ELECTRICAL SWITCHING SYSTEM

Description

[0001] The invention relates to an electrical switching system comprising a first busbar and a second busbar. The invention further relates to a circuit breaker having such an electrical switching system.

[0002] Circuit breakers typically have an electrical switching system. The electrical switching system is usually mechanically designed so that galvanic isolation can also be achieved. In this case, the electrical switching system usually has a contact and a movably mounted mating contact. In particular, the contact and mating contact are each connected to a busbar, with the mounting usually taking place via the busbars. If the circuit breaker is in the closed state, i.e. current can be carried via the circuit breaker, the contact rests on the mating contact, creating a direct mechanical connection between them. An electrical current flows via the contact and the mating contact.

[0003] To ensure that the contact is separated from the mating contact as quickly as possible in the event of an overload, one of the busbars is usually designed with a C-shaped end, with the contact or mating contact located at the free end. As a result, the electrical current flows in the same direction in the immediate vicinity of the contact and the mating contact. Therefore, the two busbars repel each other due to the resulting magnetic fields, with the effect increasing quadratically with the electrical current. If an overcurrent occurs, the magnetic fields make it easier to space the two busbars apart.

[0004] However, if a relatively strong electrical current occurs, it is possible that an uncontrolled separation of the two busbars occurs and / or that an arc forms between the contact and the mating contact, leading to a burn-off of the contact or mating contact. This causes the contact or mating contact to partially melt. In this case, it is possible that liquid material from the contact or mating contact is released and splashes onto other components of the circuit breaker, causing damage. If the arc is extinguished, the electrical current flow between the two busbars breaks down, which is why magnetic forces no longer act. As a result, with a relatively simple circuit breaker mechanism, it is possible that the mating contact falls onto the contact again or that they at least come into mechanical contact again.However, since these are partially liquefied on the surface, the contact fuses with the mating contact, making it impossible to separate them after cooling. If the fault persists, an electrical current will continue to be conducted through the circuit breaker, which could lead to damage to the component protected by the circuit breaker. The circuit breaker can also no longer be used because the fuse between the contact and the mating contact prevents it from tripping, meaning it can no longer intentionally interrupt the electrical current flow.

[0005] DE 11 45 698 B discloses a contact arrangement for circuit breakers. This arrangement has two contact points per current path for dividing the current path into two parallel sub-paths. A pivoting movement of the conductor is provided to interrupt the current flow.

[0006] DE 11 73 168 B shows a switch in which electrodynamic loop forces are used to increase contact pressure. A curved transfer movement of a conductor is provided to interrupt the current flow.

[0007] A contact arrangement for automatic switches is known from DE 17 34 691 U. Opening is intended to involve a pivoting movement.

[0008] DE 25 16 595 A1 and JP S47 6864 Y1 also disclose switches. A pivoting movement of the respective conductor is provided to interrupt the current flow.

[0009] In the switch shown in DE 11 2005 002227 T5, a conductor track is bent to interrupt the current flow.

[0010] DE 10 2011 118894 B3 and JP S59 151708 A disclose contact bridges which, in order to open, are moved vertically with respect to the busbar designed as the respective counter contact.

[0011] The invention is based on the object of specifying a particularly suitable electrical switching system and a particularly suitable circuit breaker, wherein wear is advantageously reduced and / or reliability is increased.

[0012] With regard to the electrical switching system, this object is achieved by the features of claim 1 and with regard to the circuit breaker by the features of claim 6. Advantageous further developments and refinements are the subject of the respective subclaims.

[0013] The electrical switching system is used to conduct and interrupt an electrical current. The electrical switching system is suitable, in particular provided and configured, for this purpose. In addition, the electrical switching system is suitably mechanically designed. Preferably, a rated current conducted by means of the electrical switching system is between 1 A and 125 A, expediently between 1 A and 30 A, between 30 A and 60 A, or between 60 A and 100 A. The electrical switching system is suitable, in particular provided and configured, to conduct an alternating electrical current which in particular has an electrical voltage between 100 V and 800 V, and for example of 277 V, 480 V, or 600 V. Alternatively, the electrical switching system is suitable, in particular provided and configured, to conduct a direct electrical current, wherein the electrical voltage in this case is in particular between 100 V and 1,500 V.The electrical switching system is preferably used in an industrial plant, particularly in industrial automation. Alternatively, the switching system is part of a building installation.

