EP3797438A1

EP3797438A1 - Disconnecting device for interrupting a direct current of a current path, and circuit breaker

Info

Publication number: EP3797438A1
Application number: EP19726366.8A
Authority: EP
Inventors: Manuel ENGEWALD
Original assignee: Ellenberger and Poensgen GmbH
Current assignee: Ellenberger and Poensgen GmbH
Priority date: 2018-05-23
Filing date: 2019-05-21
Publication date: 2021-03-31
Anticipated expiration: 2039-05-21
Also published as: CA3101002A1; EP3797438B1; JP2021535539A; JP7169373B2; US20210074499A1; US11410825B2; WO2019224198A1; EP3797438C0; DE102018208119A1; CN112219254A

Abstract

The invention relates to a disconnecting device (14) for interrupting a direct current of a current path (2), in particular for a circuit breaker (8), comprising a hybrid switch (16) which has a current-carrying mechanical contact system (18, 18') and a semiconductor switching system (20) connected in parallel thereto, wherein: the contact system (18, 18') has at least one stationary fixed contact (22a, 22b) and at least one moving contact (24a, 24b); the moving contact (24a, 24b) is mounted on a current-carrying contact bridge (26, 26') which is coupled to a drive system (28, 28') and which moves the moving contact (24a, 24b) in a switching movement from an open position into a closed position resting against the fixed contact (22a, 22b) with a contact force (Fk); and at least one first magnet element (38, 38') is mounted on the contact bridge (26, 26'), said first magnet element being spaced apart from a stationary second magnet element (40, 40') by an air gap (42) such that, when a current flows through the contact bridge (26, 26'), a magnetic field (B) is produced in the first magnet element (38, 38') and the first and second magnet elements (38, 38', 40, 40') are magnetically attracted, said attraction producing a magnetic force (Fm) directed in the same direction as the contact force (Fk).

Description

description

Separator for DC interruption of a current path as well

The invention relates to a disconnecting device for DC interruption of a current path, in particular for a circuit breaker, comprising a hybrid switch, which has a current-carrying mechanical contact system and a semiconductor switching system connected in parallel therewith. The invention further relates to a circuit breaker with such a separation device.

A reliable separation of electrical components or devices of a circuit or circuit is desirable, for example, for installation, assembly or service purposes and in particular for general personal protection. A corresponding switching unit or disconnecting device must therefore be able to make an interruption under load, ie without a previous shutdown of a voltage source supplying the circuit.

For load separation powerful semiconductor switches can be used. However, these have the disadvantage that even in normal operation unavoidable power losses occur at the semiconductor switches. Furthermore, with such power semiconductors it is typically not possible to ensure galvanic isolation and thus reliable personal protection. On the other hand, if mechanical switches (switching contact) are used for load separation, a galvanic separation of the electrical device from the voltage source is likewise produced when the contact opening has been made.

The electrical contacts of such a mechanical switch or contact system are often referred to as a stationary fixed contact and as opposed to it movable moving contact executed. The moving contact is in this case movable relative to the fixed contact and can be transferred from a closed position to an open position. This means that, for switching the contact system or the switching unit, the moving contact between the open position and the closed position is moved by means of a switching movement.

The contacts of the contact system in the closed position typically form a very small point of contact at which the current flow through the contact system concentrates. In operation, magnetic effects, in particular the so-called "holmic clamping force", which exert a force on the contacts which releases the contact between the moving and fixed contacts, occur during operation. In order to avoid this, such a contact system generally has a spring element which presses the moving contact against the fixed contact with a spring force, that is to say acts upon an additional contact force or contact pressure directed along the closed position.

However, in the event of a fault or overload current, it may happen that the shear force exceeds the contact force, thereby causing unwanted lifting of the contacts. In particular, with direct voltages to be switched above 24 volts (DC) switching arcs frequently occur when the current-flowing electrical contacts are disconnected, since the electric current continues to flow along an arc gap in the form of an arc discharge after opening the contacts. Since at DC voltages above about 50 volts and DC currents above about 1 ampere such switching arcs may not extinguish automatically, the contact system can be damaged or completely destroyed.

So-called hybrid separation devices are conceivable, which have a hybrid switch. Such a hybrid switch generally has a mechanical contact system and a semiconductor switching system connected in parallel therewith. The semiconductor switching system in this case has at least one power semiconductor switch, which opens in a closed contact system, that is, electrically nonconductive, and which is at least temporarily connected in an electrically conductive manner when the contact system is opened.

