Circuit protection device

Abstract

A circuit protection device is disclosed, including: a first connection terminal and a second connection terminal, a main current path and an auxiliary current path connected in parallel between a first node and the second connection terminal, a main switch connected between the first node and the main current path, and an auxiliary switch connected between the first node and the auxiliary current path, an opening mechanism having a first state in which the opening mechanism is configured to store energy and a second state, wherein, when being released from the first state, the opening mechanism is configured to move from the first state to the second state using the stored energy, to open the auxiliary switch, a trip device configured to engage the opening mechanism so as to release the opening mechanism from the first state, and a control device configured to detect a fault event and, if the fault event is detected, control the trip device to release the opening mechanism from the first state.

Description

[0001] Circuit Protection Device

[0002] The present disclosure relates to a circuit protection device, and in particular to a circuit protection device with an improved protection of electrical loads against overload and short circuits.

[0003] Technical Background

[0004] The purpose of circuit protection devices is to protect electrical circuits and loads against overload and short circuits. The circuit protection device may also be referred to as circuit breaker.

[0005] Circuit breakers are essential components in electrical systems and are used to protect electrical loads against overloads and short circuits. They function by interrupting the flow of electrical current when a fault event, such as an overload or short circuit, is detected, thereby preventing potential damage to the electrical loads and ensuring operational safety. Circuit breakers may monitor the current flowing through an electrical circuit. When the current exceeds the breaker’s nominal current for a duration longer than a predetermined value, the breaker trips, interrupting the current flow and protecting the circuit from damage. A short circuit causes a sudden surge in current. Circuit breakers detect this rapid increase and trip almost instantaneously to prevent damage and potential fire hazards. Circuit breakers are widely used in residential, industrial and automotive applications. So, damages to power lines and an electrical load can be avoided and safety regulations can be met.

[0006] With conventional circuit protection devices, there is a problem that a fuse is also blown when an overload occurs.

[0007] EP 3 248 204 Bl discloses a circuit breaker having two parallel current paths each with a contact point which, as the main and secondary current paths, are connected, via a contact device, in series with a coil of a magnetic trip. In the event of a fault, the armature opens the contact point of the main current path which is formed exclusively only by the series circuit of the contact device with the coil. To prevent the formation of an arc when the electric circuit is interrupted in the event of a fault and therefore also largely prevents contacts from burning away, an interrupter and trip insert is arranged in the secondary current path, which, in the event of a short circuit, interrupts the secondary current path and trips a switching lock to open and secure the contact device. With the known conventional circuit protection devices, there is a problem that the protection against overloads is slow. Furthermore, conventional circuit protection devices have high power dissipation during normal operation and occupy a large volume.

[0008] Summary of the Invention

[0009] It is an object of the present disclosure to provide an improved circuit protection device.

[0010] In particular, it is an object of the present disclosure to provide a circuit protection device which keeps a short circuit fuse intact when interrupting the circuit due to an overload.

[0011] Furthermore, it is an object of the present disclosure to provide a circuit protection device which interrupts the circuit in an effective and fast way.

[0012] Moreover, it is an object of the present disclosure to provide a circuit protection device which has a low power dissipation during normal operation and has a compact design.

[0013] Furthermore, it is an object of the present disclosure to provide a compact circuit protection device.

[0014] Further objects of the present disclosure will become apparent when studying the description, the claims and the drawings.

[0015] At least one of these objects is solved by the subject-matter of the independent claim. Advantageous embodiments and refinements are defined by the dependent claims.

[0016] The present disclosure is based on the finding that, in the case of a fault event, such as an overload, the overload current may be quickly interrupted when an opening mechanism is used that has a first state in which the opening mechanism comprises stored energy and / or stores energy, for example mechanic energy. Hence, the stored energy can be directly used to quickly release and switch the opening mechanism from the first state to a second state when the fault event is detected, so as to open a switch in an auxiliary current path and interrupt the current.

[0017] According to an aspect of the present disclosure, a circuit protection device includes a first connection terminal and a second connection terminal, a main current path and an auxiliary current path connected in parallel between a first node of the circuit protection device and the second connection terminal, a main switch connected between the first node and the main current path, and an auxiliary switch connected between the first node and the auxiliary current path. The main switch may be configured to open the main current path so as to interrupt the main current path and the current on the main current path. The auxiliary switch may be configured to open the auxiliary current path so as to interrupt the auxiliary current path and the current on the auxiliary current path.

[0018] The circuit protection device further includes an opening mechanism having a first state in which the opening mechanism is configured to store energy and / or comprises stored energy and a second state, wherein, in particular when being released from the first state, the opening mechanism is configured to move from the first state to the second state using the stored energy to open the auxiliary switch. The opening mechanism may be configured to automatically move from the first state to the second state when being released from the first state. The opening mechanism may be configured, while or by moving from the first state to the second state, to open the auxiliary switch. The opening mechanism may be configured to move from the first state to the second state immediately after being released from the first state.

[0019] The circuit protection device further includes a trip device configured to engage the opening mechanism so as to release the opening mechanism from the first state.

[0020] Furthermore, the circuit protection device may further include a control device configured, in the case of a fault event, to engage the trip device to release the opening mechanism from the first state. The control device may be configured to detect the fault event and, if the fault event is detected, engage the trip device to release the opening mechanism from the first state.

[0021] By providing the opening mechanism, the energy stored by the opening mechanism (in its first state) can be used to immediately and directly move the opening mechanism to interrupt the current in case of a fault event. Thereby, a switching time, also referred to as reaction time, of the circuit protection device is greatly reduced. Furthermore, it is ensured that the current is effectively and safely interrupted.

[0022] Furthermore, by providing an auxiliary switch in the auxiliary current path to interrupt the current when the fault case occurs, the current is interrupted without blowing a short circuit fuse, which may be arranged in the auxiliary current path, so that the fuse may be maintained in an intact state if the fault case is merely an overload, but not a short circuit.

[0023] The first node is a junction of an electrical circuit of the circuit protection device. The first and second connection terminals may also be a junction of the electrical circuit or may be connected to a junction. A current path may be an electrical connection between two junctions of the electrical circuit. A current path may include elements such as switches, coils, fuses, etc.

[0024] “Opening a switch” or an “opened switch” may mean that an opening angle or opening distance between a contact of the switch and a contact of the circuit in which the switch is arranged is sufficiently large that a current flowing over the switch is interrupted and / or that no current can flow over the switch.

[0025] A “Closing a switch” or a “closed switch” means that corresponding contacts of the switch and the circuit touch each other so that current can (again) flow via the switch.

[0026] The circuit protection device may be connected to an electrical load and may protect the load against overload and short circuits. The electrical load may be a DC load or an AC load. The fault case may include an overload or a short circuit. The circuit protection device may be connected in series to the load. The load may be connected to the first connection terminal or the second connection terminal of the circuit protection device.

[0027] During normal operation, i.e. when no fault event has occurred, the main switch may be closed, and the auxiliary switch may be closed. Hence, a current flows between the first connection terminal and the second connection terminal, wherein a main part of this current flows via the main current path including the main switch. Only a substantially smaller part of this current flows via the auxiliary current path.

[0028] According to a further aspect of the present disclosure, a system comprises a circuit protection device according to aspects and embodiments of the present disclosure and an electrical load connected in series to the circuit protection device via the first connection terminal or the second connection terminal. The system may be part of a building or may be part of an electric vehicle to meet safety regulations.

[0029] The circuit protection device according to embodiments of the present disclosure may also be referred to as circuit breaker.

[0030] Aspects and embodiments of the present disclosure may include one or several of the following optional features:

[0031] The trip device may further be configured to (also) open the main switch when being engaged, for example by the control device. Alternatively, or additionally, the opening mechanism may be configured to open the main switch when it is released from its first state and moves to its second state. Alternatively, or additionally, the trip device may be further configured to, when being engaged, engage the opening mechanism so as to open the main switch. Engaging the trip device may be defined as an element of the trip device being moved from a first position to a second position.

[0032] The circuit protection device may be configured such that, in the fault event, the main switch is opened before, such as prior, the auxiliary switch is opened. This has the advantage that the current via the main current path is interrupted without an arc because the current can still easily flow via the auxiliary current path. The movement of the element of the trip device may first open the main switch and then engage the opening mechanism to open the auxiliary switch.

[0033] The opening mechanism may comprise an actuator and a storage device. The storage device may have a first state and a second state. The storage device may be configured to store energy, such as mechanical energy, in the first state. The storage device may be configured to, when being released from the first state, move to the second state and, using the stored energy, to exert a force on the actuator to move the actuator from a first position to a second position. The storage device may be configured to, when being released from the first state, automatically move to the second state. The actuator may be configured to open the auxiliary switch while moving from the first position to the second position. The storage device may push the actuator from the first position into the second position.

[0034] The first position of the actuator may correspond to the storage device being in the first state, and the second position of the actuator may correspond to the storage device being in the second state. The first state of the opening mechanism may correspond to the actuator being in the first position and the storage device being in the first state, and the second state of the opening mechanism may correspond to the actuator being in the second position and the storage device being in the second state.

[0035] In the second state, the storage device may also exert a force on the actuator so as to maintain the actuator in the second position. Hence, the opening mechanism is configured to maintain the auxiliary switch open in the second state. The opening mechanism may also maintain the main switch open in the second state. This has the advantage that the main current path and the auxiliary current path cannot be closed again without external interaction from an operator after the fault event has occurred. This increases the operational safety of the circuit protection device because the operator has to manually shut the switches, and, hence, is made aware that the fault event has occurred. The opening mechanism may further comprise a release device. The release device may be further configured to release the actuator from the first position so as to also release the storage device from the first state. The trip device may be configured to engage the release device to release the actuator from the first position and / or release the storage device from the first state. The release device may be configured to hold the actuator in the first position and / or hold the storage device in the first state. The actuator, being hold by the release device in the first position, may hold the storage device in the first state. Hence, the release device may be configured to hold the storage device in the first state via the actuator. Hence, the storage device may already exert a force to the actuator while being in the first position. Correspondingly, the release device may exert a counterforce on the actuator while the actuator is in the first position. Thereby, moving the actuator from the first position to the second position may happen very quickly, meaning within a comparably short time, when the fault case occurs.