[0014] The electrical switching system has a first busbar and a second busbar, each extending in a longitudinal direction. In other words, the two busbars are arranged parallel to one another. The first busbar carries a first contact and a second contact, which are spaced apart from one another in the longitudinal direction. The spacing is expediently greater than 4 mm, 5 mm, or 1 cm. For example, the spacing is less than 5 cm, 4 cm, or 3 cm. For example, the spacing is substantially equal to 2 cm, with a deviation of up to 10%, 5%, or 0% in particular being present. The first busbar further has a first power connection. The first power connection serves to electrically contact the first busbar with other components of the electrical switching system or components of the desired area of ​​application. In particular, the first power connection is implemented by means of a terminal or the like.Alternatively, the first power connection is integrally formed with any additional components, so that the first busbar transitions into the additional component at the first power connection. Conveniently, the first power connection forms one end of the first busbar in the longitudinal direction.

[0015] The second busbar carries a first mating contact and a second mating contact, which are spaced apart from one another in the longitudinal direction. The spacing is expediently greater than 4 mm, 5 mm, or 1 cm. For example, the spacing is less than 5 cm, 4 cm, or 3 cm. Preferably, the spacing is substantially equal to 2 cm, with a deviation of up to 10%, 5%, or 0% being possible in each case. Such a spacing results in a comparatively compact electrical switching system.

[0016] In addition, the second busbar has a second power connection. In particular, the second power connection forms the boundary of the second busbar in the longitudinal direction, i.e., one of the ends of the second busbar in the longitudinal direction. The second power connection serves to electrically connect the second busbar to other components of the electrical switching system. For example, the second power connection is designed as a terminal. Alternatively, the busbar merges into another component at the second power connection, so that the second busbar is molded onto another component by means of the second power connection and is thus integral with it.

[0017] The first busbar partially overlaps the second busbar along the longitudinal direction. The contacts and the mating contacts are also located in the longitudinal direction between the two power connections in the overlap area. In addition, the second busbar is mounted so as to be movable in a transverse direction perpendicular to the longitudinal direction. For this purpose, the electrical switching system has a corresponding guide or other mechanism. This makes it possible to move the second busbar relative to the first busbar. By moving the second busbar along the transverse direction, it is thus possible to change the distance between the first busbar and the second busbar. In particular, it is possible to move the first mating contact against the first busbar and / or the first contact so that a mechanical and therefore an electrical connection exists between them.However, by moving the second busbar along the transverse direction, it is also possible to space the first contact from the first counter contact.

[0018] In summary, due to the movable mounting of the second busbar, it is particularly possible for the electrical switching system to assume two states, wherein in one state, an electrical current flow is possible from the first power connection to the second power connection via the two busbars. In this case, the contacts and the mating contacts preferably serve to conduct the electrical current. However, when the second busbar is spaced apart from the first busbar, an electrical current flow from the first power connection to the second power connection via the busbar is preferably interrupted.

[0019] Due to the longitudinal spacing of the contacts and the mating contacts, a section of the respective busbar is formed between each of them, which carries part of the electrical current in the electrically conductive state. The electrical current is carried parallel to each other in the longitudinal direction in both busbars. As a result, rectified magnetic fields are formed, which is why a magnetic force of attraction acts at least partially between the two busbars in this area. In particular, the force is essentially proportional to the product of the electrical current carried by the contact or mating contacts and the ratio of the distance between the contacts or between the mating contacts and the distance between the two busbars.

[0020] This magnetic force opposes the magnetic force developing in the contacts and the mating contacts. As a result, the resulting forces acting on the busbars due to an increasing electrical current are comparatively low. Using suitable mechanics, it is thus possible, particularly in the event of an overcurrent event that would lead to damage to the electrical switching system, i.e. in particular in the event of a multiple of the maximum or rated current of the electrical switching system, to hold the second busbar to the first busbar, thus preventing the formation of an arc. This reduces wear. In this case, fusion of the contacts with the mating contacts or other components of the respective busbar is also avoided, so that the electrical switching system can continue to be used even after such an event. This increases reliability.