In particular, when switching on, the semiconductor switching system is first activated and after a short delay, when the current flow has stabilized, the contact system is closed. Subsequently, the semiconductor switching system is deactivated and the mechanical contact system takes over the entire current. The shutdown happens accordingly in reverse order. As a result, the electric current of the arc is conducted or commutated by the contacts of the contact system to the semiconductor switching system, whereby the arc between the switching contacts of the contact system is extinguished, or does not arise from the beginning.

With such a hybrid separating device, it is thus possible to reliably prevent the switching arc between the contacts, at least in a limited current range, during a switching operation in which the moving contact is moved into the open position, ie the mechanical contact system is opened. Suitably, the separation device has a fuse, which is arranged in series with the hybrid switch. The fuse ensures reliable protection of the system at currents above this current range.

When using such a disconnecting device in a circuit breaker must be ensured that the hybrid switch safely carries the fault or overcurrent, otherwise a reliable response of the (fuse) fuse within a given characteristic is not guaranteed. In order to ensure the response of the fuse within the characteristic curve, even taking aging effects into account, an overcurrent of up to several kilo-amperes (kA) must reliably be borne by the mechanical contact system. Thus, an increase in the contact pressure is a multiple this requires what would be necessary for a low-resistance contacting of the contact system in a nominal current range. In order to ensure a safe response of the fuse, it is possible, for example, that one or more spring elements for generating the contact pressure are designed to be oversized, so that the contact force or the contact pressure at the Engekraft occurring a sufficient reserve, for example, also with respect to mechanical vibrations , having. As a result, however, both the manufacturing costs and the required space requirement for the separating device are disadvantageously increased. Furthermore, comparatively high powers are required for switching and holding the contact system. In particular, in contact systems with only a fixed contact and a moving contour, it is conceivable that the moving contact is designed as a (conductor) loop. In operation, the current flowing through the loop generates a magnetic field which causes a magnetic force to assist in the contact force. This makes it possible to compensate for the tightness. The effect is independent of the current flow direction.

It is also conceivable, for example, to direct a magnetic field of a permanent magnet directly or by means of baffles in the area of the contact system in such a way that, in cooperation with a magnetic field surrounding the moving contact during the current flow, an advantageous effect on the contact pressure results. Here, the direction of the magnetic force is dependent on the direction of current flow.

The invention has for its object to provide a particularly suitable Trennvor- direction for DC interruption of a current path. The inven tion is still the object of specifying a circuit breaker with a corresponding separator.

The separating device according to the invention is suitable for the DC interruption of a current path, in particular for a circuit breaker connected in the current circuit breaker, and set up. The particular hybrid separator has a hybrid switch for DC interruption of the current path. The hybrid switch has a switchable mechanical contact system. A "mechanical contact system" is to be understood below as meaning both a purely mechanical and an electromechanical contact system. "Switching" is understood here and below as meaning in particular a mechanical or galvanic contact separation ("opening") and / or a contact closure ("closing") of the contact system. The contact patch of the contact system is connected in parallel with a semiconductor switching system of the hybrid switch. In other words, the hybrid switch has a parallel connection of the contact system and the semiconductor switching system. The semiconductor switching system expediently has at least one controllable power semiconductor switch.

The contact system has at least one stationary fixed contact and at least one relative to this relatively movable moving contact. The moving contact is supported by a current-carrying contact bridge (switching arm). The contact bridge is in this case made of a copper material, for example. The contact bridge is coupled to a drive system which moves the contact bridge - and thus the moving contact - from an open position into a closed position which bears against the fixed contact with a contact force. In other words, the moving contact is acted upon by the drive system with a contact pressure or contact pressure, which ensures a secure contact of the contacts. The drive system is preferably designed with a spring element, wherein the contact force (closing force) is effected as a bias or as a restoring force of the spring element.

According to the invention, at least one first magnetic element is arranged on the contact bridge, which is arranged by means of an air gap to a stationary second magnetic element such that a current flow through the contact bridge, a magnetic field in the first magnetic element is effected and a magnetic attraction of the first and second Magnetic element takes place. In other words, the first magnetic element carries the magnetic field generated by the current-carrying contact bridge, with the magnetic circuit passing over the air gap. gap is closed by the second magnetic element. In the course of this attraction or magnetic interaction, a magnetic force (tensile force) which is equal to the contact force is effected, whereby the effective effective contact force of the moving contact on the fixed contact is increased.

