Switching system and circuit breaker

Abstract

The invention relates to a switching system (12) comprising two fixed contacts (24) and a movable contact bridge (26) to which two spaced-apart movable contacts (28) are attached. The switching system (12) is designed such that the contact bridge (26) can be moved into a first position in which one of the movable contacts (28) is mechanically in contact with each fixed contact (24) and into a second position in which the movable contacts (28) are spaced apart from the fixed contacts (24). The switching system (12) is further designed such that when the contact bridge (26) is moved from the first position to the second position, one of the two movable contacts (28) is first released from its associated fixed contact (24), and only then is the other movable contact (28) released from its fixed contact (24). The invention further relates to a circuit breaker (10:

Description

[0001] The invention relates to a switching system and a circuit breaker with a switching system. The switching system has two fixed contacts and a movably mounted contact bridge to which two spaced-apart moving contacts are connected.

[0002] A circuit breaker typically has a switching system that is triggered based on a signal provided by a sensor. The sensor and switching system may be integrated into a single unit, such as a bimetallic snap-action disc. When energized / closed, the bimetallic snap-action disc rests against a mating contact, and the electrical current is conducted through this. If the electrical current exceeds a certain threshold, the bimetallic snap-action disc heats up to varying degrees and is thus bent. This bending causes the bimetallic snap-action disc to move away from the mating contact, interrupting the electrical current.If the electrical current carried by the circuit breaker is comparatively large and the electrical voltage used is greater than, for example, 60 V, it is possible that an arc will form between the bent bimetallic snap-in disc and the mating contact, through which an electrical current will continue to be carried.

[0003] WO 2010 / 108565 A1 discloses a hybrid switch (hybrid isolating switch) having a mechanical switch or isolating element and semiconductor electronics connected in parallel thereto, which comprises a semiconductor switch, preferably an IGBT. The semiconductor electronics has no additional energy source and, when the mechanical switch is closed, is current-blocking, i.e., is practically currentless and voltage-free. To interrupt the current via the hybrid switch, the mechanical switch is opened, which can create an arc. The energy of the arc created when the mechanical switch opens is used by the semiconductor electronics, wherein the semiconductor electronics are connected to the mechanical switch in such a way that when the mechanical switch opens, the arc voltage across it (as a result of the arc) switches the semiconductor switch to current-conducting.

[0004] As soon as the semiconductor switch is energized, the electrical current begins to commutate from the mechanical switch to the semiconductor switch. The corresponding arc voltage or arc current also charges an energy storage device in the form of a capacitor, which provides the control voltage for the semiconductor electronics. As soon as the electrical current is commutated to the semiconductor switch, the arc extinguishes and the charging process of the energy storage device is completed. An ionized gas created by the arc exists between the switching contacts of the mechanical switch and dissipates over time. Following the charging process, a timer starts, during which the energy storage device keeps the semiconductor switch energized. After the timer period has elapsed, the semiconductor switch is switched to blocking current again.Instead of using the timer, for example, the time duration is specified based on the charge level of the energy storage device.

[0005] If the time period is chosen too short, it is possible that the ionized gas still present between the switching contacts of the mechanical switch and the applied electrical voltage will cause an arc to ignite again, causing an electrical current to flow through the mechanical switch again. Therefore, the time period is usually chosen to be relatively long, assuming that the ionized gas has sufficiently dissipated after this time and / or that the distance between the switching contacts of the mechanical switch is large enough to prevent the arc from igniting again.

[0006] Since the time period is used for all applications of the hybrid switch, the time period is increased again, although in the specific application in question, a shorter time period would have been sufficient. During this time period, an undesirable current continues to flow through the hybrid switch, which can lead to further undesirable operation and possibly damage to the components powered by the hybrid switch and / or endanger people.

[0007] The invention is based on the object of specifying a particularly suitable switching system and a particularly suitable circuit breaker, wherein a safe current interruption is expediently carried out and wherein, in particular, a switching time is shortened.

[0008] With regard to the switching system, this object is achieved according to the invention by the features of claim 1 and with regard to the circuit breaker by the features of claim 9. Advantageous embodiments and further developments are the subject of the dependent claims.

[0009] The switching system is used to switch electrical current. In other words, it is possible to enable or interrupt the flow of electrical current through the switching system by operating it. The switching system is used, in particular, to interrupt direct current. The switching system is designed, for example, to be unidirectional or bidirectional. For example, the electrical voltages that can be switched by the switching system, preferably the respective nominal voltage, are between 200 V and 3 kV, and in particular 220 V, 400 V, 650 V, 1000 V, or 1500 V.