[0021] For example, the electrical switching system is a component of a relay. The electrical switching system is preferably a component of an overcurrent protection device, such as a circuit breaker, in particular according to IEC 60947-2, or a contactor. The electrical switching system is, for example, a component of a circuit breaker or a disconnector, i.e. in particular a switch with the ability to disconnect / galvanically isolate, such as expediently a load-break switch. Alternatively or in combination with this, the electrical switching system is a component of a fuse disconnector. Preferably, the electrical switching system is a component of a circuit breaker, such as a device circuit breaker, in particular according to standard IEC 60934. The above-mentioned devices are each expediently overcurrent protection devices. The circuit breaker or another of the above-mentioned devices has, in particular, an actuating device.In particular, the second busbar is actuated by means of the actuating device, so that it is positioned relative to the first busbar depending on the respective electrical current being carried. In particular, in the event of an overcurrent event, the second busbar is spaced from the first busbar. However, if the overcurrent exceeds the maximum carrying capacity of the circuit breaker or the respective device, or at least exceeds a certain limit, the second busbar is expediently not spaced from the first busbar, and an interruption is preferably carried out by means of an overcurrent protection device or another overcurrent protection device, in particular a fuse.Due to the arrangement of the contacts and the mating contacts, any separation of the second busbar from the first busbar due to the magnetic fields is essentially prevented or can be prevented relatively easily, particularly by means of a relatively simple mechanism. Thus, the circuit breaker or the respective device can continue to be used after such use.

[0022] The circuit breaker or the respective device preferably has a detection device by means of which the electrical current conducted by the overcurrent protection device, i.e., the circuit breaker or the respective device, is detected. The detection circuit, in particular, actuates the actuating device. For example, the two devices are formed by a common component, such as a bimetal / bimetal element, which is configured, for example, as a bimetal strip or bimetal snap-action disc. Alternatively, the overcurrent protection device is actuated magnetically, thermally, hydraulically, or by a combination thereof.

[0023] The first contact preferably covers the first mating contact in the transverse direction. Alternatively, or particularly preferably in combination with this, the second contact covers the second mating contact in the transverse direction. The contacts and the mating contacts are therefore the defined points at which a transition of the electrical current flow between the two busbars takes place. By moving the second busbar, it is preferably possible to move the mating contacts against the respective contact, so that a direct mechanical connection is realized. In other words, when an electrical current is conducted by means of the electrical switching system, both the first contact is mechanically directly in contact with the first mating contact and the second contact is mechanically directly in contact with the second mating contact.

[0024] For example, the contacts or at least one of the contacts or the mating contacts or at least one of the mating contacts are formed by the respective busbar itself. Alternatively, the contacts and / or the mating contacts are formed using the same material as the respective busbars, and these are molded onto one another and thus form a single piece. However, the contacts and / or the mating contacts are particularly preferably realized using a separate component that is preferably attached to the respective busbar, for example by welding. Preferably, the contacts or the mating contacts are made of a different material than the busbars, which preferably has a comparatively high melting point and / or a comparatively low erosion resistance.Preferably, at least one of the contacts, preferably all contacts, and / or one of the mating contacts, expediently all mating contacts, is made of a silver-based contact material. Preferably, silver nickel (AgNi), silver tin oxide (AgSnO2), silver tungsten (AgW), or silver graphite (AgC) is used as the silver-based contact material. This creates a comparatively robust contact or mating contact.

[0025] For example, the first contact is formed by a cylinder. The first mating contact is also formed by a cylinder, for example. However, the first mating contact in this case is particularly preferably formed by a cylinder segment or particularly preferably by a spherical segment. As a result, when the first contact bears against the first mating contact, a contact point is always realized and tolerance compensation is provided. Therefore, contact resistance is reduced. Alternatively, or particularly preferably in combination with this, the second contact is formed by a cylinder, wherein the second mating contact is also formed by a cylinder segment or preferably by a spherical segment.In an alternative to this, the first contact is formed by a spherical segment and the first mating contact by a cylinder and / or the second contact is formed by a spherical segment and the second mating contact by a cylinder. In this way, tolerance compensation is provided in each case, ensuring that a mechanically direct contact is actually realized between the contacts and the respective mating contact. In an alternative embodiment, both the first contact and the first mating contact are each formed by a cylinder segment, wherein these are positioned at 90° to one another, thus forming an X. In this case, the second contact and the second mating contact are preferably also designed as cylinder segments.

