CN116435149A

CN116435149A - Low voltage protection switching device and method of assembly

Info

Publication number: CN116435149A
Application number: CN202310031742.XA
Authority: CN
Inventors: F.内斯; A.蒙特; G.诺尔
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 2022-01-13
Filing date: 2023-01-10
Publication date: 2023-07-14
Also published as: DE102022200297A1; EP4213175B1; EP4213175A1

Abstract

The low-voltage protection switching device according to the invention has: an insulating material case having a front side, a fastening side opposite to the front side, and a narrow side and a wide side connecting the front side and the fastening side; and a switch contact having a fixed contact arranged in a fixed position in the insulating material housing and a movable contact movable relative thereto. Furthermore, the low-voltage protection switching device has an arc extinguishing chamber and an arc rail, the first end of which is guided below the arc extinguishing chamber and the second end of which protrudes in the direction of the switching contacts. The low-voltage protection switching device further has a printed circuit board which is arranged between the arc extinguishing chamber and the fastening side, wherein the printed circuit board is electrically conductively connected to the arc rail via a voltage tap. By means of a printed circuit board which is arranged in a space-saving manner in the region of the fastening side, the low-voltage protection switching device can be equipped with additional digital functions. The voltage supply of the printed circuit board is realized here in a space-saving manner by means of an arc rail.

Description

Low voltage protection switching device and method of assembly

Technical Field

The invention relates to a low-voltage protection switching device having an insulating material housing in which a printed circuit board is arranged. The invention further relates to an assembly method for such a low-voltage protection switching device.

Background

Electromechanical protection switching devices (e.g., circuit breakers, line protection switches, fault current protection switches, and arc protection switches or fire protection switches) are used to monitor and protect electrical circuits, and are used, inter alia, as switching elements and safety elements in electrical energy supply and distribution networks. For monitoring and protecting an electrical circuit, a protection switching device is electrically conductively connected to the electrical line of the circuit to be monitored via two or more connection terminals in order to interrupt the current in the corresponding monitored line if necessary. For this purpose, the protection switching device has at least one 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 electrical circuit from the electrical circuit network. Such protection switching devices are also known in the low-voltage art as series-mounted devices

The circuit breaker is designed here exclusively for high currents. Line protection switches (so-called LS switches), also called "miniature circuit breakers" (Miniature Circuit Breaker, MCB), represent so-called overcurrent protection devices in electrical installations and are used in particular in the field of electrical power grids. The circuit breaker and the line protection switch ensure a safe shut-off in the event of a short circuit and protect the consumers and the devices from overload, for example from damage to the electrical line due to excessive heating caused by excessive currents. The circuit breaker and the line protection switch are designed to automatically shut off the circuit to be monitored in the event of a short circuit or in the event of an overload and thus to separate the circuit from the remaining line network. Circuit breakers and line protection switches are thus used in particular as switching elements and safety elements for monitoring and protecting electrical circuits in electrical power supply networks. Line protection switches are known in principle from publications DE 10 2015 217 704 A1, EP 2 980 822a1, DE 10 2015 213 375 A1, DE 10 2013 211 539 A1 or also from EP 2 685 482 B1.

To interrupt a unique phase line, a single pole line protection switch is typically used, which typically has a width of one indexing unit (corresponding to about 18 mm). For a three-phase connection (as an alternative to three single-pole switching devices), a three-pole line protection switch is used, which accordingly has a width of three graduation units (corresponding to approximately 54 mm). In this case, each of the three phase conductors is associated with a pole, i.e. a switching point. If the neutral conductor should be interrupted in addition to the three phase conductors, it is called a quadrupole device, which has four switching points: three switching points for three phase conductors and one switching point for a common neutral conductor.

Furthermore, compact line protection switches exist which, in the case of a housing width of only one graduation unit, provide two switching contacts for the individual connecting lines, namely for two phase lines (compact line protection switch of type 1+1) or for one phase line and neutral conductor (compact line protection switch of type 1+n). Compact protection switching devices of this type are known in principle from publications DE 10 2004 034 859A1, EP 1 191 562 B1 or EP 1 473 750 A1.

