FR2542133A1 - Opening control mechanism with energy accumulation for electric circuit breaker - Google Patents

Abstract

The invention relates to a control mechanism with energy accumulation by springs. The opening control system 32 includes two compression springs 38, 40 cooperating with a transmission device 42 intended to modulate the mechanical opening energy through staged relaxations of the two coaxial springs, the outer spring 40 providing a force throughout the opening stroke, the inner spring 38 being active from the start of the said stroke up to an intermediate position corresponding to the extinguishing of the arc. Application: self-blasting circuit breakers.

Description

ANERGY ACCUMULATION OPENING CONTROL MECHANISM
FOR ELECTRIC CIRCUIT BREAKER.

The invention relates to a control mechanism with storage of energy by springs, associated with the support frame of an electrical apparatus, in particular an electric circuit breaker with self-blowing, comprising a closing control system with manual and / or automatic reset, an opening control system with manual and automatic release, and a kinematic link arranged in kre, the two systems for resetting the opening system during the closing phase of the circuit breaker.

The opening of a self-blowing circuit breaker on short circuit requires relatively large mechanical opening energy to ensure the rapid setting up of the moving equipment carrying the arcing and main contacts, and to prevent the contacts from closing. under the action of the opposing pressure generated in the pistonable volume of the self-blowing device of the cylinder and piston type for compression of the insulating blowing gas. A first known solution consists in using a powerful opening spring, the relaxation of which takes place during the entire opening stroke of the moving assembly. Such an opening system is simple but nevertheless requires significant mechanical closing energy to reset the opening spring during the closing phase of the circuit breaker.

A second solution proposes to house an intermediate kinematic link chain between the control rod of the mobile contact and the piston of the self-blowing device, so as to drive the mobile contact and the piston with different movements. This command has a complicated and bulky structure.

The object of the invention is to remedy the aforementioned drawbacks and to provide a simple opening control system with reduced mechanical energy.

The opening control system according to the invention is articulated by its ends opposite the kinematic link with a crank and at a fixed point of the support frame, and comprises two coaxial compression springs cooperating with a transmission device intended to modulate the mechanical energy of opening by stepped detents of the two springs, one of the springs ensuring a force during the whole of the opening stroke, 11 other spring being active from the start of said stroke Up to an intermediate position predetermined.

 This results in attenuation of the shocks exerted on the stopper at the end of the opening stroke, as well as a reduction in the mechanical energy of closing. The intermediate position advantageously corresponds to the extinction of the arc, a small effort then being sufficient to ensure the complete opening of the circuit breaker.

The transmission device passes through the two coaxial springs and comprises - a first operating bar secured to the crank and provided with a reset crossmember capable of bearing on the ends of the two springs located on the side of the articulation point, - a second support connected to the articulation point of the chassis and fitted with at least one cross member cooperating with the opposite ends of the two springs, disposed on the side of the crank link, the cross members being separated by a variable axial distance which is minimum in position closing and maximum in the open position of the circuit breaker, - and a third actuation device with relative movement relative to the first bar and to the second support and provided with a pair of retaining members intended to stop the expansion of the spring between the intermediate position and the open position of the movable stroke, and to allow the continued relaxation of the other spring. causing said separation nt maximum between sleepers.

Other advantages and characteristics will emerge more clearly from the description which follows of an embodiment of the invention given by way of nonlimiting example and represented in the appended drawings, in which FIG. 1 is a schematic view and simplified of a three-phase circuit breaker equipped with an opening control system according to the invention; the circuit breaker being shown in the closed position; Figure 2 shows a detailed elevational view of the opening system according to the invention; Figure 3 is a longitudinal sectional view along line III-III of FIG. 2; Figure 4 is a cross-sectional view along line IV-IV of FIG. 2; Figures 5 to 7 show the simplified operation of the control system, respectively in the closed, cut and open position of the circuit breaker; FIG. 8 is a diagram of the torque as a function of the opening stroke.

With reference to fig. 1, a three-pole electric circuit breaker with self-blowing is intended for the operation and protection of public distribution networks and medium-voltage industrial networks. The three poles 12, 14, 16 separated from the circuit breaker 10 are mounted on a support frame 18 fitted with a control mechanism 20 with spring energy accumulation Each pole 12 to 16 comprises a sealed cylindrical envelope, of elongated shape extending vertically, and filled with insulating gas with high dielectric strength, in particular sulfur hexafluoride SF6 used for isolation and breaking.Each enclosure contains a main circuit and an auxiliary circuit of arc with separable contacts cooperating with a auto device
blowing, in particular with piston compression cylinder of the
SF6 gas, the set of mobile contacts and car device
supply air constituting the pole's mobile equipment. The arrangement of such a pole is described in detail in the patents
French Nos. 20496e334 and 2o441.916 by the plaintiff.

