AU692536B2

AU692536B2 - Drive arrangement for vacuum power circuit breakers, in particular in a tri-polar configuration

Info

Publication number: AU692536B2
Application number: AU21112/95A
Authority: AU
Inventors: Wolfgang Gran; Dieter Milk; Dietmar Mucksch
Original assignee: Holec Holland NV
Current assignee: Danfoss Power Solutions II BV
Priority date: 1994-03-30
Filing date: 1995-03-23
Publication date: 1998-06-11
Anticipated expiration: 2015-03-23
Also published as: BR9507447A; EP0764337A1; MX9604443A; DE19580258D2; EP0764337B1; NO963902D0; CN1146825A; WO1995027296A1; SK122796A3; NO963902L; NZ283146A; ATE167956T1; FI963912A0; TW265451B; SK280121B6; ES2120739T3; DE4411596C1; MY113784A; JPH09512945A; HUT75478A

Abstract

In a known drive arrangement in which the switching-off process is initiated after actuation, for example, of an electromagnet by a pin secured to an "off"-trigger shaft as a result of rotation of the latter, thereby enabling a roller of the switching lever to run past the "off"-trigger shaft, the switching-off process occurs when the switching lever has rotated back and the articulated lever systems have moved out of the extended position. However, as the switching lever moves past, it strikes the "off"-trigger shaft. In order to reduce the resultant wear of the "off"-trigger shaft (6) and to actuate the wiping contact (11') associated with the "off"-trigger shaft (6) only during the switching-off process, so as to attain an even greater number of switching cycles, the switching lever (1) has a circular segment (7) with the peripheral surface (9) of which the "off"-trigger shaft (6) is operationally connected in any position of the switching lever (1). Detachably mounted on the "off"-trigger shaft (6) is a trigger bar (11) for connecting and disconnecting a wiping contact (11'). The drive arrangement can also be used for small oil-volume power circuit breakers.

Description

WO 95/27296 PCT/EP95/01098 Drive device for vacuum circuit breakers, in particular with a three-pole configuration The invention relates to a drive device for vacuum circuit breakers, in particular with a threepole configuration, in which a cam disc is fitted to a closing shaft which is subject to the force of a closing spring designed as a tension spring, which cam disc rotates through about 1800 during the closing process after release of a catch which is likewise arranged on the closing shaft, and which cam disc is operatively connected to a roller of a closing lever in such a manner that, during rotation of the closing lever about a fulcrum, a bell crank system of the first circuit breaker pole is forced into the extended position, this closing lever being provided, for locking, with a second roller which is mounted firmly on this closing lever, initially moves past the halfshaft region of an "off" tripping shaft which is subject to the force of a restoring spring, and which roller rests against the half-shaft region of the "off" tripping shaft after reversal of the rotation direction of the closing lever.

In the case of electrical switch gear, that is to say in the case of high-voltage circuit breakers, it is necessary for such circuit breakers to cope unambiquously with both the closing process and the disconnection process. A precondition of this is, inter alia, the provision of a drive device which correctly ensures the sequence of the closing process and disconnection process on initiation of a switching process by operation of an elector magnet or else a push button. At the same time, the design of the drive device has to make it possible to cope with a lar e number of switching operations. Drive devices which satisfy these preconditions are known in a wide range of configurations. As an example, it is intended to mention only that according to EP 0 450 194 Al and that according to EP 0 521 585 Al.

2 In the case of a drive device which is furthermore known for a three-pole vacuum circuit breaker, as can be seen to some extent in Fig. 18 in the Holec Company document "Vacuum circuit breakers" 3994.047/E 3.10.1-1-103-20-TP-GP, an "on" initiation shaft is initially rotated after initiation of the closing process by the electromagnet or by the push button, via a pin which is connected to said "on" initiation shaft. In this case, the "on" initiation shaft is designed at its centre as a half-shaft and is operatively connected here to a catch which is mounted on the rear wall of the vacuum circuit breaker such that it can rotate. While this catch is released by this operative connection, a second catch which is seated on the closing shaft is at the same time released, the closing shaft being subject to the force of a closing spring which is designed as a tension spring. However, this means that the closing shaft on which an eccentric is fitted rotates. However, in consequence, a cam disc which is fitted firmly on the closing shaft also rotates through about 1800, pressing onto a roller of the closing lever in so doing as a result of which the closing lever, which is designed as a double lever, rotates about a fulcrum and in so doing forces a bell crank system of the first circuit breaker pole to the extended position. When this bell crank system is forced into the extended position, then the bell crank systems of the second circuit breaker pole and of the third circuit breaker pole are also forced into the extended position by means of two switching rods. This creates the preconditions for the closing process to be completed via a joint element, which is assigned to each circuit breaker pole, and a switching rocker which is likewise assigned to each circuit breaker pole. If this is the case, then the closing lever is locked in that a roller, which is likewise firmly mounted on the closing lever, moves past the half-shaft region of the "off" tripping shaft and, in so doing, rotates the latter against the force of a

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B1~ -3restoring spring. Once this roller has moved past, then the closing lever rotates, and the roller strikes against the half-shaft region of the "off" tripping shaft, and the closing process is locked.