A fault current protection switch is a protection device for ensuring protection against dangerous fault currents in electrical equipment. Such fault currents, also known as differential currents, occur when a live line portion is in electrical contact with ground. This is the case, for example, when a person touches a charged part of an electrical device: in this case, the current flows as a fault current through the body of the person concerned to the ground. In order to prevent such body currents, the fault current protection switch must quickly and safely separate the electrical device from the line network on all poles in the event of such fault currents. In general language usage, the terms "FI protection switch (abbreviated as FI switch)", "differential current protection switch (abbreviated as DI switch)", or RCD (Residual Current Protective Device, residual current protection device) may also be used equally in place of the term "fault current protection switch".

In order to detect such fault currents or differential currents, the current level in the line (e.g. phase line) leading to the consumer is compared with the current level in the line (e.g. neutral conductor) returning from the consumer by means of a so-called sum current transformer. The sum current transformer has a toroidal core through which primary conductors (outgoing and return lines) are routed. The core itself is wound with a secondary conductor or secondary winding. In the state without the fault current, the sum of the currents flowing to the consumers is equal to the sum of the currents flowing back from the consumers. If the currents are added vectorially, i.e. direction-dependent or signed, then in the absence of fault currents the signed sum of the currents in the derived and return lines is equal to zero: no induced current is induced in the secondary conductor. In contrast, in the case of a fault current or a differential current flowing to ground, the sum of the flowing-and-returning currents detected in the sum current transformer is not equal to zero. The current difference occurring here results in a voltage being induced at the secondary winding that is proportional to the current difference, so that a secondary current flows in the secondary winding. The secondary current serves as a fault current signal and, if a predetermined value is exceeded, causes the protection switching device to be triggered, and thus causes the corresponding protected circuit to be switched off by opening at least one switching contact of the protection switching device.

In a fault current protection switch, a distinction is also made between the type of equipment in which the grid voltage is dependent and the grid voltage is not dependent: the grid voltage dependent fault current protection switch has control electronics with a trigger that relies on the auxiliary voltage or the grid voltage to perform its function, whereas the grid voltage independent fault current protection switch does not require the auxiliary voltage or the grid voltage to perform the triggering function, but typically has a slightly larger sum current transformer to perform the grid voltage independent triggering, whereby a larger induced current can be generated in the secondary winding.

Arc protection switches or fire protection switches are used to detect disturbing arcs, which may occur, for example, at fault points of the electrical line (for example at loose cable terminals or due to cable breaks). If a disturbance arc occurs in series with the consumer, the normal operating current is generally not exceeded, since the operating current is limited through the consumer. For this reason, disturbing arcs are not detected by conventional overcurrent protection means, such as fuse protection means or line protection switches. In order to determine whether a disturbing arc is present, the voltage and current curves are measured over time by the fire protection switch and analyzed and evaluated with respect to the characteristic curve for the disturbing arc. In the (english) technical literature, such a protection device for detecting a disturbing arc is called "Arc Fault Detection Device (arc fault detection device)" (abbreviated to AFDD). In North America, the designation "Arc Fault Circuit Interrupter (arc fault interrupter)" (abbreviation: AFCI) is commonly used.

In addition, there are also device configurations that combine the functionality of a fault current protection switch with the functionality of a line protection switch: such a combined protection switching device is called FI/LS in german or RCBO (Residual current operated Circuit-Breaker with Overcurrent protection, residual current operated circuit breaker with overcurrent protection) in the english region. The combined device has the advantage over separate fault current protection switches and line protection switches that each circuit has its own fault current protection switch: typically the only fault current protection switch is for multiple circuits. If a fault current occurs, all protected circuits are therefore turned off. By using RCBO, only the respectively associated circuits are turned off.

Increasingly, more and more functionalities are being integrated into devices, i.e. combined protection switching devices are being developed, which cover the functional range of a plurality of individual devices: in addition to the FI/LS protection switching device described above, which combines the functional range of a conventional fault current protection switch (FI) with the functional range of a line protection switch (LS), other configurations exist in which, for example, the functionality of a fire protection switch is integrated into existing devices, such as MCB, RCD or RCBO/FILS.

