WO2005076304A1

WO2005076304A1 - Load-break switch

Info

Publication number: WO2005076304A1
Application number: PCT/DE2005/000151
Authority: WO
Inventors: Christoph RÖHLING; Jörg Teichmann
Original assignee: Siemens Aktiengesellschaft
Priority date: 2004-02-04
Filing date: 2005-01-27
Publication date: 2005-08-18
Also published as: DE102004006476B4; DE102004006476A1

Abstract

The aim of the invention is to provide a load-break switch (1) for interrupting an alternating current, provided with a main contact assembly (4), which has a displaceable main moving contact piece (2), and with a shunt arm, which is electrically connected in parallel to the main contact assembly (4) and in which an extinguishing contact assembly (8) for extinguishing an arc as well as a disconnecting contact assembly (6), which is comprised of disconnecting contact pieces and which serves to provide an electric strength, are connected in series to one another, whereby after the main contact assembly (4) is opened, current is permitted to flow over the shunt arm. In addition, this load-break switch should have a simple and cost-effective design. To this end, the invention provides that the moving main moving contact piece (2) is also one of the disconnecting contact pieces of the disconnection contact assembly (6).

Description

description

Switch disconnectors

The invention relates to a switch disconnector for interrupting an alternating current with a main contact arrangement which has a movable main moving contact piece, and with a shunt branch electrically connected in parallel with the main contact arrangement, in which a quenching contact arrangement for extinguishing an arc and an isolating contact arrangement consisting of isolating contact pieces for providing a dielectric strength in series with one another are switched, wherein a current flow through the shunt branch is made possible after opening the main contact arrangement.

Such a load break switch is already known for example from DE 195 40 552 AI. The switch disconnector disclosed there is provided for interrupting an alternating current and has a main contact arrangement consisting of a pivotable switching knife, which is connected in parallel to an auxiliary current branch in which an erase contact arrangement and an isolating contact arrangement are arranged in series with one another. When the load-break switch is switched off, the isolating contact arrangement lags behind the main contact arrangement, so that after the main contact arrangement has been opened, current can initially flow through the auxiliary current branch. When the main moving contact piece is pivoted further, the extinguishing contact arrangement is opened, which is arranged there in an extinguishing chamber filled with sulfur hexafluoride gas. When the quenching contact arrangement is opened, such a high gas flow is generated in the quenching chamber that an arc drawn between the quenching contact pieces results in a zero crossing of the alternating current for detection. delete is brought. When the main moving contact piece moves further in its end position, the isolating contact arrangement is finally opened without current, so that a sufficiently large isolating distance is also provided in the auxiliary current branch of the switch disconnector. However, the known switch disconnector is complex in terms of its design and therefore cost-intensive.

DE 38 32 493 A1 discloses an erase contact arrangement arranged in a vacuum chamber, which is connected in parallel to a main contact arrangement. The main contact arrangement and the erase contact arrangement form a parallel circuit which is arranged in series with an isolating contact arrangement.

The load switch disclosed in DE 199 18 070 Cl develops a switch disconnector described in WO 98/09310 so that the switch disconnector is also switched on again via the extinguishing contact arrangement. The quenching contact arrangement is arranged in series with a disconnecting contact arrangement in a shunt branch with which a main contact arrangement can be bridged.

The object of the invention is to provide a switch disconnector of the type mentioned at the outset, which is simplified in terms of its construction and is inexpensive.

The invention solves this problem in that the main moving contact piece is simultaneously one of the isolating contact pieces of the isolating contact arrangement.