[0010] The switching system has two fixed contacts. The fixed contacts are (mechanically) spaced apart from one another. Preferably, the fixed contact is connected to a respective electrical conductor of the switching system, preferably at the end. The respective electrical conductor is, for example, a cable or, more preferably, a busbar. The (electrical) conductors are made in particular of copper or aluminum. For example, the respective fixed contact is formed by a section of the respective conductor or at least of the same material. Alternatively, at least one or both of the fixed contacts are made of a different material, preferably of a comparatively erosion-resistant material. In other words, the erosion resistance of the material of the fixed contacts is increased compared to the respective cables.

[0011] The switching system further comprises a movably mounted contact bridge. This makes it possible to move the contact bridge. The contact bridge can be moved between a first position and a second position. For example, the path along which the contact bridge can be moved between the two positions is arbitrary. However, the path is preferably fixed. Conveniently, the two positions represent the end of the respective path.

[0012] For example, the switching system also comprises a drive by means of which the contact bridge is driven. For example, the drive is mechanically designed and comprises a spring, for example. The spring can expediently be pre-tensioned and held in the pre-tensioned state, in particular by means of a latch or the like. By releasing the latch, the spring is released so that it acts on the contact bridge, which leads to a movement of the contact bridge. In this case, in particular, the contact bridge is in the first position when the spring is latched, and by releasing the latch, the contact bridge is moved into the second position. Alternatively or in combination with this, the switching system comprises, for example, a hand lever that acts on the contact bridge. In particular, when the hand lever is actuated, the contact bridge is moved between the two positions.In particular, a locking device, a spring or the like is provided, by means of which a stable assumption of intermediate positions between the first and the second position is avoided. Alternatively or in combination with this, the drive comprises an electrical coil. A permanent magnet is preferably movably arranged within the electrical coil and is connected to the contact bridge. Thus, when the electrical coil is energized, a magnetic field is created which interacts with the magnetic field of the permanent magnet, so that the magnet and consequently the contact bridge are moved. In particular, it is thus possible to move the contact bridge between the first and the second position by energizing the electrical coils. In particular, the switching system is designed to be bistable. In one alternative, for example, the contact bridge is acted upon by means of a further force, such as a spring force.For this purpose, the switching system advantageously includes a spring, such as a leaf or coil spring. If the electrical coil is not energized, the spring force acts, so that the contact bridge is always moved to either the first or second position. By energizing the electrical coil, it is possible to move the contact bridge to the other position and, if necessary, hold it there. The switching system is thus designed to be monostable.

[0013] Two moving contacts are connected to the contact bridge and are spaced apart from one another. The moving contacts are thus electrically contacted with the contact bridge. In particular, the moving contacts are fastened to the contact bridge, and the contact bridge is made of an electrically conductive material, for example copper or aluminum. In particular, the contact bridge is rigid and, for example, a busbar. The contact bridge is expediently designed to be straight and, for example, essentially cuboid-shaped. In particular, the moving contacts are arranged at the spaced-apart ends of the contact bridge. For example, the moving contacts are made of the same material as the contact bridge and are suitably molded onto it. This makes it possible, for example, to preform the contact bridge and the moving contacts.However, it is particularly preferred for the moving contacts to be made of a different material, which advantageously offers increased resistance to erosion compared to the material of the contact bridge. Preferably, the moving contacts and the fixed contacts are made of the same material. Suitably, the fixed contacts and the moving contacts are structurally identical to each other, allowing the use of identical parts.

[0014] When the contact bridge is in the first position, one of the moving contacts is mechanically in contact with each fixed contact. Consequently, each fixed contact is electrically contacted with the respectively assigned moving contact, and the fixed contacts are electrically contacted with one another via the contact bridge. In other words, the fixed contacts are electrically connected in series. If, on the other hand, the contact bridge is in the second position, the moving contacts are spaced from the fixed contacts. Thus, the two fixed contacts are not electrically connected to one another. In this case, the two fixed contacts are preferably galvanically isolated from one another. In other words, the switching system preferably has no further components by means of which the two fixed contacts are electrically connected to one another.In summary, it is thus possible to create or calculate an electrical current flow between the two fixed contacts and thus across the switching system by moving the contact bridge between the first and second positions.

[0015] The switching system is designed such that when the contact bridge is moved from the first position, in which each fixed contact is in contact with one of the moving contacts, to the second position, in which the moving contacts are spaced apart from the fixed contacts, one of the two moving contacts is initially released from the associated fixed contact. Only when these two contacts are spaced apart from each other is the other moving contact released from the other fixed contact. In other words, the mechanical contact between the associated moving contacts and the fixed contacts is released with a time delay.

[0016] The time offset is expediently fixed and results, in particular, from the design of the contact bridge, the arrangement of the fixed contacts, and / or the speed at which the contact bridge is moved. The time offset is preferably greater than 0.01 ms and less than 0.1 ms. For example, the distance between the initially detached moving contact and the associated fixed contact is already at least 0.1 mm, 0.2 mm, 0.5 mm, or 1 mm when the other two contacts separate from each other.