[0036] The actuator may be mechanically engaged with the main switch and the auxiliary switch. The actuator may include a main contact carrier configured to open the main switch and / or an auxiliary contact carrier configured to open the auxiliary switch. A first position of the auxiliary contact carrier may correspond to the first position of the actuator, and a second position of the auxiliary contact carrier may correspond to the second position of the actuator. The auxiliary contact carrier being in the first position may correspond to the actuator being in the first position, and the auxiliary contact carrier being in the second position may correspond to the actuator being in the second position. The storage device may be constituted by or may include a spring. The first state of the storage device may correspond to the spring being compressed. The second state of the storage device may correspond to the spring being at least partially decompressed from the first state. The spring may be configured to push the actuator, in particular the auxiliary contact carrier, from the first position to the second position when being decompressed.

[0037] The circuit protection device may further comprise an activation mechanism, such as an ON- button, configured to being operated by an operator. The activation mechanism may be configured such that when operated, the activation mechanism moves the actuator from the second position to the first position and engages the release device to hold the actuator in the first position, and correspondingly moves the storage device from the second state into the first state. Hence, the activation mechanism allows for resetting the circuit protection device into normal operation after a fault event has occurred. The circuit protection device may further comprise a deactivation mechanism, such as an OFF- button, configured to being operated by an operator. The deactivation mechanism may be configured, such that when operated, the deactivation mechanism engages the release mechanism so as to release the actuator from the first position and / or release the storage device from the first state. Consequently, the main switch and the auxiliary switch may be opened when the deactivation mechanism is operated. Hence, the deactivation mechanism allows for manually interrupting the current through the circuit protection device.

[0038] The trip mechanism may be a magnetic trip mechanism. The trip mechanism may include one or more solenoids and / or may include one or more coils. The one or more coils may be wound around a common armature. The armature may be referred to as a rod.

[0039] The trip mechanism may include an armature and an overload coil wound around the armature. The overload coil may be referred to as first coil.

[0040] Alternatively, or additionally, the opening mechanism and / or the storage device may be configured to store chemical energy. The circuit protection device and / or the opening mechanism and / or the trip mechanism may be or may comprise a pyro switch. The armature of the solenoid may be included in the pyro switch, or an element of the pyro switch may take the function of the armature.

[0041] The control device may be an analog control device or may be a digital control device. The control device may include a sensor, in particular a current sensor. The control device may also include a control unit, such as a microprocessor.

[0042] The control device may be configured, in case the fault event is an overload, to energize the overload coil so as to move the armature by the magnetic force of the overload coil. Energizing the overload coil means supplying the overload coil with electrical current. The armature may be moved from a first position to a second position. Moving the armature from the first position to a second position may release the opening mechanism from the first state, and may specifically engage the release device to release the actuator from the first position so as to also release the storage device from the first state.

[0043] The control device may be configured, in case the fault event is the overload, to connect the overload coil between the first connection terminal and the second connection terminal so as to energize the overload coil. The control device may comprise a trip element. The trip element may be a thermal trip element. Most preferably the trip element may be constituted by or include at least one bimetal or thermobimetal element. Furthermore, the control device may include a trip switch connected in series with the overload coil between the first connection terminal and the second connection terminal. When the overload occurs, the bimetal element heats up and bends, thereby closing the trip switch, so that the overload coil is energized and moves the armature. The armature may be moved from the first position into the second position. Moving the armature from the first position into the second position may be considered as engaging the trip mechanism.

[0044] The control device may be configured to measure a first current, the first current being chosen from the group including: a current between the first connection terminal and the first node and / or the main current path, a current on the main current path, a current between the main current path and the second connection terminal. The control device may be configured to detect an overload as the fault event based on the measured first current. The control device may be configured to, if the overload is detected, to energize the overload coil. The overload may be detected if the first current exceeds a predetermined first value and / or if an integral based on the first current exceeds a predetermined value. The integral may an integral over time and / or may have as unit A2*s. In particular, the overload may be detected if the first current exceeds the predetermined first value and the integral reaches the predetermined value while the first current continues to exceed the predetermined first value. The predetermined first value may be considered as the nominal current, IN, of the circuit protection device.

[0045] The control unit may be a (or may be part of a) (or may include a) multimeter, e.g. a multiple measuring device or multipoint measuring device, as an electrotechnical measuring device that can be used for several measured variables and in several measuring ranges. The control unit may be a multimeter according to EP 3 588 103 Bl and it is referenced to the disclosure thereof for further consideration.

[0046] The circuit protection device may comprise a fuse and / or an electronic power relay configured to entirely interrupt a current path between the first connection terminal and the second connection terminal in case the fault event is a short circuit, in particular if current in this current path has a predetermined second value. The predetermined second value may be larger than the predetermined first value.

[0047] In a first implementation of circuit protection against short circuit currents, the fuse or relay is included between the first node and the first terminal connection. Alternatively, the fuse or relay may be included between the second terminal connection and a second node, the second node being arranged downstream of the parallel connection of the main current path and the auxiliary current path. In other words: The second node is arranged between the parallel connection of main current path with auxiliary current path and the second connection terminal. So, irrespective of any current detection from the actuator or the control device, a load is secured against a short circuit current that may flow in a fault event.

[0048] In a second implementation of protection against short circuit currents, the auxiliary current path may include the fuse or relay configured to interrupt the auxiliary current path based on a current therethrough having the predetermined second value. Alternatively, or additionally, the auxiliary current path may include an electronic power relay configured in the same way as the fuse. The fuse and / or the electronic power relay may be used to interrupt the auxiliary current path in case the fault event is a short circuit. In either the first or the second implementation, the trip device may include a current coil connected between the first connection terminal and the first node and wound around the armature. The current coil may be referred to as second coil. The trip device may be configured such that, in case the fault event is a short circuit, a magnetic force formed by the energized current coil moves the armature from the first position to the second position, so as to open the main switch, in particular via the opening mechanism.

[0049] This allows the circuit detection device to effectively protect the load against short circuits. When a short circuit occurs, the main switch is opened so that the short circuit current flows through the auxiliary current path where the fuse is located. The circuit protection device should be designed such that in the event that current with the predetermined second value flows between the first connection terminal and the second connection terminal, the main switch should open prior interruption of the auxiliary current path by means of the fuse or relay. Here, no arc is formed when opening the main switch because the short circuit current can still flow via the auxiliary current path. The fuse then blows and effectively interrupts the short circuit. Such a design can for instance be achieved by choosing a delaying fuse that has some degree of time delay before blowing, the time delay being sufficient for the trip device to open the main switch.

[0050] Preferably, main switch and auxiliary switch are mechanically stacked other each other. This reduces the mechanical effort for switching these two switches.

[0051] The circuit protection device may further comprise an isolation switch connected between the second terminal connection and a second node, the second node being arranged between the parallel connection of main current path with auxiliary current path and the second connection terminal. This isolation switch enables a two-pole isolation that may be a desired or statuary design requirement for circuit protection devices in a fault event. Such a statuary design requirement can for instance be derived from technical standardization VDE SPEC 90037. The first pole is isolated when opening the main switch and the auxiliary switch. The second pole is additionally isolated when the isolation switch is opened. This isolation switch should be opened only after the main switch and the auxiliary switch are already open to avoid arcs.

[0052] The auxiliary switch of the circuit protection device may be a series connection of two or more switches, wherein all these series-connected two or more switches are mechanically connected to each in order to open simultaneously. As explained above, the auxiliary switch opens after the main switch is already opened. This means that opening the auxiliary switch interrupts the current path between the first connection terminal and the second connection terminal. As explained above, this interruption is processed quick by using the above-explained trip device and the stored energy. However, even the fastest interruption may not prevent the causing of arcs. These arcs may damage the contacts of the auxiliary switch if these contacts are not designed properly. To avoid such damages at the contacts of the auxiliary switch caused by any switching arcs, these contacts are usually dimensioned with a sufficient thickness and have large area to be resistant against these arcs. However, such dimensions of the contacts of the auxiliary switch heavily increase the outer dimensions of the circuit protection device and also increase the costs as greater switches are more expensive than smaller switches. Using two or more switches as the auxiliary switch and assuring a simultaneous switching thereof via respective mechanism, allows the use of smaller switches as the current is spread to all switches equally.

[0053] Preferably, the two or more switches are mechanically stacked other one another with respective contact bars being mechanically connected to enable a simultaneous opening. This allows identical current paths within the circuit protection device and ensures that the current is spread equally between all series-connected switches. In addition, such stacking of these two or more switches also enables the simultaneous opening in an easier manner.

[0054] Preferably, three switches are stacked other one another to form the auxiliary switch, as this number (three) is a reasonable tradeoff between ensuring simultaneous switching, sizing of the individual switches and allowing huge currents to pass the circuit protection device.

[0055] Preferably, a distance of a contact bar of the main switch to a main contact carrier of the main switch is shorter than a distance of a contact bar of the auxiliary switch to an auxiliary contact carrier that is mechanically connected to the main contact carrier such that when the actuator moves from the first position to the second position using the stored mechanic energy, the main switch opens prior the auxiliary switch. More preferably, a distance of a contact bar of an isolation switch to a contact carrier of the isolation switch is larger than the distance of the contact bar of the auxiliary switch to the auxiliary contact carrier of the auxiliary switch that is mechanically connected to the contact carrier of the isolation switch such that when the actuator moves from the first position to the second position using the stored mechanic energy, the auxiliary switch opens prior the isolation switch.