The mechanical energy of opening and closing of the mechanism 20 is transmitted to the actuating rod (not shown
felt) of the mobile crew of each pole through the intermediary
diary of a rotary shaft 22 mounted for sealing in a
bearing (not shown) of the corresponding envelope. AT
inside the pole, the shaft 22 is kinematically connected
to the actuating rod of the moving assembly by a
internal connecting rod - crank. The opposite end
of the rotary shaft 22 of each pole is equipped with a
external mechanical connection with a control crank 24. The external cranks 24 of the three poles are
articulated on the other hand on rods of a rod 26
joint training stétendant in the direction
alignment of the poles. The rod 26 straight is delivered
bent to a crank 28 principal.de return rotatably mounted on an extension of the shaft 22 of the central pole 14,
and cooperating directly with the control mechanism 20.

The latter has a spring closing system
of energy accumulation (not shown), articulated on a
first crank pin 30 of the return crank 28. This sys
closing valve with manual or electric reset
is not part of the invention, and is described in detail
in French patent NO 1,586,097 of the applicant.

The intervention of this closing system causes the
circuit breaker 10 tripping by simultaneous pivoting
counterclockwise from the crank 28
and three external 24 cranks.

The control mechanism 20 also includes a system
opening with energy storage springs, designated
by the general reference 32. This system 32 is automatically bandaged during the closing phase, and is mechanically coupled by a connecting rod 33 to a second crank pin 34 located on the crank 28 opposite the first crank pin 32. A latch (not shown) cooperates with a miss trigger and with a plurality of automatic triggers, in particular with current emission, lack of voltage, overcurrent ... Unlocking the lock causes the intervention of the opening 32 which ensures the separation of the contacts of the poles 12 to 16 by limited pivoting clockwise from the return crank 28 and the external cranks 24.

According to the invention, the opening control system 32 is hooked to a fixed point 36 of articulation arranged in the upper middle zone of the support frame 18, and comprises two coaxial compression springs 38, 40, with stepped detents controlled during the opening stroke by a transmission device 42 (fig. 2 to 4). The latter has a first operating bar 44 located in an axial plane of the two helical springs 38, 40.

One 46 of the ends of the bar 44 is articulated by an axis 48 to the connecting rod 33 of the crank 28, and the opposite end carries an upper cross member 50 for resetting the springs 38, 4-0. The bar 44 is capable of sliding axially inside a second support 52 with two symmetrical twin bars 52a, 52b extending parallel to the first bar 44. The support 52 is connected by its upper end 54 to the point of articulation 36 secured to the chassis 18; the lower end of each bar 52a, 52b. is provided with a crosspiece 56a, 56b for supporting the coaxial springs 38, 40 The opposite faces of the latter are in engagement at the end of the reset stroke on the one hand on the upper rearming member 50 capable of sliding between the two twin bars 52a, 52b, and on the other hand on the lower crosspieces 56a, 56b of the support 52 articulated at point 36. The axial distance between the upper 50 and lower crosspieces 56a, 56b is variable during the opening or arming stroke. Each crosspiece 56a, 56b of support may have a rectilinear shape whose dimension corresponds substantially to the diameter of the external compression spring 40, or be equipped (fig. 4) d 'a pair of radial curved fins.

A third actuating device 58 is mounted idly on the second support 52 and comprises a pair of parallel bars 58a, 58b arranged on either side of the paired bars 52a, 52b The two bars 58a, 5Sb are each equipped at their ends opposite retaining members 6Oa, 62a; 68b, 62b, axially separated by a fixed distance and intended to limit the relaxation of the internal spring 38 during the opening stroke of the control system 32. The retaining members 60a, 62a; 60b, 62b are formed by flanges folded at right angles or by protuberances projecting from the corresponding bars 58a, 58b to serve as support for the internal spring 38.

It is noted that the five bars 44, 52a, 521b S 58a, 58b csn- stitutives of the transmission device 42 extend parallel in the axial direction of the springs 38, 40, the third device 58 acting only on the internal spring 38.

The operation of the opening control system 32 according to the invention is illustrated schematically in Figures 5 to 8
CLOSING POSITION
In the armed and closed position of the circuit breaker (fig. 1 and 5), the two coaxial compression springs 38, 40 are on the one hand bearing against the crosspieces 56a, 56b of the bars 52a, 52b secured to the point of articulation 36 , and are on the other hand compressed on the opposite side by the cross-member 50 for resetting the first bar 44 in mechanical connection with the return crank 28 The axial distance separating the cross-member 50 from the opposite cross-members 56a, 56b is minimum and is less than the fixed axial distance provided between the retaining members 60a, 62a; 6Ob, 62b opposite bars 58a, 58b of the third device 58. The latter is inactive in the closed armed position.