[0017] Thus, if an electrical current flow is to be terminated by means of the switching system, the contact bridge is moved from the first position, in which an essentially negligible electrical voltage arises due to the direct mechanical contact of the moving contacts with the fixed contacts via the switching system, to the second position. If no arc or the like occurs between the first moving contact and the associated fixed contact, the current flow between the two fixed contacts is essentially terminated immediately. Thus, the separation of the other moving contact from the associated fixed contact occurs essentially without current, so that there is essentially no load there.

[0018] If, however, the air between the first moving contact and the associated fixed contact is ionized due to the applied electrical voltage and / or the conducted electrical current, an arc can form there, so that the current flow continues. However, a greater electrical voltage is applied across the switching system than when the contact bridge is in the first position. In other words, an arc voltage is already applied across the switching system. If the other moving contact is subsequently moved away from the fixed contact, the electrical voltage then applied is not sufficient, for example, to ionize the air there, so that no arc is formed between this moving contact and the fixed contact. As a result, the electrical current flow through the switching system breaks down, which is why the other arc is extinguished.Thus, by appropriately selecting the time offset and / or the actual distance between the moving contact and the fixed contact when the other moving contact is released from the other fixed contact, it is possible to ensure that no second arc is formed and thus the electrical current flow through the switching system is safely terminated, thereby shortening the switching time. This simplifies the design because the two moving contacts are separated from the two fixed contacts by moving the contact bridge. In other words, in particular, two individual switches are switched with a time offset, each of which is assigned one of the fixed contacts and one of the moving contacts, for which only the contact bridge needs to be moved.

[0019] When the contact bridge is moved, for example, the assignment of the moving contacts to the fixed contacts is changed. However, it is particularly preferred that the assignment remains the same, so that after the contact bridge is moved from the first position to the second position and back, the same contacts are in contact with one another again. For example, when the contact bridge is moved from the second position to the first position, the moving contacts make contact with the respective fixed contact simultaneously, or this also occurs at different times, for example. The switching system expediently comprises a housing within which the contact bridge and the fixed contacts are arranged, so that damage to them is avoided.

[0020] In one embodiment, each moving contact is connected to the contact bridge via a spring or at least a length-adjustable component. In the unloaded state, the distance between the moving contacts and the contact bridge varies, which is why the moving contacts detach from the fixed contacts at different times.

[0021] For example, when moving from the first position to the second position, the contact bridge is only or at least also rotated. The switching system in particular has a suitable bearing for this. However, it is particularly preferred if the contact bridge is connected to a slide that is mounted so as to be longitudinally displaceable. In other words, it is possible to move the slide in a longitudinal direction, and when the slide is moved in the longitudinal direction, the contact bridge is moved from the first position to the second position. In particular, the contact bridge is also moved at least partially in the longitudinal direction. This simplifies construction and makes it possible, in particular, to use a drive with a permanent magnet arranged in an electrical coil. When the contact bridge is in the first position, the contact bridge is in particular arranged substantially perpendicular to the longitudinal direction of the slide.

[0022] For example, the contact bridge is rigidly attached to the slide. However, it is particularly preferred that the contact bridge be mounted on the slide so that it can rotate. Thus, when the slide is moved longitudinally, the contact bridge is also adjusted longitudinally. Due to the rotatable mounting on the slide, an additional rotational movement of the contact bridge can also occur. By means of the rotatable connection, a delayed release of the moving contacts from the fixed contacts can still be achieved when the slide is moved only longitudinally, thereby simplifying the design.

[0023] For example, the bearing point of the contact bridge, which in particular represents the connection of the contact bridge to the slide, is off-center with respect to the two moving contacts. The bearing point is therefore preferably not located at the center of gravity of the contact bridge and / or the assembly consisting of the contact bridge and the moving contacts. Thus, when the slide is moved, the contact bridge is at least partially pivoted with respect to the bearing point due to the acting inertia. Consequently, one of the two moving contacts is initially released from the associated fixed contact. In other words, the temporally staggered spacing of the moving contacts from the fixed contacts occurs solely due to the choice of the position of the bearing point, and no further components are required. This reduces manufacturing costs and increases robustness.