The disconnection process is also initiated in the case of this known drive device once again by means of an electromagnet or by means of a push button. In this case, the "off" tripping shaft is rotated by a pin which is mounted on said "off" tripping shaft, until the roller can move past the "off" tripping shaft. In consequence, the closing lever can rotate back, and the bell crank systems move out of the extended position.

The switching rockers can thus rotate, and the disconnection process takes place under the influence of the disconnection springs, which are designed as compression springs, are assigned to each moving contact of the three circuit breaker poles and are stressed during the closing process.

The closing process and disconnection process of the vacuum circuit breaker are coped with 20 unambiguously by means of this known drive device for three-pole vacuum circuit breakers, and a predetermined number of switching operations are achieved.

h r. The wear on the "off" tripping shaft is, however, significantly influenced by the fact that the closing lever strikes the "off" tripping shaft while moving past it.

The operation of the wiper which is assigned to the "off" tripping shaft and is required in order to emit a signal during the switching process is in this case carried out both during the closing process and dur4ing the disconnection process.

In accordance with the invention there is provided a drive device for vacuum circuit breakers, in particular with a three-pole configuration, in which a cam disc is fitted to a closing shaft which is subject to the force of a closing spring designed as a tension 1/4' spring, which cam disc rotates through about 1800

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3A during the closing process after release of a catch which is likewise arranged on the closing shaft, and which cam disc is operatively connected to a roller of a closing lever in such a manner that, during rotation of the closing lever about a fulcrum, a bell crank system of the first circuit breaker pole is forced into an extended position, this closing lever being provided, for locking, with a second roller which is mounted firmly on this closing lever, initially moves past the half-shaft region of an "off" tripping shaft which is subject to the force of a restoring spring, and which roller rests against the half-shaft region of the "off" tripping shaft after reversal of the rotation direction of the closing lever, characterized in that the closing lever has a widened region above its fulcrum on its side pointing towards the "off" tripping shaft which widened region is designed as a circular segment in such a manner that the "off" tripping shaft is operatively connected to the circumferential surface of the circular segment in every position of the closing lever, even in the locked state, and in that a tripping bracket is mounted on the "off" tripping shaft can be decoupled from the "off" tripping shaft in order to S* connect and disconnect a wiper and, on initiation 00 of a disconnection process, rotates the "off" tripping shaft with its half-shaft region in order to unlock the closing lever via a stop element which is connected to the "off" tripping shaft At least one embodiment of the invention provides a drive device Lor vacuum circuit breakers, in particular with a. three-pole configuration, in which, on the basis of a cam disc which is fitted on the closing shaft and is operatively connected to a roller of a closing lever, the closing lever resting against the half-shaft region of an "off" tripping

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r -4 shaft for the purpose of locking after carrying out the closing process, of reducing the wear on the "off" tripping shaft which results from the closing lever moving past and the striking associated therewith and, furthermore, of operating the wiper, which is assigned to the "off" tripping shaft, only during the disconnection process, so that a vacuum circuit breaker is provided which ensures an even greater number of switching operations.

This is achieved in that the closing lever has a widened region above its fulcrum on its side pointing towards the "off" tripping shaft, which widened region is designed as a circular segment in such a manner that the "off" tripping shaft is operatively connected to the circumferential surface of the circular segment in every position of the closing lever, even in the locked state, and in that a tripping bracket is mounted on the "off" tripping shaft, can be decoupled from the "off" 20 tripping shaft in order to connect and disconnect a S wiper and, on initiation of a disconnection process, rotates the "off" tripping shaft with its half-shaft region in order to unlock the closing lever via a stop element which is connected to the "off" tripping shaft.

As a result of the fact that the "off" tripping shaft now rests on the circumferential surface of the circular segment of the closing lever in every position which it assumes, and to be precise irrespective of whether the closing lever is located in the "on" switching position or else in the "off" switching position, the "off" tripping shuft is no longer struck when the closing lever moves past said "off" tripping shaft. However, this means that the "off" tripping shaft is no longer a part subject to wear within the drive device, so that the preconditions are created at this point in the drive device such that switching operations in the order of magnitude of 40,000 can now Salways be achieved. In this case, it is advantageous if the second roller with which the closing lever is provided is arranged in the upper region of the circumferential surface of the circular segment, so that the frictional resistance to be overcome on the circumferential surface of the circular segment of the closing lever on initiation of the movement of the "off" tripping shaft is small.

