EP3537466B1 - Electromechanical protective switching device - Google Patents

Description

The invention relates to an electromechanical protective switching device - in particular a residual current circuit breaker - with an insulating housing, an electromechanical tripping relay which is accommodated and held in the housing and has a plunger which is movably mounted between a ready-to-trip position and a tripped position, and a resetting device for resetting the plunger in the ready-to-release position.

Electromechanical protective switching devices - for example circuit breakers, miniature circuit breakers or residual current circuit breakers - are used to monitor and protect an electrical circuit and are used in particular as switching and safety elements in electrical energy supply and distribution networks. To monitor and protect the electrical circuit, the protective switching device is electrically conductively connected to an electrical line of the circuit to be monitored via two or more connection terminals in order to interrupt the electrical current in the respective monitored line if necessary. For this purpose, the protective switching device has a switching contact which can be opened when a predefined state occurs—for example when a short circuit or a fault current is detected—in order to separate the monitored circuit from the electrical mains. Such protective switching devices are also known as modular installation devices in the field of low-voltage technology.

In electrical installation technology, protective switching devices suitable for this purpose - for example residual current circuit breakers or residual current circuit breakers - are used to detect a so-called residual or residual current in order to protect people from dangers that can arise when live parts of electrical systems are touched. differential currents can occur if, for example, a fault current flows to earth via defective insulation or - in the event of contact - through the human body. To detect such a fault or differential current, the magnitude of the current in a line leading to an electrical consumer, for example a phase line, is compared with the magnitude of the current in a line leading back from the electrical consumer, for example a neutral conductor, using a so-called summation current transformer . This has a ring-shaped magnetic core through which the primary conductors (return electrical lines) are passed. The magnetic core itself is wrapped with a secondary conductor or a secondary winding. When there is no residual current, the sum of the electric currents flowing to the load is equal to the sum of the electric currents flowing back. If the currents are added vectorially, ie directional or signed, it follows that the signed sum of the electric currents in the outgoing and return lines in the fault-free state is equal to zero: no induction current is induced in the secondary conductor.

Conversely, in the case of a fault or residual current that flows to earth, the sum of the electric currents flowing in or out, which is recorded in the summation current transformer, is not equal to zero. The resulting current difference causes a voltage that is proportional to the current difference to be induced at the secondary winding, as a result of which a secondary current flows in the secondary winding. This secondary current serves as a fault current signal and, after a predetermined value has been exceeded, triggers the protective switching device and consequently—by opening a switching contact—to the disconnection of the correspondingly secured circuit.

In general usage, instead of the term "residual current circuit breaker", the terms FI circuit breaker (short: FI switch), residual current circuit breaker (in short: DI switch) or RCD (residual current protective device) are used in the same way.

In the case of residual current circuit breakers, a distinction is also made between mains voltage-dependent and mains voltage-independent device types: while mains-voltage-dependent residual current circuit breakers have control electronics with a trigger that is dependent on an auxiliary or mains voltage to fulfill their function, mains-voltage-independent residual current circuit breakers do not need an auxiliary or mains voltage to implement the triggering function, but instead have an electronic control system To implement mains voltage-independent tripping, it usually has a slightly larger summation current transformer, with which a larger induction current can be generated in the secondary winding. Since the residual currents determined in this way are usually comparatively small, they also only have a low energy density. Therefore, the fault current cannot be used directly and immediately to trigger a switching mechanism, as is the case with a circuit breaker, for example, with the help of a magnetic coil and an impact armature in the event of a short-circuit trip. Instead, an electromechanical tripping relay is usually used to implement line-voltage-independent residual current tripping.

The tripping relay is electrically connected to the summation current transformer via the secondary winding. However, because of the mostly low residual current, the tripping relay has only a comparatively low tripping force, which is usually not sufficient for a direct tripping of the switching mechanism in order to open the switching contact immediately when a fault current occurs. Instead, the protective switching device has an additional energy store, which the tripping relay acts on when tripping occurs. Such an electromagnetic tripping device is known, for example, from the German patent specification DE19735413B4 previously known.