[0056] Preferably, based on the different distances the order of switch opening when the actuator moves from the first position to the second position, e.g. when using the stored mechanic energy is as follows: the main switch opens first, then the one or more auxiliary switch open, and finally, the isolation switch opens.

[0057] Preferably, based on the different distances the order of switch closing when the actuator moves from the second position to the first position is as follows: the isolation switch closes first, then the one or more auxiliary switch closes, and finally, the main switch closes.

[0058] As the mechanical connector mechanically connects all carriers of the respective switches, and all carrier move in the same direction once the latch mechanism is released, the opening of the respective switches does never occur simultaneously, it is rather followed by the predefined sequence, namely first, the main switch opens as its distance is shortest, followed by opening of the auxiliary switch as its distance is larger than the distance but shorter than the distance and finally by opening of the isolation switch as its distance is larger than the distance and much larger than distance. This mechanical structure provides a simple but very robust mechanism to enable the desired functionality of the circuit protection device.

[0059] So, the different distances mentioned above ensure that the switches are switched off in the following order: first, the main switch, then the one or more auxiliary switch, and finally the isolation switch. When switched back-on, this order is exactly reverse, with the isolation switch first, then the auxiliary switch(es), and finally the main switch. Such sequences are especially important in cases, in which they are switched-off or switched-on under load condition, because with this distances it is ensured that there is no arcing (which may lead to contact wear) in the main switch and in the isolation switch, which form the main current path, and therefore their impedance must be as low as possible throughout their entire service life.

[0060] Description of the Drawings In the following detailed description, the figures show:

[0061] Fig. la a circuit protection device according to a first embodiment of the present disclosure;

[0062] Fig. lb a circuit protection device according to a variant of the first embodiment of the present disclosure;

[0063] Fig. 1c a circuit protection device according to another variant of the first embodiment of the present disclosure;

[0064] Fig. Id a circuit protection device according to further variant of the first embodiment of the present disclosure;

[0065] Fig. 2a a circuit protection device according to a second embodiment of the present disclosure;

[0066] Fig. 2b a circuit protection device according to a another embodiment of the present disclosure;

[0067] Fig. 2c a circuit protection device according to a variant of the other embodiment of the present disclosure;

[0068] Fig. 3a-c details of the circuit protection device according to an embodiment of the present disclosure;

[0069] Fig. 4 a circuit protection device according to a third embodiment of the present disclosure;

[0070] Fig. 5a an exemplary embodiment of a series-connection of switches to form an auxiliary switch in closed state;

[0071] Fig. 5b an exemplary embodiment of a series-connection of switches to form an auxiliary switch in open state;

[0072] Fig. 6 shows an exemplary schematic work principle of the opening mechanism 48 in a first state; and Fig. 7a-c Exemplary diagrams showing time delays current overload condition or short circuit condition.

[0073] Detailed Description

[0074] In the following description, same and corresponding elements are denoted by same reference signs, and the description thereof is not repeated. However, the same elements do not carry reference signs in each of the figures, in order to not obscure the figures and hinder the understanding of the functioning of the embodiments of the present disclosure. The embodiments and features described in the following may be explicitly combined, and should be understood as separate embodiments.

[0075] Fig. la shows a circuit protection device according to a first embodiment of the present disclosure.

[0076] The circuit protection device 10 includes a first connection terminal 12 and a second connection terminal 14, a main current path 16 and an auxiliary current path 18 routed or connected in parallel between a first node 20 of the circuit protection device and a second node 20a. The second node 20a is connected in series to the second connection terminal 14. Further, the circuit protection device 10 includes a main switch 22 connected between the first node 20 and the main current path 16, and an auxiliary switch 24 connected between the first node 20 and the auxiliary current path 18. The main switch 22 is configured to open the main current path 16 so as to interrupt the main current path 16 and a current on the main current path 16. The auxiliary switch 24 is configured to open the auxiliary current path 18 so as to interrupt the auxiliary current path 18 and a current on the auxiliary current path 18.

[0077] The auxiliary current path 18 of Fig. la may comprise a fuse 26 connected in series to the auxiliary switch 24. The fuse 26 may be a short circuit fuse, i.e. configured to interrupt the auxiliary current path 18 in case of a short circuit. Instead of or in addition to the fuse, an electronic power relay may be employed.

[0078] Fig. lb shows a circuit protection device according to a variant of the first embodiment of the description. The embodiment of Fig. lb is similar to the embodiment shown in Fig. la, except for the differences described in the following:

[0079] In the variant as shown in Fig. lb, the fuse 26 is arranged either between the first connection terminal 12 and the first node 20 or alternatively it is arranged between a second node 20a and the second connection terminal 14. So, any connected load is protected irrespective of the interruption of the main current path 16 or the auxiliary current path 18 in the event of a short circuit in order to protect the load (not shown in Fig. lb) against permanent damages.

[0080] Fig. 1c shows a circuit protection device according to another variant of the first embodiment of the description. The embodiment of Fig. 1c is similar to the embodiment shown in Fig. la or Fig. lb, except for the differences described in the following and its particular teaching can freely be combined with either Fig. la or with Fig. lb.

[0081] The circuit protection device 10 of Fig. 1c further comprises an isolation switch 15 that is connected between the second terminal connection 14 and the second node 20a. This isolation switch 15 enables a two-pole isolation that may be a desired or statuary design requirement for circuit protection devices 10 in a fault event, such as a current overload or short-circuit fault event. The first pole is isolated when opening the main switch 22 and the auxiliary switch 24. The second pole is additionally isolated when the isolation switch 15 is opened. This isolation switch 15 is always opened after the main switch 22 and the auxiliary switch 24 are already open to avoid arcs.

[0082] Fig. Id shows a circuit protection device according to further variant of the first embodiment of the description. The embodiment of Fig. Id is similar to the embodiment shown in Fig. la, Fig. lb or Fig. 1c, except for the differences described in the following and the particular teaching of Fig. Id can freely be combined with each of the teachings of Fig. la and Fig. lb and Fig. 1c:

[0083] The auxiliary switch 24 of the circuit protection device 10 as shown in Figs, la to 1c is built as a series connection of three switches 24a, 24b, 24c. Each switch 24a, 24b, 24c has two connection contacts (herein commonly referenced as 241a and 241b) and a contact bar (herein commonly referenced as 242). The first terminal of switch 24a is connected to the first node 20 and the second terminal of switch 24c is connected to the second node 20a. The number of switches 24 a-c is exemplary, and this number can be increased or decreased in view of the exact application in which the circuit protection device 10 should be used.

[0084] All series-connected switches 24 a to 24c are mechanically connected to each in order to open simultaneously. As explained above, the auxiliary switch 24 of Figs, la-c opens after the main switch 22 is already opened. This means that opening the auxiliary switch 24 interrupts the entire current path between the first connection terminal 12 and the second connection terminal 14. As will be explained below and has been indicated above, this interruption is processed quick by using trip device 30 and stored energy from storage device 47. However, even the fastest interruption may not prevent the causing of arcs. These arcs may damage the contacts of the auxiliary switch 24 if these contacts are not designed properly. To avoid such damages at the individual contacts of the auxiliary switch 24 caused by any switching arcs., the contact bar and the terminals of the switch 24 needs to be dimensioned accordingly. However, such dimensions of the contacts of the auxiliary switch 24 heavily increase the outer dimensions of the circuit protection device 10 and also increase the costs as greater switches are more expensive than smaller switches. Using three series-connected switches 24a-c as the auxiliary switch 24 and assuring a simultaneous switching thereof via respective mechanism, allows the use of smaller switches 24a-c in comparison to only one auxiliary switch 24 as the current is spread to all switches 24a-c equally.

[0085] The circuit protection device 10 of Fig. la, Fig. lb and Fig. 1c may be connected in series to an electrical load (see load 34 in Figs. 2a to 2c and 4) and may protect any electrical load against overload and short circuits that hereinafter are also referred to as fault events. The electrical load may be a DC load or an AC load.

[0086] As further illustrated in Fig. 3a, during normal operation, i.e. when no fault event (preferably fault event is either an overload condition or a short circuit condition, each being detected by control unit 32) has occurred, the main switch 22 is closed, and the auxiliary switch 24 is closed. Hence, current flows between the first connection terminal 12 and the second connection terminal 14 mainly via the main current path 16 including the main switch 22. Only a very small part of the current between the first connection terminal 12 and the second connection terminal 14 flows via the auxiliary current path 18 including the auxiliary switch 24, and as shown in Fig. 3a representing the case of Fig. la, also the fuse 26.

[0087] The circuit protection device 10 further includes an opening mechanism 28. The opening mechanism 28 has a first state in which the opening mechanism is configured to store energy and a second state, in which the energy stored in the first state is released. The opening mechanism 28 may be configured to being released from the first state. When being released from the first state, the opening mechanism 28 is configured to move from the first state to the second state using the stored energy, and thereby open the auxiliary switch 24, illustrated by arrow 25 in Figs, la to Id. The opening mechanism 28 may be configured to automatically move from the first state to the second state when being released from the first state. The opening mechanism 28, when being released, may also be configured to open the main switch 22 or increase an opening angle or opening distance of the main switch 22, illustrated by arrow 27. Details thereof will be described in relation to Figs. 2 and 3a-c. The circuit protection device 10 further includes a trip device 30 configured to engage the opening mechanism 28 so as to release the opening mechanism 28 from the first state. Furthermore, the circuit protection device 10 further includes a control device 32 configured, in the case of a fault event - such as an overload condition or a short circuit condition - to control the trip device 30 to release the opening mechanism 28 from the first state.