However, on the other hand, the wiper which is assigned to the "off" tripping shaft is also subject to less stress since the tripping bracket, which is mounted on the "off" tripping shaft and can be decoupled from the "off" tripping shaft for connecting and disconnecting the wiper contact, and in interaction with the stop element which is connected to the "1off" tripping shaft results in the wiper now being operated only during the disconnection process. Since this thus obviates operation of the wiper during the closing process, the stress on the wiper contact for the purpose of emitting a signal is reduced by half, so *that the drive device designed according to the 20 invention has a positive influence overall in terms of a large number of switching operations and thus in temqs of the vacuum circuit breaker having a long service life.

:In a further embodiment of the invention, 25 the tripping bracket, which is mounted 'on the "off" tripping shaft such that it can be decoupled, is mounted on pins on the "off" tripping shaft such that it can rotate, while the "off"' tripping shaft itself is mounted both in the intermediate wall and in the front wall of the vacuum circuit breaker such that it can rotate. In this case, the tripping bracket h/As a recess on its upper side pointing towards the fulcrum of the closing lever, in which recess the electromagnet or push button which operates the tripping bracket engages, that is to say is securely guided while the tripping bracket is being forced downwards. At the same time, the tripping bracket is connected on its ~RA side opposite the recess to a tension spring which is Mounted underneath the tripping bracket, preferably on -0

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6 the intermediate wall of the vacuum circuit breaker, thus ensuring that the tripping bracket is reset to its original position by the tension spring when the electromagnet or push button which operates the tripping bracket is no longer engaging in the recess in the tripping bracket.

Any desired component may, of course, be used for the stop element, which is connected to the "off" tripping shaft by means of its half-shaft region, provided it is suitable for driving the "off" tripping shaft by means of the stop on the tripping bracket during rotation of the tripping bracket on said "off" tripping shaft, in order to initiate the disconnection process by rotation of the "off" tripping shaft.

However, it has been found to be useful to use a pin for the stop element, which is connected to the "off" tripping shaft, running in the radial direction.

Finally, in order likewise to have a reducing influence on the wear of the components of the drive device, it is expedient if the bearing of the bell crank system which is connected to the closing lever, is a roller bearing, one lever of the bell crank system being formed by the closing lever itself.

The invention is intended to be explained in more detail in the following text with reference to an exemplary embodiment. In the associated drawings: Fig. 1 shows a view of the drive device in the region of the closing lever in the "on" position, Fig. 2 shows a view of the drive device in the region of the closing lever in the "off" position, and Fig. 3 shows a plan view of the tripping bracket which is mounted.on the "off" tripping shaft of the drive device according to Figs. 1 and 2.

As Fig. 1 shows, the closing lever 1, which is arranged such that it can pivot at its centre about fulcrum 2, has in its upper region a roller 3 which, when a closing process takes place, interacts with the cam -7 disc 5 which is located on the cloning shaf t 4. The closing lever 1 is provided on the side pointing towards the "of f tripping shaf t 6 with a widened region which ik designed as a circular segment 7.

As can also be seen from Fig. 2, the "~of..i tripping shaft 6 is located with its half-shaft region 8 on the circumferential surface 9 of the circular segment 7 in every position of the closing lever 1, so that, as the closing lever I moves past, it no longer strikes the "off" tripping shaft 6. At the same time, the "off" tripping shaft 6 touches a roller 10 when the closing lever I. is in the closed position, this roller 10 being arranged in the upper region of the circumferential surface 9 of the circular segment 7, such that the closing lever I is locked when the "off" tripping shaft 6 is in the position shown.

As can be seen in conjunction with Fig. 3, a tripping bracket 11 is mounted on the "of f"1 tripping shaft 6 and can be decoupled from the "off" tripping shaft 6 in order to connect and disconnect a wiper 11' This decouapling is achieved in that the trippir~j bracket 11 is mounted on pins 12 of the "off" tripping shaf t 6 such that it can rotate, the "of f" tripping shaf t 6 being mounted both in the intermediate wall 13 and in the front wall 14 of the vacuum circuit breaker such that it can rotate. A stop element 15 is connected to the "off" tripping shaft 6, is in the form of a pin and strikes against the tripping bracket 11 when, in order to initiate a disconnection process, an electromaVnet 11" engages in the recess 16 in the tripping bracket 11. As a consequence of this, the tripping bracket 11 is rotated on the "off" tripping shaft 6 against the force of a restoring spring designed as a tension spring 17 which is mounted on the intermediate wall 13, nc in so doing drives the "off" tripping shaft 6 via the stop element 15 in the form of a pin, in that this "off"' tripping shaft 6 is likewise rotated, such that this leads to the closing lever 2 being unlocked. The closing lever 1 is released by the unlocking and pivots about the 8fulcrum 2 into the position which can be seen from Fig.