Due to the low forces, the tripping relay is designed as a precision mechanical assembly, which has a coil and a plunger mounted movably relative thereto in a housing. The plunger can be actuated by a movably mounted armature which, in the rest state, is held in its rest position by a permanent magnet against the force of a release spring. When it is triggered, a magnetic field caused by the coil energized with the induction current weakens the magnetic field of the permanent magnet, which reduces its holding force so that it is no longer sufficient to hold the armature against the force of the trigger spring against its pole faces in the rest state. As a result, the tripping spring causes the armature, and thus the plunger, to move from its rest position ready for tripping to its tripped position. Due to the small dimensions and the low energy density, the precision mechanics of the tripping relay are comparatively vulnerable and sensitive to shocks and/or vibrations. Such shocks, which occur in particular when the plunger is mechanically reset from its released position to its rest position ready for release, can lead to false releases and must therefore be avoided at all costs.

In order to return the plunger to its rest position ready for tripping, the protective switching device has a reset element which is mechanically coupled to the switching mechanism and is raised against a spring element when the protective switching device is switched on. After the switching mechanism has been triggered, the restoring element—driven by the spring element—is moved against the plunger, as a result of which the plunger is reset from its triggered position to its rest position. Since the movement of the switching mechanism is highly dynamic, the restoring element also hits the plunger at high speed and pushes it back into its rest position. This highly dynamic reset movement, which is tantamount to hitting the plunger, is undesirable because it can damage the sensitive tripping relay. For example, the highly dynamic movement of the restoring element lead to a change in the geometric arrangement of the components inside the tripping relay - in particular the magnetic air gap - as a result of which the holding force of the tripping relay - and thus the tripping properties of the protective switching device - are changed in an impermissible manner. Since the tripping currents of the protective switching device also change over the service life, up to and including its inoperability, this effect represents a significant risk for the tripping accuracy of the protective switching device and must therefore be avoided at all costs.

In addition to the pure fault current or residual current protective devices, there are also device designs in which the functionality of a residual current circuit breaker (FI or DI) is combined with the functionality of a miniature circuit breaker (LS): Such combined protective switching devices are known in German as FILS or as LSDI, in English-speaking countries mostly referred to as RCBO (residual current operated circuit breaker with overcurrent protection). Compared to separate residual current circuit breakers and miniature circuit breakers, these combination devices have the advantage that each circuit monitored for short circuit and overload (LS functionality) has its own FI protection (FI or DI functionality): Normally, a single residual current circuit breaker used for multiple circuits. If a fault current occurs, all protected circuits are switched off as a result. However, the use of RCBO devices makes it possible to interrupt only the circuit concerned. This significantly improves the availability of the electrical supply network.

Furthermore, since the space available for applications in electrical installation technology—for example in an electrical installation distribution board—is usually very limited, there is a need to make the protective switching devices as compact as possible. This applies in particular to so-called combination devices, in which more and more functionalities are being integrated into the devices, so that they expand the range of functions cover several individual devices. In addition, the protective switching devices should be able to be used or used for ever higher nominal current intensities. All of these developments mean that less and less installation space is available inside the devices.

It is therefore the object of the present invention to provide an electromechanical protective switching device--in particular a residual-current circuit breaker--which is characterized by consistently high triggering accuracy over the entire service life.

According to the invention, this object is achieved by the electromechanical protective switching device according to claim 1 . Advantageous configurations of the electromechanical protective switching device according to the invention are the subject matter of the dependent claims.

The electromechanical protective switching device according to the invention, which is designed in particular as a residual current circuit breaker, has an insulating housing and an electromechanical tripping relay which is accommodated and held in the insulating housing and in turn has a plunger which is movably mounted between a rest position ready for tripping and a tripped position. Furthermore, the protective switching device has a resetting device for resetting the plunger into the rest position ready for triggering. For this purpose, the restoring device has a base body that is movably mounted in the housing and to which a damping element is attached, which is designed to act on the plunger when the base body moves, in order to return it to the rest position ready for triggering. The damping element is designed to be elastic in such a way that the impulse of the base body acting on the plunger is damped as a result.