[0088] Fig. 2a shows a circuit protection device according to a second embodiment of the present disclosure. Figs. 2b and 2c show a circuit protection device according to another embodiment of the present disclosure in two variants. Fig. 3a-c show details of the circuit protection device according to an embodiment of the present disclosure. The circuit protection device shown in Fig. 2a may be the circuit protection device 10 described in reference to Fig. la or Fig. lb. The circuit protection device shown in Figs. 2b and 2c may be the circuit protection device 10 described in reference to Fig. 1c or Fig. Id. In principle for Figs. 2a and 2b, the same disclosure applies as provided for Figs. 2b and 2c unless otherwise stated herein. The circuit protection device according to the second embodiment will now be described by referring to Figs. 2a, and further by referring to Figs. 3a-c.

[0089] In Fig. 2b, another embodiment is shown that in contrast to Fig. 2a also comprises the isolation switch 15 as described in Figs. 1c and Id. The load 34 is arranged as disclosed in Fig. lb.

[0090] In Fig. 2c, a variant of the other embodiment is shown that in contrast to Fig. 2a also comprises the isolation switch 15 as described in Figs. 1c and Id and only the load 34 is arranged differently compared to Fig. 2b.

[0091] In case, the circuit protection device is implemented according to the embodiments of Fig. 2b and Fig. 2c, the trip device 30 may comprise only an overload coil 36 (shown in Fig. 2a, Figs. 3a-3c, Fig. 4) and may not have a current coil 38 (shown in Fig. 2a, Figs. 3a-3c, Fig. 4). Such implementations without current coil 38 are intended for circuit protection devices of lower rated currents, for example in the range up to 100 ampere.

[0092] Fig. 3a shows the circuit protection device during normal operation, when the switches 22 and 24 are closed. Fig. 3b shows the circuit protection device 10 in a moment when the trip device 30 releases the opening mechanism 28 from its first state. Fig. 3c shows the circuit protection device after release of the opening mechanism 28 from its first state and when the opening mechanism is in the second state, and when the main switch 22 and the auxiliary switch 24 are open. As shown in Fig. 3c, the main switch 22 and the auxiliary switch 24 may each include at least one, preferably two or more, contacts 221a,b and 241a,b, in order to effectively and securely interrupt currents on the main current path 16 and the auxiliary current path 18 that even have a high intensity and high voltage.

[0093] The contacts 221a,b and 241a,b may be mounted to a main contact bar 222 and an auxiliary contact bar 242, respectively, configured to simultaneously move the contacts 221a,b and 241a,b to and from respective contacts of the main current path 16 and auxiliary current path 18, respectively, in order to close and open the main switch 22 and the auxiliary switch 24, respectively, but the present disclosure is not limited thereto. The main contact bar 222 and / or the auxiliary contact bar 242 may be springy and / or elastic and / or may be formed as clamp.

[0094] Fig. 3a shows a first position of the main contact bar 222 and a first position of the auxiliary contact bar 242, corresponding to the main switch 22 and the auxiliary switch 24 being open, respectively. Fig. 3c shows a second position of the main contact bar 222 and a second position of the auxiliary contact bar 242, corresponding to the main switch 22 and the auxiliary switch 24 being closed, respectively. Fig. 3b shows the main switch 22 in the second position and the first the auxiliary switch 24 in the first position.

[0095] The actuator 46 may comprise a main contact carrier 223 and an auxiliary contact carrier 243. The main contact carrier 223 may also be referred to as a first main contact carrier 223 in contrast to a second main contact carrier 226 described in further detail below. The actuator 46 may also include the second main contact carrier 226. The auxiliary contact carrier 243 is movable along and against a direction illustrated by arrow 29. Also, the main carrier 223 is movable along and against direction 29. The auxiliary contact carrier 243 has a first position, shown in Fig. 3a and 3b, and a second position, shown in Fig. 3c, along direction 29. Also, the main contact carrier 223 has a first position, shown in Fig. 3a, and a second position, shown in Fig. 3b and 3c, along direction 29. The auxiliary contact carrier 243 is configured, while moving from its first position to its second position, to push the auxiliary contact bar 242 from its first position to its second position so as to open the auxiliary switch 24. The main contact carrier 223 is configured, while moving from its first position to its second position, to move the main contact bar 222 from its first position to its second position so as to open the main switch 22. The main contact bar 222 may be fixedly mounted to the main contact carrier 223. The auxiliary contact bar 242 may be fixedly mounted to the auxiliary contact carrier 243. The second position of the main contact carrier 223 is such that a distance (e.g. an opening distance) between the contacts 221a,b of the main switch 22 and the corresponding contacts of the main current path 16 is large enough so as to prevent arcing when the switch is opened, and in particular prevent re-arcing in in case the fuse 26 is blown in the auxiliary current path 18. Similarly, the second position of the auxiliary contact carrier 243 is such that a distance (or opening distance) between the contacts 241a,b of the auxiliary switch 24 and the corresponding contacts of the auxiliary current path 18 is large enough so as to prevent arcing when the switch is opened.

[0096] As shown in Fig. 2a, the circuit protection device 10 is connected in series to a load 34 via the first connection terminal 22.

[0097] According to embodiments, the trip device 30 is formed by a solenoid having an overload coil 36 and a current coil 38, which are wound around an armature 40 of the solenoid. The current coil 38 is connected between the first connection terminal and the first node 20. The solenoid may be implemented in a ITS-LS 2924B solenoid armature. The trip device 30 is used for opening the main switch 22 in the event of an overload current as well as a short circuit, each being a fault event.

[0098] According to embodiments, the control device 32 includes a multimeter 42 and a shunt 44 arranged between the main current path 16 and the second connection terminal 22, but the location of the shunt 44 is not limited thereto. The control device 32, for example using the shunt 44, is configured to measure a current I between the first connection terminal 12 and the second connection terminal 14. The multimeter may be connected to a power supply, illustrated in the figures by the connection terminals “+” and The power supply may supply between 24 V and 48 V to the multimeter. The control device 32 may include a control unit that is multimeter, such as described in EP 3 588 103 Bl and it is referenced to the disclosure thereof for further consideration.

[0099] Furthermore, the control device 32 is configured to energize the overload coil 36, by supplying current thereto. Specifically, energizing the overload coil 36 moves the armature 40 from a first position, shown in Fig. 3a, to a second position, shown in Fig. 3b. Thereby, the trip device 30 is engaged. When the armature 40 moves from the first position to the second position, the opening mechanism 28 is engaged and released, illustrated by arrow 31 in Fig. 2a. Specifically, as described in further detail below, when the armature 40 moves from the first position to the second position, a latch mechanism 50 of the opening mechanism 28 is engaged to release an actuator 46 from a first position and / or release a storage device 47 from a first state. The armature 40 may also be considered as an actuator. As shown in Fig. 3a, during normal operation, when the armature 40, illustrated in the figures by an arrow, is in its first position and the main contact carrier 223 is in its first position, there may only a small gap between the main contact carrier 223 and the armature 40, namely at the end of the arrow, so that the reaction speed of the opening mechanism 28 and the circuit protection device 10 when a fault event occurs may be increased.

[0100] The opening mechanism 28 is mechanically engaged with the switches 22, 24. The opening mechanism 28 comprises the actuator 46, including the main contact carrier 223 and the auxiliary contact carrier 243, a storage device 47, including a spring 48, and a release mechanism 50. The spring 48 may also be referred to as auxiliary opening spring or opening thrust spring. The spring 48 may have a relatively high spring force compared to the springs described further below.

[0101] The spring 48 may have a first state, in which the spring 48 is compressed and thereby stores mechanic energy. Fig. 3a shows the spring in the first state. In the first state, the spring 48 may be compressed between the auxiliary contact carrier 243 and a stop 481 of the storage device 47.

[0102] Instead of the combination of the opening mechanism 28 including the spring 48 and the trip mechanism 30 including a solenoid, a pyro switch or equivalent element may be used. According to such embodiments, the spring 48 of the opening mechanism 28 and the solenoid of the trip mechanism 30 may be replaced by the pyro switch. The pyro switch may be configured to store the energy, in form of chemical energy, instead of the spring 48. The armature 40 may be comprised in the pyro switch or the pry switch may include an element having the function of the armature 40.

[0103] The auxiliary contact carrier 243 is movable relative to the stop 481 along the direction 29. When being released from the compressed first state, the spring 48 moves into a second state in which the spring 48 is at least partially decompressed compared to the first state. Fig. 3b shows the moment the spring 48 is released from the first state and Fig. 3c shows the spring in the second state. While moving from the first state to the second state, the spring 48 exerts a force onto the auxiliary contact carrier 243 and pushes the auxiliary contact carrier 243 from the first position to the second position. As detailed above, this pushes the auxiliary contact bar 242 to its second position, thereby opening the auxiliary switch 24. The auxiliary contact carrier 243 may be in the first position when the spring 48 is in the first state, corresponding to the opening mechanism 28 being in the first state, and the auxiliary contact carrier 243 may be in the second position when the spring 48 is in the second state, corresponding to the opening mechanism 28 being in the second state, but the disclosure is not limited thereto.

[0104] The spring 48 may also push against the auxiliary contact carrier 243 while being in the first state. Furthermore, while in the second position, the spring 48 may still exert a force on the auxiliary contact carrier 243 so as to maintain the auxiliary contact carrier 243 in the second position. Hence, the opening mechanism 28 may be configured to maintain the auxiliary switch 24 opened.

