EP4699156A1

EP4699156A1 - Tripping unit for a circuit breaker, circuit breaker and method for operating a tripping unit

Info

Publication number: EP4699156A1
Application number: EP24708132.6A
Authority: EP
Inventors: Werner Dichler
Original assignee: Eaton Intelligent Power Ltd
Current assignee: Eaton Intelligent Power Ltd
Priority date: 2023-04-19
Filing date: 2024-02-15
Publication date: 2026-02-25
Also published as: WO2024217719A1; GB2629178A; GB202305753D0

Abstract

The tripping unit (1) comprises a solenoid (2), a core (3) at least partially surrounded by the solenoid and a permanent magnet (4). At the first end of the core (3), the core is connected to a releasing mechanism (5) configured to break a connection between contacts of the circuit breaker. The permanent magnet (4) is arranged at the second end of the core (3) opposite to the first end. A magnetic direction of the permanent magnet and a magnetic direction of an electromagnet formed by the solenoid and the core are opposite to one another.

Description

Tripping unit for a circuit breaker, circuit breaker and method for operating a tripping unit

A tripping unit , in particular for a circuit breaker, and a circuit breaker are speci fied . Furthermore , a method for operating a tripping unit is speci fied .

A task to be solved is , inter alia, to provide a tripping unit with an increased trip force . Another task to be solved is , inter alia, to provide a circuit breaker comprising such a tripping unit and a method for operating such a tripping unit .

These tasks are solved by a tripping unit comprising the features of independent claim 1 , by a circuit breaker comprising the features of claim 9 and by a method comprising the features of claim 12 . Advantageous embodiments and further developments are the subj ect-matter of the respective dependent patent claims .

In at least one embodiment , the tripping unit comprises a solenoid, a core at least partially surrounded by the solenoid and a permanent magnet . At the first end of the core , the core is connected to a releasing mechanism configured to interrupt an electrical connection between contacts of the circuit breaker . The permanent magnet is arranged at the second end of the core opposite to the first end . A magnetic direction of the permanent magnet and a magnetic direction of an electromagnet formed by the solenoid and the core are opposite to one another . The solenoid is formed, for example , with a coil which preferably comprises copper . In particular, the solenoid comprises at least two electrical contacts . A current and/or a voltage can be applied to the electrical contacts of the solenoid . In case that a supply voltage is applied to the electrical contacts of the solenoid, the solenoid together with the core forms an electromagnet . A magnetic direction of the electromagnet is determined by the supply voltage applied to the electrical contacts of the solenoid . The magnetic direction is preferably parallel to the main extension direction of the solenoid .

A coil of the solenoid may be a quadratic coil or a circular coil . That is , for example a quadratic coil comprises a quadratic cross-section and a circular coil comprises a circular cross-section . The cross-section may be perpendicular to a main extension direction of the solenoid .

The core is preferably formed with a metal . In particular, the metal of the core is a ferromagnetic metal . For example , the core comprises iron or an iron alloy or is made of iron or an iron alloy .

The core comprises , for example , a rectangular elongated shape . A main extension direction of the core extends between the first end and the second end of the core . In particular, the solenoid at least partially surrounds the core in directions perpendicular to the main extension direction of the core . In the case that the solenoid comprises two electrical contacts , a first electrical potential may be applied to a first electrical contact of the solenoid arranged in the vicinity of the first end of the core and a second electrical potential may be applied to a second electrical contact of the solenoid in the vicinity of the second end of the core . For example , the first electrical potential is smaller than the second electrical potential . That is , the first electrical contact of the solenoid forms a minus pole of the solenoid and the second electrical contact of the solenoid forms a plus pole of the solenoid . In this case , the magnetic direction of the electromagnet formed by the solenoid and the core is parallel to a first direction pointing from the first end to the second end of the core .

Preferably the permanent magnet follows the core in the first direction .

The permanent magnet is formed of a magnetic material . For example , the permanent magnet is a neodymium magnet or the li ke . In particular, the permanent magnet may comprise a ceramic, for example comprising barium and/or strontium ferrite , an alloy comprising aluminium, nickel and/or cobalt , and/or an alloy comprising samarium and cobalt .

The permanent magnet is preferably fixedly attached to a housing of the circuit breaker . In particular, the permanent magnet is arranged inside the housing .

It is also possible that the permanent magnet is arranged outside of the housing . In this case the permanent magnet is preferably fixedly attached to the housing . It is possible that additionally or alternatively the core and/or the solenoid are arranged inside the housing . In particular, the solenoid is fixedly connected to the housing . The core is preferably movable with respect to the housing .