In particular in multipole fault current protection switches (either as pure fault current protection switches or as combined device configurations, such as FI/LS or RCBO), and in combined protection switching devices, electronic functional components are used, which are necessary for realizing one or more functions of the respective protection switching device. Such electronic functional components must on the one hand be arranged, i.e. accommodated and held, in the hermetically sealed housing of the respective protective switching device and must also be supplied with electrical energy.

Disclosure of Invention

The object of the present invention is therefore to provide an alternative low-voltage protection switching device and an assembly method for a low-voltage protection switching device, which are distinguished by an improved component arrangement and by a simple assembly at a low production cost.

According to the invention, this technical problem is solved by a low-voltage protection switching device and an assembly method according to the invention. An advantageous embodiment of the low-voltage protection switching device and the assembly method according to the invention is the subject matter of the present invention.

The low-voltage protection switching device according to the invention has a housing of insulating material which itself has a front side, a fastening side opposite the front side, and narrow and wide sides connecting the front side and the fastening side, and has a switching contact which has a fixed contact arranged in a stationary manner in the housing and a moving contact which is movable relative to the fixed contact. Furthermore, the low-voltage protection switching device has an arc extinguishing chamber and an arc rail, a first end of which is guided below the arc extinguishing chamber and a second end of which protrudes in the direction of the switching contacts. Furthermore, the low-voltage protection switching device has a printed circuit board which is arranged between the arc extinguishing chamber and the fastening side, wherein the printed circuit board is electrically conductively connected to the arc rail via a voltage tap.

The available construction space in the interior of the insulating-material housing is very limited and must therefore be utilized efficiently. The printed circuit board for equipping the low-voltage protection switching device according to the invention with additional digital functions, such as communication functions or monitoring functions, is therefore arranged in a space-saving manner in the region of the fastening side of the insulating-material housing. For the voltage supply of the printed circuit board, the printed circuit board is spatially adjacent to the arc rail. Since the arc rail is always at the nominal voltage, the printed circuit board can be supplied with the required operating voltage by means of a voltage tap, i.e. via an electrically conductive connection to the arc rail.

In an advantageous embodiment of the low-voltage protection switching device, a second switching contact and a second arc rail associated with the second switching contact are arranged in the insulating-material housing, wherein the printed circuit board is electrically conductively connected to the second arc rail via a second voltage tap.

In a further advantageous embodiment of the low-voltage protection switching device, the insulating-material housing has a width of only one graduation unit.

In this way, multipole line protection switches, compact low-voltage protection switching devices having a width of only one graduation unit, and protection switching devices of a combination, for example of the FI/LS or RCBO type, can all be equipped with additional digital functions.

In a further advantageous embodiment of the low-voltage protection switching device, the insulating-material housing is composed of a plurality of modules arranged next to one another, wherein a switching contact and an arc rail associated with the switching contact are arranged in each of the plurality of modules. The printed circuit board extends across the plurality of modules and is electrically conductively connected to each of the arc tracks by way of its own voltage tap.

In a further advantageous embodiment of the low-voltage protection switching device, the plurality of modules of the insulating-material housing are essentially identical in structure.

By virtue of the modular construction of the insulating material housing, larger, different protective switching devices having a width of a plurality of graduation units can also be formed in a simple manner without the need to associate this with a large number of housing variants. The storage and logistics costs and thus the production costs can be significantly reduced.

In a further advantageous embodiment of the low-voltage protection switching device, the voltage tap is designed as a leaf spring tap.

The structural approach of the printed circuit board to the arc rail means that the voltage tap is designed as a leaf spring tap, which represents a structurally simple possibility and which can be assembled in a simple manner without additional tools. The manufacturing costs are thereby further reduced.

In a further advantageous embodiment of the low-voltage protection switching device, the leaf spring taps are assembled on the printed circuit board as components to which SMDs (Surface Mounted Devices, surface mount devices) can be attached.

By using a standard leaf spring tap which is mounted on the printed circuit board together with the remaining SMD components in the context of the SMD mounting of the printed circuit board, i.e. is positioned there and contacted there, an efficient production of the printed circuit board can be achieved and thus a further reduction in the production costs of the low-voltage protection switching device can be achieved.

In the assembly method according to the invention for a low-voltage protection switching device of the type described above, the printed circuit board is assembled by being inserted into an insulating material housing, whereby contact of the arc rail arranged in the insulating material housing with the printed circuit board is achieved.