As a result of the current flow, in addition to the contact force of the drive system, a force action is effected between the two magnetic elements, which increases the contact pressure and thus counteracts any resulting axial force. In other words, the contact force and the magnetic force are directed against the tightening force. The force effect is independent of the current flow direction and is thus always increasing the contact force.

Both the constraining force and the induced magnetic force increase in proportion to the square of the current flowing through the contact system. This means that in the case of an overcurrent or fault current, both the clamping force and the magnetic force increase in the same way, so that the magnetic force is always sufficiently dimensioned by the magnetic elements in order to compensate the confining force. Thus, a reliable and reliable installation of the contacts is always ensured. In particular, unwanted lifting of the contacts is advantageously and easily counteracted even in the event of a fault or overcurrent. As a result, a particularly suitable separation device for DC interruption of a current path is realized.

In particular, the additional magnetic force for the contact pressure is generated only when it is needed to reliably press the moving contact against the fixed contact. In contrast to the prior art, it is thus not necessary to provide a higher-dimensioned contact pressure spring of the drive system, which reduces the Fierstellungskosten and the space requirement of Trennvor- direction. Furthermore, comparatively low tightening and flat energies or powers when switching the contact system or the hybrid switch are therefore necessary. Due to the reduced holding energy, the heat development of the drive system is reduced, whereby a particularly space-compact drive system can be used. Furthermore, higher nominal streams feasible. In the case of a design as a bistable contact system, it is thus possible, for example, to use comparatively weak permanent magnets. Since the mechanical contact system is part of a hybrid switch, occurs during a switching, especially when opening the contacts, no (switching) arc. As a result, effects due to contact erosion can be essentially neglected, as a result of which the tuning of the magnetic elements through the air gap can be set or predetermined particularly effectively. In particular, the separating device thus has substantially no change at least with regard to the force effect of the magnetic elements over their service life.

The stationary second magnetic element is preferably not part of the hybrid switch, in particular not part of the movable contact system. The second magnetic element is arranged for example on a housing of the separating device or the circuit breaker, so that the point of application of the magnetic force caused is arranged outside or at a distance from the drive system of the contact system. As a result, the function of the magnetic elements is always guaranteed. The air gap has, for example, a clear width of about 0.3 mm (millimeters) to 1 mm. Preferably, the air gap in particular has a clear width of about 0.5 mm.

According to the invention, the current-carrying contact bridge is thus used itself to generate a magnetic field assisting the drive system. The magnetic elements thus act as an additional electromagnetic actuator or solenoid, whose magnetic force acts directly on the contact bridge, so that the occurring repulsion of the contacts at higher currents, in particular in the kilo-ampere range (kA), reliable and reliable compensation. In particular, the contact system of the separating device according to the invention requires no additional permanent magnets for generating the supporting tensile or closing force (magnetic force), whereby the separating device is particularly cost-effective. Furthermore, the function is independent of the Current flow direction, so that the contact system and thus the separation device is essentially used bidirectionally.

In contrast to the prior art, the pulling action of the magnetic elements according to the invention enables an optimized current conduction by means of the contact bridge in comparison to the repulsion of a loop-shaped contact bridge (conductor loop). This allows a very space-compact design of the separation device. Furthermore, maximum effect is achieved with closed contacts. In contrast, in the case of larger strokes of the contact (increased separation distance, higher voltages), a conductor loop would have to be made correspondingly wide and thus ineffective. Thus, the contact bridge itself is particularly space-compact and material-saving executable, which continue loss of power of the contact system can be reduced. In a suitable development, the mechanical contact system has two fixed contacts and two moving contacts. Suitably, the moving contacts are moved substantially simultaneously, ie synchronously, so that switching takes place essentially simultaneously at both switching or contact points. In other words, the contact system - and thus the hybrid switch - two preferably spaced pairs of contacts or separation points. As a result, a particularly reliable switching of the contact system is possible, whereby the switching behavior of the separating device is improved.

In an advantageous embodiment, the first magnetic element and the second magnetic element are each made of a soft magnetic material, in particular of a soft magnetic iron material. A soft-magnetic material or material is to be understood here in particular as meaning a ferromagnetic material which is easily magnetized in the presence of a magnetic field. This magnetic polarization is generated in particular by the electrical current in the current-carrying contact bridge. The polarization increases the magnetic flux density in the respective magnetic element many times over. This means that a soft magnetic material "strengthens" an external magnetic field around its respective material permeability. Thereby ensures that the highest possible magnetic force between the magnetic elements is generated, so that the tightening force is always reliably compensated.