The tripping relay is used to trip the protective switching device if a fault current occurs. The plunger moves from the rest position ready for release to the released position emotional. The reset device is used to reset the plunger to its original rest position. With a corresponding movement of the base body, the damping element acts on the plunger, as a result of which the plunger is moved back into its rest position. Due to the elastically designed damping element, the impulse of the sluggish and comparatively massive base body is not transmitted to the ram. Only the comparatively low mass of the damping element exerts an impulse on the plunger. The risk of damage to the sensitive tripping relay can be significantly reduced by gently returning the plunger to its rest position, which means that consistently high tripping accuracy can also be achieved over the service life of the protective switching device.

According to the invention, the base body can be moved between a first position ready for recovery and a second position. The damping element is not firmly clamped to the base body, but rather has a degree of freedom against the movement of the base body into the second position.

When the base body is moved into the second position, the plunger is returned to its rest position. Due to the coupling of the damping element to the base body according to the invention, the damping element can lift off the base body counter to this movement when the base body moves into the second position. This applies at least to the part or section of the damping element that comes into contact with the plunger. Due to this structural design, the damping element moves at a lower speed in the direction of the second position than the base body. Since the damping element is also designed to be spring-elastic, the impulse exerted on the plunger is thereby further damped, as a result of which the risk of damage to the sensitive tripping relay is further reduced.

In a further advantageous development of the protective switching device, the base body is rotatably mounted in the insulating material housing.

In a further advantageous development of the protective switching device, the base body can be moved via a spring element supported in the insulating material housing.

The spring element represents an energy accumulator which, when the protective switching device is triggered and the switching mechanism is released as a result, provides the force required to move the base body from its first position, which is ready to be reset, into its second position.

In a further advantageous development of the protective switching device, the insulating housing with a width of only one pitch unit (TE) has a first current path area for accommodating a first primary conductor and a second current path area for accommodating a second primary conductor.

The protective switching device has a compact design with a width of only one pitch unit, which corresponds to approx. 18 mm. For reasons of electrical insulation, the two current path areas inside the insulating housing are separated from one another by a housing partition or the like, i.e. arranged separately from one another.

In a further advantageous development, the protective switching device is designed as an RCBO combination device which, in addition to the functionality of a residual current circuit breaker, has the functionality of a circuit breaker.

The design of the protective switching device as an RCBO combination device follows the fundamental trend of integrating more and more functionality into the switching devices while maintaining a design that is as compact as possible.

Figuren 1 bis 3

schematische Darstellungen eines elektromechanischen Schutzschaltgerätes in verschiedenen Ansichten;

Figuren 4 bis 6

schematische Detaildarstellungen des geöffneten Schutzschaltgerätes in verschiedenen Betriebszuständen.

An exemplary embodiment of the electromechanical protective switching device is explained in more detail below with reference to the accompanying figures. In the figures are:

Figures 1 to 3

schematic representations of an electromechanical protective switching device in different views;

Figures 4 to 6

schematic detailed representations of the open protective switching device in various operating states.

In the various figures of the drawing, the same parts are always provided with the same reference numbers. The description applies to all drawing figures in which the corresponding part can also be seen.

In the Figures 1 to 3 an electromechanical protective switching device 1 in the design as a mains voltage-independent residual current circuit breaker is shown schematically in various views. While figure 1 shows a view from below of the protective switching device 1 is in figure 2 a corresponding side view of the protective switching device 1 is shown; figure 3 shows a top view which in turn corresponds to this. The protective switching device 1 according to the invention has an insulating housing 2 with a front side 4, a fastening side 5 opposite the front side 4, and narrow sides 6 and broad sides 7 connecting the front side 4 and the fastening side 5. In its interior, the insulating material housing 2 has a first current path area 8 and a second current path area 9 which are separated from one another by a housing partition 10 . The housing partition 10 extends from one narrow side 6 to the other narrow side 6 and thus runs essentially parallel to the broad sides 7. The two current path regions 8 and 9 are thus arranged next to one another in a width direction B.