The printed circuit board is thus inserted into the insulating material housing and is fixed with the housing cover, so that the printed circuit board is thereby accommodated and held in the insulating material housing on the one hand and, on the other hand, is brought into contact with the arc rail by this insertion, whereby the printed circuit board can be supplied with the required operating voltage. By avoiding additional working steps, assembly costs can be significantly reduced.

In an advantageous embodiment of the assembly method, in the upstream assembly step, the insulating-material housing is assembled from a plurality of modules, wherein the printed circuit board is inserted into the plurality of modules, whereby contact with a plurality of arc tracks of the plurality of modules takes place.

By selecting different modules, various protective switching devices can be formed without thereby negatively affecting the assembly of the printed circuit board.

Drawings

Embodiments of a low voltage protection switching device and method of assembly are described in more detail below with reference to the accompanying drawings. In the drawings:

fig. 1 shows a schematic view of a single pole insulating material housing for a low voltage protection switching device;

fig. 2 shows a schematic diagram of a multipole low-voltage protection switching device;

fig. 3 shows a schematic diagram of an open low-voltage protection switching device;

fig. 4 shows a schematic detail of a low-voltage protection switching device according to the invention.

In the different figures of the drawings, identical components are always provided with identical reference numerals. The description applies to all figures in which corresponding components may also be identified.

Detailed Description

Fig. 1 schematically shows a single-pole insulating material housing 10 for a low-voltage protection switching device 1 in a side view. The insulating material case 10 has a front side 11, a fixed side 12 opposite to the front side 11, and a narrow side 13 and a wide side 14 connecting the front side with the fixed

sides

11, 12. An actuating element 5 for manually actuating the low-voltage protection switching device 1 is arranged on the front side 11. At the opposite fastening side 12, the insulating-material housing 10 can be fastened at the top hat rail 9 by means of a fastening device suitable therefor.

Fig. 2 shows a schematic diagram of the multipole low-voltage protection switching device 1 in a perspective view. The low-voltage protection switching device 1 is formed by four modules 10-1, 10-2, 10-3, 10-4 arranged next to one another (i.e. wide-sided), each having a single-pole insulating-material housing 10 with a width B of one graduation unit TE, which corresponds to approximately 18mm. By means of a combination of two or three modules 10-1, 10-2, 10-3, 10-4, a two-pole or three-pole low-voltage protection switching device can also be formed accordingly.

Four external conductors (primary or neutral) are connected to the illustrated four pole low voltage protection switching device 1, wherein switching contacts for interrupting the respective external conductor are arranged, i.e. accommodated and held, in each module 10-1, 10-2, 10-3, 10-4. In addition to the functionality of a pure line protection switch for interrupting the current in the event of a short circuit or an electrical overload, a protection function for fault currents can also be integrated in the four-pole low-voltage protection switching device 1, so that a four-pole FI/LS or RCBO is formed by the combination of the four modules. Furthermore, other functional components, for example for implementing communication functions or monitoring functions, can also be integrated into the individual modules 10-1, 10-2, 10-3, 10-4.

Fig. 3 shows a schematic illustration of the low-voltage protection switching device 1 in a disconnected state, with the cover of the front broad side 14 omitted in order to make the interior of the insulating-material housing 10 visible. For interrupting the current flowing through the outer conductor, a switching contact is used, which has a fixed contact 2 arranged in a stationary manner in the insulating-material housing 10 and a moving contact 3 arranged in a moving manner in the insulating-material housing 10 by means of a moving contact carrier 4. The moving contact carrier 4 can be actuated by a switching mechanism (not shown) of the low-voltage protection switching device 1, and can be actuated manually, among other things, by an actuating element 5 arranged on the front side 11. Furthermore, the short-circuit triggering device 6 also acts on the switching mechanism in order to interrupt the current flowing through the switching contact in the event of a short circuit.