According to the invention, a common movable contact piece is provided both for the main contact arrangement and for the isolating contact arrangement. The main moving contact is in an operating position of the switch disconnector, in which a current flow through the main contact arrangement is made possible, in contact with a main fixed contact piece of the main contact arrangement. In the operating position, the main moving contact piece can also contact one of the isolating contact pieces of the isolating contact pieces. In a departure from this, the main moving contact piece only contacts the main fixed contact piece in the operating position, but before the main contact pieces of the main contact arrangement are disconnected, the main moving contact piece comes into contact with the disconnecting contact piece of the separating contact arrangement assigned to it, so that a shunt of the main contact arrangement and thus the pulling out of a switch-off arc between the contact pieces of the main contact arrangement is avoided. Such an arc could damage the surface material of the main contact arrangement due to the high level of heat and reduce the durability of the circuit breaker. After the main contact arrangement has been opened, the current therefore flows according to the invention via the shunt branch and thus via the quenching contact arrangement and via the isolating contact arrangement connected in series in this regard, until the contact pieces of the quenching contact arrangement finally open and the arc is drawn between the contact pieces of the quenching contact arrangement. If the alternating current to be interrupted passes zero, the arc is extinguished in a known manner. By opening the isolating contact arrangement without current, a sufficiently large isolating distance is finally provided to maintain the required dielectric strength.

By using a common moving contact piece both for the main contact arrangement and for the isolating contact arrangement, a separate drive with a time-consuming synchronization of the switching processes using coordinated kinematics has become superfluous.

The switch disconnector according to the invention is provided for interrupting a nominal current and is set up for operation with large quantities. In comparison to so-called circuit breakers, which are able to interrupt significantly higher short-circuit currents, the switch disconnector is therefore inexpensive. The maximum current that the switch disconnector according to the invention can still interrupt is, for example, 2 kA.

The quenching contact arrangement is advantageously arranged in a vacuum chamber. In the context of the invention, this is an inexpensive vacuum tube which is provided, for example, neither with contact pressure springs nor with other additional components which drive up the production costs of the vacuum tube. According to this further development, it is possible, for example, that the extinguishing contact pieces only result from the pressure difference

The force acting between the vacuum of the vacuum tube and the outside atmosphere is held together. Deviating from this, however, it is also possible within the scope of the invention to provide the vacuum tube with inexpensive contact pressure springs which generate contact pressure.

The isolating contact arrangement advantageously has a pivotably mounted swivel bracket as isolating contact piece, which can be pivoted by the main moving contact piece before the isolating contact arrangement is opened. According to this further development, a separating contact piece is realized as a swivel bracket, which is provided at its free end for contacting the main moving contact piece and, for example, on a nem fixed support frame of the switch disconnector is hinged. The articulation enables the swivel bracket to be pivoted through the main moving contact piece, which thereby contacts the swivel bracket and, in other words, takes it along a certain path length of a common swivel path. However, the separation or switching path of the main moving contact piece differs from that of the swivel bracket, so that there is finally a lifting of the main moving contact piece from the swivel bracket. The movement paths of the swivel bracket and the main moving contact piece are adjusted to one another in such a way that the disconnection of the disconnection contact arrangement takes place without current, that is to say after the disconnection of the extinguishing contact arrangement.

According to a further development which is advantageous in this regard, the swivel bracket has at its end facing the main movement contact piece a snap mechanism which allows the swivel bracket to be carried along by the main movement contact piece in a switch-off direction, but when the main movement contact piece moves in a switch-on direction opposite to the switch-off direction, the main movement contact piece is guided past allows the swivel bracket. By moving the main moving contact piece past the swivel bracket in the switch-on direction, renewed contact between the contact pieces of the main contact arrangement is subsequently made possible. In the switch-off direction, on the other hand, the snap mechanism ensures that the main moving contact piece takes the swivel bracket along until the main moving contact piece and the swivel bracket are separated from one another due to different switching paths.

According to an expedient further development in this regard, the snap mechanism has a plastic one Holding section and a metal snap bracket pivotally mounted on the holding section, wherein the snap bracket has an end-side driving lug, which is in contact with the main contact element in a contact position of the isolating contact arrangement, and a stop end opposite the driving lug, which in the contact position of the isolating contact arrangement bears against the swivel bracket and prevents swiveling of the swivel bracket in the direction of switching off the main moving contact piece.

