Electrical device and electrical fuse system

Abstract

The utility model relates to an electrical device (1) and an electrical fuse system, the electrical device (1) comprising: an electrical element (2) comprising a body (2A) and a terminal (3); an electrical conductor (5) electrically connected to the terminal (3) by a fusible joint; an arc shield (6); at least one electrically conductive spring (7) and an electrically conductive connection element (8), the at least one electrically conductive spring (7) and the connection terminals of the electrically conductive connection element (8) being in electrical contact, the at least one electrically conductive spring (7) being pre-stressed and being configured to urge an arc shield (6) between the terminal (3) and the electrical conductor (5), the arc shield (6) being electrically conductive by urging the arc shield (6). The at least one electrically conductive spring (7) is electrically disconnected from the connection terminal (3) of the electrically conductive connection element (8).

Description

Technical Field

[0001] The invention relates to an electrical device, a fuse system comprising the device, a process for triggering the fuse system and an assembly method. Background Art

[0002] Standard thermal protection varistors typically contain a metal oxide varistor (MOV) material, a thermal disconnect system and a connected indicator system.

[0003] Varistors are voltage-dependent components that overheat in the event of a significant electrical surge in the main circuit.

[0004] The thermal disconnect system is a mechanical movement and heat triggering system that is used to ensure that the main circuit is completely disconnected in the event that the varistor overheats due to an inrush event.

[0005] The indicator system is configured to provide an electrical signal of a disconnected state. It must be isolated from the high voltage main circuit, which makes the design and assembly of the thermal protection varistor of the prior art very complicated and expensive, as disclosed in, for example, published documents US6636403 B2, EP 2511915 A1, US 9496112 B2, US 6430019B1, US11482354 B2 and CN106711983 A. Utility Model Content

[0006] It is therefore the object of the present invention to provide an improved or simplified device, fuse system and assembly solution.

[0007] The invention provides an electrical device, which may be a thermal protection resistor comprising at least an electrical element, wherein the electrical element comprises a body and a terminal.

[0008] The body may comprise or may be a varistor.The varistor may comprise or may consist of a metal oxide varistor (MOV) material such as, for example, ZnO.

[0009] The body may have any suitable shape, such as a plate-like shape, a cylindrical shape, or a rectangular parallelepiped shape.

[0010] The terminal may be an electrode or another metallization on the surface of the body. The terminal comprises a conductive material. The terminal may comprise a metal or a metal alloy. Preferably, a second terminal may be applied on another surface of the body. Two terminals may be applied on two opposite surfaces of the body in order to apply a voltage to the body.

[0011] The electrical device further comprises an electrical conductor electrically connected to the terminal by a fusible joint, such as a solder joint. The electrical conductor may be an electrically conductive metal wire such as a copper wire or the like such as a leaf spring.

[0012] The electrical device further comprises an arc shield and two conductive springs, wherein, at least in a normal operation state, connecting terminals of the two conductive springs are in electrical contact.

[0013] Alternatively, as described herein, the electrical device may also comprise only one conductive spring which can be prestressed and a further conductive connection element which is different from the spring, instead of the second spring. The alternative conductive connection element must be inserted separately.

[0014] All other embodiments can also be designed with other electrically conductive connecting elements than springs.

[0015] Preferably, at least one of the springs or both of the springs are in direct mechanical contact with the arc shield.Preferably, the electrical contact between the two springs is forced by the arc shield holding the springs in a predetermined position.

[0016] At least one of the springs or both of the springs may be mechanically pressed against the arc shield.

[0017] If only one spring is pressed against the arc shield, the other spring may abut against a structural element of the housing of the electrical device.

[0018] The cross section of the spring can have any shape, such as rectangular or circular. The outer shape of the spring can be any shape, such as U-shape or S-shape.

[0019] The electrical device may include a housing, which is preferably electrically insulating and encapsulates all other parts of the electrical device. The housing may be or include a casting or a molding, and may include or consist of a non-conductive material such as a plastic material. The casting may be cast around other elements of the electrical device, preferably at least around the electrical components. Other structural elements besides the electrical components may be covered by an additional cover, which may be another part of the housing.

[0020] According to the invention, at least one of the two conductive springs is prestressed and configured to push the arc shield between the terminal and the electrical conductor when the fusible joint becomes loose and the electrical conductor is electrically disconnected from the terminal. The arc shield is then pushed to the previous position of the fusible joint, which becomes loose due to melting at high temperature.

[0021] The arc shield is positioned accordingly and is under prestress due to the application of prestressed springs on the arc shield.