[0026] The first and / or second busbar is preferably made of a metal, wherein the metal is, for example, copper, i.e., pure copper, or a copper alloy, such as brass. Due to the use of copper, a comparatively low ohmic resistance is present, which increases the efficiency of the electrical switching system. Particularly preferably, the copper is provided with a coating made, for example, of silver, tin, or nickel. As a result, connecting additional components to the busbar is simplified, and damage and / or reaction, in particular oxidation, is avoided.

[0027] For example, the first busbar and / or the second busbar is produced by casting, milling, embossing, or punching. This simplifies adaptation to different circumstances. Preferably, the first busbar is designed as a metal strip. Alternatively, or particularly preferably in combination with this, the second busbar is designed as a metal strip. This simplifies production of the two busbars. The thickness of the metal strip is comparatively small in one dimension, for example between 0.8 mm and 5 mm. In particular, the thickness is perpendicular to the longitudinal direction. Preferably, a punching process is used to produce the busbars, so that they are punched from a sheet metal. In other words, the busbars are designed as a stamped and bent part. This simplifies production and consequently reduces manufacturing costs.

[0028] For example, the two busbars are arranged parallel to one another so that they each have a comparatively small thickness in the same direction. In particular, the smallest extent of the metal strips, i.e. the thickness, is parallel to the transverse direction. In other words, the metal strips forming the two busbars are arranged perpendicular to the transverse direction. This simplifies connecting or at least forming the contacts or mating contacts. Alternatively, the two busbars are arranged parallel to the transverse direction. This increases robustness, particularly when the second busbar is moved transversely against the first busbar via the contacts and the mating contacts, and bending of the busbars is avoided. In summary, the second busbar is arranged parallel to the first busbar.

[0029] Particularly preferably, the second busbar is arranged perpendicular to the first busbar. For example, the main extension direction of the second busbar is substantially perpendicular to the transverse direction, and the extension of the first busbar is substantially parallel to the transverse direction and the longitudinal direction. However, particularly preferably, the first busbar is arranged substantially perpendicular to the transverse direction, and the second busbar is arranged substantially parallel to the longitudinal direction and parallel to the transverse direction. Due to the perpendicular arrangement of the two busbars to one another, mechanical stability is increased. It is also possible to adapt the busbars to the corresponding areas of application. Furthermore, when the second busbar is arranged in the transverse direction, the space required perpendicular to the transverse direction and perpendicular to the longitudinal direction is reduced, so that a comparatively compact electrical switching system can be realized.

[0030] Particularly preferably, the second busbar between the two mating contacts has a projection directed towards the first busbar. Even when the contacts are in direct mechanical contact with the respective mating contacts, the projection in particular remains spaced apart from the first busbar, so that uncontrolled current conduction, in particular the formation of an arc, is avoided. Alternatively or in combination with this, the first busbar between the two contacts has a projection directed towards the second busbar. However, the first busbar between the two contacts is particularly preferably free of projections and expediently smooth. This simplifies production of the first busbar.

[0031] Due to the protrusion, the distance between the first and second busbars is reduced, thus increasing the magnetic forces that press the two busbars together. Furthermore, due to the protrusion, the cross-section of the second busbar is enlarged, thus reducing the ohmic resistance. In particular, the second or first busbar is formed as a metal strip and arranged perpendicular to the first busbar, thus simplifying the production of the protrusion.

[0032] For example, the first busbar is rigidly arranged and, in particular, held stationary. Alternatively, the first busbar is also mounted to be movable in the transverse direction. When the electrical switching system is opened, the first busbar is preferably also moved transversely away from the second busbar. However, it is particularly preferred that the first busbar is spring-loaded in the transverse direction, with the springs pressing the first busbar towards the second busbar. If the electrical switching system is in the electrically conductive state, the spring force is compressed by the second busbar or a force acting on the second busbar. This creates a frictional connection between the two busbars via the contacts and mating contacts, which improves the flow of current via the contacts or mating contacts.If, for example, the electrical switching system is shocked, the contacts do not move apart from their mating contacts, and therefore no arc is formed. In addition, the spring load at least partially compensates for the magnetic forces acting on the busbars that push them apart as the electrical current flow increases, so that a comparatively large electrical current can also be carried. Since the two contacts and mating contacts are spaced apart longitudinally, and the arrangement of the power connections creates a magnetic force that pushes the busbars towards each other, only a comparatively weak spring is required, which on the one hand simplifies production. On the other hand, it is not necessary to apply a comparatively large force to the second busbar in order to compress the spring.This simplifies the design of the electrical switching system, which further reduces manufacturing costs.