Soft magnetic materials have a coercive force of less than 1000 A / m (amperes per meter). As a soft magnetic material, for example, a soft magnetic iron (RFe80 - Rfe120) having a coercive force of 80 to 120 A / m is used. Also conceivable, for example, the use of a cold strip, such as EN10139-DC01 + LC-MA ("Trafo sheet"), whereby a particularly cost-effective design is realized.

In one conceivable embodiment, the first magnetic element and the second magnetic element are designed as a paired yoke-armature pair. One of the magnetic elements here is designed as an approximately U-shaped or horseshoe-shaped magnetic yoke, wherein the respective other magnetic element is suitably designed as a flat anchor plate.

In an advantageous embodiment, the contact bridge is approximately rectangular executed, wherein two moving contacts are provided, which are arranged on the opposite end faces of the contact bridge. As a result, a particularly simple construction of the movable parts of the contact system is realized. Preferably, the moving contacts are arranged on a common plane surface of the contact bridge, the coupling to the drive system suitably taking place at the contact surface opposite the contact surface of the contact bridge.

In an expedient embodiment, the first magnetic element is designed as a U-shaped magnetic yoke, which rests in the region of the horizontal U-leg on the contact bridge. The first magnetic element or magnetic yoke rests against the drive system with the horizontal U-leg, in particular in the region of the mechanical coupling, wherein the magnetic yoke at least partially surrounds the contact bridge by means of the vertical U-legs. Suitably, the vertical U-legs engage around the contact bridge in such a way that the vertical U-legs of the first magnetic element of the contact bridge project in the direction of the fixed contacts and are spaced from one another by means of a free-end air gap to a second magnetic element designed as an armature plate. The second magnetic element or the armature plate is in this case substantially transversely to the contact bridge, that is oriented approximately parallel to the horizontal U-leg of the first magnetic element or magnetic yoke.

In an expedient development, the switching movement of the contact bridge, that is to say the movement of the contact bridge effected by means of the drive system and / or the magnetic elements, is linear. The conjunction "and / or" here and in the following is to be understood in such a way that the features linked by means of this conjunction can be formed both together and as alternatives to one another. This allows a structurally particularly simple design and arrangement of the drive system and the contact bridge as well as the magnetic elements.

In an alternative, equally advantageous embodiment, the contact bridge is designed substantially U-shaped, wherein two moving contacts are arranged on each one free end of a respective vertical U-leg. The alternative embodiment of the contact bridge is inexpensive to produce and allows particularly large separation distances between the contacts, ie large clearances between the contacts in the open position. In this embodiment, the drive system is preferably designed as a hinged armature magnet system, whereby a particularly cost-effective, space-compact and durable separation device is realized.

In additional or further aspect of this embodiment provides that along the vertical U-legs of the contact bridge each arranged as an anchor plate first magnetic element is arranged. Furthermore, two U-shaped or horseshoe-shaped magnetic yoke designed second magnetic elements are provided, which are arranged in the region of the fixed contacts, and which each have two vertical U-legs, which the respective opposite At least sectionally encompassing arranged vertically U-legs of the contact bridge. This ensures a particularly uniform and generating or effecting of the supporting magnetic force in the area of the moving contacts.

In a particularly suitable development, the switching movement of the contact bridge takes place by means of a pivoting or rotary movement. The pivot axis or axis of rotation is in this case oriented in particular along or parallel to the horizontal U leg of the contact bridge. Preferably, the contact bridge is fastened or held to an approximately U-shaped spring element of the drive system, which is produced, for example, as a stamped part from a spring steel. The pivotal or rotary movement is in this case realized in particular by a folding armature magnet system, the contact pressure being brought about by the bending elasticity of the spring element. By the pivoting or rotary movement particularly large separation distances between the contacts are generated or implemented in a simple manner, whereby a particularly secure and reliable electrical isolation of the separation device is realized.

Furthermore, in particular, the design with a U-shaped spring element, the vertical U-legs are arranged substantially flush with those of the contact bridge, to the effect that the contact system is reliably held in the closed position even with external vibrations or shocks. In particular, in such rotary contact systems it is possible to position the center of gravity of the moving contact bridge near the pivot point or the axis of rotation.