[0024] Particularly preferably, the bearing point is formed by an extension of the contact bridge, which runs in particular perpendicular to the rest of the contact bridge and the longitudinal direction of the slide. In this case, the extension is inserted into a slotted guide of the slide which runs in the longitudinal direction of the slide and is formed in particular by a gap. Due to the rotatable mounting and the slotted guide, rotation and longitudinal displacement of the contact bridge with respect to the slide is therefore possible, at least to a limited extent. When the contact bridge is in the first position, movement of the contact bridge with respect to the slide is expediently not possible and in particular inhibited due to the direct contact of the moving contacts on the fixed contacts. Preferably, the extension also rests on one end of the slotted guide.In the second position, however, movement of the contact bridge relative to the slide is possible, at least to a limited extent. Thus, when the slide is moved longitudinally, the locking of the contact bridge is initially removed, allowing it to move freely relative to the slide, at least to a limited extent. Due to the off-center arrangement of the extension, the moving contact that is closer to the bearing point is initially released from the associated fixed contact. When the extension hits the opposite end of the guide rail, further movement of the slide rail completely separates the contact bridge and thus the other moving contact from the fixed contact. Thus, the time offset between the release of the two moving contacts from the respective fixed contact is set based on the length of the guide rail, which simplifies construction.

[0025] For example, essentially free movement of the contact bridge relative to the slide is enabled. However, the contact bridge is particularly preferably supported on the slide by means of a spring. Thus, unless further forces act on it, the contact bridge is in a predefined position relative to the slide. In this case, the contact bridge is supported asymmetrically on the slide in particular by means of the spring. Therefore, unless further forces act, the contact bridge is tilted relative to the slide and thus its longitudinal direction. If the contact bridge is in the first position and the slide is subsequently moved, the contact bridge is tilted relative to the slide by means of the spring, so that a subsequent release of the moving contacts from the fixed contacts occurs.

[0026] For example, the spring is arranged in the guide rail so that the extension is pressed towards one end of the guide rail by means of the springs when the moving contacts are not in contact with the fixed contacts. When the latter are in contact, however, the spring is particularly compressed. Alternatively, for example, the spring is offset laterally with respect to the bearing point and / or the guide rail is not present. For example, only a single spring is present. However, it is particularly preferred to have two springs or the like, which are arranged in particular on different sides of the bearing point. The two springs enable a comparatively precise setting of the times at which the moving contacts are released from the fixed contacts. For example, the bearing point is arranged off-center with respect to the two moving contacts. Alternatively, the bearing point is arranged essentially centrally between the moving contacts.For example, the springs are offset at different distances from the bearing point, or, more conveniently, they are at the same distance from the bearing point, which simplifies design. For asymmetrical support, the springs are designed differently and, in particular, have different spring constants, so that when no additional forces act on the contact bridge, it is tilted relative to the longitudinal direction of the slider.

[0027] In one embodiment, one of the two fixed contacts is spring-loaded so that it can be moved, at least to a small extent, preferably in the longitudinal direction of any slide or at least in the direction in which the contact bridge can be moved. For example, any conductor to which this fixed contact is attached is designed as a leaf spring or the like. Alternatively, for example, the conductor is supported on the side opposite the fixed contact by means of a spring or the like on the possible housing. The fixed contact is therefore in a different position when a force is exerted on it. When the contact bridge is in the first position, the two fixed contacts are therefore arranged on a straight line. When the contact bridge is in the second position, the two fixed contacts are also arranged on a straight line.However, the two straight lines are tilted relative to each other. In summary, when the contact bridge is moved to the second position, the spring-loaded fixed contact of the contact bridge is moved behind, at least in part, resulting in a delayed release from the associated moving contact.

[0028] For example, only one of the two fixed contacts is spring-loaded, or expediently both. The spring load creates tolerance compensation, which is why comparatively high manufacturing tolerances can be selected, ensuring that in the first position each moving contact rests against the assigned fixed contact. Preferably, the springs assigned to the two fixed contacts are at least partially tensioned. However, the level of preload is different, so that when the contact bridge is moved, the two fixed contacts are moved towards the contact bridge to different extents. For example, there is a slider to which the contact bridge is connected. For example, the contact bridge is also connected to the slider so that it can rotate, so that a comparatively large time offset can be achieved.Alternatively, the contact bridge is rigidly attached to the slider, which simplifies construction.

[0029] For example, the switching system is essentially formed solely by the fixed contact, any conductors, the contact bridge, and the moving contact, as well as the bearings of the contact bridge, in particular any slider. For example, the switching system comprises no further components, or at least the two fixed contacts are galvanically isolated from each other when the contact bridge is in the second position. This increases safety.

[0030] Alternatively, the switching system comprises further components or at least one electrical component by means of which the two fixed contacts are electrically connected to one another. In other words, the electrical component is connected in parallel to the contact bridge. The two fixed contacts are electrically connected by means of the electrical component, regardless of the position of the contact bridge. The electrical component has a variable electrical conductivity. In other words, the electrical component comprises at least two states, wherein in one of the states it is electrically conductive and in the other it is not. Thus, a variable electrical resistance is provided by means of the electrical component. Expediently, the electrical component is electrically conductive in one of the two states and not in others.

