ELECTRONIC SWITCHING DEVICE

Description

[0001] The invention relates to a switching device with a first and a second switching point.

[0002] In the development of electronic switching devices, there are modifications that combine a semiconductor switching point with a mechanical contact. A distinction is made between mechanical switching contacts connected in parallel to a transistor array and those connected in series. There are also product segments with switching devices that feature both series-connected and parallel mechanical switching points. The operating element of these switching devices acts directly on the parallel contact, or the mechanical contacts are implemented as relay contacts and are indirectly actuated electrically via a state machine in a time-coordinated manner.

[0003] The disadvantage of these switching devices is that a forced opening of the galvanic contacts is not possible. Furthermore, they lack a standardized isolating function and do not provide galvanic opening in the event of an overload.

[0004] From EP 2 234 136 A1, a DC circuit breaker is known which includes a contact unit. The contact unit has mechanical contacts and a semiconductor switch connected in series with the mechanical contacts. The DC circuit breaker further comprises a switching mechanism unit with an actuating handle for manual operation, which is movably attached to the housing, a position detection unit for detecting the actuating position of the actuating handle, and a control unit. The control unit switches off the contact unit when an overcurrent occurs. The control unit is configured to first switch off the semiconductor switch and then control a trigger to switch off the mechanical contacts, thereby switching off the contact unit.

[0005] From WO 2014 / 110625 A1, a switching module for connecting a load to an AC power supply is known, comprising an electromechanical switch, wherein electrical energy is not required to maintain the latched open state or the latched closed state, wherein the switching module further comprises a semiconductor switch in series with the electromechanical switch, as well as a control module for periodically driving the semiconductor switch from an ON state to an OFF state during part of an AC cycle, and a storage device which is fed from the voltage drop across the semiconductor switch and which drives the semiconductor switch and provides an electrical OFF signal to the electromechanical switch.

[0006] The object of the present invention is to design an electronic switching device according to the requirements profile set out above.

[0007] This problem is solved according to the invention by a switching device according to claim 1. Advantageous embodiments and further developments, which can be used individually or in combination with one another, are the subject of the dependent claims.

[0008] According to the invention, this problem is solved by a switching device comprising: a first, manually operated, separable switching point, wherein a change in the rotation angle of the operating point is to be determined via a rotation angle position sensing element, whereby a signal is generated at a certain rotation angle, which is passed on to an evaluation and control unit, and a second switching point, preferably a semiconductor switching point, which acts as a circuit breaker prior to the first switching point, wherein galvanic isolation is effected subsequently in a contact arrangement in the first switching point by means of a switching state transformer. wherein the control unit (24) comprises a control element (2) which is mounted on a cylindrical body (26) and wherein the control element (2) is flanged to one end region of the cylindrical body (26) and a projecting collar (27) is flanged to the cylindrical body (26) at the other end region and wherein the projecting collar (27) acts upon the rotation angle position sensing element (25) during a corresponding rotation movement of the control unit (2).

[0009] The electronic switching device or protective switching device according to the invention preferably has a single- or double-pole disconnectable switching point and a switching point actuated by a kinematic actuator for the galvanic isolation of a circuit. This galvanic switching point, including the operating element, can be arranged together with the semiconductor switching point and the electronic function blocks on the control board or printed circuit board in a common device housing or in a separate, separate, but attachable housing. An electronically switching semiconductor switching point, for example IGBTs in antiparallel connection or comparable circuits, is connected in series with this. The electronic switching device according to the invention also has further electronic function blocks in the form of a circuit for controlling the semiconductor switching element to change the switching state.

[0010] Furthermore, there is an electronic function block for a circuit to differentiate between a nominal operating current, an overload current or a short-circuit current, which has an electronic connection to the control circuit for the semiconductor switching element in order to generate a trigger or shutdown signal in case of a fault.

[0011] A cooling element, for example in the form of a heat sink, which is installed in the electronic switching device, serves to dissipate the waste heat from the semiconductor switching point.

[0012] The switching device also features a user-operated control element that indicates the different switching states, i.e., the on state, the off state, the "TRIPPED" status, and the reset after a tripped state. The control element is also designed to ensure a standard-compliant isolating function even with welded contacts.

[0013] Additional functional components of the electronic switching device according to the invention can consist of an element functioning as a switching state transformer, which converts an electrical trigger signal into a mechanical force-displacement quantity for triggering the magnetic release. The electrical trigger signal is a current flow that interacts with the magnetically based operating principles of the magnetic release. This switching mechanism requires a rechargeable and rechargeable energy storage device, for example in the form of a capacitor, for the electrical energy, as well as an electromagnetic field coil for triggering the release, which is initially held in its starting position by magnetic force.

