EP1237169B1 - High voltage circuir breaker with spring actuator with an additional energy recuperating spring - Google Patents

Description

The invention relates to a high-voltage electrical circuit breaker, such as a self-blowing and compressed gas circuit breaker, comprising a breaking chamber with at least one movable contact in the chamber which is actuated by means of a mechanical control device. springs for opening or closing the circuit breaker, the control including at least a first spring exerting a force tending to move the movable contact to open the circuit breaker and a second spring exerting a force tending to move the movable contact to close the circuit breaker while cocking the circuit breaker; first spring, and wherein an additional spring is provided to exert an additional force which accumulates with the force exerted by the first spring at the beginning of the opening of the circuit breaker.

Such a circuit breaker is already known to U.S. Patent No. 4,228,333 . In the control device of this circuit breaker, the additional spring contributes to increasing the moving speed of the moving contact at the beginning of the opening. This additional spring stops exerting the additional force when the movable contact has moved a certain distance during its opening stroke, so as not to hinder the slowing down of the moving contact at the end of opening. But this provision of the additional spring requires to provide greater energy to the second spring to ensure the closing of the circuit breaker, because it must not only arm the first spring but also the additional spring.

An object of the invention is to provide a particular arrangement of a circuit breaker as defined above, which does not require additional energy to arm the additional spring during closing.

Another object of the invention is to propose a particular arrangement of such a circuit breaker which also makes it possible to recover and store part of the kinetic energy of the mobile contact at the end of opening or closing, for use respectively at the beginning of a subsequent closing or opening operation.

For this purpose, the subject of the invention is an electric circuit breaker comprising an interrupting chamber with at least one movable contact in the chamber which is actuated by means of a mechanical spring mechanism for opening or closing the circuit breaker, the control including in the at least one first spring exerting a force tending to move the movable contact to open the circuit breaker and a second spring exerting a force tending to move the movable contact to close the circuit breaker while arming the first spring, and wherein an additional spring is provided for exert an additional force that is cumulative to the force exerted by the first spring at the beginning of the opening of the circuit breaker, characterized in that the additional spring is mounted such that before the end of the opening of the circuit breaker, the resultant of the force exerted by the additional spring to move the moving contact is reversed to oppose the movement of the moving contact.

Thus, at the end of opening of the circuit breaker, the additional spring is armed by the displacement of the moving contact and it is therefore not necessary to use a portion of the energy of the second spring of the control to reset the additional spring when closing the circuit breaker. Since the moving contact essentially moves due to its own kinetic energy at the end of the opening, the additional spring can be used to recover and store a part of this kinetic energy that is otherwise conventionally consumed in a damping device.

In a particular embodiment of the circuit breaker according to the invention, the control comprises a rotary shaft coupled in motion to the movable contact and rotated alternately by the first or the second spring. The additional spring is coupled to the rotary shaft via a lever attached to the shaft and occupying two extreme angular positions corresponding to the positions of the movable contact when the circuit breaker is respectively open or closed. The force exerted by the additional spring on the lever is oriented so that its rotational component changes direction when the lever passes through an intermediate angular position moving from an extreme angular position to the other extreme angular position. Thus, the lever functions as a pendulum with the additional spring. At the beginning of the opening, the resultant of the force exerted by the additional spring accumulates with that of the force exerted by the first spring, which tends to accelerate the speed of displacement of the movable contact. At the beginning of the closing, the resultant of the force exerted by the additional spring accumulates with that of the force exerted by the second spring, so that it is possible to reduce the energy of the control necessary to switch on the circuit breaker.

In a particular embodiment of the circuit breaker according to the invention, the additional spring is coupled to the lever by means of a return pulley which makes it possible to dispose the additional spring near the breaking chamber of the circuit breaker in order to reduce the current. Congestion circuit breaker. This additional spring is preferably always armed in compression.

In a particular embodiment of the circuit breaker according to the invention, the lever connected to the additional spring is a triangle-shaped lever having a vertex coincident with the rotary shaft, two other vertices being respectively coupled to the movable contact and the additional spring.

An embodiment of the circuit breaker according to the invention is described below in more detail and illustrated in the drawings.

The figure 1 very schematically represents a circuit breaker according to the invention in the closed position.

The figure 2 very schematically represents the circuit breaker of the figure 1 but in the open position.

On the figures 1 and 2 , reference numeral 1 designates a breaking chamber of a circuit breaker, for example a breaking chamber with auto-blow and reduced gas compression of an electric circuit breaker. The interrupting chamber is generally filled with a dielectric gas at a pressure of a few bars, such as SF6.

The reference 2 designates a movably mounted contact, for example in translation, in the interrupting chamber. This movable contact 2 is moved by a mechanical spring control 3 to open or close the circuit breaker. In the example illustrated in the figures, the control 3 comprises in particular a main rotary shaft 4 on which is fixed a drive lever 5 which is coupled to the movable contact 2 by an articulated mechanical connection 6 so that the rotational movement of the shaft 4 and therefore the lever 5 is converted for example into a translational movement of the movable contact 2 in the chamber 1.