[0033] The circuit breaker has an electrical switching system comprising a first busbar extending in a longitudinal direction, carrying a first contact and a second contact spaced apart therefrom in the longitudinal direction, and having a first power terminal, and a second busbar extending in the longitudinal direction, carrying a first mating contact and a second mating contact spaced apart therefrom in the longitudinal direction, and having a second power terminal. The second busbar is mounted so as to be movable in a transverse direction perpendicular to the longitudinal direction, wherein the first busbar partially overlaps the second busbar along the longitudinal direction. In the longitudinal direction, the contacts and the mating contacts are arranged between the two power terminals in the overlap region. The circuit breaker further comprises an actuating device by means of which the second busbar is actuated.The distance between the second busbar and the first busbar is adjusted by means of the actuating device. It is preferably possible to use the actuating device to move each of the contacts against one of the mating contacts and also to space them apart from them, suitably in the transverse direction. In particular, the actuating device itself is actuated as a function of an electrical current flowing through the circuit breaker, in particular by means of a detection device. The detection device has, for example, a corresponding sensor. The circuit breaker is preferably designed as a magnetic, thermal, or hydraulic circuit breaker, or a combination thereof.

[0034] The circuit breaker is suitably a component of a circuit breaker or a disconnector, in particular a load-breaker. A disconnector is understood to mean, in particular, a circuit breaker with a disconnecting function and / or an integrated fuse. The load-breaker expediently comprises a fail-safe element, in particular an overcurrent protection device / overcurrent protection device, such as a fuse, which is suitably electrically connected in series with the electrical switching system. If a comparatively large electrical current flows through the electrical switching system, which would lead to damage if the electrical switching system were opened, the electrical current is interrupted, in particular, by means of the overcurrent protection device. Preferably, an overcurrent protection device is used here whose tripping time is shorter than the tripping time of the actuating device.Consequently, the flow of electrical current is interrupted due to the overcurrent protection device / overcurrent protection equipment and not due to the operation of the electrical switching system. This means that even after the overcurrent protection device, in particular the fuse, has been replaced, the circuit breaker remains operational. However, in the case of an electrical current that would not cause damage if the electrical switching system were opened, but which is, for example, greater than a certain limit, the electrical current is interrupted by separating the second busbar from the first busbar in the transverse direction. This means that after resetting the second busbar or other components of the circuit breaker, the circuit breaker can be used again. This also allows a comparatively large number of switching operations due to the comparatively low wear, which reduces costs and increases reliability.In summary, the circuit breaker is ready for use again after being interrupted by the overcurrent protection device, in particular if the electrical current flow was stopped due to another protective mechanism, for example by means of another overcurrent protection device, in particular a fuse.

[0035] The further developments and advantages explained in connection with the electrical switching system can also be transferred to the circuit breaker and vice versa.

[0036] An embodiment of the invention is explained in more detail below with reference to a drawing. In the drawings: Fig. 1 shows a schematic diagram of an industrial plant with a circuit breaker, Fig. 2 shows the circuit breaker having an electrical switching system in an open state, and Fig. 3 shows the circuit breaker in a closed state.

[0037] Corresponding parts are provided with the same reference numerals in all figures.

[0038] In Figure 1 A schematic diagram of an industrial plant 2 is shown, which has a power supply 4 and an actuator 6 operated therewith. The power supply 4 provides an alternating electrical voltage of 50 Hz or 60 Hz. The electrical voltage is in particular 277 V or 480 V. The actuator 6 comprises, for example, an electric motor or a press and is electrically coupled to the power supply 4 by means of a line 8, so that the actuator 6 is energized via the line 8.

[0039] Furthermore, the industrial plant 2 comprises a circuit breaker 10, which in one embodiment is a component of the line 8 and is arranged in a control cabinet (not shown in detail). Alternatively, the circuit breaker 10 is arranged on the power supply 4 or on the actuator 6. The circuit breaker 10 has a protective switch 12 and an overcurrent protection device 14 connected in series therewith. The electrical series connection is incorporated into one of the wires of the line 8.