[0105] The latch mechanism 50 includes a first latch element 501 and a second latch element 502. Each of the first latch element 501 and the second latch element 502 may each be formed as and / or may include a hook. The function of the first latch element 501 and the second latch element 502 is to maintain the auxiliary switch 24 closed during normal operation. The first latch element 501 may be fixedly mounted to the auxiliary contact carrier 243. The first latch element

[0106] 501 moves together with the auxiliary contact carrier 243 and vice versa. The latch mechanism 50 further includes a latch lever 504. The latch lever 504 is configured to rotate around a rotation axis 503 of the latch mechanism 50. The rotation axis 503 is perpendicular to the direction 29, but the present disclosure is not limited thereto. The latch lever 504 is rotatably mounted to the rotation axis 503 and cannot translatively move along or against direction 29.

[0107] The latch lever 504 has a first end to which the second latch element 502 is mounted, and a second end 504a. The latch lever 504 is configured to rotate around the rotation axis 503 at a point between the first end and the second end 504a. The first latch element 501 and the second latch element 502 may engage with each other in a first state of the latch mechanism 50 so that the first latch element 501 is prevented from moving in direction 29 by the second latch element 502, as described next.

[0108] The latch mechanism 50 has a first state, shown in Fig. 3a, in which the latch lever 504 has a first rotational position relative to the rotation axis 503 such that the two latch elements 501,

[0109] 502 are engaged with each other. That is, the first latch element 501 is prevented from moving relative to the second latch element 502 in the direction 29. Since the first latch element 501 is mounted to the auxiliary contact carrier 243, the auxiliary contact carrier 243 is also prevented from moving in the direction 29 from its first position to its second position. Hence, the auxiliary switch 24 remains closed. Also, in its first state, the latch mechanism 50 holds the spring 48 in its first state. Consequently, the latch mechanism 50, in its first state, holds the auxiliary contact carrier 243 in its first position against the force exerted onto it by spring 48, as shown in Fig. 3a.

[0110] Fig. 3b shows the latch mechanism 50 in a second state. In the second state, the latch lever 504 has a second rotational position in which it is rotated or pivoted around the rotation axis 503 relative to the first rotational position. In the second state of the latch mechanism 50, and respectively in the second rotational position of the latch lever 504, the latch elements 501, 502 have a relative position to each other such that the auxiliary contact carrier 243 can freely move together with the latch element 501 along the direction 29 from its first position to its second position, for example by the force exerted onto the auxiliary contact carrier 243 by the spring 48.

[0111] Consequently, the latch mechanism 50 is configured to release the spring 48 from the first state and / or release the auxiliary contact carrier 243 from the first position when being in the second state.

[0112] The trip device 30, in particular the armature 40, is configured to engage the latch mechanism 50, to move the latch mechanism 50 from the first state to the second state by rotating the latch lever 504 around the rotation axis 503 as described above to release the spring 48 from the first state.

[0113] According to exemplary embodiments, and as shown in Figs. 3a-c, the trip device 30 engages the latch mechanism 50 via the main contact carrier 223, but the present disclosure is not limited thereto. According to these embodiments, when the armature 40 moves from its first position to its second position, it pushes the main contact carrier 223 from its first position (Fig. 3a) to its second position (Fig. 3b, 3c). The second end 504a of the latch lever 504 and the main contact carrier 223 may be arranged such that they contact each other while the main contact carrier 223 moves from the first position to the second position. The second end 504a may be formed in such a way that when it is contacted by the main contact carrier 223, the latch lever 504 is rotated around the rotation axis 503 as described above, to move from its first rotational position to its second rotational position. To that end, the second end 504a of the latch lever 504 may be arc shaped or slope shaped. The moment of (first) contact between the second end 504a of the latch lever 504 and the main contact carrier 223 is shown in Fig. 3b.

[0114] The trip device 30 is also configured to open the main switch 22, which is illustrated by arrow 33 in Fig. 2a. As already described, when the armature 40 moves from its first position to its second position, it pushes the main contact carrier 223 from its first position (Fig. 3a) to its second position (Fig. 3b, 3c). This in turn pushes the main contact bar 222 from its first position to its second position, thereby opening the main switch 22.

[0115] A time of opening the main switch 22 may be earlier than a time of opening the auxiliary switch 24. This ensures that the main current path 16 is interrupted before the auxiliary current path 18 is opened. The time of opening the main switch 22 is earlier than the time of opening the auxiliary switch 24 because for opening the main switch 22, only the main contact carrier 223 must move. In contrast thereto, for opening the auxiliary switch 24, the main contact carrier 223 must move, which in turn engages the latch mechanism 50, which in turn leads to a movement of the auxiliary contact carrier 243. Hence, for opening the auxiliary switch 24, movement of the three elements 223, 50 and 243 is necessary.

[0116] The auxiliary contact carrier 243 may be configured to being moved from the second position to the first position against direction 29. The auxiliary contact carrier 243 may be configured, when being moved from the second position to the first position, to close the auxiliary switch 24 and close the main switch 22, and preferably to first close the auxiliary switch 24 before the main switch 22.

[0117] To that end, the auxiliary contact carrier 243 may comprise a connection element 244 configured to push a second main contact carrier 226 against the direction 29, when the auxiliary contact carrier 243 is moved from its second position to its first position. When the auxiliary contact carrier 243 is moved to its first position, the auxiliary contact bar 242 is also moved to its first position. This in turn closes the auxiliary switch 24.

[0118] A main closing spring 227 of the opening mechanism 28 is arranged between the second main contact carrier 226 and the main contact bar 222. When the second main contact carrier 226 is pushed or moved against the direction 29, a force is transmitted to the main contact bar 222 via the closing spring 227 which is compressed to push and move the main contact bar 222 into its second position, which in turn closes the main switch 22. The function of the main closing spring 227 is to maintain the main switch 22 closed during normal operation. The main closing spring 227 may be compressed between the second main contact carrier 226 and the main contact bar 222 and / or the main contact carrier 223, in particular during normal operation.

[0119] According to an embodiment, the auxiliary contact bar 242 may include two bronze spring plates, which may be arranged in parallel with each other, that clamp the respective (fixed) contacts of the auxiliary current path 16. In this case, each of the contacts 241a,b may be formed by two contacts or contact points respectively formed on the two spring plates. This contact force may act perpendicular to the direction 29. A frictional force, which is formed due to the contact force between the spring plates and the contacts of the auxiliary current path 16 and which acts along and against direction 29 of said contact force, may constitute an auxiliary closing spring 245. Hence, the auxiliary closing spring 245, as shown in Figs. 3a-c, may not be provided as a separate element, but may be regarded as a virtual spring. The function of the frictional force or spring 245 is to provide a contact force in the auxiliary switch 24 so that current can flow through the auxiliary current path 18. The spring force of the spring 48 is larger than the frictional force, so that the frictional force can be overcome when the auxiliary switch 24 is opened by the spring 48.

[0120] The latch mechanism 50 may include a lever spring 505 and a lever spring stop 505a. The lever spring 505 may be a compressing spring. The lever spring 505 may be compressed between the lever spring stop 505a and the latch lever 504 in the first state of the latch mechanism 50, corresponding to the first rotational position of the latch lever 504, as shown in Fig. 3a. The lever spring 505 may contact the latch lever 504 between the rotation axis 503 and the second end 504a. The lever spring 505 may be configured to keep or return the latch lever 504 in the first rotational position shown in Fig. 3a and therefore keep or return the latch mechanism 50 in the first state. The first latch element 501 may act as a stop for the second latch element 502 and the latch lever 504 against being pushed further than the first position by the lever spring 505.

[0121] The lever spring 505 may be further compressed when the second end 504a of the latch lever 504 and the main contact carrier 223 contact each other, and the latch lever 504 is rotated around the rotation axis 503 and moves from its first rotational position to its second rotational position as described above, while the main contact carrier 223 moves from the first position to the second position, as shown in Fig. 3b. As illustrated in Fig. 3c, when the latch mechanism 50 has been engaged, the lever spring 505 may decompress and rotate the latch lever 504 from its second rotational position. A stop (not shown in the figures) may prevent the lever spring 505 from rotating the latch lever 504 to far, in particular farther than the first rotational position.

[0122] Next, the operation of the circuit protection device 10 is described in case an overload occurs as a fault event. During normal operation, illustrated by Fig. 3a, when the current I measured via the shunt 44 exceeds a predetermined first value, the nominal value IN, the control device 32 will start calculating the integral of I2over time, corresponding to an energy integral. If the current I continues to exceed IN until the integral reaches a predetermined value, corresponding to a TCC value, the control device 32 will activate or energize the overload coil 36. That is, a current flows through the overload coil 36 which in turn forms a magnetic force which acts on the armature 40, thereby moving the armature 40 from its first position to its second position. This in turn moves the main contact carrier 223 into its second position and thereby opens the main switch 22 (also illustrated by arrow 33 in Fig. 2a). At this moment, the current on the main current path 16 is interrupted. The second position of the main contact carrier 223 and the opened main switch 22 are shown in Fig. 3b.

[0123] As described above, when the main contact carrier 223 moves from its first position to its second position, it engages the latch mechanism 50 by turning the latch lever 504 so that the spring 48 is released from its first state and moves in its second state (also illustrated by arrow 31 in Fig. 2a). This will push the auxiliary contact carrier 243 at high speed from its first position to its second position, which will also open the auxiliary switch 24, thus also interrupting the current on the auxiliary current path 18 and leaving the fuse 26 intact. The opened main switch 22, the opened auxiliary switch 24, the second position of the main contact carrier 22 and the second position of the auxiliary contact carrier 243 are shown in Fig. 3c.