In a preferred application, the separation device described above is part of a circuit breaker. The circuit breaker is suitably connected in a circuit between a DC source and a load or a load, so that upon actuation of the circuit breaker, the separator galvanically separates the load or the load from the DC source. The circuit breaker is designed in particular as a hybrid circuit breaker or as a hybrid (power) relay or as a circuit breaker device with a downstream fuse, and has a feed connection, via which a line-side and thus current-carrying power line is connected, and a load connection, via which the load side outgoing power line can be connected.

Preferably, the circuit breaker is suitable and arranged for switching high voltages and direct currents, for example in the range of 6 kA. For this purpose, the separator is suitably dimensioned accordingly to such high currents to lead and safely switch. The inventive separation device thus ensures reliable and reliable switching of the circuit breaker, even with high overcurrents or fault currents.

Embodiments of the invention are explained in more detail with reference to a drawing. Show:

1 is a schematic representation of a circuit with a DC source and with a consumer and with an interposed circuit breaker,

2 is a perspective view of a mechanical contact system of

Circuit breaker

3 is a sectional view of the contact system,

4 is a perspective view of the contact system,

5 is a side view of the contact system,

6 is a plan view of an underside of the contact system,

Fig. 7 in perspective view an alternative embodiment of the

Contact system in a closed position,

8 is a perspective view of the alternative embodiment of the contact system in an open position,

9 shows a side view fragmentary the contact system in the alternative embodiment, 10 is a sectional view of a longitudinal section of the contact system, and FIG. 11 is a sectional view of a cross section of the contact system.

Corresponding parts and sizes are always provided with the same reference numerals in all figures.

1 shows a schematic and simplified representation of a circuit 2 for guiding a (direct) current I. the circuit 2 has a Gleichstromquel- le 4 with a positive pole 4a and a negative pole 4b, between which an operating voltage U is applied. In the circuit 2, a load or a consumer 6 is connected. Between the positive pole 4a and the load 6, a circuit breaker 8, for example in the form of a hybrid power relay, interconnected.

The circuit breaker 8 is connected on the one hand by means of a feed connection 10 to a source-side and thus current-carrying power line, and on the other hand by means of a load connection 12 connected to the load side outgoing power line.

The circuit breaker 8 has a series circuit of a hybrid separator 14 and a fuse 15. In this case, the separating device 14 is designed with a hybrid switch 16, which has a mechanical contact system 18 and a series connection of a semiconductor switching system 20 and an auxiliary relay 21 connected in parallel therewith. The semiconductor switching system 20 is shown in FIG. 1 by way of example by means of a controlled power semiconductor switch, in particular by means of an IGBT (Insulated Gate Bipolar Transistor).

In this case, the additional relay or isolating element 21 ensures galvanic separation of the current path 2 when the isolating device 14 is triggered. The isolating device 14 is suitable and designed to safely carry the current I in the event of a fault or overcurrent until the time delay Fuse 15 triggers. A safe carrying of the current I is understood here in particular to mean that the contacts of the mechanical contact system 18 are not interrupted or lifted off. A first embodiment of the contact system 18 will be explained in more detail below with reference to FIGS. 2 to 6. The contact system 18 shown in FIG. 2 has two stationary fixed contacts 22a, 22b, which are connected on the one hand to the feed terminal 10 and on the other hand to the load terminal 12 electrically conductive. The fixed contacts 22a, 22b are each guided to an associated electrical connection 23a, 23b, by means of which the contact system 18 can be connected to the circuit 2.

The contact system 18 also has two moving contacts 24a, 24b, which are supported by a common, current-carrying contact bridge 26. The contact bridge 26 is coupled to a drive system 28, by means of which the contact bridge 26 on the fixed contacts 22a, 22b is added or moved away.

For switching the contact system 18, the contact bridge 26 can be moved by means of the drive system 28 in the course of a switching movement from an open position into a closed position. FIGS. 2 to 6 show the contact system 18 in the closed position, in which the moving contacts 24a, 24b are in electrically conductive contact contact with the respective fixed contact 22a, 22b at the respective contact points.

In the exemplary embodiment of FIGS. 2 to 6, the switching movement caused by the drive system 28 during opening and closing of the contact system 18 takes place linearly along a (positioning) direction of the drive system 28 oriented perpendicular to the contacts 22a, 22b, 24a, 24b ,

The elongated, straight, approximately plate-shaped contact bridge 26 is made for example as a stamped part made of copper. The moving contacts 24a and 24b are arranged here on the opposite end faces of the approximately rectangular contact bridge 26. The moving contacts 24a and 24b are on the fixed contacts 22a and 22b facing flat surface or bottom 30 of the contact bridge 26th arranged. At the opposite arranged plan side or surface 32 of the contact bridge 26, the drive system 28 is arranged.