A physical first current path 11 runs in the first current path region 8, which extends from one narrow side 6 to the other narrow side 6 and is electrically conductively connected during installation to an electrical first connection conductor—usually the phase conductor P—of the electrical circuit to be monitored. Accordingly, a physical second current path 12 runs in the second current path area 9, which also extends from one narrow side 6 to the other narrow side 6 and is electrically conductively connected during installation to a second electrical connection conductor—usually the neutral conductor N—of the electrical circuit to be monitored . The protective switching device 1 thus has a phase conductor side (P-side), in which the first current path 11 is arranged and which thus corresponds to the first current path area 8, and a neutral conductor side (N-side), which corresponds to the second current path area 9 corresponds and in which the second current path 12 is arranged.

In the area of the narrow sides 6, each of the two current path areas 8 and 9 has electrical connection terminals 13—an input terminal assigned to the respective current path area 8 or 9 and an output terminal correspondingly assigned to this current path area 8 or 9. The connection terminals 13 are accommodated and held in the insulating material housing 2 . The connection conductors P and N can be plugged into the associated connection terminal 13 through openings (not shown) formed in the insulating material housing 2 and can be fastened there in an electrically conductive manner. The respective input terminal 13 of the respective current path area 8 or 9 is electrically conductively connected to the respective output terminal 13 of this current path area 8 or 9 via the two current paths 11 or 12 .

On its front side 4, the mains voltage-independent residual current protective switching device 1 according to the invention also has an actuating element 3 for manual operation of the protective switching device 1 on. The actuating element 3 is coupled inside the insulating housing 2 via a switching mechanism of the protective switching device 1 with one or more switching contacts 15 in such a way that these can be opened and closed manually by means of the actuating element 3 . The protective switching device 1 can be fastened to a snap-in or top-hat rail via the fastening side 5 opposite the front side 4 . Such snap-in or top-hat rails are used as standard in electrical installation distribution boards for fastening series installation devices. Advantageously, the insulating housing 2 has a width of only one pitch unit (1TE, corresponds to approximately 18 mm).

the Figures 4 to 6 show schematic detailed representations of the open protective switching device 1 in different operating states. These representations each show a side view of the broad side of the neutral conductor 7 of the protective switching device 1, with a front housing cover of the insulating housing 2 having been removed in each case in order to enable a glimpse into the interior of the protective switching device 1 in this way.

The protective switching device 1 has an electromechanical tripping relay 20 on its neutral conductor side, which is accommodated and held in the insulating housing 2 . The tripping relay 20, for its part, has a plunger 21, which is movably mounted between a rest position ready for tripping and a tripped position and, when a fault current is present at the residual current circuit breaker and its detection via a summation current transformer (not shown), actuates a tripping lever, thereby releasing a latch and as a result, the opening of the switching contacts 15 is initiated. After the triggering, the plunger 21 is not automatically pulled back into the triggering relay 20 from its triggered position into its rest position ready for triggering, but has to be pushed back into the triggering relay 20 from the outside.

For this purpose, the protective switching device 1 has a resetting device 30, which is used to reset the plunger 21 from the tripped position back into its rest position ready for tripping. The restoring device 30 in turn has a base body 31 which is mounted in the insulating material housing 2 so that it can rotate between a first position ready for restoring and a second position. In order to apply the force required for the restoring movement of the base body 31 into the second position, the restoring device 30 also has a spring element 33, the first end 33-1 of which acts eccentrically on the base body 31, and the second end 33-2 of which acts on a spring element formed on the insulating material housing 2 Holding element 14 is fixed. When the protective switching device 1 is switched on, the reset device 30 is first pulled up by the switching mechanism against the spring force of the spring element 33 and remains in this raised, reset-ready first position until the protective switching device 1 is triggered and its switching mechanism is triggered. As a result of this triggering, on the one hand the switching contacts 15 are opened and on the other hand the resetting device 30 is no longer held in the first position. Instead, the base body 31 moves at high speed towards the tripping relay 20 within a few milliseconds and pushes the plunger 21 back into its starting position, i.e. into its rest position.