The reference 7 designates the trigger spring of the control 3 used to open the circuit breaker. The spring 7 works on the shaft 4 by means of a lever 8 integral with the shaft 4 and a chain 9 stretched between the free end of the lever 8 and the spring 7. In the closed position of the circuit breaker as shown in figure 1 the spring 7 is armed and exerts a return torque on the lever 8 tending to rotate the shaft 4 in the direction indicated by the arrow O. A releasable triggering catch CO is provided to block the rotation of the shaft 4 when the circuit breaker is closed. After an opening order of the circuit breaker, this pawl CO is unlocked, which causes the rotation of the shaft 4 and the angular displacement of the lever 5, which displacement is transformed by the link 6 into a translational movement of the moving contact 2 .

The mechanical control 3 further comprises a system for closing the circuit breaker, which comprises in particular a spring 10 working on an engagement shaft 11 via a crank wheel 12 integral with the shaft 11. This wheel crank 12 is a toothed wheel which comprises a crankpin 13 connected by a chain 14 to the spring 10. It is here coupled to an electric motor 15 via a gear train 16, the motor 15 serving to arm the spring 10 after closing the circuit breaker. The shaft 11 carries an engagement cam 17 on which is engaged a roller lever 18 integral with the shaft 4. When the engagement spring 10 is armed, it exerts a restoring force on the wheel 12 tending to rotate the shaft 11 in the direction indicated by the arrow F. A releasable locking pawl CF is provided to block the rotation of the engagement shaft 11. After a circuit breaker close command, from an open position as shown in FIG. figure 2 , this pawl CF is unlocked, which causes the rotation of the shaft 11 and the angular displacement of the cam 17 in the direction of the arrow F. The rotational movement of the cam 17 is transmitted to the roller lever 18, this which causes the rotation of the shaft 4 in the opposite direction of the arrow O. The spring 7, which was expanded in the open position of the circuit breaker, is again armed when the circuit breaker closes due to the rotation of the tree 4.

In the initial position of the spring mechanical control, the two springs 7 and 10 are relaxed and the circuit breaker is open. Rotation of the wheel 12 driven by the motor 15 in the direction indicated by the arrow F causes the tensioning of the spring 10 so that the control is then in the position illustrated on the figure 2 . The locking pawl CF is then released, and the spring 10 expands to exert a return torque on the shaft 11 which is rotated in the direction indicated by the arrow F. The rotation of the shaft 11 causes the rotation of the engagement cam 17, which rotates, in a direction opposite to the direction O, the roller lever 18 integral with the shaft 4. The rotation of the shaft 4 puts the spring 7 into tension and causes an angular movement of the lever 5 which is converted into a translational movement of the movable contact 2. The circuit breaker is then closed and the rotation of the shaft 4 is blocked by the triggering paw CO. The spring 10 is then turned back on using the motor 15 and the rotation of the shaft 11 is blocked by the locking pawl CF. The position of the command 3 is then that of figure 1 . In this position, the control 3 is ready for an opening sequence opening opening of the circuit breaker.

More particularly, following the release of the trigger paw CO, the spring 7 relaxes and exerts a restoring force causing the shaft 4 to rotate in the direction indicated by the arrow O, which causes a displacement of the movable contact 2 leading to the complete opening of the circuit breaker. The kinetic energy of the mobile contact remaining available at the end of opening is consumed in a damper 19 coupled to the shaft 4. The circuit breaker is closed by unlocking the pawl CF, which causes the relaxation of the spring 10 and causes the rotation of the shaft 11 in the direction of the arrow F. The rotational movement of the shaft 11 is transmitted to the shaft 4 via the cam 17 and the lever 18, but in the opposite direction, which simultaneously causes the displacement of the contact. movable 2 to a fully closed position of the circuit breaker and the power of the spring 7 via the lever 8. The spring 10 is then switched back on using the motor 15 as indicated above.

According to the invention, an additional spring 20 is coupled to the shaft 4 to exert on the latter a return torque contributing on the one hand to the displacement of the moving contact at the beginning of opening of the circuit breaker and secondly to the slowdown of this displacement at the end of opening. In particular, the spring 20 is coupled to the shaft 4 by means of the lever 5 which is here a triangular lever having a vertex coincident with the shaft 4 and two other vertices respectively coupled to the movable contact 2 and the additional spring 20.