Contacts of the circuit breaker may be electrically separated by the releasing mechanism . That is , when the releasing mechanism is activated, an electrical circuit into which the circuit breaker is integrated is interrupted . This means that by activation of the releasing mechanism the circuit breaker may be activated, i . e . , released . Interruption of the electrical connection between the contacts of the circuit breaker is preferably temporary . That is , the connection may be re-established .

Since the core is connected to the releasing mechanism, the releasing mechanism may be activated by the movement of the core . In particular, a movement of the core is at least partially trans ferred to the releasing mechanism, which preferably causes an activation of the releasing mechanism . For example , at a tripping event the solenoid is provided with the supply voltage . Thereby, a magnetic field is established by the solenoid which causes the core to move due to magnetic interactions . In particular, the core moves such that it is centred or tends to centre in the solenoid . That is , due to the detection of the tripping event , the core is moved in order to activate the releasing mechanism . For example , i f the circuit breaker is a residual current device circuit breaker, the tripping event is activated i f a residual current is observed . The releasing mechanism is preferably integrated in the housing of the circuit breaker .

Preferably, the releasing mechanism, i . e . , the circuit be reset by a handle of the circuit breaker . The releasing mechanism may be therefore connected to the handle of the circuit breaker . After activation the handle may be in an "OFF" position, indicating that the electrical connection between the contacts of the circuit breaker, and hence the electrical circuit into which the circuit breaker is integrated, is interrupted . The handle may be moved to an "ON" position, for example , after a cause for a tripping event activating the circuit breaker is overcome , to reset the releasing mechanism . Thus , the tripping unit may be reset by the handle .

A tripping unit described herein is based inter alia on the following technical considerations . Voltage-dependent circuit breakers have to work with voltages down to 85 V, which is commonly an AC voltage . In the case of low voltages , a trip force is much lower and could be too low to trip the releasing mechanism . That is , at low voltages the tripping unit may not work as intended and the releasing mechanism may not be activated . In conventional tripping units that do not comprise a permanent magnet , the release mechanism is activated by supplying the solenoid with a current such that the electromagnet is formed, which causes the core to move due to magnetic attraction . As the core is connected to the releasing mechanism, the movement of the core is used to activate the releasing mechanism . The tripping unit described herein makes use of the idea of us ing a permanent magnet , the magnetic direction of which is opposite to the magnetic direction of an electromagnet formed by the solenoid and the coil of the tripping unit . As a result , the trip force can be increased . During a tripping event , the permanent magnet repulses the core of the electromagnet because of their opposite magnetic directions . Therefore , the trip force is increased by the magnetic repulsion of the permanent magnet and the electromagnet formed by the core and the solenoid . This means in particular that in case of a trip, the trip force is a sum of the magnetic repulsion of the permanent magnet and the electromagnet and the centring of the core within the solenoid . Using a permanent magnet in addition to an electromagnet for tripping the releasing mechanism is a cost- ef fective solution for lower external supply voltages of the tripping unit .

Furthermore , in a steady state , i . e . a non-tripping state , the permanent magnet attracts the core and holds it in position . Advantageously, this increases a shock resistance of the circuit breaker as the risk of an accidental movement , and hence an accidental activation of the releasing mechanism, due to mechanical shock is reduced .

According to at least one embodiment of the tripping unit , in a first state of the tripping unit the core is in a first position and in a second state of the tripping unit the core is in a second position . In the first position the core is in contact with the permanent magnet and in the second position the core is at a distance from the permanent magnet . In particular the core is only partially surrounded by the core in the first position when seen, for example , in a plane view . In the first state , for example , a centre of gravity of the core and a centre of gravity of the solenoid do not overlap seen in their main extension directions . That is , core is not centred in the solenoid . I f the supply voltage is provided to the solenoid a force acts on the core that moves the core inside the solenoid in order to centre the core inside the solenoid .

According to at least one embodiment of the tripping unit , the release unit is inactive in the first state and active in the second state . That is in the second state , an electrical connection between the electrical contacts of the circuit breaker is interrupted . For example , at a tripping event , the tripping unit switches from the first state to the second state . Thereby, the core is moved from the first position to the second position . As a result the releasing mechanism is activated due to the movement of the core .