The highly dynamic movement of the base body 31 in the direction of the plunger 21 is not unproblematic, since it is equivalent to a hit or impact on the plunger 21, which results in the armature (not shown) of the tripping relay 20 coupled to the plunger 21 at the end of the contact movement of the plunger 21 would hit the pole faces of the magnet legs (not shown) of the triggering relay 20 with its pole faces. Because of the high speed and the relatively large, inertial mass of the base body 31, there is a risk that the pole faces could be damaged and the magnetic air gap could be changed, thereby reducing the holding force—and thus the tripping properties of the tripping relay 20 - would change. In order to avoid these consequences, the restoring device 30 has an elastic damping element 32 which is intended to act on the plunger 21 when the base body 31 moves into the second position in such a way that the latter is gently returned to its rest position ready for triggering.

In figure 4 a first state is shown for this purpose, in which the base body 31 is twisted counterclockwise against the force of the spring element 33 and is in the first position ready for reset. The spring element 33 serves as a tension spring, against the tensile force of which the reset device 30 is pulled up via its switching mechanism when the protective switching device 1 is switched on and is fixed in this state - which is also referred to as the "ready-to-trip state" or "loaded state" of the reset device 30. In this state, which represents the first position of the base body 31 ready for reset, the damping element 32 is clearly spaced from the plunger 21 of the tripping relay 20 and, after the protective switching device 1 has tripped and the fixation of the reset device 30 has been released, enables it to be reset with the help of the spring force applied by the spring element 33 of the ram 21.

figure 5 shows a second state of the protective switching device 1 immediately after the plunger 21 has been returned to its rest position by the damping element 32. The base body 31 of the restoring device 30 has not yet reached its end position of the restoring movement, ie its second position. The plunger 21 , on the other hand, has already been completely returned to its rest position ready for triggering by the damping element 32 , with the damping element 32 still being in contact with the plunger 21 . This state, in which the plunger 21 is already in its rest position and the damping element 32 is still in contact with the end of the plunger 21, is also referred to as the “applied state”.

figure 6 shows a third state of the triggering relay 20 and the reset device 30 immediately after the in figure 5 state shown: the damping element 32 is still in contact with the plunger 21, which has been returned to its rest position, but the base body 31 has now reached its second position, into which it can be moved after the protective switching device 1 has been triggered and the associated loosening of the fixing of the Restoring device 30 was accelerated by the spring force applied via the spring element 33 . However, the impulse required to return the plunger 21 to its rest position ready for triggering is not transmitted directly from the base body 31 but indirectly via the damping element 32 to the plunger 21 . Since the damping element 32 is elastic, the momentum of the base body 31 acting on the plunger 21 during the movement of the base body 31 into the second position is thereby damped.

Furthermore, the damping element 32 is not only elastic, but also has a degree of freedom relative to the base body 31 against its movement into the second position, i.e. the damping element 32 is not firmly clamped to the base body 31, but mechanically coupled to the base body 31 in such a way that the free end of the damping element 32, which serves to reset the plunger 21, can lift relative to the movement of the base body 31 in its second position. This moment of lifting of the free end of the damping element 32 from the base body 31 against its direction of movement into the second position is in figure 6 shown: the position of the free end of the damping element 32 corresponds to that in figure 5 position shown, but the base body 31 has now reached its second position.