[0022] According to the invention, by pushing the arc shield, the connection terminals of the two conductive springs are electrically disconnected, preferably because at least one of the springs is relaxed by pushing the arc shield between the terminal and the electrical conductor, while the other spring is, for example, maintained at a defined position or relaxed to another position compared to the at least one spring.

[0023] With the disclosed configuration, the spring required to prestress the arc shield is also adapted to provide a closed circuit that is opened when the fusible joint loosens and melts.

[0024] In particular, according to an embodiment, the two conductive springs can be terminal wires of an indicator circuit, so-called indicator pins, wherein the indicator circuit is configured to indicate electrical contact between the electrical conductor and the terminal, wherein the indicator circuit is configured to close when the electrical conductor and the terminal are electrically connected.

[0025] On the other hand, when the fusible joint becomes loose, the indicator circuit is opened due to the spring releasing contact, and the electrical conductor and the terminal are electrically disconnected.

[0026] By means of the disclosed configuration, the spring required for prestressing the arc shield is also adapted to provide an indicator circuit configured to indicate electrical contact between the electrical conductor and the terminal, wherein the indicator circuit is advantageously separate from the main circuit comprising the electrical component, the terminal and the electrical conductor. Thus, no additional galvanic isolation is required between the two circuits.

[0027] Furthermore, by using a spring, the indicator circuit does not require other additional structural elements of the electrical device which would not be required without the indicator circuit.

[0028] In other words, the spring has two functions. First, to provide a mechanical force to trigger the disconnection of the terminal and the electrical conductor. Second, to provide a signal for the indicator circuit, which is isolated from the main circuit with a higher voltage.

[0029] Therefore, instrumentation can be minimized and the assembly process can be simplified.

[0030] In other words, in the event of overheating of the electrical device, in particular the electrical component and its body, the at least one spring is used to force the arc shield to move out when the fusible joint is broken. At the same time, the contact between the springs is broken and can thus be used as an electrical indicator for an overheating event. To this end, a signaling device, such as an LED, can be arranged in the circuit with the spring.

[0031] This means that the spring has two functions: providing a mechanical force to trigger a thermal disconnection between the terminal and the electrical conductor and providing a signal for an indicator circuit that is isolated from the high voltage main circuit.

[0032] The arc shield provides protection from arcing events and ensures electrical disconnection between the terminal and the electrical conductor in the event of an overheating event when the fusible joint becomes loose.

[0033] According to an embodiment, after the arc shield is pushed, the two conductive springs are configured to disconnect the electrical connection through the space gap.

[0034] This configuration is beneficial in ensuring electrical isolation between the springs, thereby generating or terminating an indication signal.

[0035] According to an embodiment, both conductive springs are pre-stressed and configured to urge the arc shield between the terminals.

[0036] This configuration is advantageous because the prestress can be maximized.Since the two springs are configured to move to different positions when relaxed, a spatial gap is provided.

[0037] According to an embodiment, the two conductive springs comprise a conductive metal, preferably at least one of copper and a copper alloy, which are highly conductive materials.

[0038] According to an embodiment, the body of the electrical component is a varistor, preferably a metal oxide varistor. By the disclosed arrangement and mechanism, the varistor is advantageously protected from overheating events.

[0039] The invention also relates to an electrical fuse system comprising an electrical device according to any one of the embodiments described above.

[0040] In an electrical fuse system, a fusible joint between an electrical conductor and a terminal is configured to loosen when the electrical component is heated because the fusible joint includes or consists of a low temperature melting metal, such as a solder material such as solder.

[0041] The arc shield is configured to be pushed between the electrical conductor and the terminal by at least one of the two conductive springs when the fusible joint becomes loose. Therefore, the arc shield can remove the residue of the fusible joint.

[0042] The terminals and electrical conductors are then electrically disconnected, and further current flow and further heat generation through the electrical component is prevented.

[0043] At the same time, the two conductive springs are then disconnected electrically by the relaxation of at least one spring when the arc shield moves. Therefore, the disconnection of the spring provides a signal for indicating the triggering of the fuse.

[0044] The invention also relates to the process of triggering a fuse and indicating the triggering of a fuse as disclosed above.

[0045] The invention also relates to a process of triggering an electrical fuse system by electrical disconnection between two conductive springs and indicating the triggering of the electrical fuse system.

[0046] The signaling device may signal an electrical disconnection between the two conductive springs. The signaling device may be an LED. The device may signal an electrical disconnection by cutting off.