According to at least one embodiment , the solenoid is supplied with the supply voltage in the second state . By supplying the solenoid with the supply voltage , the solenoid together with the core forms the electromagnet . That is , by supplying the solenoid with current , the electromagnet is activated . By activating the electromagnet , the core is repelled from the permanent magnet since the magnetic directions of the permanent magnet into the electromagnet are opposite to each other . This repulsion together with the magnetic interactions of the core and the solenoid causes the movement of the core from the first position to the second position . As a result , the releasing mechanism is activated and the electrical connection between the electrical contacts of the circuit breaker is interrupted . This means in particular that the releasing mechanism may be activated by supplying the solenoid with a supply voltage .

According to at least one embodiment , the supply voltage is a recti fied AC voltage or a DC voltage . By using a recti fied AC or a DC voltage for the supply voltage , the magnetic direction of the electromagnet may be fixedly, which means in particular constant over time , defined . That is , even i f the tripping unit is externally supplied by an AC voltage , the magnetic direction of the electromagnet may not change over time . In this case , the tripping unit preferably comprises a diode . The diode may act as a recti fier .

According to at least one embodiment , the supply voltage is at least 80 V . Preferably, the supply voltage is at most 100 V . By using the permanent magnet , such low voltages for the supply voltage of the solenoid are possible . That is , the tripping unit may also be used for circuit breakers that are supplied with very low voltages .

According to at least one embodiment , the core is attracted by the permanent magnet in the first position . Preferably, the core is in contact with the permanent magnet in the first position . Since the core is made of a magnetic material , the core is attracted by the permanent magnet . Due to the attraction of the core to the permanent magnet , the robustness of the tripping unit against mechanical shock may be increased . That is , the risk of a movement of the core from the first position to the second position by accident , thereby accidentally activating the releasing mechanism, is signi ficantly reduced . As a consequence , the risk of a mal function of the tripping unit may be reduced .

According to at least one embodiment , the releasing mechanism comprises a lever spring which is configured to keep the core in the first position . The lever spring may push a part of the releasing mechanism towards the core . This ensures that by moving the core from the first position to the second position, the movement is trans ferred to the releasing mechanism which allows an activation of the releasing mechanism . Furthermore , by the lever spring, the robustness of the tripping unit against mechanical shock may be further increased .

According to at least one embodiment , the tripping unit further comprises a microcontroller . The microcontroller is configured to initiate a switching between the first state and the second state of the tripping unit . Preferably, the microcontroller is further configured to detect a tripping event which makes it necessary to activate the releasing mechanism . Further, preferably the microcontroller is configured to supply the solenoid with the supply voltage in the case that the tripping event is detected . This means in particular that the microcontroller is configured to control and activate the tripping unit .

According to at least one embodiment , the core is loosely attached to the releasing mechanism . Preferably, the core is al so loosely attached to the permanent magnet . This means in particular that the core is not fixed to the releasing mechanism and/or the permanent magnet by a fixing means . Such a fixing means may be , for example , a screw, a rivet , a glue or the like . For example , the core is moveable with respect to the housing of the circuit breaker, the solenoid, the permanent magnet and/or the releasing mechanism .

Furthermore , a circuit breaker is described . The circuit breaker comprises a tripping unit described herein . Therefore , all features disclosed for the tripping unit are al so disclosed for the circuit breaker and vice versa .

According to at least one embodiment of the circuit breaker, the circuit breaker comprises at least two electrical contacts . In an active state of the releasing mechanism the electrical contacts are electrically separated from each other and/or from input contacts and in an inactive state of the releasing mechanism the electrical contacts are electrically connected to one another and/or to the input contacts . This means in particular that by activating the releasing mechanism, for example as described above , the electrical contacts may be electrically separated from one another . That is , during a tripping event , the tripping unit may activate the circuit breaker .

According to at least one embodiment , the circuit breaker is a residual current device , a residual current operated circuit breaker or a residual current operated circuit breaker with overcurrent protection . For example , the circuit breaker relies on the concept of detecting a residual current in the circuit in which the circuit breaker is integrated . Detecting such a residual current will activate the circuit breaker . That is , the detection of a residual current is the tripping event which may trip the tripping unit in order to activate the circuit breaker . Furthermore , a method for operating a tripping unit is described . The method is configured to operate a tripping unit as described herein . Therefore , all features disclosed for the method are also disclosed for the tripping unit and vice versa .

According to at least one embodiment , the method comprises the following steps . In a method step A) , a tripping event is detected .

In a method step B ) , the electromagnet formed by the solenoid and the core is activated by supplying the solenoid with a supply voltage .

In a method step C ) , the releasing mechanism is activated by movement of the core from the first position to the second position .