2. The closing lever 1 forms a bell crank system together with the second lever 19, the second lever 19 being mounted at the fulcrum 21 at which a guide lever 22 engages which in turn is mounted at a fulcrum 23 via the bearing 24, which is a roller bearing, and the lower lever 18 of the closing lever 1 is connected to a switching rod 25 which leads to the bell crank system of the adjacent circuit breaker pole this connection also being made by a switching rod to the third circuit breaker pole which ensures that, when the lock of the closing lever 1 is released by the "off" tripping shaft 6, all three circuit breaker poles of the vacuum rircuit breaker are essentially disconnected at the same time.

If the tripping bracket 11 is released again ~.:after it has be,,a operated by the electromagnet 11", t~ien the tripping bracket 11 is reset by t~,e tension Off**:spring 17 to the position which can be seen in Fig. 2.

However, this means that the tripping bracket 11 is not operated during a closing process which now follows this, in which the closing lever 1 is forced, by rotation of the closing shaf t 4 and by means of the cam S. 5.disc 5 which is located on the closing shaft 4, via the roller 3 from the position which can be seen in Fig. 2 into the position which can be seen in Fig. 1, thatL is to say into the closed position, even though the "off" :tripping shaft 6 now rotates again. This ensures that the wiper 11 is also not operated during the closing process.

In the claims that follow and in the summary of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprising" is used in the sense of "including", i.e. the features specified may be associated with further features in various embodiments of the invention.

Claims

1. Drive device for vacuum circuit breakers, in particular with a three-pole configuration, in which a cam disc is fitted to a closing shaft which is subject to the force of a closing spring designed as a tension spring, which cam disc rotates through about 1800 during the closing process after release of a catch which is likewise arranged on the closing shaft, and which cam disc is operatively connected to a roller of a closing lever in such a manner that, during rotation of the closing lever about a fulcrum, a bell crank system of the first circuit breaker pole is forced into an extended position, this closing lever being provided, for locking, with a second roller which is mounted firmly on this closing lever, initially moves past the half-shaft region of an "off" tripping shaft which is subject to the force of a restoring spring, and which roller rests against the half-shaft region of the "off" tripping shaft after reversal of the rotation direction of the closing lever, characterized in that the closing lever has a widened region above its fulcrum on its side pointing towards the "off" tripping shaft which widened region is designed as *0 25 a circular segment in such a manner that the "off" tripping shaft is operatively connected to the circumferential surface of the circular segment in evety position of the closing lever even in the locked state, and in that a tripping bracket is mounted on the "off" tripping shaft can be decoupled from the "off" tripping shaft in order to connect and disconnect a wiper and, on initiation of a disconnection process, rotates the "off" tripping shaft with its helf-shaft region in order to unlock the closing lever via a stop element which is connected to the "off" tripping shaft

2. Drive device according to Claim 1, characterized in that the tripping bracket is 2. Drv dvie acorig o lim I mounted on pins of the "off" tripping shaft such that it can rotate, while the "off" tripping shaft is mounted both in an intermediate wall and in a front wall of the vacuum circuit breaker such that it can rotate.

3. Drive device according to Claim 1 and 2, characterized in that the tripping bracket has a recess on its upper side which points towards the fulcrum of the closing lever in which recess the electromagnet or push button which operates the tripping bracket engages.

4. Drive device according to any one of Claims 1 to 3, characterized in that the tripping bracket is connected on its side opposite the or a recess to the restoring spring which is mounted underneath the tripping bracket preferably on the or an intermediate wall of the vacuum circuit breaker.

Drive device according to any one of Claims 1 to 4, characterized in that a stop element which is connected ta the '"off" tripping shaft by means of the half-shaft region o" the latter is a pin. e: 20

6. Drive device according to Claim 1, characterized 9 in that the second roller with which the closing lever is provided is arranged in the upper region of the circumferential surface of the circular segment.

7. Drive device according to Claim 1, characterized 25 in that the bearing of the bell crank system which is •o connected to the closing lever is a roller bearing, one lever of the bell crank system being formed by the closing S"lever itself.

8. A device substantially as described herein with reference to the accompanying drawings. Dated this 19th day of March 1998 Holec Holland N.V. By their Patent Attorneys GRIFFITH HACK