In a preferred embodiment, the main moving contact piece is designed as a rotatable switching knife. The rotatable switching knife can be driven, for example, by means of a drive shaft. In a departure from this, the main moving contact piece is implemented as a switching rod which carries out a lifting movement.

According to a preferred further development, the swivel bracket is connected to the extinguishing contact arrangement in order to initiate a switching movement. Due to the mechanical connection of the swivel bracket to the extinguishing contact arrangement, complex electronic synchronization between the isolating contact arrangement and the extinguishing contact arrangement is avoided.

According to an expedient further development in this regard, a movable extinguishing movement contact piece of the extinguishing contact arrangement is rigidly connected to a driver pin which is arranged in an elongated hole of the swivel bracket. The synchronization of the opening is determined in this embodiment by the length of the elongated hole. So the pivoting of the swivel bracket has no effect on the extinguishing contact arrangement until the driver pin strikes one end of the elongated hole. Then by taking the Swivel bracket initiated by the main contact arrangement, a switching movement in the erase contact arrangement with which the contact pieces of the erase contact arrangement are separated from one another. Only after the arc is extinguished is there a separation of the contact pieces of the isolating contact arrangement, which are thus separated from one another without current.

A torsion spring is advantageously provided for holding the swivel bracket on the main fixed contact piece. According to this advantageous further development, after the disconnecting contact arrangement has been disconnected, the swivel bracket moves in a direction opposite to the switch-off direction. For example, after it is switched off, it bears against the stationary main fixed contact piece of the main contact arrangement.

Advantageously, a compression spring is provided for pressing an extinguishing movement contact piece of the extinguishing contact arrangement against a fixed extinguishing contact piece in this regard. The additional compression spring makes it even more difficult for the contacts of the extinguishing contact arrangement to be lifted off by electrodynamic forces.

Further expedient refinements and advantages of the invention are the subject of the following description of exemplary embodiments of the invention with reference to the figures of the drawing, components with the same function being provided with the same reference numerals and wherein

FIG. 1 shows an exemplary embodiment of the disconnector according to the invention in a side view,

Figure 2 is an enlarged view of a vacuum tube of an erase contact arrangement and Figure 3 shows an embodiment of a snap mechanism of the isolating contact arrangement.

Figure 1 shows an embodiment of the switch disconnector 1 according to the invention in a schematic side view. The switch disconnector 1 shown there has a main contact arrangement 4 consisting of a main moving contact piece 2 and a stationary main fixed contact piece 3, an isolating contact arrangement 6 consisting of a swivel bracket 5 and the main moving contact piece 2, and an extinguishing contact arrangement 8 arranged in a vacuum tube 7, which is not shown in the figures , Furthermore, an earth contact 9 is provided, which comes into contact with the main moving contact piece 2 in an off position. The disconnector 1 is held in a support frame 10, which is only indicated schematically and which can also serve as a stop limiting the switching movement, for example for the swivel bracket 5.

The main fixed contact piece 3 of the main contact arrangement 4 is fixedly connected to the housing 10 and serves to hold the vacuum tube 7, which is firmly connected to the main moving contact piece 3 via screwing means 11. From the main fixed contact piece 3, an erasable fixed contact piece (not recognizable in FIG. 1) extends into the vacuum tube 7, which is located on the end face of an erase moving contact piece, which in turn is electrically connected to the pivot bracket 5. The quenching motion contact piece arranged within the vacuum tube 7 is guided in the vacuum tube 7 in a longitudinally movable manner and is sealed off from the outside by means of a metal bellows 12. To initiate a switching movement in the vacuum tube 7, the quenching movement contact piece is rigidly connected to a non-conductive switching rod 13, which is in the switching direction of the Extinguishing movement contact piece extends and is provided in the transverse direction with a driver pin 13a, which is arranged in an elongated hole 14 of a coupling piece 15. The coupling piece 15 is firmly connected to the swivel bracket 5. At its end facing away from the main movement contact piece 2, the swivel bracket 5 is articulated on the housing 10 by means of an axis of rotation 16, so that swiveling of the swivel bracket 5 in the switch-off direction indicated by the arrow is made possible.