[0031] In particular, the electrical conductivity depends on the electrical voltage applied between the two fixed contacts. For example, the level of electrical conductivity is provided intrinsically by the electrical component or expediently predetermined by interconnection with other components of the switching system, for example with other electrical and / or electronic components. The electrical component comprises, for example, a varistor, a Zener diode, and / or a suppressor diode. The electrical component is a semiconductor switch, such as an IGBT, MOSFET, or GTO, and is formed, for example, by means of the latter.

[0032] If no electrical voltage is applied between the fixed contacts, the electrical component is expediently electrically non-conductive. Thus, the electrical current carried by the switching system is essentially only conducted via the contact bridge, so that comparatively low electrical losses occur. If, on the other hand, an electrical voltage greater than a limit value occurs between the fixed contacts, the electrical component is electrically conductive, at least temporarily or for a specific time window. When the first moving contact is moved away from the associated fixed contact, and in particular when the arc occurs, the electrical component is expediently placed in the electrically conductive state so that the electrical current is also conducted via it.If the other moving contact is subsequently moved away from the associated fixed contact, the applied electrical voltage is insufficient to ignite another arc there due to the parallel-connected electrical component. As a result, the electrical current flow across the contact bridge collapses, causing the arc to extinguish. The other moving contact is then moved away from the associated fixed contact, but no arc forms due to the low level of the now applied electrical voltage. In particular, the electrical component is subsequently returned to the electrically non-conductive state, so that no further electrical current flows through the switching system.

[0033] For example, the electrical component is wired in such a way that if the electrical voltage applied between the fixed contacts exceeds a certain limit, which is in particular lower than the voltage caused by the arc between the spaced-apart moving contact and the associated fixed contact, the component is switched to the electrically conductive state. In particular, the electrical voltage generated by the arc is used to switch the electrical component to the electrically conductive state, so that no separate power supply is required.

[0034] The circuit breaker serves to electrically protect a line and / or an actuator that is energized during operation via one or the line. In particular, the circuit breaker is electrically contacted with the line and is suitable, in particular provided and configured, for this purpose. The circuit breaker expediently has one or preferably two terminals, each of which is suitable, in particular provided and configured, for the electrical line(s) to be connected. For example, the terminals are designed in the manner of receptacles for a busbar, cable lugs, or insulation displacement contacts.

[0035] In particular, the circuit breaker is provided and configured to interrupt the electrical current flow conducted via the circuit breaker in the event of an overcurrent that is, for example, four times the nominal current, i.e., the electrical current conducted by the circuit breaker during normal operation. The circuit breaker expediently comprises a sensor for detecting the electrical current conducted therethrough, so that the overcurrent can be determined. Alternatively, or in combination, the circuit breaker is provided and configured to detect a short-circuit current or a so-called "arc" that occurs in the actuator / cable and subsequently interrupt the electrical current flow via the circuit breaker.

[0036] For example, the circuit breaker is designed in such a way that the electrical current flowing through it is interrupted if it exceeds a limit value. The limit value can be static, adapted to the respective application, or time-dependent. For example, the interruption occurs as soon as the limit value is exceeded, or only if the limit value has been exceeded for a specific period of time. For example, the circuit breaker has a control input, and based on the signals received via the control input, the circuit breaker is switched to the electrically conductive or electrically non-conductive state, for example. This makes it possible to control the circuit breaker remotely, i.e. to operate it from a distance, which increases convenience.

[0037] For example, the circuit breaker is suitable, in particular intended and configured, for applying an electrical voltage greater than 220 V or 500 V and, for example, less than 2000 V if the circuit breaker is electrically non-conductive. The circuit breaker is expediently used to protect an electrical voltage between 400 V and 1500 V and, for example, between 650 V and 800 V, and is suitable, intended and / or configured for this purpose.

[0038] For example, the circuit breaker is used in an AC system, so that an AC voltage is applied to the circuit breaker during operation. However, the circuit breaker is particularly preferably used in a DC system and thus serves to protect a DC circuit. In other words, during normal operation, a direct current is carried by the circuit breaker / a direct voltage is applied to the circuit breaker. The electrical current carried by the circuit breaker during normal operation is suitably greater than 10 A, 20 A, or 50 A. In particular, the rated current, i.e. the maximum electrical current carried by the circuit breaker during normal operation, is less than 200 A or 150 A.

[0039] The switching system comprises two fixed contacts and a movably mounted contact bridge to which two spaced-apart moving contacts are connected. The switching system is designed such that the contact bridge can be moved into a first position, in which one of the moving contacts is mechanically in contact with each fixed contact, and into a second position, in which the moving contacts are spaced from the fixed contacts. The switching system is further designed such that when the contact bridge is moved from the first position to the second position, one of the two moving contacts is first released from the associated fixed contact, and only subsequently is the other moving contact released from the other fixed contact.