[0047] The invention also relates to an assembly method for an electrical device, the method comprising the following steps:

[0048] - providing an electrical component comprising a body and terminals,

[0049] - connecting the terminal and the electrical conductor by means of a fusible joint material,

[0050] - applying an arc shield adjacent to the electrical conductor and two conductive springs,

[0051] At least one of the two conductive springs is prestressed, wherein the arc shield is pressed against the electrical conductor by the at least one prestressed conductive spring, and wherein the connecting terminals of the two conductive springs are electrically connected.

[0052] According to an embodiment, in the step of applying two conductive springs, a spring double element is applied, wherein the two springs are constructed in one single component and wherein the spring double element is divided into two single conductive springs after application, for example by cutting it into two parts.

[0053] Other configurations may be based on any of the embodiments described above.

[0054] In the following, the invention is described exemplarily by the accompanying drawings. The invention is not limited by the examples. The details of the examples may be different from the manner described below and combined in any suitable manner. The detailed steps or embodiments of the following examples may be combined with the steps or embodiments of the above-mentioned electrical device or assembly method. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] The accompanying drawings show as follows:

[0056] Figure 1 : A perspective view of a first embodiment of an electrical device without an insulating cover. For better illustration, the insulating cover is omitted. The figure shows the device in a manufactured state before the spring is separated.

[0057] Figure 2: A perspective view of a first embodiment of an electrical device without an insulating cover. For better illustration, the insulating cover is omitted. The figure shows the device in an operating state after the spring is separated but before the fuse is triggered.

[0058] Figure 3 : corresponds to Figure 2 Side view of.

[0059] Figure 4 : A perspective view of a first embodiment of an electrical device without an insulating cover. For better illustration, the insulating cover is omitted. The figure shows the device in a state when the fuse is triggered.

[0060] Figure 5 : corresponds to Figure 4 Side view of.

[0061] Figure 6 : The first step of the manufacturing method of the second embodiment for manufacturing an electrical device is to assemble an electrical component including a body and terminals.

[0062] Figure 7 : The second step of the manufacturing method of the second embodiment for manufacturing an electrical device: Encapsulating the electrical component.

[0063] Figure 8 : The third step of the manufacturing method of the second embodiment for manufacturing an electrical device is to assemble the arc shield, the spring and the electrical conductor.

[0064] Fig. 9 : The fourth step of the manufacturing method of the second embodiment for manufacturing an electrical device: The electrical conductor is contacted to the terminal by solder.

[0065] Fig.10 : The fifth step of the manufacturing method of the second embodiment for manufacturing an electrical device. The housing of the electrical device is closed by a cover.

[0066] Fig.11 : Fifth step of the production method of the second embodiment for producing an electrical device: The double spring element is separated into two springs.

[0067] Fig.12 : A perspective view of a second embodiment of an electrical device without an insulating cover. For better illustration, the insulating cover is omitted. The figure shows the device in an operating state after the spring is separated but before the fuse is triggered.

[0068] Fig.13 : A perspective view of a second embodiment of an electrical device without an insulating cover. For better illustration, the insulating cover is omitted. The figure shows the device in a state when the fuse is triggered. DETAILED DESCRIPTION

[0069] In particular, Figure 1 The first embodiment relates to an electric device 1 .

[0070] The electrical device comprises an electrical component 2 having a first terminal 3 and a second terminal 4. The terminals are configured as metal terminals.

[0071] Only the terminals are freely exposed. The rest of the electrical component 2, in particular the varistor body, is encapsulated in a housing 9 comprising an insulating casting, such as a plastic casting or a polymer casting.

[0072] Other elements may be covered by an additional cover (not shown) so as to cover and protect all elements of the electrical device 1. The housing 9 and the cover form the casing of the device 1.

[0073] The first terminal 3 is in electrical contact with the electrical conductor 5. The contact is preferably configured as a fusible solder joint. At a temperature below the melting temperature of the fusible solder joint, the solder joint is solid and the first terminal 3 and the conductor 5 are mechanically fixed together by the solder joint.

[0074] The electric conductor 5 in this example is configured as a spring conductor in the shape of a leaf spring.

[0075] Adjacent to the elastic portion of the spring conductor 5, the arc shield 6 abuts to the spring conductor. The arc shield 6 is pressed against the spring conductor 5 by a spring 7. The spring 7 is electrically conductive.

[0076] During manufacture, the spring 7 is inserted as a double spring element which is subsequently separated into the spring 7 and the additional spring 8. This method simplifies the assembly process.

[0077] In an alternative embodiment, another electrically conductive connection element 8 other than a spring may be used instead of the second spring 8. The alternative electrically conductive connection element 8 has to be inserted separately.