Below the short-circuit triggering device 6, an arc extinguishing chamber 20 is arranged in the insulating material housing 10, which chamber has a plurality of arc extinguishing plates 21 arranged parallel to one another at a distance from one another. Furthermore, an arc rail 30 is arranged in the insulating-material housing 10, the first end 31 of which is guided below the arc-extinguishing chamber 20 and the second end 32 of which protrudes as a free end into the switch contact region of the switch contact. The lower end of the arc extinguishing chamber 20 is thus directed in the direction of the fastening side 12. If the moving contact 3 is moved away from the fixed contact 2 by the moving contact carrier 4, an arc is generated at this point in time when current flows through the switching contact, which arc first burns between the fixed contact 2 and the moving contact 3. From the moving contact 3 at a distance from the fixed contact 2, the arc commutates to the free end 32, i.e. the arc foot on the moving contact side jumps to the free end 32 of the arc rail 30. The arc is guided through the guide rail 30 in the direction of the arc-extinguishing chamber 20, in which the arc is divided into partial arcs by the arc-extinguishing plates 21 and finally brought to extinction.

Fig. 4 shows a schematic detail of a low-voltage protection switching device 1 according to the invention, which has essentially the same structure as the low-voltage protection switching device shown in fig. 3. In the insulating material housing 10 of the low-voltage protection switching device 1, as described above, further functional components, for example for realizing a communication function or a monitoring function, can also be arranged. In order to supply the required operating voltage for the other functional components, a voltage tap, i.e. an electrically conductive connection to the charging member, is required. In the case of multipolar low-voltage protection switching devices, the voltage tapping is advantageously performed through all the external conductors (phase conductor and neutral conductor) in order to be able to determine, for example, the potential difference between the external conductors in a simple manner.

The voltage taps are advantageously arranged on the printed circuit board 40, since the space available for this is very limited in the interior of the insulating-material housing 10. In the example shown, the voltage tap is designed as a leaf spring tap 41, which can be assembled on the printed circuit board 40 as a standard component in the SMD assembly category of the printed circuit board. However, the use of the leaf spring taps 41 is not absolutely necessary in the sense of the present invention and is therefore understood to be merely exemplary; thus, other possibilities for implementing a suitable voltage tap are likewise included.

In the embodiment shown in fig. 4, the printed circuit board 40 is arranged, i.e. accommodated and held, in the insulating-material housing 10 below the arc-extinguishing chamber 20, i.e. between the arc-extinguishing chamber 20 and the fastening side 12. A housing cover 19 is provided for fixing and protecting the printed circuit board 40 from the environment, which housing cover is fastened at the fastening side 12 of the insulating-material housing 10 after assembly of the printed circuit board 40.

The spatial position of the printed circuit board 40 in the insulating-material housing 10 is very advantageous, since the first end 31 of the arc rail 30 is also located in this region. Since the arc rail 30 is permanently at the nominal voltage during operation of the low-voltage protection switching device 1, the voltage tapping and thus the voltage supply of the at least one further functional component can be carried out in a simple manner by the arc rail 30.

In particular in the case of multipole low-voltage protection switching devices, it can happen that a plurality of functional components, which are separate from one another in terms of construction and are arranged in the individual modules 10-1, 10-2, 10-3, 10-4, must be supplied with the required operating voltage. In this case, it is advantageous to design the printed circuit board 40 as a common voltage supply for the plurality of modules 10-1, 10-2, 10-3, 10-4, which extends over the plurality of modules 10-1, 10-2, 10-3, 10-4 forming the low-voltage protection switching device 1 in the region of the broad side 12 and takes the voltage at the plurality of arc rails 30 arranged in the respective module 10-1, 10-2, 10-3, 10-4 by means of a plurality of voltage taps 41 which are specifically associated with the respective arc rail 30. In this case, the printed circuit board 40 has a number of voltage taps 41, which corresponds to the number of poles or external conductors (phase conductors and neutral conductors) that can be connected to the low-voltage protection switching device 1.

The assembly method according to the invention for a low-voltage protection switching device 1 as described above is briefly described below: here, the printed circuit board 40 is fitted into the accommodation space formed in the insulating material case 10 and pushed with the case cover 19. The receiving space is dimensioned in this case such that the printed circuit board 40 is received and held in the insulating-material housing 10 by this insertion. Furthermore, the receiving space is arranged in the insulating-material housing 10 such that, by means of the insertion of the printed circuit board 40, contact of the printed circuit board 40 with the first end 31 of the arc rail 30 is already achieved. In this case, the contact is made by means of a voltage tap, which is preferably designed as a leaf spring tap 41.