[0124] The auxiliary switch 24 may be held open by the spring 48. Furthermore, the main switch may be held open by a main opening spring 224 of the opening mechanism 28. The main opening spring 224 is compressed between a stop 225 of the opening mechanism 28 and a second main contact carrier 226. Hence, the main opening spring 224 pushes the main contact carrier 223 via the second main contact carrier 226 along the direction 29 when the second main carrier 226 does not experience a force transmitted from the auxiliary main carrier 243 via the connection element 244 (explained in further detail below). When the switches 22, 24 are held open, galvanic isolation is established.

[0125] Next, the operation of the circuit protection device 10 is described in case a short circuit occurs as a fault event. At the moment when a short circuit current flows through the current coil 38 of the trip mechanism 30, the current coil 38 forms a magnetic force which acts on the armature 40. Thereby, the armature 40 is moved from its first position into its second position which will immediately open the main switch 22 (illustrated by arrow 33 in Fig. 2a), interrupting the current on the main current path 16. Hence, the entire (short circuit) current will flow on the auxiliary current path 18, which in turn causes the fuse 26 to blow.

[0126] Similar to the overload case, the latch mechanism 50 is then engaged (illustrated by arrow 31 in Fig. 2a) so that the spring 48 is released from its first state and moves in its second state. This will push the rod 46 at high speed from its first position to its second position, which will also open the auxiliary switch 24. The switches 22, 24 may also be held open in the same way as explained for the overload case.

[0127] The armature 40 may be configured to return, in particular automatically return, to its first position from its second position if both switches 22, 24 are open and / or if both the overload coil 36 and the current coil 38 are no longer energized.

[0128] The circuit protection device 10 may further comprise an activation mechanism 52, such as an ON-button or knob, configured to being operated by an operator. The activation mechanism 52 may be configured such that when operated, the activation mechanism moves the auxiliary contact bar 242 and the main contact bar 222 from their second position to their first position, thereby closing the auxiliary switch 24 and the main switch 22, respectively, and moves the spring 48 from the second state into the first state. Furthermore, operating the activation mechanism 52 brings the latch mechanism 50 into its first state, i.e. it engages the latch mechanism 50 to hold the spring 48 in the first state. The activation mechanism 52 may compress the lever spring 505 and / or bring the latch lever 504 into its first rotational position. Hence, the activation mechanism allows an operator to manually close the switches 22, 24 and reset the circuit protection device 10 to be prepared again for normal operation after a fault event has occurred.

[0129] The circuit protection device 10 may further comprise a deactivation mechanism 54, such as an OFF-button, configured to being operated by an operator. The deactivation mechanism 54 may be configured, such that when operated, the deactivation mechanism 54 engages the latch mechanism 50 to release spring 48 from the first state. When the latch mechanism 50 is engaged and the auxiliary contact carrier 243 moves to its second position, the connection element 244 no longer pushes against the second main contact carrier 226. Thereby, the second main carrier 226 does not longer experience a force transmitted from the auxiliary main carrier 243 via the connection element 244. This allows the main opening spring 224 to decompress and push the main contact carrier 223 via the second main contact carrier 226 to the second position along direction 29, thereby also moving the main contact bar 222 to its second position and opening the main switch 22. The OFF-button or deactivation mechanism 54 may be configured as or may comprise a push button. The deactivation mechanism 54 may be configured to (manually) push the armature 40, in particular from the outside, instead of energizing the coil, which means that the deactivation procedure engaged by the deactivation mechanism 54 may be the same as for an overload or short circuit. Hence, it can be said that the mechanical engagement or connection between the main contact carrier 223 and the auxiliary contact carrier 243 provided by the connection element 244 and the second main contact carrier 226 ensures the correct sequence of opening and closing of the main switch 22 and the auxiliary 24 with respect to each other.

[0130] Thus, the main switch 22 and the auxiliary switch 24 may be opened. Hence, the deactivation mechanism 54 allows for manually interrupting the current through the circuit protection device 10.

[0131] The function of the deactivation mechanism 54 may be integrated into the activation mechanism 52, as shown in Figs 3a-3c, for example by providing the activation mechanism 52 as a knob which can be toggled so as to manually turn the switches 22, 24 on and off.

[0132] The control device 32 may be configured to allow remotely engaging the trip mechanism 30 to open the main switch 22 and the auxiliary switch 24. To that end, an appropriate signal may be sent to the control device 32 causing the control device 32 to energize the overload coil 36, which in turn moves the armature 40. Hence, remotely engaging the trip mechanism 30 functions in a similar way as the overload operation of the circuit protection device 10.

[0133] The circuit protection device 10 may have a mechanical barrier that prevents the switches 22, 24 from being closed if the fuse 26 is not inserted. Furthermore, in the auxiliary current path 20, a current indicator 56 may be provided so that an operator may detect that a fault event has occurred, for example, when the fuse 26 is blown after a short circuit and / or when the switch 22 is turned off after an overload. The fault event may be alarmed visually, e.g. with an LED, and / or remotely with an appropriate signal. The current indicator 56 may be activated by a (small) flow of current through the auxiliary current path 18 during normal operation. This indicates that the auxiliary current path 18 is connected (not broken). The auxiliary current path 18 is closed when switch 22 is turned on and this is signaled by the current indicator 56. If the current indicator 56 is deactivated, this indicates that the auxiliary current path 18 is interrupted, which in turn means that a fault event has occurred. For example, the current indicator 56 may emit light if activated, and may emit no light if deactivated.

[0134] Furthermore, the multimeter 42 control device 32 may include a temperature sensor. If a predetermined temperature is exceeded, an alarm may be automatically triggered. These measures help to improve safety of the circuit protection device. The circuit protection device 10 of Fig. 2a may be referred to as smart circuit protection device. The smart circuit protection device is suitable for protecting all types of circuits with AC or DC voltage and allows for setting of the TCC (time current characteristic) triggering characteristic and the nominal current. The smart circuit protection device may include a built-in multimeter, which may constantly monitor what is happening in the circuit and send the data to a human operator.

[0135] Fig. 4 shows a circuit protection device according to a third embodiment of the description. The embodiment of Fig. 4 is similar to the embodiment shown in Fig. 2a, except for the differences described in the following.

[0136] The control device 32 includes a trip element 58 formed by a bimetal element. The bimetal element 58 is connected between the current coil 38 of the trip mechanism 30 and the first node 20. Correspondingly, during normal operation, the current also flows through the bimetal element 58.

[0137] Further, the control device 32 includes a trip switch 60 connected in series with the overload coil 36 in a current path 62 between the first connection terminal 12 and the first node 20. According to an embodiment, the current path 62 may also be connected between the first connection terminal 12 and the second connection terminal 14.

[0138] Next, operation of the circuit protection device 10 in case of an overload is described. When the current over the bimetal element 58 exceeds the nominal value IN, the bimetal element 58 heats up strongly and bends. If such a current continues for a longer time, the bimetal element 58 bends so much that it closes the switch 60 (arrow 61 in Fig. 4). This in turn energizes the overload coil 36, and thus the armature 40 is moved. The further operation is the same as in overload operation of the embodiment of Fig. 2a.

[0139] Embodiments of the present disclosure relate to a circuit protection device having a solenoid with two coils, two parallel current paths, namely a main current path with an operating switch, an auxiliary current path with a load switch, a push rod to open and close the switches, a spring and a latch. The operating switch in the main current path, which in case of overload or short circuit diverts the entire current through the auxiliary current path. The auxiliary current path has a fuse for interrupting the short circuit current. The disclosed switch opening solution using the solenoid with two coils, the push rod, the latch and the spring ensures a sequence of safe opening of the switches in case of overload and short circuit. The circuit protection device may also have an ON and OFF button mechanism and a current indicator. There may also be a built- in lock on the ON button, which prevents switching ON if the fuse in the auxiliary current path is not inserted.

[0140] The circuit protection device according to embodiments of the present disclosure provides a compact device for protecting an electrical load against fault events, such as an overload or a short circuit. Furthermore, low power dissipation is ensured throughout the entire service live of the circuit protection device. Furthermore, the circuit protection device allows for an adjustable TCC characteristic as well as of the nominal current IN of the device. Furthermore, circuit protection device may remain identical for a certain range of nominal currents and voltages. High-quality monitoring of what is happening in the circuit protection device and the status of the device is enabled. In case of circuit interruptions due to overload, the fuse remains undamaged. Finally, the fuse is not subject to cyclic aging.

[0141] Fig. 5a and Fig. 5b show an exemplary embodiment of the above described auxiliary switch 24 of the circuit protection device 10 that is realized as a series connection of three switches 24a, 24b, 24c as already shown in Fig. Id. Each switch 24a, 24b, 24c comprises a respective contact bar 242a, 242b, 242c to open or close the respective switch. Fig. 5a shows the auxiliary switch 24 in a closed state (as shown in Figs. 3a, 3b) and Fig. 5b shows the auxiliary switch in an open state (as shown in Figs. 2, 3c).

[0142] As shown in Fig. 5a, in the closed state of auxiliary switch 24, the first terminal 241aa of switch 24a is connected to the first node 20 (shown in Fig. Id). Contact bar 242a connects the first terminal 241aa of the switch 24a with the second terminal 24 lab of the switch 24a. The second terminal 24 lab is connected via electrical connector 24ab to the first terminal 241ba of switch 24b. Contact bar 242b connects the first terminal 241ba of the switch 24b with the second terminal 241bb of the switch 24b. The second terminal 241bb is connected via electrical connector 24bc to the first terminal 24 lea of switch 24c. Contact bar 242c connects the first terminal 24 lea of the switch 24c with the second terminal 241cb of the switch 24c. The second terminal 241cb of switch 24c is connected to the second node 20a (shown in Fig. Id). In other words: The opening mechanism 28 provides a force via arrow 25 to the three switches 24a, 24b, 24c so that all contact bars 242a, 242b, 242c are closed and the first node 20 is connected to the second node 20a.