[0078] Figure 2 The springs 7 and 8 after separation are shown. The springs are configured as leaf springs. After separation, the two springs 7 and 8 can be used as terminals of an electrical circuit for indicating the state of the fuse system.

[0079] If you can Figure 1 or Figure 2 As can be seen in FIG. 1 , the springs 7 and 8 are inserted into specially designed retaining hooks of the housing, in particular the housing 9 .

[0080] Therein, the spring 8 is prestressed and held by the holding hook, and the spring 7 is prestressed by the arc shield 6. When the arc shield 6 moves toward the fusible joint, the spring 7 relaxes.

[0081] exist Figure 2In the operating state shown in , both springs 7 and 8 are prestressed and abut each other. Therefore, a closed circuit can be formed by connecting the two springs to an external conductor. Current can flow from spring 7 to spring 8, and an electrical signal can be generated.

[0082] In the event of an overheating event in the electrical component, in particular the varistor body, the fusible joint melts and the arc shield 6 is pressed between the first terminal 3 and the electrical conductor 5 by the spring 7, as shown in FIG. Figure 4 As shown in the figure.

[0083] Thus, electrical contact and current flow between the terminal 3 and the electrical conductor 5 are blocked, and heat generation in the varistor body can be further prevented. The fuse has been triggered.

[0084] Since the spring 8 is held in the original position by the retaining hooks of the housing, the contact between the two springs 7 and 8 is also interrupted by the spatial distance between the relaxed spring 7 and the spring 8 which has moved toward the arc shield 6 .

[0085] As a result, the current flow in the indicator circuit ceases, thereby indicating an overtemperature event in the main circuit.

[0086] Figure 3 Shown with Figure 2 The side view corresponding to the stereogram.

[0087] exist Figure 3 In FIG. 1 , a cover 10 is shown. Through a window 11 in the cover, the electrical conductor 5 is visible (operating state).

[0088] After the fuse has been triggered and the arc shield 6 has moved, the arc shield 6 is visible through the window 11, thereby indicating the changed state. Figure 5 A side view of the device in the triggered state is also shown in FIG. , which shows the window 11 .

[0089] exist Figures 6 to 13 In the second embodiment, the second embodiment is described in detail. Figures 6 to 11 The manufacturing process is shown, and Fig.12 and Fig.13 Again, the device and Figure 2 and Figure 4 Operations and trigger states similar to those of the first embodiment.

[0090] Figure 6 The first step of the manufacturing process is shown. An electrical component 2 is assembled comprising a body 2A and terminals 3 and 4. The terminals 3 and 4 comprise or consist of a conductive metal such as copper, nickel, silver, gold, etc. or a metal alloy.

[0091] The first terminal is configured to be contacted by the electrical conductor 5 .

[0092] The second terminal has been provided with a conductor portion 4A for external contact.

[0093] In the second step of the manufacturing process of the electrical device, the electrical components are encapsulated in a polymer or plastic casting or housing 9. Polymers or plastics are electrically insulating.

[0094] The conductor portion 4A of the second terminal and the contact portion 3A of the first terminal are exposed for electrical contact.

[0095] Special retaining hooks 12 are built into the outer shape of the housing 9 for accommodating further elements such as the springs 7 and 8 , the arc shield 6 and the electrical conductor 5 .

[0096] exist Figure 8 , the third step of the manufacturing process of the electrical device is shown. The arc shield 6 , the springs 7 and 8 and the electrical conductor 5 are assembled with the encapsulated electrical component 2 to construct the electrical device 1 .

[0097] The arc shield 6 , the springs 7 and 8 and the electrical conductor 5 can be arranged and fixed by means of the retaining hooks 12 .

[0098] The arc shield 6 of the illustrated embodiment is pivoted by being fixed about the axis of the housing 9 .

[0099] As in Figure 8 or Fig. 9 As shown in FIG. 3 , two springs 7 and 8 abut against the arc shield 6. At least the spring 7 pushes the arc shield 6 into position in which it covers the contact portion 3A.

[0100] For operation of the device 1, the electrical conductor 5 is in contact with the contact portion 3A of the terminal 3 by means of solder, which forms a fusible solder joint, as in Fig. 9 As shown in .

[0101] Likewise, the electrical conductor 5 is formed as a leaf spring. The arc shield 6 is pivoted into a prestressed state, in which the springs 7 and 8 push the arc shield 6 against the electrical conductor 5 and towards the contact portion 3A.