[0040] Each of the two fixed contacts is expediently electrically connected, for example via a corresponding busbar or other line, to one of the possible connections, preferably directly. The circuit breaker suitably comprises a housing within which the switching system is arranged. The circuit breaker preferably comprises a control unit by means of which the switching system is operated. In particular, an adjustment of the contact bridge is initiated by means of the control unit. Expediently, the switching system or at least the circuit breaker comprises an electrical coil in which in particular an armature is arranged which is mechanically fastened to the contact bridge. In this case, depending on the current supplied to the electrical coil, the contact bridge is moved between the two positions. The current supplied to the electrical coil is preferably provided by means of the control unit. In particular, the control unit is connected to the possible sensor in terms of signals.

[0041] For example, the circuit breaker is suitable, in particular intended and configured, for use in a motor vehicle, such as a passenger car (car) or a commercial vehicle, for example, a lorry (truck), a train, or an aircraft. Alternatively, the circuit breaker is used, for example, in its intended use in a facility, such as an industrial facility, a telecommunications facility, or a data center. The invention further relates to such a use of the circuit breaker.

[0042] The further developments and advantages explained in connection with the switching system are also to be transferred analogously to the circuit breaker / its use and to each other and vice versa.

[0043] In the following, exemplary embodiments of the invention are explained in more detail with reference to a drawing. In the drawings: Fig. 1 schematically shows an electrical circuit with a circuit breaker comprising a switching system, and Fig. 2 - 4 each schematically simplifies different designs of the switching system.

[0044] Corresponding parts are provided with the same reference numerals in all figures.

[0045] In Fig. 1 shows a simplified schematic of an electrical circuit 2 designed as a direct current circuit. The electrical circuit 2 has a voltage source 4 designed as a direct current source, which provides an electrical direct voltage of 400 V. The voltage source 4 supplies current to a load 6, which is electrically connected to the voltage source 4 by two lines 8.

[0046] A circuit breaker 10 is incorporated into one of the two lines 8. The circuit breaker 10 comprises a switching system 12, a current sensor 14, and a control unit 16, which are arranged in a common circuit breaker housing 18. Two terminals 20 are incorporated into the circuit breaker housing 18, to which the line 8 is connected. These terminals 20 are electrically connected within the circuit breaker housing 18 by means of the switching system 12 and the current sensor 14 connected in series therewith. The electrical current conducted via the circuit breaker 10 is thus conducted via the switching system 12 and the current sensor 14. The control unit 16 reads the current sensor 14 and determines the level of the conducted electrical current. If this exceeds a limit value, the control unit 16 actuates the switching system 12 and sets it to an electrically non-conductive state.Thus, the electrical current flow through the circuit breaker 10 is interrupted and consequently the current supply to the load 6 is terminated.

[0047] The switching system 12 has two conductors 22, each formed by a busbar, one of which is guided to one of the terminals 20 and the other to the current sensor 14. The two conductors 22 are spaced apart from one another, and a fixed contact 24 is welded to each end on the same side. The switching system 12 further comprises a contact bridge 26, which is formed as a busbar made of copper, and to each end of which a moving contact 28 is connected. Each moving contact 28 is arranged substantially congruent with a fixed contact 26.

[0048] The contact bridge 26 is connected to a slide 32 which is mounted so as to be displaceable in a longitudinal direction 30, so that the contact bridge 26 is also mounted so as to be movable, namely by means of the slide 32. The slide 32 is driven by a drive (not shown in detail) which is operated by the control unit 16. In this case, it is possible to move the contact bridge 26 between a first and a second position. In the first position, one of the two moving contacts 28 is mechanically in contact with each fixed contact 24, whereas in the second position the moving contacts 28 are spaced apart from the fixed contacts 24. When the contact bridge 26 is in the first position, the two fixed contacts 24 are short-circuited by means of the contact bridge 26 and the two moving contacts 28, i.e., they are contacted with one another with a low resistance.In contrast, the fixed contacts 24 are not electrically contacted with each other by means of the contact bridge 26 when the contact bridge is in the second position.

[0049] The switching system 12 further comprises an electrical component 34, by means of which the two conductors 22 and thus also the two fixed contacts 24 are electrically connected. The electrical component 34 is thus electrically connected in parallel to the contact bridge 26. The electrical component 34 is a semiconductor switch, wherein a control input of the semiconductor switch (not shown in detail) is electrically connected to the two conductors 22 so that it is actuated depending on the electrical voltage applied across it. The electrical component 34 is thus electrically conductive depending on the electrical voltage applied between the two fixed contacts 24. The control input is also electrically contacted to the control unit 16 so that the conductivity of the electrical component 34 can also be adjusted by means of the control unit, i.e. whether the semiconductor switch is in the electrically conductive state or in the electrically non-conductive state.

