WO2007031494A2

WO2007031494A2 - Mechanism for controlling a current distributing cell and tumbler therefor

Info

Publication number: WO2007031494A2
Application number: PCT/EP2006/066236
Authority: WO
Inventors: Alain Quemin; Daniel Piccoz; Myriam Bastard; Mathieu Nesme
Original assignee: Areva T & D Sa
Priority date: 2005-09-13
Filing date: 2006-09-11
Publication date: 2007-03-22
Also published as: ATE472813T1; ES2348859T3; WO2007031494B1; EP1925006A2; FR2890779A1; EP1925006B1; CN101263570A; FR2890779B1; CN101263570B; WO2007031494A3; DE602006015207D1

Abstract

The invention concerns a mechanism for controlling a current distributing cell and a tumbler therefor. The control mechanism comprises a first interrupt tumbler (4) rotatably mounted on a shaft (8) between an open position wherein the first tumbler is in open position and a closed position wherein the first tumbler is in closed position; a second tumbler (2), for example of a ground disconnect rotatably mounted on a shaft (6) between an open position wherein the ground disconnect is in open position and a closed position wherein the ground disconnect is in closed position. The interrupt tumbler and/or the ground disconnect tumbler (2, 4) are made of a thermoplastic material, preferably selected from the family of polyoxymethylenes.

Description

MECHANISM FOR CONTROLLING CURRENT DISTRIBUTION CELL AND TUMBLER FOR THIS MECHANISM

DESCRIPTION

TECHNICAL AREA

The invention relates to a control mechanism of a current distribution cell comprising a first rotary tumbler mounted on an axis between an open position in which a first switch is open and a closed position in which the first switch is in position. closed position; a second tumbler rotatably mounted on an axis between an open position in which a second switch is open and a closed position in which the second switch is in the closed position. It also relates to a tumbler for this mechanism comprising a central portion and two parallel flanges connected to the central portion, each of the flanges comprising a receiving zone for receiving a colon. The current distribution cells, for example the medium voltage cells, comprise two members: a first switch which establishes or cuts the passage of the current in the cell and a second switch which makes it possible to connect the cables of the cell to the potential OV. The second switch is a protection of the operator, for example to carry out maintenance.

The members are controlled by a spring-loaded control mechanism that is maneuvered using a removable lever. This type of mechanism is mainly used for medium voltage switchgear. However, it also applies to high voltage transmission and distribution activities.

The power transmission parts of spring mechanisms, in particular tumblers, are subject to two main constraints:

- aging for a long time up to thirty years, including in saline atmosphere;

- High mechanical forces that can reach high values up to 1000 N in permanent force and 3000 N in maneuvering force. These parts also undergo repeated shocks up to 100,000 cycles. The energy of the spring to be dissipated is preferably between 10J and 100J.

There are various embodiments of tumblers in currently known control mechanisms. Tumblers are known made of mechanically welded steel parts. Tumblers made of steel or cast aluminum are also known. However, these mechanisms have disadvantages. Indeed, the axes used in these tumblers are metallic. It is therefore necessary to mount them on bearings which constitutes additional parts and increases the cost. In addition, these bearings must be greased which requires maintenance operations. Finally, the fats used tend to gel (or freeze or coagulate), resulting in a risk of seizure. Since we do not know the behavior long term of these greases and that the preventive maintenance is not always done by the user, we must have a higher energy to allow a functioning even in the absence of fat or if this one deteriorated to overcome higher friction forces.

The tumblers of the prior art also have a number of other disadvantages. They require anti-corrosion protection. They also have the risk of damage and abrupt failure in fatigue.

The parts, especially when made of steel, are heavy and therefore demanding energy for their movement. They deform, take the game over the maneuvers or break in fatigue. They are of a complex realization because of the problems related in particular to their resistance to corrosion which requires specific treatments, these parts are therefore expensive. The subject of the invention is a control mechanism of a current distribution cell and a tumbler for the mechanism of this cell which overcomes these disadvantages. It proposes a safe mechanism throughout the life of the mechanism. These objects are achieved according to the invention, in that the first tumbler and / or the second tumbler are made of a thermoplastic material.

Thus, it is possible to remove the bearings thanks to a good coefficient of friction of the plastic material used. The weakness of friction at the axis and their constancy over the lifetime of the mechanism allows a reduction of the energy to be implemented for the same kinematics. Decreasing the weight of the parts is an additional factor that contributes to the reduction of the energy to be used. This reduction in energy, in turn, leads to a reduction of the energy dissipated in the shocks, which prevents damage and consequent deformation of the tumbler parts. In addition, the production of thermoplastic parts provides the following additional advantages:

- decrease in the number of pieces. Complex shapes can be created with a molded plastic part;

- insensitivity to the environment. It is not necessary to provide protection against corrosion. Rusting phenomena and galling can not occur; - better shock behavior. There is less evolutionary matings so less play. The risks of rupture are very reduced because of the elastic behavior of the material. It is not necessary to add elastomer dampers to absorb the residual energy not used to maneuver the moving parts of the electrical equipment;

- Reduction of the energy required to maneuver because there is more lubrication of the parts and risk of aging of the greases and their deterioration (dessication, coagulation); - elimination of maintenance operations, in particular lubrication and painting, to protect areas attacked by corrosion phenomena; lower costs of construction and maintenance of tumblers because of the reduction in the number of parts, the lower cost of plastics and their faster implementation because there is a possibility of making clipping zones for assemblies. Preferably, the thermoplastic material is chosen from the family of polyoxymethylenes (POMs).