[0143] As shown in Fig. 5b, in the open state of auxiliary switch 24, the first terminal 241aa of switch 24a is not connected to the first node 20 (shown in Fig. Id). Contact bar 242a connects the first terminal 241aa of the switch 24a with the second terminal 24 lab of the switch 24a. The second terminal 24 lab is not connected via electrical connector 24ab to the first terminal 241ba of switch 24b. Contact bar 242b connects the first terminal 241ba of the switch 24b with the second terminal 241bb of the switch 24b. The second terminal 241bb is not connected via electrical connector 24bc to the first terminal 24 lea of switch 24c. Contact bar 242c connects the first terminal 24 lea of the switch 24c with the second terminal 241cb of the switch 24c. The second terminal 241cb of switch 24c is not connected to the second node 20a (shown in Fig. Id). In other words: The opening mechanism 28 ensures that all contact bars 242a, 242b, 242c of the respective three switches 24a, 24b, 24c are open by providing a sufficient distance d24 so that the first node 20 is not connected to the second node 20a.

[0144] As shown schematically in Figs. 5a and 5b, the switches 24a to 24c are stacked one another in such a manner that their contact bars 242a, 242 b, 242c are dimensionally aligned such that a force that is applied via open mechanism 28 enables the same lateral movement of all three contact bars242a, 242 b, 242c which results in an identical distance d24 in each of the three switches 24a, 24b, 24c. So, simultaneous opening and closing of all three switches 24a, 24b, 24c is possible with the least mechanical effort. This is achieved by a mechanically fixed connection of all three contact bars 242a, 242 b, 242c, indicated as 244 in Fig. 5a and 5b.

[0145] The electrical connectors 24ab and 24bc are preferably u-shaped to reduce the outer dimension of the resulting auxiliary switch 24, but the shape is not limited thereto as any suitable shape for such a connector can be used. It is even possible that these electrical connectors are wires or printed circuit board traces.

[0146] The number of switches 24 a-c is exemplary, and this number can be increased or decreased in view of the exact application in which the circuit protection device 10 should be used.

[0147] Fig. 6 shows an exemplary schematic work principle of the opening mechanism 48 in a first state. Here the main switch 22 and the auxiliary switch 24 are closed (similar to Fig. 3a). In addition, the isolation switch 15 is now shown in closed state. Thus, Fig. 6. reflects the normal operation of the circuit protection device 10 in which no fault event is detected. This means that main switch 22 as well as auxiliary switch 24 respectively connect the first node 20 to the second node 20a. This also means that isolation switch 15 connects the second node 20a to the second terminal connection 14. Isolation switch 15 is shown in greater details with its first and second contacts 151a,b and the contact bar 153 as well as spring 153 that ensures save closing state during normal operation (cf. description for references 227 and 245 with similar functionality). As is further shown in Fig. 6, there are different distances d22, d24 and dl5 between the respective carriers 223, 243, 153 and their respective contact bars 222, 242 and 152. The distances d22, d24 and dl5 are disconnection movements, meaning these are the required distances that the carrier needs to be moved before a respective contact bar 222, 242, 152 can begin to open the respective switch 22, 24, 15.

[0148] To be more precise, the distance d22 is the distance between the main carrier 223 and the contact bar 222 of the main switch 22. This distance d22 is smaller than the distance d24 and much smaller than the distance d 15.

[0149] To be more precise, the distance d24 is the distance between the auxiliary carrier 243 and the contact bar 242 of the auxiliary switch 24. This distance d24 is greater than the distance d22 but smaller than the distance d 15.

[0150] To be more precise, the distance dl 5 is the distance between the carrier 154 and the contact bar 153 of the isolation switch 15. This distance dl5 is greater than the distance d24 and much greater than the distance d22.

[0151] The distance d22 may be 0,6 mm; the distance d24 may be double the distance d22, e.g. 1.2 mm and the distance dl 5 may be six times the distance d24, e.g. 7.2 mm.

[0152] As the mechanical connector 244 mechanically connects all carriers 223, 243, 154, and all carrier move in the same direction once the latch mechanism 50 is released, the opening of the respective switches 22, 24, 15 does never occur simultaneously, it is rather followed by the predefined sequence, namely first, the main switch 22 opens as its distance d22 is shortest, followed by opening of the auxiliary switch 24 as its distance is larger than the distance d22 but shorter than the distance d 15 and finally by opening of the isolation switch 15 as its distance is larger than the distance d24 and much larger than distance d22.

[0153] Based on this specific different distances d22, d24 and d 15, the order of switch-opening when the actuator 46 moves from the first position to the second position, e.g. when using the stored mechanic energy is as follows: the main switch 22 opens first, then the one or more auxiliary switches 24 open, and finally, the isolation switch 15 opens.

[0154] Based on this specific different distances d22, d24, dl 5, the order of switch closing when the actuator 46 moves from the second position to the first position is as follows: the isolation switch 15 closes first, then the one or more auxiliary switches 24 closes, and finally, the main switch 22 closes.

[0155] So, the different distances d22, d24, dl 5 mentioned above ensure that the three switches 22, 24, 15 are switched off in the following order: first, the main switch 22, then the one or more auxiliary switch 24, and finally the isolation switch 15. When switched back-on, this order is exactly reverse, with the isolation switch 15 first, then the auxiliary switch(es) 24, and finally the main switch 22. Such sequences are especially important in cases, in which they are switched-off or switched-on under load condition, because with these different distances d22, d24, dl 5 it is ensured that there is no arcing (which may lead to contact wear) in the main switch 22 and in the isolation switch 15, which form the main current path 16, and therefore their impedance must be as low as possible throughout their entire service life.

[0156] The trip device 30, in particular the armature 40, is configured to engage the latch mechanism 50, to move the latch mechanism 50 from the first state to the second state to release the spring 48 from the first state as described above.

[0157] As can be seen, the respective carriers 243, 223 and 154 are all mechanically connected to each other by mechanical connector 244. The mechanical connector 244 may be identical with the connector 244 of Figs. 5a and 5b or at least has the same functionality. As already described above, latch mechanism 50 (not shown) has a first state so that auxiliary switch 24 remains closed. Also, in its first state, the latch mechanism 50 holds the spring 48 in its first state. Consequently, the latch mechanism 50, in its first state, holds the auxiliary contact carrier 243 in its first position against the force exerted onto it by spring 48. If the latch mechanism 50 is in a second state, it is configured to release the spring 48 from the first state and / or release the auxiliary contact carrier 243 from the first position when being in the second state.

[0158] Figs. 7a to 7c show exemplary voltage / current diagrams for exemplary fault events to verify the ability to interrupt overload currents and short circuits detected by a circuit protection device 10 of this disclosure.

[0159] In Fig. 7a, two different diagrams are provided. In the upper diagram of Fig. 7a, the total current Itotai and the current through the auxiliary switch 24 Iauxswitch as well as the voltage drop over “no load” are measured for 500 milliseconds for an overload condition. In the lower diagram, a portion of the upper diagram between 225.69 milliseconds to 239.77 milliseconds is shown with enlarged scale. Here, an exemplary overload current of 129.60 ampere at 805.82 volts are applied. The marked five different time points Cl to C5 mean the following conditions:

[0160] Cl - Switching on the current through the trip device 30, here an exemplary overload current of 129,60 ampere is used.

[0161] C2 - Main switch 22 starts to open

[0162] C3 - Current flows through the auxiliary switch 24 (main switch 22 remains open)

[0163] C4 - Auxiliary switch 24 starts to open

[0164] C5 - Current flow is completely interrupted

[0165] The following time differences are measured:

[0166] Cl to C2 is the time required for the current through the main switch 22 before trip device 30 is activated (main switch turn-off time), here 5.019 milliseconds.

[0167] C2 to C3 is the time required for the current to be diverted from the main switch 22 to the auxiliary switch 24, here 115.385 microseconds.

[0168] C3 to C4 is the time delay for opening the auxiliary switch 24, here 405.510 microseconds.

[0169] C4 to C5 is the time required to extinguish the arc in the auxiliary switch 24, here 6.835 milliseconds.

[0170] Cl to C3 is the time required from the moment the trip device 30 is activated to the moment the entire current flows through the auxiliary switch 24, here 5,135 milliseconds.

[0171] Cl to C5 is the total time from triggering to complete interruption of current in this specific overload condition, here 12.376 milliseconds.

[0172] In Fig. 7b, two different diagrams are provided. In the upper diagram of Fig. 7b, the total current Itotai and the current through the auxiliary switch 24 Iauxswitch as well as the voltage drop over “no load” are measured for 500 milliseconds for an overload condition. In the lower diagram, a portion of the upper diagram between 225.7 milliseconds to 236.95 milliseconds is shown with enlarged scale. Here, an exemplary overload current of 126.48 ampere at 407.10 volts are applied. The marked five different time points Cl to C5 have the same meaning as in Fig. 7a and it is referenced thereto. The following time differences are measured:

[0173] Cl to C2 is the time required for the current through the main switch 22 before trip device 30 is activated (main switch turn-off time), here 4.814 milliseconds.

[0174] C2 to C3 is the time required for the current to be diverted from the main switch 22 to the auxiliary switch 24, here 94.651 microseconds.

[0175] C3 to C4 is the time delay for opening the auxiliary switch 24, here 338.041 microseconds.

[0176] C4 to C5 is the time required to extinguish the arc in the auxiliary switch 24, here 3.651 milliseconds.

[0177] Cl to C3 is the time required from the moment the trip device 30 is activated to the moment the entire current flows through the auxiliary switch 24, here 4.908 milliseconds.

[0178] Cl to C5 is the total time from triggering to complete interruption of current in this specific overload condition, here 8.897 milliseconds.