In the case shown, the movement of the base body 31 into its second position is stopped by the housing of the tripping relay 20 . The inertial mass of the base body 31 thus meets at the end of the movement in the second position not on the plunger 21, but on the housing of the trigger relay 20, whereby the risk of damage to the sensitive components of the trigger relay 20 is significantly reduced. In principle, however, it is also possible to stop the movement of the base body 31 into its second position by means of a stop or projection formed on the insulating material housing 2 in order to avoid any vibration acting on the tripping relay 20 .

According to the invention, no rigid base body 31 acts on the plunger 21 to reset it. Instead, a damping element 32 is provided for this purpose, which is coupled to the base body 31 in such a way that the free end of the damping element 32 can release from the base body 31 when it moves into the second position. Thus, the inertial mass of the base body 31 does not strike the plunger 21. Instead, the base body 31 moves further into its second position until it finally hits a suitable stop - for example the housing of the triggering relay 20 or a contour fixed to the housing - which triggers the pulse of the base body 31 receives. In this way, the pole faces of the magnet legs are not additionally loaded by the inertial mass of the base body 31, since only the small inertial mass of the damping element 32 strikes the pole faces via the plunger 21. The dynamic load on the pole faces of the magnet legs is thereby minimized without reducing the static force component that is required for a reliable reset process.

For reasons of space, the cushioned return function was divided into two separate springs: the relatively strong tension spring 33 provides the force required to reset the plunger 21, while the damping element 32, designed as a torsion spring, reduces the dynamic load - i.e. the impact or impact that is exerted on the plunger 21 hits the pole faces of the magnet legs. This division allows the plunger 21 to be returned in a damped manner to its rest position ready for tripping, particularly in compact switching devices with a housing width of only one division unit.

Reference List

1

protective switching device

2

insulating housing

3

actuator

4

front

5

mounting side

6

narrow side

7

broadside

8th

first current path area

9

second current path area

10

housing partition

11

first current path

12

second current path

13

terminal block

14

holding element

15

switching contact

16

fixed contact

17

moving contact

20

trip relay

21

pestle

30

reset device

31

body

32

damping element

33

spring element

B

latitude direction

P

first connection conductor / phase conductor

N

second connection conductor / neutral conductor

Claims (5)

1. Electromechanical protective switching device (1), in particular residual-current circuit breaker, having

   - an insulating-material housing (2),

   - an electromechanical tripping relay (20) which is received and held in the insulating-material housing (2) and has a plunger (21) which is mounted moveably between a ready-to-trip inoperative position and a tripped position,

   - a resetting device (30) for returning the plunger (21) to the ready-to-trip position, wherein the resetting device (30) has a main body (31) mounted moveably in the insulating-material housing (2) and to which a damping element (32) is fastened, the damping element being designed to act on the plunger (21) in the event of a movement of the main body (31) in order to return the plunger to the ready-to-trip position, wherein the damping element (32) is formed elastically in such a way that the pulse of the main body (31) acting on the plunger (21) is damped as a result,

   - and wherein the main body (31) is movable between a ready-to-reset first position and a second position, characterized

   - in that the damping element (32) is not fixedly clamped to the main body (31) but rather has a degree of freedom counter to the movement to the second position, so that a free end of the damping element (32), which serves for returning the plunger (21), can lift off relative to the main body (31) counter to a movement of the main body to its second position.
2. Protective switching device (1) according to Claim 1, characterized
   in that the main body (31) is rotationally mounted in the insulating-material housing (2).
3. Protective switching device (1) according to either of the preceding claims,
   characterized
   in that the main body (31) is movable by means of a spring element (33) supported in the insulating-material housing (2).
4. Protective switching device (1) according to one of the preceding claims,
   characterized
   in that the insulating-material housing (2), given a width of just one subdivision unit (TE), has a first current path region (8) for receiving a first primary conductor (P) and a second current path region (9) for receiving a second primary conductor (N).
5. Protective switching device (1) according to one of the preceding claims,
   characterized in that
   the protective switching device (1) is in the form of an RCBO combination device which, in addition to the functionality of a residual-current circuit breaker, has the functionality of a line circuit breaker.

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