Prior to step A) , the tripping unit is preferably in the first state and the releasing mechanism is further preferably inactive . This means that by performing the steps A) to C ) , the tripping unit is tripped, which activates the releasing mechanism which consequently activates the circuit breaker .

According to at least one embodiment of the method, the tripping event in step A) is detected by the microcontroller of the tripping unit and the supply voltage in step B ) is provided by the microcontroller .

According to at least one embodiment of the method, the tripping unit is externally supplied with an AC voltage . In step B ) the solenoid is supplied with a recti fied AC voltage . Preferbly the tripping unit comprises a diode . In particular, the diode serves as a recti fier for the AC current .

Further advantages and advantageous embodiments and further developments of tripping unit , the circuit breaker and the method described herein will become apparent from the following exemplary embodiments shown in connection with schematic drawings . Identical elements , elements of the same kind or elements having the same ef fect , are provided with the same reference signs in the figures . The figures and the proportions of the elements shown in the figures are not to be regarded as true to scale . Rather, individual elements may be shown exageratedly large for better representability and/or for better comprehensibility .

In the figures :

Figure 1 shows a schematic view of a tripping unit in a first state according to an exemplary embodiment ;

Figure 2 shows a schematic view of a tripping unit in a second state according to the exemplary embodiment ;

Figure 3 shows a schematic view of a circuit breaker according to an exemplary embodiment ; and

Figure 4 shows a schematic circuit of the circuit breaker according to the exemplary embodiment .

Figure 5 shows a schematic circuit of the circuit breaker according to a comparative example . The tripping unit 1 in the first state 11 of Figure 1 comprises a solenoid 2 and a core 3 . The solenoid 2 surrounds the core 3 partially . The solenoid 2 is a copper coil with a circular cross-section taken perpendicular to the drawing plane of figure 1 . The core 3 comprises iron and has a first end 31 and a second end 32 . In the view figures 1 and 2 the core 3 is partially covered by the solenoid 2 , in particular in regions where the core 3 is illustrated with dashed lines .

A permanent magnet 4 is arranged at the second end 32 of the core 3 . The permanent magnet 4 is formed, for example with a neodymium magnet . The permanent magnet 4 comprises a magnetic direction 40 . For example , a south pole of the permanent magnet 4 faces the core 3 and the north pole of the permanent magnet 4 faces away from the core 3 .

The core 3 is in a first position 33 . In the first position 33 , the core 3 is in contact with the permanent magnet 4 . In particular, the core 3 and the permanent magnet 4 touch each other . That is , the core 3 and the permanent magnet 4 are in direct contact . Since the core 3 comprises iron, the core 3 is attracted to the permanent magnet 4 by magnetic forces . Due to this attraction, the core 3 is advantageously kept in the first position 33 .

In contrast to the tripping unit 1 in the first state 11 , the core 3 is in a second position 34 i f the tripping unit 1 is in a second state ( compare figure 2 ) . In the second position 34 , the core 3 is arranged at a distance 41 from the permanent magnet 4 . That is , in a transition from the first state 11 to the second state 12 , the core 3 moves from the first position 33 to the second position 34 . This is achieved by applying a supply voltage 20 to first and second contacts 21 , 22 of the solenoid 2 . By applying the supply voltage 20 , the core 3 and the solenoid 2 form an electromagnet .

The supply voltage 20 is applied such that a magnetic direction 30 of the electromagnet is opposite to the magnetic direction 40 of the permanent magnet 4 . As a result , the permanent magnet 4 and the core 3 repel each other . I f the south pole of the permanent magnet 4 faces the core 3 , a minus pole of the solenoid 2 is preferably formed by the first electrical contact 21 and a plus pole of the solenoid 2 is preferably formed by the second electrical contact 22 .

Figure 3 shows a circuit breaker 100 described herein in a schematic sectional view . The circuit breaker 100 comprises a tripping unit 1 , for example the tripping unit 1 according to figure 2 , and a releasing mechanism 5 . The tripping unit 1 and the releasing mechanism 5 are arranged in a housing 105 of the circuit breaker 100 . In the view figure 3 the core 3 is partially covered by the solenoid 2 , in particular in regions where the core 3 is illustrated with dashed lines .

At the first end 31 of the core 3 , the core 3 is connected to the releasing mechanism 5 . In particular, the core 3 touches the releasing mechanism 5 at the first end 31 . That is , the core 3 is loosely attached to the releasing mechanism 5 . In particular, no fixed connection is present between the core 3 and the releasing mechanism 5 .