[0179] As can be seen from Figs. 7a and 7b, the circuit protection device as described herein is suitable to detect an overload condition well within the time durations as defined by the standard, such as VDE SPEC mentioned above.

[0180] In the diagram of Fig. 7c, the total current Itotai and the current through trip device 30 Itrip device as well as the voltage drop over “no load” are measured between 19 milliseconds to 39 milliseconds for short circuit condition. Here, an exemplary short circuit current of 24,329.40 ampere (greater than 24 kilo ampere) at 805.82 volts are applied.

[0181] In a case, in which the fuse 26 is arranged in the auxiliary current path 18 as exemplarily shown in Fig. 2a, the short circuit current in a short circuit fault event flows through the current coil 38 of the trip device 30 and causes as a strong magnetic field, so that the trip device 30 opens the main switch 22 and the entire short circuit current flows through the fuse 26, which immediately blows.

[0182] However, in a case where fuse 26 is inserted in series to the paths 16 and 18 as shown in Fig. 2b and 2c, the fuse 26 immediately blows due to the high short circuit current. In both cases, the time is too short for the control unit 32 to lead the current through the overload coil 36 or through the trip device 30 in Fig. lb and 1c.

[0183] Fig. 7c shows an oscillogram of a short-circuit tripping implementation for a circuit protection device 10 according to Fig. 2c in which as indicated above, the trip device 30 only comprises an overload coil 36 and does not have a current coil 38. Such circuit protection devices 10 are intended for lower rated currents, for example up to 100 ampere. Therefore, no current flow through the trip device 30 can be recorded in the diagram of Fig. 7c and so, only three time points Cl to C3 are shown in that oscillogram of Fig. 7C. Time point Cl indicates the time when the short-circuit current is turned on, time point C2 is the moment when the fuse 26 melts and an arc is formed, time point C3 is the moment when all the current is completely interrupted. The following time differences are measured as can be seen from Fig. 7C:

[0184] Cl to C2 is the time required until the fuse 26 blows after the current has been turned-on, here 232.797 microseconds.

[0185] C2 to C3 is the time duration at which an arc is, here 5.27 milliseconds.

[0186] Cl to C3 is the total time required from the moment at which the short circuit current is switched-on until the current paths are interrupted completely, here 5.510 milliseconds.

[0187] The maximum current value between Cl to C3 is 2,23 kiloampere. The maximum current value between Cl to C2 is 2,01 kiloampere. The maximum voltage value between Cl to C3 is 1.22 kilovolts. The melting integral between Cl to C2 is 272.45 A2s- The U-I integral between Cl to C3 is 1.29 kilojoule.

[0188] As can be seen from Fig. 7c, the circuit protection device 10 as described herein is suitable to detect a short circuit condition well within the time durations as defined by the standard, such as VDE SPEC mentioned above.

Claims

Patent claims1. A circuit protection device (10), including: a first connection terminal (12) and a second connection terminal (14), a main current path (16) and an auxiliary current path (18) connected in parallel between a first node (20) and the second connection terminal (14), a main switch (22) connected between the first node (20) and the main current path (16), and an auxiliary switch (24) connected between the first node (20) and the auxiliary current path (18), an opening mechanism (28) having a first state in which the opening mechanism (28) comprises stored energy and a second state, wherein, when being released from the first state, the opening mechanism (28) is configured to move from the first state to the second state using the stored energy to open the auxiliary switch (24), a trip device (30) configured to engage the opening mechanism (28) so as to release the opening mechanism (28) from the first state, and a control device configured (32) to detect a fault event and, if the fault event is detected, engage the trip device (30) to release the opening mechanism (28) from the first state.

2. The circuit protection device of claim 1, wherein the trip device (30) is configured to also open the main switch (22), in particular via the opening mechanism (28), when being engaged by the control device (30) to release the opening mechanism (28) from the first state.

3. The circuit protection device of claim 2, wherein the circuit protection device is configured such that the main switch (22) is opened prior to the auxiliary switch (24) being opened.

4. The circuit protection device of any one of the preceding claims, wherein, in the second state, the opening mechanism (28) is configured to maintain the auxiliary switch open (24).

5. The circuit protection device of any one of the preceding claims, wherein the opening mechanism (28) comprises an actuator (46) and a storage device (47) configured to store mechanic energy in a first state of the storage device (47), and, when being released from the first state, to exert a force on the actuator (46) to move the actuator (46) from a first position to a second position, using the stored mechanic energy, wherein the actuator (46) is configured to open the auxiliary switch (46) while moving from the first position to the second position.

6. The circuit protection device of claim 5, wherein the opening mechanism (28) further comprises a release device (50) configured to hold the actuator (46) in the first position, and / or hold the storage device (28) in the first state, the release device (50) being further configured to release the storage device (47) from the first state, wherein the trip device (30) is configured to engage the release device (50) to release the storage device (47) from the first state.

7. The circuit protection device of claim 5 or 6, wherein the storage device (47) is constituted by a spring configured to push the actuator (46) or an element thereof from the first position to the second position when being decompressed.

8. The circuit protection device of any one of claims 5 to 7, further including an activation mechanism (52), in particular a first button, wherein operating the activation mechanism (52) moves the actuator (46) from the second position to the first position and engages the release device (50) to hold the actuator (46) in the first position.

9. The circuit protection device of any one of claims 5 to 8, further comprising a deactivation mechanism (54), in particular a second button, wherein operating the deactivation mechanism (54) releases the actuator (46) from the first position and / or releases the storage device (47) from the first state.

10. The circuit protection device of any one of the preceding claims, wherein the trip mechanism (28) includes an armature (40) and an overload coil (36) wound around the armature (40), wherein the control device (32) is configured, in case the fault event is an overload, to energize the overload coil (36) so as to move the armature (40) by the magnetic force of the overload coil (36) and release the opening mechanism (28) from the first state.

11. The circuit protection device of claim 8, wherein the control device (32) comprises a trip element (58), preferably a thermal trip element, most preferably including a bimetal element, and a trip switch (60) connected in series with the overload coil (36) between the first connection terminal (12) and the first node (20), wherein the trip element (58) is configured, in case the fault event is the overload, to close the trip switch (60) so as to energize the overload coil (36).

12. The circuit protection device of any one of claims 8 or 9, wherein the control device (32) is configured to measure a first current, the first current being chosen from the group including the following: a current between the first connection terminal (12) and the main current path (16), a current on the main current path (16), a current between the main current path (16) and the second connection terminal (14), wherein the control device (32) is configured to detect an overload as the fault event based on the measured first current, and, based on the overload being detected, to energize the overload coil (36).

13. The circuit protection device of any one of the preceding claims, further including a fuse (26), or an electronic power relay, arranged between the first terminal connection (12) and the first node (20) or arranged between the second terminal connection (14) and a second node (20a), and configured to interrupt the current path between the first connection terminal and the second connection terminal based on a predetermined current therethrough.

14. The circuit protection device of any one of the preceding claims, wherein the auxiliary current path (18) includes a fuse (26), or an electronic power relay, configured to interrupt the auxiliary current path (18) based on a predetermined current therethrough.

15. The circuit protection device of any one of the preceding claims, wherein the trip device (30) includes a current coil (38) connected between the first connection terminal (12) and the first node (20) and wound around the armature (40), wherein the trip device (30) is configured such that, in case the fault event is a short circuit, a magnetic force formed by the energized current coil (38) moves the armature (40) so as to open the main switch (22), in particular via the opening mechanism (28).

16. The circuit protection device of any of the preceding claims, wherein the main switch (22) and the auxiliary switch (24) are mechanically stacked other each other.

17. The circuit protection device of any one of the preceding claims, further comprising an isolation switch (15) connected between the second terminal connection (14) and a second node (20a), the second node (20a) being arranged between the parallel connection of main current path (16) with auxiliary current path (18) and the second connection terminal (14).

18. The circuit protection device of any one of the preceding claims, wherein the auxiliary switch (24) is a series connection of two or more switches (24a, 24b, 24c) and all the two ormore switches (24a, 24b, 24c) are mechanically connected to each other to enable a simultaneous opening.

19. The circuit protection device of claim 18, wherein the two or more switches (24a, 24b, 24c) are mechanically stacked other each other with the respective contact bars (242) being mechanically connected.

20. The circuit protection device of any one of the preceding claims 5 to 19, wherein a distance (d22) of a contact bar (222) of the main switch (22) to a main contact carrier (223) of the main switch (22) is shorter than a distance (d24) of a contact bar (242) of the auxiliary switch (24) to an auxiliary contact carrier (243) of the auxiliary switch (24) that is mechanically connected to the main contact carrier (223) such that when the actuator (46) moves from the first position to the second position using the stored mechanic energy, the main switch (22) opens prior the auxiliary switch (24).

21. The circuit protection device of claim 20, wherein a distance (dl 5) of a contact bar (152) of an isolation switch (15) to a contact carrier (154) of the isolation switch is larger than the distance (d24) of the contact bar (242) of the auxiliary switch (24) to the auxiliary contact carrier (243) of the auxiliary switch (24) that is mechanically connected to the contact carrier (154) of the isolation switch (15) such that when the actuator (46) moves from the first position to the second position using the stored mechanic energy, the auxiliary switch (24) opens prior the isolation switch (15).

22. The circuit protection device of claim 21, wherein based on the different distances (d22, d24, dl 5) the order of switch opening when the actuator (46) moves from the first position to the second position is as follows: the main switch (22) opens first, then the one or more auxiliary switch (24) open, and finally, the isolation switch (15) opens.

23. The circuit protection device of claim 21 or 22, wherein based on the different distances (d22, d24, dl 5) the order of switch closing when the actuator (46) moves from the second position to the first position is as follows: the isolation switch (15) closes first, then the one or more auxiliary switch (24) closes, and finally, the main switch (22) closes.

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