[0102] Subsequently, the housing of the electrical device 1 is closed by a cover 10 placed on the housing 9, thereby covering all the components of the device 1. Only the electrical conductors 5 and the conductor parts 4A for external electrical contact of the electrical components in the electrical main circuit (operating circuit) are exposed; and the springs 7 and 8 for external electrical contact and connection of, for example, signaling devices are used to establish a separate indicator circuit.

[0103] In particular, springs 7 and 8 can be inserted again as a single spring dual element, which is then Fig.11 In the subsequent step shown in , it is separated into two single springs.

[0104] Fig.12 A perspective view of a second embodiment of an electrical device without an insulating cover is again shown. For better illustration, only the insulating cover is omitted. The figure shows the device in an operating state after the spring is separated but before the fuse is triggered.

[0105] When the body 2A of the electrical component 2, such as the varistor body 2A, and the adjacent terminals 3, 4 are overheated, the solder material melts and the fusible solder joint becomes loose. During this time, the springs 7 and 8 push the arc shield 6 between the electrical conductor 5 and the first terminal 3. The arc shield 6 moves by pivoting.

[0106] After the arc shield 6 has been pivoted, the springs 7 and 8 that were in electrical contact before the pivoting are no longer in electrical contact, since the connecting terminals are prestressed differently and the movement of the springs, in particular the connecting terminals, during relaxation is different.

[0107] Fig.13 The device is shown in a state when the fuse is triggered. The indicator circuit formed by the spring and the external conductor is also interrupted. Therefore, the interruption of the indicator circuit indicates the interruption of the main circuit.

[0108] Reference numerals

[0109] 1 Electrical installation

[0110] 2Electrical components

[0111] 2A electrical component body

[0112] 3First terminal

[0113] 3A contact part

[0114] 4 Second terminal

[0115] 4A conductor part

[0116] 5 Electrical Conductors

[0117] 6Arc shield

[0118] 7 Spring

[0119] 8 Conductive connecting element, such as a second spring

[0120] 9 Shell

[0121] 10 covers

[0122] 11. Window

[0123] 12Holding hook

Claims

1. An electrical device (1), characterized in that: The electrical device (1) comprises: An electrical component (2), the electrical component (2) comprising a body (2A) and a terminal (3), an electrical conductor (5) electrically connected to the terminal (3) via a fusible joint, An arc shield (6), at least one conductive spring (7) and a conductive connecting element (8), wherein the at least one conductive spring (7) and the connecting terminals of the conductive connecting element (8) are in electrical contact, wherein the at least one conductive spring (7) is prestressed and configured to push the arc shield (6) between the terminal (3) and the electrical conductor (5) when the fusible joint becomes loose and the electrical conductor (5) and the terminal (3) are electrically disconnected, Wherein, by pushing the arc shield (6), the at least one conductive spring (7) and the connecting terminal of the conductive connecting element (8) are electrically disconnected.

2. The electrical device (1) according to claim 1, characterized in that The at least one conductive spring (7) and the conductive connecting element (8) are terminal lines of an indicator circuit, the indicator circuit being configured to indicate electrical contact between the electrical conductor (5) and the terminal (3), wherein the indicator circuit is configured to be closed when the electrical conductor (5) and the terminal (3) are electrically connected.

3. The electrical device (1) according to claim 1 or 2, characterized in that: After the arc shield (6) is pushed, the at least one conductive spring (7) and the conductive connecting element (8) are configured to disconnect the electrical connection through a spatial gap.

4. The electrical device (1) according to claim 1 or 2, characterized in that: The conductive connecting element (8) is configured as a second conductive spring, and the two conductive springs are prestressed and configured to push the arc shield (6) between the terminals (3).

5. The electrical device (1) according to claim 1 or 2, characterized in that: The at least one conductive spring (7) and / or the conductive connecting element (8) comprises at least one of copper and a copper alloy.

6. The electrical device (1) according to claim 1 or 2, characterized in that: The body (2A) of the electrical component (2) is a varistor.

7. The electrical device (1) according to claim 6, characterized in that The varistor is a metal oxide varistor.

8. An electric fuse system, characterized in that: The electrical fuse system comprises an electrical device (1) according to claim 1 or 2.

9. The electrical fuse system according to claim 8, It is characterized in that The fusible joint between the electrical conductor (5) and the terminal (3) is configured to loosen when the electrical component (2) is heated. wherein the arc shield (6) is configured to be pushed between the electrical conductor (5) and the terminal (3) by the at least one conductive spring (7) when the fusible joint becomes loose, and When the arc shield (6) is pushed between the electrical conductor (5) and the terminal (3), the at least one conductive spring (7) and the conductive connecting element (8) are electrically disconnected.

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