3 shows in a sectional representation a detail of a longitudinal section of the contact system 18 along the line III-III according to FIG. 2. As can be seen comparatively clearly in the sectional view of FIG. 3, the drive system 28 has a spring-loaded punch 34 for actuating or moving the contact bridge 26. The stamp 34 is at least partially from an example as

Coil spring executed spring element 36 surrounded, which is also referred to below as a contact pressure spring. The contact pressure spring 36 is in this case arranged such that in the closed position there is at least a certain spring tension whose restoring force acts as a contact force Fk or contact pressure on the contact bridge 26, and thus on the moving contacts 24a and 24b (FIG. 4). In other words, the moving contacts 24a and 24b are acted upon by the drive system 28 with a contact pressure or contact pressure, which ensures a secure contact of the contacts 22a, 22b, 24a, 24b. The contact force Fk is oriented along the actuating or actuating direction of the drive system, ie along the direction along which the linear switching movement of the contact system 18 takes place.

At the contact bridge 26, a magnetic element 38 is arranged. The magnetic element 38 is embodied as an approximately horseshoe-shaped or U-shaped magnetic yoke whose horizontal U-leg 38a is arranged on the upper side 32 of the contact bridge 26. The U-leg 38a has a central, unspecified, circular recess, through which the punch 34 is guided at least in sections. The U-leg 38a is arranged transversely, that is to say essentially vertically, to the contact bridge 26.

At the opposite end sides of the U-leg 38a a vertical U-leg 38b is formed in each case. The U-legs 38b are perpendicular to the U-leg 38a and the contact bridge 26, that is substantially parallel to Stamp 34, oriented. In this case, the U-legs 38b engage around the contact bridge 26 so that the U-legs 38b at least partially protrude axially at their respective free ends of the lower side 30 of the contact bridge 26, thus projecting beyond the lower side 30. Spaced to the free ends of the U-legs 38b, a second magnetic element 40 is arranged. The magnetic element 40 designed as a flat, approximately rectangular armature plate is arranged parallel to the U-leg 38a, ie transversely to the contact bridge 26.

In the closed position shown in the figures, the free ends of the U-legs 38b are kept spaced apart from the anchor plate 40 by means of an air gap 42. The armature plate 40 is stationary, so in terms of a housing of the separator 14 or the circuit breaker 8 fixed to the housing, arranged. The magnetic yoke 38 and the armature plate 40 are each made of a soft magnetic material, in particular of a soft magnetic iron material.

As can be seen in particular in FIGS. 4 and 5, the U-legs 38b have an approximately funnel-shaped cross-sectional shape in the plane spanned by the longitudinal directions of the U-legs 38b and the contact bridge 26. The U-leg 38b in this case has a frustoconical or trapezoidal area, which is integrally formed on the base on the U-leg 38a, and an approximately rectangular area which is integrally formed on the base side of the trapezoidal area opposite the base. The rectangular area here forms the free end of the U-leg 38b. In the U-leg 38b, as shown for example in Fig. 4, a circular recess 44 may be introduced.

As can be seen in particular in the plan view shown in FIG. 6 with a view of the underside 30, the anchor plate 40 has an approximately hourglass-shaped, ie waisted, cross-sectional shape in the plane defined by the longitudinal directions of the contact bridge 26 and the U-leg 38a. The sidecut or taper is in this case arranged centrally along the respective longitudinal side and in the region of the fixed contacts 22a and 22b. As indicated schematically in FIG. 4 by means of arrows, the electric current I is fed via the fixed contact 22a and the moving contact 24a into the contact bridge 26 and is removed from the contact system 18 via the moving contact 24b and the fixed contact 22b. Due to magnetic effects occurs at the contact points formed by the contact pairs 22a, 24a and 22b, 24b each have an Engekraft Fe, which is oriented in opposite directions to the contact force Fk.

The contact force Fk, that is to say the spring force of the contact pressure spring 36, is in particular dimensioned such that in the case of a normal current, that is to say in the case of an electrical current I, the current intensity is less than or equal to a normal or

Nominal value, the tightness Fe is reliably compensated. This means that the contact force Fk at a normal current is always greater than the clamping force Fe, so that an unwanted lifting the moving contacts 24a, 24b of the fixed contacts 22a, 22b reliably and easily prevented.