The main moving contact piece 2 is rotatably connected at its end facing away from the main fixed contact piece 3 to a drive shaft 17, by means of which a switch-off movement in the direction of the arrow shown can be generated. The end of the main moving contact piece 2 facing the main fixed contact piece 3 passes over the circular path 18 indicated in FIG. 1 and thereby hits the free end of the pivoting bracket 5 with a snap mechanism 19, so that pivoting of the pivoting bracket 5 causes the pivoting bracket 5 to pivot. However, the swivel bracket 5 covers a second circular path 19 with its end facing the main movement contact piece 2. The main movement contact piece 2 and the swivel bracket 5 therefore remain in contact with one another until the disconnection contact pieces of the disconnection contact arrangement 6 come apart due to the different switching paths. This takes place at a waypoint 20 at which the circular paths 18 and 20 intersect again.

After the initiation of a rotary movement by the drive shaft 17, the main contact arrangement 4 is initially disconnected, but a current flow through an essentially through the erase contact arrangement 8 and the isolating contact clock arrangement 6 trained shunt branch is enabled. This also causes the swivel bracket 5 to pivot slightly, the driver pin 13a being moved within the elongated hole 14.

When the swivel bracket 5 is pivoted further by the main movement contact piece 2, the driving pin 13a finally stops at the lower end of the elongated hole 14, so that when the swivel bracket 5 is moved further, the extinguishing movement contact piece of the extinguishing contact arrangement 8 is lifted off the stationary fixed extinguishing contact piece, thereby causing an arc is pulled in the vacuum tube 7. Due to the vacuum, the arc is extinguished and the current flow is interrupted when the AC current passes through zero.

With a further rotary movement, the isolating contact arrangement 6 finally reaches the position 21, in which the isolating contact arrangement 6 is disconnected without current.

With a still further rotary movement in the switch-off direction, the main moving contact finally comes into contact with the ground contact 19.

Provided on the axis of rotation 16 is a torsion spring, not shown in FIG. 1, which after the separation of the

Isolating contact arrangement 6 causes the swivel bracket 5 to pivot back into the position shown in FIG. 1. In this position, the swivel bracket 5 rests on the main fixed contact piece 3.

To switch on, a rotational movement opposite to the direction of the arrow shown in FIG. 1 is introduced into the drive shaft 17 and the main movement contact piece of the Ground contact 9 pivoted back to the main fixed contact piece 3, where it first strikes against the snap mechanism 19. However, the snap mechanism 19 enables the main moving contact piece to be guided past, which will be discussed in more detail below.

FIG. 2 shows a further exemplary embodiment of the switch disconnector according to the invention and in particular illustrates the electrical and mechanical connection of the extinguishing contact arrangement 8 arranged in the vacuum tube 7 to the swivel bracket 5. In particular, it can be seen in this illustration that the extinguishing movement contact piece has a metallic and thus electrically conductive conductor strip 22 is connected to the swivel bracket 5.

In FIG. 2, the coupling piece 15, which is firmly connected to the swivel bracket 5, has a flange section 23, on which a contact pressure spring 24 is supported, via the end of which, facing away from the flange section 23, a pressing force can be introduced into the extinguishing contact arrangement. Appropriate configurations of the elongated hole 14 thus enable a pressure force to be generated via the swivel bracket 5 of the coupling piece 15 and the contact spring 24, which is added to the force resulting from the pressure difference between the vacuum and the outside atmosphere.