[0014] The electronic switching device can also be equipped with a reset device to return the triggered magnetic release (MAGLATCH) to its initial holding position, thus restoring its readiness to trigger again. The crucial advantage of the magnetic release is that, in the event of a fault, in addition to the preemptive shutdown of the semiconductor switch, an additional, series-connected galvanic gap is subsequently de-energized. This offers the further technical advantage that, even in the case of a faulty, shorted-out, i.e., low-resistance, semiconductor switch, the load is still reliably galvanically isolated from the mains.

[0015] A further additional function of the electronic switching device can consist of a rotary angle position sensing element, which determines the switching state of the operating element, particularly for the change in switching position shortly before, initiated by the operating element, the knee joint kinematics (switching lock) leaves its switched-on position and switches to the switched-off state. This sensing can be implemented, for example, by means of a handle-operated electrical push button on the circuit board. This electrical push button is operatively connected to the control circuit of the semiconductor element(s).

[0016] If the operating element is rotated from the switched-on position, preferably at an angle of 90° to the mounting plane of the electromagnetic release, a couple of degrees towards the switched-off position, this pressure switch signals to the IGBT control that the semiconductor switching point is switched off. During the further rotation towards 0°, i.e., into the switched-off state, the manually operated, disconnectable switching point moves into a galvanically isolated open position.

[0017] First, the dead center of the mechanical knee joint, which is preferably at, for example, 72°, must be traversed. Starting from the activated position at an angle of 90° until the knee joint is moved to preferably 72°, a remaining rotation angle of 18° remains, which provides a sufficient time offset to actuate the leading pressure switch.

[0018] In the event of an overload, the control element initially remains in the ON 90° position. The electronic overload function block detects this and, via the semiconductor control function block, first generates a shutdown signal to the semiconductor switching point. Subsequently, an electrical trigger signal is generated for the magnetic switching state transformer, which in turn mechanically releases the knee joint kinematics, which then galvanically opens the first switching point.

[0019] The major advantage of the electronic switching device according to the invention lies in the fact that, through the advance switching of the pressure switch and the function-coupled deactivation of the semiconductor switching point, the galvanic contact can be opened without current, thus allowing it to be significantly smaller. This means that arc-conducting and arc-quenching devices can be omitted from the switching device. This results in a space-optimized design. Furthermore, a communication module is included, which enables future bus integration, as well as an external power supply for the switching device.

[0020] It corresponds to a special embodiment of the concept according to the invention that the switching device has evaluation electronics which have a circuit for controlling a semiconductor switching element.

[0021] A special embodiment of the concept according to the invention can consist in the switching device having a short-circuit overcurrent evaluation circuit.

[0022] It corresponds to a special embodiment of the concept according to the invention that the evaluating functional component is the semiconductor switching element or an additional one.

[0023] A further development of the concept according to the invention can consist in the switching device being designed as an integrated switching device, i.e., the functions of the switching device are housed in one casing.

[0024] A special embodiment of the concept according to the invention can consist in the fact that the switching device is designed as a modular switching device, i.e., the different functions of the switching device are arranged in a plurality of housing enclosures.

[0025] It corresponds to a specific embodiment of the concept according to the invention that the operating element, the magnetic release, and the contact arrangement for galvanic isolation are formed in a first housing, and the power electronics in a second housing. Here, the term power electronics is defined as the conversion of electrical energy using switching electronic components. This includes the electronic evaluation units listed above.

[0026] A further development of the concept according to the invention can consist in the switching device having an element with a function as a switching state transformer, which converts an electrical signal into a force / displacement transmission in the magnetic release.

[0027] A special embodiment of the concept according to the invention can consist in the switching device having a mechanical return device which resets the magnetic trigger after triggering.

[0028] It corresponds to a special embodiment of the concept according to the invention that the rotary angle position sensing element is designed as an electrical pressure switch or as an inductive proximity switch or as a Hall sensor with magnetic encoder or in the form of a printed circuit board mountable light barrier solution on a printed circuit board.

[0029] A further development of the concept according to the invention can consist in the switching device having a communication module for a communication environment in the field.

[0030] A special embodiment of the concept according to the invention can consist in the switching device having an external power supply.

[0031] It corresponds to a special embodiment of the concept according to the invention that the magnetic release has a plunger acted upon by a release spring in the release direction and a coil, wherein a current flow through the coil generates a magnetic flux H coil in the event of release and wherein the plunger is held in a first attracted switching position by a magnetic flux H remanence, which is caused by a magnetic remanence system.