In this case, the magnetic elements 38 and 40 prevent an error or overcurrent, in which the current intensity of the current I exceeds the nominal value, that the clamping force Fe separates the contacts 22a, 22b, 24a, 24b from one another. In the case of such an overcurrent, the contact force Fk of the contact pressure spring 36 is not sufficient to reliably compensate for the increasingly large tightening force Fe.

During a current flow through the contact bridge 26, a magnetic field is generated around the contact bridge 26 by the current I. The magnetic field polarizes the soft magnetic yoke 38 and the soft magnetic armature plate 40, where the magnetic flux density in the region of the magnetic elements 38, 40 is substantially increased compared to the environment. Thus, a magnetic circuit between the magnetic yoke 38, the air gap 42 and the armature plate 40 is formed.

By the spacing by means of the air gap 42 thus an attractive magnetic force Fm between the magnetic yoke 38 and the armature plate 40 is effected. Since the anchor plate 40 is stationary or fixed to the housing in the circuit breaker 8, Thus, the magnetic yoke 38 is pulled onto the armature plate 40 back. The resulting magnetic force Fm is thus rectified to the contact force Fk of the contact pressure spring 36, so that the magnetic force Fm and the contact force Fk add up to a resultant total force, which counteracts the Engekraft Fe Thus, the contact pressure between the contacts 22a, 22b , 24a, 24b increased, whereby a lifting of the contacts 22a, 22b, 24a, 24b, even in the event of a fault or overcurrent, reliably and reliably counteracted.

The current-carrying contact bridge 26 thus generates a magnetic field which supports the drive system 28 and is used to boost the contact pressure. The magnetic elements 38, 40 thus act at a current flow through the contact bridge 26 as an additional electromagnetic actuator or Flubmagnet whose effected magnetic force Fm via the U-leg 38a directly on the contact bridge 26 and thus on the moving contacts 24a, 24b acts.

An alternative, second embodiment of the contact system 18 'is explained in more detail below with reference to FIGS. 7 to 11. In this embodiment, the contact bridge 26 'is designed as a substantially U-shaped copper part, wherein the two moving contacts 24a, 24b are arranged on a respective free end of a vertical U-leg 26'a.

Along the vertical U-legs 26a 'of the contact bridge 26' is in each case designed as an anchor plate magnetic element 38 'is arranged. The drive system 28 'of the contact device 18' is designed in this embodiment as a hinged armature magnet system, wherein only one of the hinged armature coupled, approximately U-shaped spring element 46 is shown. The U-legs 26'a and the anchor plates 38 'and the U-legs 46a are in this case essentially stacked in a stacked arrangement.

The vertical U-legs 46a of the spring element 46 are arranged substantially flush with the U-legs 26a 'of the contact bridge 26', the hori zontal U-leg 46b of the spring element 46 spaced from the horizontal U-leg 26'b the contact bridge 26 'is arranged. In other words, the U-legs 46a have a greater length along the longitudinal direction of the leg than the U-legs 26'a, so that the U-leg 46b is arranged along the leg longitudinal direction above the U-leg 26'b.

The spring element 46 is made of a flexurally elastic material, for example spring steel, so that a pivoting or rotary mobility of the drive system 28 'is realized by the substantially freestanding U-leg 46b. In particular, the U-legs 46a of the spring element 46 are thus held pivotably or rotatably relative to a pivot or rotary axis S extending parallel to the U-leg 46b.

The switching movement is thus in this embodiment, in particular by pivoting the contact bridge 26 'about the pivot axis S. This pivotal movement is shown in Fig. 7, which shows the contact system 18' in a closed position, and in Fig. 8, which the contact system 18th 'in an open position, indicated. By the pivoting or rotary motion comparatively large separation distances between the contacts 22a, 22b, 24a, 24b are realized.

In this embodiment, two stationary magnetic elements 40 'are provided, which are fixed to the housing on an insulating, ie electrically non-conductive, housing 48 of the circuit breaker 8. The magnetic elements 40 'are formed in cross section as horseshoe or U-shaped magnetic yokes, which extend at least in sections along the leg longitudinal direction of the U-legs 26'a, 46'. The magnetic yokes 40 'are thus designed essentially as cylindrical molded parts with a horseshoe or U-shaped base or cross-sectional area.