Figure 3 shows the snap mechanism 19 in more detail. It can be seen here that the snap mechanism 19 has a metallic snap bracket 25 which is articulated on a holding section 26 made of plastic. The holding section 26 is fastened to the end of the swivel bracket 5 facing the main moving contact piece 2. In this case, the snap-over bracket 25 has a driver nose 27 facing the main movement piece 3 and one of this averted stop arm 28, which rests on the swivel bracket 5 in the position shown. When the moving contact piece 2 rotates, in FIG. 3 from bottom to top, the main moving contact piece 2 strikes against the lower side of the driving lug 27, so that a rotating movement is initiated in the articulated snap-in bracket 25 and the stop arm 28 is lifted off the swivel bracket 5. In this way, the main movement contact piece 3 can slide past the swivel bracket 5. The driver nose 27 slips over the circular path designated 29 in FIG.

In the switch-off direction, the main movement contact piece 3 presses the driving lug 27 downwards and thus the stop arm 28 against the swivel bracket 5, so that the swivel bracket 5 is carried along by the main movement contact piece 2 in its downward movement. The holding section 26 made of plastic ensures a defined current flow via the snap-in bracket 25. A current flowing via the shunt branch thus flows into the main moving contact piece 2 via the stop arm 28 and the driving lug 27.

Claims

claims

1. Switch disconnector (1) for interrupting an alternating current with a main contact arrangement (4), which has a movable main moving contact piece (2), and with a shunt branch electrically connected in parallel with the main contact arrangement (4), in which an extinguishing contact arrangement (8) for extinguishing of an arc and an isolating contact arrangement (6) consisting of isolating contact pieces for providing a dielectric strength are connected in series, wherein after opening the main contact arrangement (4) a current flow through the shunt branch is made possible, characterized in that the main moving contact piece (2) simultaneously one of the isolating contact pieces the isolating contact arrangement (6).

2. switch disconnector (1) according to claim 1, d a d u r c h g e k e n n z e i c h n e t that the quenching contact arrangement (8) is arranged in a vacuum chamber (7).

3. Switch-disconnector (1) according to claim 1 or 2, so that the isolating contact arrangement (6) has a pivotably mounted swivel bracket (5) as isolating contact piece which can be pivoted through the main moving contact piece (2) to open the isolating contact arrangement (6).

4. switch disconnector (1) according to claim 3, characterized in that the swivel bracket (5) on its the main moving contact piece (2) end facing a snap mechanism (19) which allows the swivel bracket (5) to be carried along by the main movement contact piece (2) in a switch-off direction, but when the main movement contact piece (2) moves in a switch-on direction opposite the switch-off direction, the main movement contact piece (2) is guided past the swivel bracket (5 ) enables.

5. switch-disconnector (1) according to claim 4, characterized in that the snap mechanism (19) has a plastic holding section (26) and a pivotable on the holding section (26) mounted metal snap bracket (25), the snap bracket (25) over an end-side driving lug (27) which is in contact with the main moving contact piece (2) in a contact position of the isolating contact arrangement (6), and has a stop end (28) opposite the driving lug (27) which, in the contact position of the isolating contact arrangement ( 6) rests on the swivel bracket (5) and prevents the swivel bracket from swiveling in the direction of switching off the main moving contact piece (2).

6. switch-disconnector (1) according to one of the preceding claims, d a d u r c h g e k e n n z e i c h n e t that the main moving contact piece (2) is designed as a rotatable switching knife.

7. Switch-disconnector (1) according to one of claims 3 to 6, characterized in that the swivel bracket (5) is connected to initiate a switching movement with the extinguishing contact arrangement (8).

8. Switch-disconnector (1) according to claim 7, so that a movable extinguishing contact piece of the extinguishing contact arrangement (8) is rigidly connected to a driving pin (13a) which is arranged in an elongated hole (14) of the swivel bracket (5).

9. switch-disconnector (1) according to one of claims 3 to 8, g e k e n n z e i c h n e t d u r c h a torsion spring for holding the pivot bracket (5) on the main fixed contact piece (3).

10. switch-disconnector (1) according to one of the preceding claims, g e k e n n z e i c h n e t d u r c h a compression spring (24) for pressing an extinguishing movement contact piece of the extinguishing contact arrangement (8) against a fixed extinguishing contact piece in this regard.