[0040] In this example, the rated current of circuit breaker 10 is 60 A. If the rated current is exceeded by more than a certain limit, for example, 1.1 times the rated current, the electrical current flow is interrupted by means of circuit breaker 12. In other words, in this case, circuit breaker 12 is triggered and thus opened. The overcurrent protection device 14, however, does not trigger in this case. It only triggers at five times the rated current, i.e., at 300 A, with the tripping time being shorter than the tripping time of circuit breaker 12. In this case, the electrical current flow is interrupted by means of the overcurrent protection device 14, whereas circuit breaker 12 remains in the electrically conductive state.Due to such a wiring of the circuit breaker 12 and the overcurrent protection device 14, the circuit breaker 10 is essentially immediately ready for use by resetting the circuit breaker 12 if the rated current is exceeded by a comparatively small amount. Furthermore, component replacement is not necessary, thus reducing operating costs. However, if the overcurrent is comparatively large, i.e., in particular, greater than 300 A, damage is possible when switching using the mechanically equipped circuit breaker 12. In this case, an arc occurs, which can lead to damage to components of the circuit breaker 12. Since the circuit breaker 12 is not triggered, it is not damaged, and the circuit breaker 10 is also ready for use again after the overcurrent protection device 14 is replaced.

[0041] In Figure 2the circuit breaker 12 is in an open and in Figure 3 in the closed state, each shown in a partially simplified schematic. The circuit breaker 12 has a detection device 16, by means of which the electrical current conducted by the circuit breaker 12 is detected. An actuating device 18 is actuated and consequently driven by the detection device 16. In a variant not shown in detail, the detection device 16 and the fastening device 18 are realized by means of a common component. In the variant shown, however, these are separate components, and the detection device 16 is a bimetal, by means of which a spring-loaded mechanism is held in a specific position. During operation, the electrical current conducted by the circuit breaker 12 flows through the bimetal snap-action disk 16, and the spring-loaded mechanism is a component of the actuating device 18.

[0042] A second busbar 20 is actuated by means of the actuating device 18 and is moved by it in a transverse direction 22. In the closed state and in the open state of the circuit breaker 12, the second busbar 20 is located in two different positions in the transverse direction 22. The second busbar 20 is a component of an electrical switching system 24, which has a guide (not shown in detail) for the second busbar 20, so that it can be moved in the transverse direction 22. Any other movement of the second busbar 20, however, is prevented due to the guide. In other words, the second busbar 20 is mounted so as to be movable in the transverse direction 22.

[0043] The second busbar 20 extends in a longitudinal direction 26, which is perpendicular to the transverse direction 22, and the second busbar 20 is stamped from a metal sheet and thus formed as a metal strip. The second busbar 20 is stamped from a copper sheet and provided with a silver coating. The metal strip forming the second busbar 20 is arranged parallel to the transverse direction 22, so that the second busbar 20 has the smallest extent perpendicular to the transverse direction 22 and perpendicular to the longitudinal direction 26. The second busbar 20 extends essentially in the longitudinal direction 26 and has the greatest extent there.

[0044] A first mating contact 28 and a second mating contact 30 are connected to the second busbar 20, such as by welding, soldering, or riveting. In other words, the second busbar 20 supports the two mating contacts 28, 30, and the two mating contacts 28, 30 lie on a common straight line running in the longitudinal direction 26. The two mating contacts 28, 30 are structurally identical to one another and are formed by a spherical segment. The mating contacts 28, 30 are also made of a material different from the busbar 20, namely silver nickel (AgNi). The first mating contact 28 is connected in the region of one end of the second busbar 20 in the longitudinal direction 26, and the second mating contact 30 is spaced from the first mating contact 28 in the longitudinal direction 26, with a distance of 2 cm between them.Furthermore, the second busbar 20 has a second power connection 32, which is formed by means of the end of the second busbar 20 opposite the first counter contact 28 in the longitudinal direction 26.