CUT
When a short-circuit current appears, the self-blowing circuit breaker requires a large initial opening energy for the rapid setting of the moving assembly and to avoid reclosing of the contacts under the effect of the opposing pressure which develops during the arc period in the surge volume of the self-blowing device. This energy is available after the release of the lock by the trigger.

The first operating bar 44 is then released, and is biased in translation to the right (FIG. 6) under the action of the unidirectional expansion of the two springs 38, 40 acting simultaneously on the cross-member 50. The two bars 52a, 52b twin of the second support 52 remain stationary Up to an intermediate position of the opening stroke corresponding to the extinction of the arc (fig. 6) for a maximum arc time. The internal spring 38 then bears on the retaining members 6Oa, 62a; 60b, 62b, opposite bars 58a, 58b of the third device 58 which stops the continuation of its relaxation.

OPENING POSITION
After the arc extinguishes, the opening speed of the control system 32 is reduced to the fully open position (fig. 7) by neutralizing the internal spring 38. The relaxation continues with the single spring 40 external causes a slight pivoting in the senstrigonometric of the system 32 around the point of articulation 36.

We notice in fig. 8 the significant decrease in torque from the cut-off position. This also results in a reduction of the shocks on the opening end-of-travel stop.

CLOSING
The closing of the circuit breaker 10 by means of the control system with closing springs ensures automatic resetting of the opening springs 38, 40. The passage of the system 32 of FIG. 7 in fig. 5 is carried out in the opposite direction of opening, and allows a reduction in the energy of r closing at the start of the closing stroke. from an intermediate position of the closing stroke, - the tran-siation continued to the left of the first bar 44 (fig. 6) actuated by the return crank 28 causes the simultaneous compression of the two springs 38 , 40.

The invention is of course in no way limited to the mode of implementation more particularly described and shown in the accompanying drawings, but it extends quite the contrary to any variant remaining within the framework of mechanical equivalents} in particular that in which the control mechanism is applicable to any type of electrical equipment other than self-blowing.

Claims (6)

Claims  1. Control mechanism with storage of energy by springs, associated with the support frame of an electrical apparatus, in particular an electric circuit breaker with self-blowing, comprising a closing control system with manual and / or automatic reset, a control system d opening with manual and / or automatic tripping, and a kinematic link arranged between the two systems to reset the opening system during the closing phase of the circuit breaker, characterized in that the opening control system ( 32) is articulated by its ends opposite to the kinematic link with a crank (28) and at a fixed point (36) of the support frame (lu), and comprises two coaxial compression springs (38,40) cooperating with a transmission device (42) intended to modulate the mechanical opening mechanism by staggered detents of the two springs (38, 40), one (40) of the springs ensuring an ef- fort during the entire opening stroke, the other spring (38) being active from the start of said race to a predetermined intermediate position. 2. Control mechanism according to claim 1, charac terized in that the transmission device (42) passes through the two coaxial springs (38,40) and comprises - a first operating bar (44) integral with the crank (28 ) and provided with a cross-member (50) for resetting capable of bearing on the ends of the two springs (38, 40) situated on the side of the point (36) of articulation,  a second support (52) connected to the point (36) and equipped at least with a crosspiece (56a, 56b) cooperating with the opposite ends of the two springs (38,40), arranged on the side of the crank link (28) , the crosspieces (50 and 56a, 56b) being separated by a variable axial distance which is minimum in the closed position and maximum in the open position of the circuit breaker, - and a third actuating device (58) with relative movement relative to the first bar (44) and to the second support (52) and provided with a pair of retaining members (66a, 62a; 6bob, 62b) intended to stop the relaxation of the spring g38) between the intermediate position and the open position of the movable stroke, and to allow continued relaxation of the other spring (40) causing said maximum spacing between the crosspieces (50 and 56a, 56b). 3. Control mechanism according to claim 2, characterized in that the first bar (443, the second support (52) and the third actuating device (58) extend parallel in the axial direction of the coaxial springs (38 , 40), and that the third device (58) acts on the internal spring (38). 4. Control mechanism according to claim 2 or 3, characterized in that the second support (52) comprises two bars (52a, 52b) paired between which is interposed with radial clearance the first bar (44) grout, 'health, and that the crosspiece (56aS 56b) of the corresponding bar (52a, 52b) presses a rectilinear or curved shape which can be adapted to the diameter of the external spring (40). 5. Control mechanism according to claim 4, characterized in that the third actuating device (58) is provided with a pair of parallel bars (58a, 58b) arranged radially on either side of the bars (52a , 52b) of the second support (52), and that the retaining members (60a, 62a; 60b, 62b) of the internal spring (38) are formed by flanges folded at right angles or by protuberances formed at the opposite ends of each bar (58a, 58b). 6. Control mechanism according to one of claims 1 to 5, characterized in that the coming into abutment in the intermediate position of the third actuating device (58) with the spring (38) occurs substantially after the extinction of the arc by the self-blowing device.