[0050] In Fig. 2 shows a section of the switching system 12 with the contact bridge 26 in the second position. The contact bridge 26 is rotatably mounted on the slide 32 by means of a plain bearing, forming a bearing point 36, wherein the axis of rotation is perpendicular to the longitudinal direction 30 and the course of the contact bridge 26. Projections 38 running perpendicular to the longitudinal direction 30 and essentially parallel to the contact bridge 26 are formed on both sides of the slide 32 and are thus rigidly attached to the slide 32. A spring 60 is arranged between each projection 38 and the contact bridge 26, so that the contact bridge 26 is supported on both sides of the bearing point 36 by means of one of the springs 40 relative to one of the projections 38. Since this is rigidly attached to the slide 32, the contact bridge 26 is also supported on the slide 32 by means of the springs 40.

[0051] The spring stiffness of the two springs 40 differs from one another, which is why the contact bridge 26 is supported asymmetrically on the slide 32. Due to the rotatable mounting on the slide 32, the contact bridge 26 is therefore not arranged perpendicular to the longitudinal direction 30, but rather tilted relative to it when no further forces act on the contact bridge 26, as is the case in the second position. As a result, one of the two moving contacts 28 is located closer to the associated fixed contact 24 compared to the other moving contact 28 and the associated fixed contact 24.

[0052] When the slider 32 is moved in the longitudinal direction 30 towards the two conductors 22 and the contact bridge 26 has been moved into the first position, the two moving contacts 28 each rest against the associated fixed contact 24, and the contact bridge 26 is arranged essentially perpendicular to the longitudinal direction 30 due to the arrangement of the two fixed contacts 24. A different amount of mechanical energy is stored by means of the two springs 40. When the slider 32 and thus the contact bridge 26 are moved in the longitudinal direction 30 away from the conductors 22, i.e. when the switching system 12 is actuated, the different preload of the two springs 40 causes the contact bridge 26 to tilt, so that one of the two moving contacts 28 initially detaches from the associated fixed contact 24.If a comparatively high electrical current is carried by means of the circuit 2 and / or a comparatively high electrical voltage is applied, it is possible that an arc forms between these two contacts 28, 24, so that a current flow continues to exist between the two conductors 22.

[0053] The electrical voltage generated by the arc between the two conductors 22 causes the electrical component 34 to become electrically conductive, for example, due to appropriate wiring or by means of the control unit 16. Consequently, the electrical current commutates to the electrical component 34 connected in parallel with the contact bridge 26, whose resistance is lower. As a result, the arc breaks down between the two spaced contacts 24, 28. Upon further movement of the slider 32 in the longitudinal direction 30, the two springs 40 are further relaxed until the same mechanical energy is stored in them, so that the contact bridge 26 is tilted relative to the longitudinal direction 30. Upon further movement of the slider 32, the remaining moving contact 28 is thus detached from the other fixed contact 24.Since no electrical current is then carried across the contact bridge 26, the air is no longer ionized there, so that no arc is formed there either. In other words, they are separated from one another without a load. If the electrical component 34 is subsequently placed in the electrically non-conductive state, no arc is ignited there, so that the flow of electrical current through the switching system 12 is interrupted. In summary, the switching system 12 is designed such that when the contact bridge 26 is moved from the first position to the second position, first one of the two moving contacts 28 is released from the associated fixed contact 24 and only subsequently is the other moving contact 28 released from the other fixed contact 24.

[0054] In Fig. Figure 3 shows a section of an alternative embodiment of the switching system 12. Here, the contact bridge 26 is rigidly connected to the slide 32, which is still present and movable in the longitudinal direction 30. The two moving contacts 28 are still connected to the contact bridge 26, and the two fixed contacts 24 are connected to the two conductors 22. However, the springs 40, which are supported on the circuit breaker housing 18, are assigned to the two conductors 22. In other words, the two fixed contacts 24 are thus spring-loaded. If the moving contacts 28 are not in contact with any of the fixed contacts 24, the fixed contacts 24 are offset from one another in the longitudinal direction 30.When the slider 32 is now moved in the longitudinal direction 30, one of the two moving contacts 28 initially comes into contact with the associated fixed contact 24, and upon further movement of the slider 32 in the longitudinal direction 30, the associated spring 40 is compressed, at least until the remaining moving contact 28 also makes direct mechanical contact with the associated fixed contact 24. Upon an opposite movement of the slider 32, the two springs 40 44 are released, whereby the two fixed contacts 24 are moved to different positions in the longitudinal direction 30. Thus, one of the two moving contacts 28 is initially released from the associated fixed contact 24. Consequently, the two fixed contacts 24 lie on a straight line in the first position and in the second position, with the two straight lines being tilted relative to one another.