The releasing mechanism 5 comprises a lever spring 50 which is configured to push the releasing mechanism 5 towards the core 3. That is, in particular in the first state 11, the lever spring 50 is configured to keep the core 3 in the first position 33. In the first state 11, the releasing mechanism 5 is inactive. The releasing mechanism 5 is configured to interrupt an electrical connection between electrical contacts 101, 102 of the circuit breaker 100. This means that if the releasing mechanism 5 is activated, the circuit breaker 100 is tripped and interrupts an electrical circuit in which the circuit breaker 100 is integrated.

In Figure 3 the releasing mechanism 5 is activated. The releasing mechanism 5 is activated if the core 3 is in second position 34. This means that the releasing mechanism 5 may be activated by applying the supply voltage 20 to electrical contacts 21, 22 of the solenoid 2.

The releasing mechanism 5 is in particular activated if a tripping event is detected. For example, a tripping event may be a residual current in a circuit in which the circuit breaker 100 is integrated. For example, the tripping event is detected by a microcontroller 6. The microcontroller 6 is in particular part of the tripping unit 1 (compare figure 4) .

If the tripping event is detected, the supply voltage 20 is applied to the solenoid 2. Thereby the solenoid 2 and the core 3 form an electromagnet and, as a result, the core 3 is repelled by the permanent magnet 4. Furthermore, due to magnetic forces, the core 3 is moved inside the solenoid 2. Thus, due to the magnetic forces of the electromagnet and the permanent magnet 4, the core 3 moves from the first position 33 to the second position 34. This movement activates the releasing mechanism 5. As a result, electrical connection between electrical contacts 101, 102 of the circuit breaker 100 is interrupted and the electrical circuit into which the circuit breaker 100 is also interrupted.

The circuit breaker 100 further comprises a handle 110 by which the releasing mechanism 5 may be reset. That is, for example if the malfunction of the electrical circuit into which the circuit breaker 100 is integrated is overcome, the circuit breaker 100 may be reset.

In figure 4 the tripping unit 1 is in the second state 12, since an electrical connection between the electrical contacts of the circuit breaker 101, 102 is interrupted. The circuit breaker 100 may further comprise external contacts 103, 104 for the tripping unit 1. For example, a first electrical contact 103 of the tripping unit 1 is a so-called line port and a second electrical contact 104 is a so-called neutral port. Via the electrical contacts 103, 104 the tripping unit 1 is supplied with an external voltage. The external voltage is, for example, an AC voltage. Due to the permanent magnet, the external voltage for the tripping unit 1 may be smaller than 100 V. For example, the external voltage comprises a magnitude of 85 V. The external voltage in particular supplies the microcontroller 6 by which a tripping event may be detected.

In particular, the microcontroller 6 supplies the solenoid 2 with the supply voltage 20. The supply voltage 20 is preferably a rectified AC voltage. More preferably the supply voltage 20 is a rectified AC voltage with a fixed sign. This ensures that the magnetic direction 30 of the electromagnet 3 is fixed, i.e., constant over time. For providing a rectified AC voltage to the solenoid 2, the tripping unit 1 preferably comprises a diode 61. The diode 61 serves as a rectifier.

In contrast to figure 4, the comparative example 200 of figure 5 does not comprise a diode 61. Instead the comparative example 200 of figure 5 comprises a bridge rectifier 62. Due to the bridge rectifier 62 an AC voltage may be applied to the solenoid. The sign of this voltage changes over time with the frequency of the external AC voltage applied to the external electric contacts 103, 104. As a result, the magnetic direction 30 of the electromagnet 3 is not fixed, i.e., constant over time. That is, a comparative tripping unit 10 of the comparative example 200 cannot comprise a permanent magnet and work as the tripping unit 1 described herein. As a result, the comparative tripping unit 10 requires an external voltage, provided by the external electrical contacts 103, 104 of at least 100 V. For example, the external voltage in the comparative example 200 of figure 5 is 110 V.