The magnetic elements 40 'each have a in the closed position parallel to the U-legs 26'a, 46' oriented horizontal U-legs 40a 'on. At the back-like U-legs 40a 'of the magnetic yoke 40' are two vertical U-legs 40'b molded. The U-legs 40'b of the magnetic yoke 40 'engage around - as can be seen in FIG. 9 - in the closed position, at least in sections, the respectively opposite vertical U-limb 26'a of the contact bridge 26', so that between the free ends of the U-legs 26'a and the respective anchor plate 38 'of the air gap 42 is formed.

As can be seen on the basis of the sectional views of FIG. 10 and FIG. 11, current I flows through limbs 26 'a, 26' b of contact bridge 26 'to form a magnetic field B, which independently of the current direction causes magnetic elements 38 ', 40' mutually attracting magnetic force Fm causes, whereby the contact force Fk is reinforced due to the spring tension of the spring element 46.

The invention is not limited to the embodiments described above. Rather, other variants of the invention can be derived therefrom by the person skilled in the art without departing from the subject matter of the invention. In particular, furthermore, all the individual features described in connection with the exemplary embodiments can also be combined with one another in other ways, without departing from the subject matter of the invention.

LIST OF REFERENCE NUMBERS

2 circuit

4 DC power source

4a positive pole

4b negative pole

6 load / consumer

8 circuit breaker

10 feed connection

12 load connection

14 separating device

15 fuse

16 hybrid switches

18, 18 'contact system

20 semiconductor switch system

22a, 22b fixed contact

23a, 23b connection

24a, 24b moving contact

26 contact bridge

26 'contact bridge

26'a, 26'b U-thighs

28, 28 'drive system

30 plane / underside

32 plane surface / top side

34 stamp

36 spring element / contact pressure spring

38 magnetic element / magnetic yoke

38a, 38b U-thighs

38 'magnetic element / anchor plate 40 magnetic element / anchor plate

40 'magnetic element / magnetic yoke

40'a, 40'b U-thighs

42 air gap 44 recess

46 spring element

46a, 46b U-thighs

48 housing

U operating voltage

I electricity

Fk contact force

Fm magnetic force

Fe tightness

S pivot axis / axis of rotation

B magnetic field

Claims

claims

1. Separating device (14) for DC interruption of a current path (2), in particular for a circuit breaker (8), comprising a hybrid switch (16), softer a current-carrying mechanical contact system (18, 18 ') and a parallel thereto connected semiconductor switching system (20) .

- wherein the contact system (18, 18 ') at least one stationary fixed contact (22a, 22b) and at least one moving contact (24a, 24b),

- Wherein the moving contact (24a, 24b) on a with a drive system (28, 28 ') coupled current-carrying contact bridge (26, 26') is arranged, which the moving contact (24a, 24b) in a switching movement from an open position to a fixed contact (22a, 22b) moves with a contact force (Fk) applied closed position, and

wherein at least one first magnetic element (38, 38 ') is arranged on the contact bridge (26, 26'), which is so spaced by means of an air gap (42) to a stationary second magnetic element (40, 40 ') in the case of a current flow through the contact bridge (26, 26 '), a magnetic field (B) is effected in the first magnetic element (38, 38') and a magnetic attraction of the first and second magnetic elements (38, 38 ', 40, 40 '), wherein attraction causes a magnetic force (Fm) equal to the contact force (Fk).

2. Separating device (14) according to claim 1,

characterized,

the mechanical contact system (18, 18 ') has two fixed contacts (22a, 22b) and two moving contacts (24a, 24b).

3. separating device (14) according to claim 1 or 2,

characterized,

in that the first magnetic element (38, 38 ') and the second magnetic element (40, 40') are each made of a soft magnetic material, in particular of a soft magnetic iron material.

4. Separating device (14) according to one of claims 1 to 3,

characterized,

that the contact bridge (26 ') is substantially U-shaped, wherein two Be wegkontakte (24a, 24b) are arranged on each one free end of a vertical U-leg (26'a).

5. Separating device (14) according to claim 4,

characterized,

- That along the vertical U-legs (26 'a) each designed as an anchor plate first magnetic element (38') is arranged, and

- That two designed as a magnetic yoke second magnet elements (40 ') are provided, which are arranged in the region of the fixed contacts (22a, 22b), and which each have two vertical U-legs (40'b), which the respective oppositely arranged vertical U-legs (26'a) of the contact bridge (26 ') engage around at least in sections.

6. Separating device (14) according to claim 4 or 5,

characterized,

that the switching movement of the contact bridge (26 ') is a pivotal or rotary movement.

7. Circuit breaker (8) with a separating device (14) according to any one of claims 1 to 6.