[0055] In Fig. 4 shows a further modification of the switching system 12, wherein the two conductors 22 with the fixed contact 24 connected thereto are arranged in a different configuration than in the Fig.2 are not changed. The slide 32 is again present and is mounted so as to be movable in the longitudinal direction 30. The slide 32 has a slotted guide 42 running in the longitudinal direction 30, which is formed by a gap running in the longitudinal direction 30. An extension of the contact bridge 26 (not shown in detail) is arranged within the slotted guide 24, wherein the extension runs perpendicular to the longitudinal direction 30 and perpendicular to the course of the remaining part of the contact bridge 26. By means of design measures (not shown in detail), removal of the extension from the slotted guide 42 is avoided, but no other movement is prevented, so that the contact bridge 26 is connected to the slide 32 so as to be displaceable in the longitudinal direction 30 and also rotatable. In other words, the bearing point 36 is now formed by the extension of the contact bridge 26, which is inserted into the slotted guide 42 of the slide 23 running in the longitudinal direction 30.The extension is supported by means of the spring 40 at the end of the link 42 facing away from the two conductors 22 in the longitudinal direction 30 and is not located in the middle between the two moving contacts 28. In other words, the bearing point 36 is off-center with respect to the two moving contacts 28.

[0056] In the first position, i.e. when the moving contacts 28 are in direct mechanical contact with the fixed contact 24, the contact bridge 26 is offset towards the end of the link 52 offset from the two conductors 22, and the spring 40 is maximally compressed. The complete contact bridge is located in a plane that is perpendicular to the longitudinal direction 30. When the slide 32 is moved longitudinally away from the conductors 22, the spring 40 is at least partially released. Due to the eccentric connection to the slide 32, the contact bridge 26 initially tilts, so that here too one of the two moving contacts 28 is initially spaced apart from the associated fixed contact 24, while the others remain in mechanical contact. Only when the slide 32 has been moved sufficiently far in the longitudinal direction 30 is the other moving contact released from the other fixed contact 24.

[0057] The invention is not limited to the exemplary embodiments described above. Rather, other variants of the invention can also be derived therefrom by those skilled in the art without departing from the subject matter of the invention. In particular, all individual features described in connection with the individual exemplary embodiments can also be combined with one another in other ways without departing from the subject matter of the invention. List of reference symbols 2 circuits 4 Voltage source 6 Last 8 Line 10 circuit breakers 12 switching system 14 Current sensor 16 Control unit 18 circuit breaker housings 20 connections 22 ladders 24 fixed contact 26 Contact bridge 28 moving contact 30 Longitudinal direction 32 sliders 34 electrical component 36 bearing point 38 overhang 40 spring 42 backdrop QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] WO 2010 / 108565 A1

[0003]

Claims

[1] Switching system (12) comprising two fixed contacts (24) and a movably mounted contact bridge (26) to which two spaced-apart moving contacts (28) are connected, and which is designed such that the contact bridge (26) can be moved into a first position in which one of the moving contacts (28) is mechanically in contact with each fixed contact (24) and into a second position in which the moving contacts (28) are spaced from the fixed contacts (24), and that when the contact bridge (26) is moved from the first position to the second position, first one of the two moving contacts (28) is released from the associated fixed contact (24) and only subsequently is the other moving contact (28) released from the other fixed contact (24). [2] Switching system (12) according to claim 1, characterized by that the contact bridge (26) is connected to a longitudinally displaceable slide (32). [3] Switching system (12) according to claim 2, characterized bythat the contact bridge (26) is rotatably mounted on the slide (32). [4] Switching system (12) according to claim 3, characterized by that the bearing point (36) is off-center with respect to the two moving contacts (28). [5] Switching system (12) according to claim 4, characterized by that the bearing point (36) is formed by means of an extension of the contact bridge (26) which is inserted into a slotted guide (42) of the slide (23) running in the longitudinal direction (30). [6] Switching system (12) according to one of claims 3 to 5, characterized by that the contact bridge (26) is supported asymmetrically on the slide (32) by means of a spring (40). [7] Switching system (12) according to one of claims 1 to 6, characterized by that at least one of the two fixed contacts (24) is spring-loaded, wherein the two fixed contacts (24) in the first position and in the second position are each arranged on a straight line which are tilted relative to one another. [8] Switching system (12) according to one of claims 1 to 7, characterized by that the two fixed contacts (24) are electrically connected by means of an electrical component (34) which is electrically conductive as a function of an electrical voltage applied between the two fixed contacts (24). [9] Circuit breaker (10) with a switching system (12) according to one of claims 1 to 8.

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