The top P of the lever 5 coupled to the spring 20 occupies two extreme angular positions respectively corresponding to the two positions of the movable contact 2 when the circuit breaker is completely closed or completely open. When the lever 5 occupies one or the other of its two extreme angular positions, the additional spring 20 is armed to the maximum. On the figure 1 , the extreme angular position of the lever 5 corresponding to the complete closing of the circuit breaker is indicated by the reference E1 while the other extreme angular position of the lever 5 corresponding to the complete opening of the circuit breaker is indicated by the reference E0 on the figure 2 . Typically, the angular travel of the lever 5 and therefore of the vertex P is about 60 °. Whatever the angular position of the lever 5, the force vector exerted by the spring always has the same direction since the spring 20 is always armed either in compression or tension. In the exemplary embodiment shown, the spring 20 is always more or less reinforced in compression. Although the strength exerted by the spring 20 always has the same direction, the resultant of this force exerts a torque on the shaft 4 and changes direction between the extreme positions E1 and E0. Indeed, there is an intermediate angular position I, also called neutral position, for which the resultant or rotational component of the force exerted by the spring 20 on the lever 5 is canceled to change direction when the lever 5 is moved from an extreme angular position to the other extreme angular position. The return torque exerted by the spring 20 on the lever 5, and thus on the rotary shaft 4, reverses when the neutral position is moved in such a way that the lever 5 functions as a pendulum around this position. When the lever 5 occupies the neutral position PM, the additional spring 20 is expanded to its maximum. The return force exerted by the spring 20 on the vertex P of the lever 5 then passes through the axis of rotation of this lever, that is to say by the axis of the rotary shaft 4, as shown in dashed lines on the figure 2 .

When the lever 5 moves from the extreme angular position to the other extreme position, during an opening or closing phase, the spring 20 expands first until the lever 5 passes through its position. intermediate angular PM. During this first angular displacement of the lever 5, the restoring torque exerted by the spring 20 on the rotary shaft 4 is added to that exerted by the spring 7 on the same shaft 4, and contributes to driving the shaft 4 in rotation . After crossing the lever 5 of its neutral position, the spring 20 is progressively armed since the restoring torque that it exerts on the lever 5 is reversed. The spring 20 then opposes the angular movement of the lever 5 and thus the displacement of the movable contact 2.

The intermediate angular position of the lever 5 is chosen such that during its displacement from its intermediate angular position PM to its extreme angular position E0 during an opening phase of the circuit breaker, the spring 2 accumulates and stores part of the kinetic energy of the moving contact which is normally consumed in the damper 19 at the end of opening. The energy stored in the spring 20 at the end of opening is restored at the beginning of the subsequent closing phase and is added to that provided by the spring 10 to drive the shaft 4 in rotation. Conversely, the energy stored by the spring 20 at the end of closing is restored at the beginning of the subsequent opening phase and is added to that provided by the spring 7 to drive the shaft 4 in rotation.

With this construction, the additional spring 20 is fully armed at the end of each opening or closing operation, thanks to the kinetic energy of the moving contact 2. Of course, the spring 20 is calibrated in an adequate manner with respect to to the triggering spring 7 and the triggering spring 10 so that it can be cocked until the lever 5 occupies an extreme angular position.

Preferably, the spring 20 is disposed inside the mechanical control 3, and is coupled to the lever 5 by a chain engaged on a return pulley 21. Such an arrangement makes it possible to place the spring 20 close to the chamber of cut to reduce the size of the circuit breaker. The lever 5 can also be coupled to the spring 20 by an articulated connection.

Claims (5)

1. An electric circuit-breaker including an interrupting chamber (1) with at least one moving contact (2) inside the chamber, the moving contact being actuated by means of a springloaded mechanical control mechanism (3) so as to open or close the circuit-breaker, the control mechanism including at least one first spring (7) exerting a force tending to move the moving contact to open the circuit-breaker, and a second spring (10) exerting a force tending to move the moving contact to close the circuit breaker white loading the first spring (7), and in which circuit-breaker an additional spring (20) is provided for exerting an additional force that is added to the force exerted by the first spring (7) at the beginning of circuit-breaker opening, characterized in that the additional spring (20) is mounted so that, before the end of circuit-breaker opening, the resultant of the force exerted by the additional spring for moving the moving contact is reversed so as to oppose the movement of the moving contact.
2. A circuit-breaker according to claim 1 in which the control mechanism includes a rotary shaft (4) movably coupled to the moving contact (2) and rotated alternately by the first spring (7) and by the second spring (10) and in which the additional spring (20) is coupled to the rotary (4) shaft via a lever (5) fixed to the rotary shaft and occupying two end angular positions (E0, E1) corresponding to the positions of the moving contact when the circuit-breaker is respectively open or closed, the force exerted by the additional spring (20) on the level (5) being oriented so that its rotational component changes direction when the lever (5) goes through an intermediate angular position (PM) as it goes from one end angular position towards the other end angular position.
3. A circuit-breaker according to claim 2, in which the additional spring (20) is couple to the lever (5) via a pulley (21).
4. A circuit-breaker according to claim 3, in which the additional spring (20) is loaded in Compression.
5. A circuit-breaker according to any of claims 2-4, in which said lever (5) is a triangular-shaped lever or bell-crank that has one vertex that coincides with the rotary shaft and two other vertices coupled respectively to the moving contact (2) and to the additional spring (20).

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