In the case of a multipole low-voltage protection switching device 1, the individual modules 10-1, 10-2, 10-3, 10-4 forming the protection switching device 1 are first assembled "wide-side by wide-side" in an upstream assembly step, which takes place before the printed circuit board 40 is inserted into the receiving space of the cross-module, which is now formed by the plurality of modules 10-1, 10-2, 10-3, 10-4. With the installation of the printed circuit board 40 in the receiving space provided for this purpose, the plurality of arc tracks 30 are again contacted by voltage taps, which are arranged on the printed circuit board 40 and are associated specifically with the respective arc track 30, which voltage taps are advantageously in turn embodied as leaf spring taps 41.

List of reference numerals:

1 Low-voltage protection switching device

2 fixed contact

3 moving contact

4 motion contact carrier

5 operating element

6 short circuit trigger device

9 top hat type guide rail

10. Insulating material shell

10-1 Module

10-2 module

10-3 module

10-4 module

11 front side

12 fastening side

13 narrow sides

14 broad sides

19 housing cover

20 arc extinguishing chamber

21. Arc extinguishing plate

30. Arc guide rail

31 first end portion

32. Second end portion

40. Printed circuit board with improved heat dissipation

41 leaf spring tap

Width B

Claims

1. A low-voltage protection switching device (1) has

An insulating material housing (10) having a front side (11), a fastening side (12) opposite the front side, and narrow and wide sides (13, 14) connecting the front side and the fastening side (11, 12),

a switching contact having a fixed contact (2) arranged in a stationary manner in a housing (10) and a moving contact (3) which is movable relative to the fixed contact,

an arc extinguishing chamber (20),

an arc rail (30), a first end (31) of which is guided below the arc extinguishing chamber (20) and a second end (32) of which protrudes in the direction of the switch contact,

-a printed circuit board (40) arranged between the arc extinguishing chamber (20) and the fastening side (14), wherein the printed circuit board (40) is electrically conductively connected to the arc rail (30) by means of a voltage tap.

2. The low-voltage protection switching device (1) according to claim 1, wherein a second switching contact and a second arc rail (30) associated with the second switching contact are arranged in the insulating-material housing (10), wherein the printed circuit board (40) is electrically conductively connected to the second arc rail (30) by a second voltage tap.

3. Low-voltage protection switching device (1) according to any of the preceding claims, wherein the insulating-material housing (10) has a width of only one graduation unit (TE).

4. Low-voltage protection switching device (1) according to claim 1, wherein the insulating-material housing (10) consists of a plurality of modules (10-1, 10-2, 10-3, 10-4) arranged alongside one another, wherein a switching contact and an arc rail (30) associated with the switching contact are arranged in each of the plurality of modules (10-1, 10-2, 10-3, 10-4), wherein the printed circuit board (40) extends across the plurality of modules (10-1, 10-2, 10-3, 10-4) and is electrically conductively connected with each arc rail (30) by means of its own voltage tap, respectively.

5. The low voltage protection switching device (1) of claim 4 wherein the plurality of modules (10-1, 10-2, 10-3, 10-4) of the insulating material housing (10) are substantially structurally identical.

6. Low-voltage protection switching device (1) according to any of the preceding claims, wherein the voltage tap is designed as a leaf spring tap (41).

7. Low voltage protection switching device (1) according to claim 6, wherein the leaf spring tap (41) is assembled on the printed circuit board (40) as a SMD-capable component.

8. An assembly method for a low-voltage protection switching device (1) according to any one of claims 1 to 7, wherein a printed circuit board (40) is assembled by being encased in an insulating material housing (10), whereby contact of an arc rail (30) arranged in the insulating material housing (10) with the printed circuit board (40) is achieved.

9. The assembly method according to claim 8, wherein in the upstream assembly step the insulating material housing (10) is assembled from a plurality of modules (10-1, 10-2, 10-3, 10-4), wherein the printed circuit board (40) is encased in the plurality of modules (10-1, 10-2, 10-3, 10-4), whereby contact with a plurality of arc rails (30) of the plurality of modules (10-1, 10-2, 10-3, 10-4) is made.