a spring (13) mounted on the first contact (1, 2, 3) and adapted to cooperate with the second contact (4, 5, 6) at the end of the closing of the device to ensure the damping of the displacement of the first contact and the indexing of the same with respect to said second contact,

the first contact (1, 2, 3) being the moving contact and the second contact (4, 5, 6) being the fixed contact,

the above-mentioned moving contact (1, 2, 3) comprises two blades (1a, 1b) mechanically connected to each other by a shaft (25), and the above-mentioned spring (13) comprises two windings (17, 18) connected by a so-called horizontal chain (19), the spring (13) comprising two free end parts (20, 21) respectively fixed to the two blades (1a, 1b), the two windings (17, 18) being respectively mounted around two ends (8, 9) of the above-mentioned shaft (25), the ends (8, 9) of the shaft (25) being located outside the blades (1a, 1b), the two blades also respectively comprising grooves (14, 15) extending substantially parallel to the longitudinal axis of the blades and intended to slidingly accommodate the above-mentioned chain (19), the horizontal chain (19) of the spring (13) being located outside the moving contact (1a, 1b), 2. 3) cooperates with the fixed contacts (4, 5, 6) when closed, so that when the moving contact comes into contact with the fixed contacts through its entry radius R1, this causes the compression of the spring (13) and therefore the sliding of the chain (19) within the groove (14, 15), after which the chain (19) engages in the notch (24) of the fixed contacts (4, 5, 6), producing damping and the above-mentioned indexing.

2. Device according to claim 1, characterized in that said spring (13) is mounted so as to be telescopic with respect to the first contact (1, 2, 3) and cooperates with a connection member (24) carried by said second contact (4, 5, 6), the connection member (24) being adapted to produce the attachment of the two contacts in their closed position, while allowing said first contact to be opened.

3. The pop-up prevention device of claim 1, wherein the connection member (24) comprises a notch (24) provided in the second contact (4, 5, 6).

4. The anti-bounce device according to any one of the preceding claims, characterized in that the moving contact (1, 2, 3) is of the rotary type.

5. The anti-bounce device according to claim 3, characterized in that the above-mentioned notch (24) comprises an entrance radius R1 and an exit radius R2, and the compression ratio of the spring (13) and the above-mentioned entrance radius R1 and exit radius R2 are chosen so as to attach the moving contact to the fixed contact (4, 5, 6) in the closing direction of the moving contact (1, 2, 3) while allowing it to open on the opposite command.

6. A bounce prevention device according to any one of the preceding claims 1 to 3, wherein said moving contact is a so-called main contact intended to carry a rated current or a ground contact belonging to a ground circuit breaker.

7. Medium voltage electrical protection device, characterized in that it comprises an anti-bounce device according to any one of the preceding claims.

8. Electrical protection device according to claim 7, characterized in that each pair formed by a fixed contact (4, 5, 6) and a moving contact (1, 2, 3) belonging to the device comprises a bounce prevention means according to any one of claims 1 to 6.

9. Electrical protection device according to claim 7 or 8, characterized in that it is a switch.

10. Electrical protection device according to claim 9, characterized in that it is a medium voltage circuit breaker.