The invention is not restricted to the exemplary embodiments by the description on the basis of said exemplary embodiments. Rather, the invention encompasses any new feature and also any combination of features, which in particular comprises any combination of features in the patent claims and any combination of features in the exemplary embodiments, even if this feature or this combination itself is not explicitly specified in the patent claims or exemplary embodiments. Re ferences

1 tripping unit

2 solenoid

3 core

4 permanent magnet

5 releasing mechanism

6 microcontroller

10 comparative tripping unit

11 , 12 first , second state of tripping unit

20 supply voltage

21 , 22 electrical contacts of the solenoid

30 magnetic direction of electromagnet

31 , 32 first , second end

33 , 34 first , second position of the core

40 magnetic direction of permanent magnet

41 distance

50 lever spring

61 diode

62 bridge recti fier

100 circuit breaker

101 , 102 contacts of circuit breaker

103 , 104 external electrical contacts for the tripping unit

105 housing

110 handle

200 comparative example of a circuit breaker

Claims

1. A tripping unit (1) for a circuit breaker (100) comprising :

- a solenoid ( 2 ) ,

- a core (3) at least partially surrounded by the solenoid (2) and

- a permanent magnet (4) , wherein

- at a first end (31) the core (3) is connected to a releasing mechanism (5) configured to interrupt an electrical connection between contacts (101, 102) of the circuit breaker (100) ,

- the permanent magnet (4) is arranged at a second end (32) of the core (3) opposite to the first end (31) ,

- a magnetic direction (40) of the permanent magnet (4) and a magnetic direction (30) of an electromagnet formed by the solenoid (2) and the core (3) are opposite to one another,

- in a first state (11) of the tripping unit (1) the core (3) is in contact with the permanent magnet (4) and in a second state (12) of the tripping unit (1) the core is at a distance (41) from the permanent magnet (4) ,

- the solenoid (2) is configured to be supplied with a supply voltage in the second state (12) such that the core (3) and the solenoid (2) form the electromagnet, and

- in the second state (12) the core (3) is repelled from the permanent magnet (4) such that a repulsion of the core (3) from the permanent magnet (4) together with magnetic interactions of the core (3) and the solenoid (2) causes a movement of the core (3) from the first state (11) to the second state (12) .

2. The tripping unit (1) according to claim 1, wherein

- in the first state (11) the releasing unit (5) is inactive, and

- in the second state (12) the releasing unit (5) is active .

3. The tripping unit (1) according to claim 1, wherein

- the supply voltage (20) is a rectified AC voltage, and

- the supply voltage (20) is at least 80 V.

4. The tripping unit (1) according claims 1 or 3, wherein the supply voltage (20) is at most 100 V.

5. The tripping unit (1) according to one of claims 1 to 4, wherein in the first position (33) the core (3) is attracted by the permanent magnet (4) .

6. The tripping unit (1) according to one of claims 1 to 5, wherein the releasing mechanism (5) comprises a lever spring (51) and the lever spring (51) is configured to keep the core (3) in the first position (33) .

7. The tripping unit (1) according to one of claims 1 to 6, further comprising a microcontroller (6) , wherein the microcontroller (6) is configured to initiate a switching between the first state (11) and the second state (12) of the tripping unit (1) .

8. The tripping unit (1) according to one of the preceding claims, wherein the core (3) is loosely attached to the releasing mechanism (5) and/or the permanent magnet (4) .

9. A circuit breaker (100) comprising the tripping unit (1) according to one of the preceding claims.

10. The circuit breaker (100) according to claim 9, further comprising at least two electrical contacts (101, 102) , wherein

- in an inactive state of the releasing mechanism (5) the electrical contacts (101, 102) are electrically connected to input contacts (103, 104) , and

- in an active state of the releasing mechanism (5) the electrical contacts (101, 102) are separated from the input contacts (103, 104) .

11. The circuit breaker (100) according to claim 9 or 10, wherein the circuit breaker (100) is a Residual Current Device, a Residual Current operated Circuit Breaker or a Residual current operated Circuit Breaker with Overcurrent protection.

12. Method for operating a tripping unit (1) according to one of claims 2 to 9 comprising the following steps:

A) detecting of a tripping event,

B) activating the electromagnet formed by the solenoid (2) and the core (3) by supplying the solenoid (2) with a supply voltage (20) ,

C) activating the releasing mechanism (5) by moving the core (3) from the first position (33) to the second position ( 34 ) , wherein prior to step A) the tripping unit (1) is in the first state (11) and the releasing mechanism (5) is inactive .

13. Method according to claim 12, wherein

- in step A) the tripping event is detected by a microcontroller (6) of the tripping unit (1) , and

- in step B) the supply voltage (20) is provided by the microcontroller (6) .

14. Method according to claim 12 or 13, wherein

- the tripping unit (1) is externally supplied with a AC current,

- in step B) the solenoid (2) is supplied with a rectified AC current, and

- the tripping unit (1) comprises a diode (61) .