[0045] The electrical switching system 24 further comprises a first busbar 34, which is made of the same material as the second busbar 20. In other words, the first busbar 34 is also a metal strip stamped from a copper sheet and provided with a nickel coating. The first busbar 34 is oriented perpendicular to the transverse direction 22 and thus extends primarily in the longitudinal direction 26 and transversely to the transverse direction 22. Consequently, the second busbar 20 is arranged perpendicular to the first busbar 34. The first busbar 34 carries a first contact 36 and a second contact 38, which are structurally identical to one another. The contacts 36, 38 are cylindrical and thus formed by a cylinder. The contacts 36, 38 are also made of the same material as the mating contacts 28, 30, namely silver nickel (AgNi).

[0046] The two contacts 36, 38 lie on a common straight line running in the longitudinal direction 26 and are arranged congruent with the mating contacts 28, 30. The first contact 36 is assigned to the first mating contact 28 and the second contact 38 to the second mating contact 30. Consequently, when the second busbar 20 is moved in the transverse direction 22 towards the first busbar 34, the first mating contact 28 is brought against the first contact 36 and the second mating contact 30 against the second contact 38, so that they are mechanically in direct contact with one another. In summary, the first contact 36 covers the first mating contact 28, and the second contact 38 covers the second mating contact 30 in the transverse direction 22. In other words, the contacts 36, 38 and the respective mating contacts 28, 30 are arranged parallel to one another and directly above one another.Consequently, the two contacts 36, 38 are also spaced apart from each other in the longitudinal direction 26, namely by 2 cm, the second contact 38 being connected to one end of the first busbar 34 in the longitudinal direction.

[0047] Consequently, the two busbars 20, 34 overlap in the longitudinal direction 26, forming an overlap region 40. The first busbar 34 extends beyond the overlap region 40 on one side in the longitudinal direction 26, and the second busbar 20 extends beyond the overlap region 40 on the opposite side in the longitudinal direction 26. The overlap region 40 is thus essentially equal to 2 cm plus the extension of the mating contacts 28, 30 or the contacts 36, 38 in the longitudinal direction 26.

[0048] The first busbar 34 has a first power terminal 42, which forms the end of the first busbar 34 opposite the second contact 38. Consequently, the first power terminal 42, as well as the second power terminal 32, are arranged outside the overlap region 40. Thus, the contacts 36, 38 and the mating contacts 28, 30 are arranged in the longitudinal direction 26 between the two power terminals 32, 42 in the overlap region 40.

[0049] Furthermore, the electrical switching system 24 has two springs 44, which are spaced apart from one another in the longitudinal direction 26 and oriented in the transverse direction 22. The two springs 44 are supported on a housing (not shown in detail) and the first busbar 34, so that the first busbar 34 is spring-loaded in the transverse direction 22.

[0050] During operation of the circuit breaker 12, the two power terminals 32, 42 are connected to other components of the circuit breaker 10. To conduct current via the circuit breaker 12, the electrical switching system 24 is placed in the electrically conductive state. For this purpose, the second busbar 20 is moved in the transverse direction 22 so that the counter contacts 28, 30 press against the contacts 36, 38. In particular, the second busbar 20 is locked by means of the actuating device 28 in the position which is Figure 3is shown. Here, the force applied to the second busbar 20 by means of the actuating device 18 is such that the first busbar 34 is also moved in the transverse direction 22 and the springs 44 are compressed. As a result, a force-fitting connection is realized between the contacts 36, 38 and the corresponding mating contacts 28, 30. As a result, the electrical current can flow via the first current connection 42 into the first busbar 34 and from there partly via the first contact 36 and the first mating contact 28 into the second busbar 20. A further part of the electrical current is introduced into the second busbar 20 via the second contact 38 and the second mating contact 30. The electrical current is conducted out of the second busbar 20 via the second current connection 32.

[0051] As a result, the electrical current flows parallel in the transverse direction 22 in the two contacts 36, 38 and the associated mating contacts 28, 30. Furthermore, the electrical current flows parallel in the longitudinal direction 26 in the overlap region 40 in the two busbars 20, 34. Thus, a rectified magnetic field is formed in each of the two busbars 20, 34 in the overlap region 40, which presses the two busbars 20, 34 towards one another in the overlap region 40. To reinforce this effect, the second busbar 20 has a projection 46 directed towards the first busbar 34 in the overlap region 40 between the two mating contacts 28, 30. The projection 46 forms one end on the second busbar 20 in the transverse direction 22, so that the mating contacts 28, 30 are set back in the transverse direction 22 with respect to the projection 46.However, the projection 46 is spaced apart from the first busbar 34, thus preventing the electrical current from directly jumping from the first busbar 34 to the second busbar 20, in particular the projection 46. The force pressing the two busbars 20, 34 together increases with increasing electrical current and counteracts any force that pushes the busbars 20, 34 apart in the transverse direction 22. Such a force is, in particular, a magnetic force caused by the electrical current flowing in the transverse direction 22.