More preferably, the thermoplastic material has a Young's modulus of between 1000 and 12000 MPa and a tensile strength of between 20 and 250 MPa.

By way of example, the material is chosen from the group comprising Delrin POM 100 and POM Delrin 100 ST, the characteristics of which are defined below.

Other features and advantages of the invention will become apparent upon reading the following description of an exemplary embodiment given by way of illustration with reference to the appended figures. In these figures:

- Figure 1 is a perspective view of the power portion of a control mechanism for a current distribution cell, the switch being in the open position; FIG. 2 is a detailed perspective view of the first switch tumbler of FIG. Figure 1 is a detail view in perspective of the second switch tumbler of Figure 1;

- Figure 4 is a perspective view similar to Figure 1 but in which the spring is in the intermediate position substantially close to the dead point;

- Figure 5 shows the mechanism of Figures 1 and 4 the first switch being in the closed position; Figure 6 is a front view of the switch mechanism in the open position, the second switch in the closed position.

In Figure 1, the reference 2 designates an earthing switch tumbler and the reference 4 a switch tumbler. The tumbler 2 is rotatably mounted on a disconnector shaft 6 and the tumbler 4 is rotatably mounted on a switch shaft 8. The shafts 6 and 8 are metallic. They are mounted between a front plate (not shown) mounted parallel to the rear plate. Columns 12 are mounted between the front plate and the rear plate. These columns serve to limit the rotational movement of the tumblers 2 and 4. A spring 14 is mounted between the tumbler 2 and the tumbler 4. The spring 14 is pivotally mounted at one end on the tumbler 2 about an axis of Earthing spring 16 and is pivotally mounted at its other end on the switch tumbler 4 about a switch spring axis 18. A disc 20 is rotatably mounted on the same shaft 8 as the tumbler 4. A rod 22 is pivotally mounted at one of its ends on the disc 20. At its other end, the rod 22 is pivotally mounted on a driver 24 which drives the switch through its axis.

There is shown in Figure 2 a tumbler forming part of the mechanism of Figure 1. It comprises a central portion or hub 30 and two parallel flanges 32 connected to the central portion. Each of the flanges 32 has reception zones 34 in the shape of an arc of a circle. As can be seen in Figure 1, the receiving zones 34 are intended to receive the column 12 when the switch is moved from the open position to the closed position and vice versa.

FIG. 3 shows a perspective view of an earthing switch tumbler. In the same way, it comprises a central portion or hub 36 and two parallel flanges 38 on which are formed reception zones 40 in the shape of a circular arc intended to receive the corresponding column 12 when the tumbler moves from its open position to its closed position and vice versa. In Figure 1 the mechanism has been shown earthing switch in open position and switch in open position also. This mechanism is operated using a control lever that is placed on the front of the mechanism. In FIG. 4, the tumbler 4 has rotated a few tens of degrees so that the axis 18 of the spring has moved, which leads to the neutral position shown in FIG. the spring is aligned with the pivot axis 8 of the tumbler. At this stage, only the tumbler 4 and the spring 14 are moving.

Once past the dead point, the spring 14 relaxes and takes the relay of the operator: it drives the tumbler switch 4 rotating. The control lever is disengaged and no longer intervenes in the maneuver. Shortly after the passage of the neutral point, the tumbler switch rotated comes to hit the drive disk which is itself rotated. The drive disk then rotates the driver via the connecting rod 22. The function of the disk assembly 20, connecting rod 22, coach 24 is therefore to relocate the maneuver. The operator turns the trumbler to a certain level, but the actual operation of the switch is higher with the coach 24.

On the side of the earthing switch 2, the operation is the same, but without deporting the information. The tumbler 2 directly actuates the earthing switch on the electrical equipment. There is therefore also a phase of energy accumulation (compression of the spring by the operator by means of the control lever) and a phase of release of this energy by the relaxation of the spring. However, the power released is less important because the compression stroke is lower. The tumbler of the earthing switch thus passes from its open position shown in Figures 1, 4 and 5 to its closed position shown in Figure 6. The tumblers 2 and 4, the disk 20, the rod 22 and the driver 24 are made of polyoxymethylene (POM). More preferably they are made of a thermoplastic material having a Young's modulus of between 1000 and 12000 MPa and a tensile strength of between 20 and 250 MPa. By way of a particular example of such a material is cited Delrin 100® or Delrin 100ST® whose main mechanical characteristics are as follows.

It is noted that the plastic parts have a mechanical strength 4 to 5 times lower than that of equivalent parts made of steel or aluminum.

Claims

A control mechanism of a current distribution cell comprising:

- A first switch tumbler (4) rotatably mounted on a shaft (8) between an open position in which a first switch is in the open position and a closed position in which the first switch is in the closed position; a second switch tumbler (2) mounted rotating on a shaft (6) between an open position in which a second switch is in the open position and a closed position in which the second switch is in the closed position, characterized in that the first tumbler (4) and / or the second tumbler (2) are made of a thermoplastic material.

2. Switch tumbler for a control mechanism of a current distribution cell, comprising a central portion (30) and two parallel flanges (32) connected to the central portion (30), each of the flanges having a receiving zone

(34) for receiving a colon (12), characterized in that it is made of a thermoplastic material.

3. Mechanism according to claim 1 or tumbler according to claim 2, characterized in that the thermoplastic material is selected from the family of polyoxymethylenes (POM).

4. Mechanism or tumbler according to claim 3, characterized in that the material thermoplastic has a Young's modulus between 1000 and 12000 MPa.

5. Mechanism or tumbler according to claim 3 or 4, characterized in that the thermoplastic material has a breaking strength of between 20 and 250 MPa.