[0052] Due to the at least partial compensation of the force pushing the two busbars 20, 34 apart, the busbars 20, 34 are not pushed apart in an uncontrolled manner even with a comparatively high electrical current, which could lead to the burning of the contacts 36, 38 and the mating contacts 28, 30, as well as their partial melting. If the partially melted contacts 36, 38 or mating contacts 28, 30 were placed on top of one another again, they would melt, which is why a further movement of the second busbar 20 in the transverse direction 22 would be impossible. Therefore, with such a high electrical current, which is at least five times the rated current, the overcurrent protection device 14 is triggered, which is why the electrical current is stopped. However, the electrical switching system 24 remains in the electrically conductive state.

[0053] If, however, a comparatively small overcurrent occurs, this is detected accordingly by the detection device 16. As a result, the actuating device 18 is actuated, and consequently the second busbar 20 is lifted off the first busbar 34 in the transverse direction 22. Therefore, an electrical current flow between the first and second power connections 42, 32 is interrupted. The switched electrical current is comparatively small, so that damage to the contacts 36, 38 and the mating contacts 28, 30 does not occur.

[0054] The invention is not limited to the embodiment described above. List of reference symbols

[0055] 2Industrial plant 4Power supply 6Actuator 8Cable 10Circuit breaker 12Circuit breaker 14Overcurrent protection device 16Detecting device 18Actuating device 20Second busbar 22Transverse direction 24Electrical switching system 26Longitudinal direction 28First counter contact 30Second counter contact 32Second power connection 34First busbar 36First contact 38Second contact 40Overlap area 42First power connection 44Spring 46Protrusion

Claims

1. Electrical switching system (24), in particular of a circuit breaker (12), comprising a first busbar (34), which extends in a longitudinal direction (26) and carries a first contact (36) and a second contact (38) that is spaced apart therefrom in the longitudinal direction (26), and which has a first current connection (42), and comprising a second busbar (20), which extends in the longitudinal direction (26) and carries a first mating contact (28) and a second mating contact (30) that is spaced apart therefrom in the longitudinal direction (26), and which has a second current connection (32), wherein the first busbar (34) partially overlaps the second busbar (20) along the longitudinal direction (26), wherein, in the longitudinal direction (26), the contacts (36, 38) and the mating contacts (28, 30) are arranged between the two current connections (32, 42) in the overlap region (40), wherein, owing to the spacing between the contacts (36, 38) and the mating contacts (28, 30) in the longitudinal direction (26), a section of the respective busbar (20, 34) is formed between them, with which section some of the electric current is conducted in an electrically conductive state, wherein the electric current is conducted in the longitudinal direction (26) in both busbars (20, 34) in parallel, characterized in that the second busbar (20) is mounted so as to be movable in a transverse direction (22) perpendicular to the longitudinal direction (26).

2. Electrical switching system (24) according to Claim 1, characterized in that the first busbar (34) and the second busbar (20) are in the form of metal strips.

3. Electrical switching system (24) according to Claim 2, characterized in that the second busbar (20) is arranged perpendicular to the first busbar (34), wherein the first busbar (34) is arranged in the longitudinal direction (26) and transversely to a transverse direction (22) and the second busbar (20) is arranged parallel to the longitudinal direction (26) and parallel to the transverse direction (22).

4. Electrical switching system (24) according to one of Claims 1 to 3, characterized in that the second busbar (20) has a projection (46) directed towards the first busbar (34) between the two mating contacts (28, 30).

5. Electrical switching system (24) according to one of Claims 1 to 4, characterized in that the first busbar (34) is spring-loaded in the transverse direction (22).

6. Circuit breaker (12) comprising an actuating device (18) and comprising an electrical switching system (24) according to one of Claims 1 to 5, wherein the second busbar (20) is actuated by means of the actuating device (18).