[0032] A further development of the concept according to the invention can consist in the magnetic trigger having an armature, a permanent magnet and an intermediate yoke, which are partially surrounded by an outer yoke, a coil which surrounds the intermediate yoke and a return spring which surrounds the armature, wherein the direction of movement of the armature is parallel to the alignment of the coil windings of the coil.

[0033] A special embodiment of the concept according to the invention can consist in the magnetic trigger having a yoke in which a permanent magnet and a coil are arranged, and an armature which is positioned on the yoke via a pre-tensioned return spring, wherein the movement of the armature during a current flow through the coil is designed as a rotational movement by means of the pre-tensioned return spring.

[0034] The electronic switching device according to the invention comprises a first assembly, which includes an operating element, an energy storage device, a magnetic release mechanism, and a contact arrangement consisting of a movable contact bridge with contact pieces and two opposing, fixedly positioned contact bridges with contact pieces, which form the galvanic opening point. The movable contact bridge is spring-mounted. The second assembly of the electronic switching device comprises a printed circuit board, which is connected to the magnetic release mechanism via an element.

[0035] The element functions as a switching state transformer.

[0036] Further details and advantages of the invention are explained below with reference to exemplary embodiments and the drawing.

[0037] This shows: Fig. 1 in a schematic overview representation a partial section of an electronic switching device according to the invention with a magnetic release and its electronic connection; Fig. 2 in a schematic view from above, the partial section of the electronic switching device according to Fig. 1 ; Fig. 3 in a perspective view the interaction of a control unit of the electronic switching device with a rotary angle position querying element in the initial position; Fig. 4 in an enlarged perspective section, the position of the control unit relative to the rotation angle position querying element in the initial position according to Fig. 3 ; Fig. 5 in a perspective view the interaction of the control unit of the electronic switching device with the rotary angle position querying element in the trigger position; Fig. 6 in an enlarged perspective section, the position of the control unit relative to the rotation angle position querying element in the trigger position according to Fig. 5 ; Fig. 7 in a perspective view the interaction of the control unit of the electronic switching device with the rotary angle position querying element in the movement from the trigger position to the starting position; Fig. 8 in an enlarged perspective section the position of the control unit to the rotation angle position querying element in the movement from the trigger position to the starting position according to Fig. 7 ; Fig. 9 in a perspective view a partial section of an electronic switching device according to the invention with a magnetic trigger and its electronic connection in the initial position according to Fig. 3 und 4 ; Fig. 10 in a perspective view a partial section of an electronic switching device according to the invention with an electromagnetic trigger and its electronic connection in the trigger position according to Fig. 5 und 6 ; Fig. 11 in a schematic representation a first embodiment of a magnetic release without flux amplification by a ferromagnetic yoke with a magnetic remanence system in the initial state; Fig. 12 in a schematic representation the magnetic trigger according to Fig. 11 with flux amplification by a ferromagnetic yoke with a magnetic remanence system in the initial state; Fig. 13 in a schematic representation the magnetic trigger according to Fig. 11 with flux amplification by a ferromagnetic yoke with a magnetic remanence system in the event of triggering; Fig. 14 A schematic representation shows a second embodiment of a magnetic release with an angled design, in the circuit state when the magnetic force is greater than the spring force and the coil is de-energized; Fig. 15 in a schematic representation the exemplary embodiment according to Fig. 14 , in the circuit state, when the spring force is greater than the sum of the magnetic force and the force of the coil; Fig. 16 A schematic representation shows an exemplary embodiment based on the design of Fig. 14 und 15 of the magnetic trigger with angled design, where the coil windings are positioned on a circuit board; Fig. 17 a schematic representation of a third embodiment of a magnetic trigger for an electronic switching device according to the invention; Fig. 18 in a schematic top view the armature of the magnetic release Fig. 17 in the circuit state of a coil that is not currently powered; Fig. 19 in a schematic top view of the armature of the magnetic release according to the Fig. 17 and 18 in the circuit state of a current-carrying coil.

[0038] Fig. 1 Figure 1 shows a partial section of an electronic switching device according to the invention, featuring a magnetic release and its electronic connection. The electronic switching device comprises a first unit 1, which includes an operating element 2, an energy storage device 3, a magnetic release 4, and a contact arrangement 5 consisting of a movable contact bridge 6 with contact pieces and two opposing, fixed contact bridges 7 with contact pieces, which form the galvanic opening point. The movable contact bridge is spring-mounted. The second unit 8 of the electronic switching device includes a printed circuit board 9, which is connected to the magnetic release 4 via an element 10. The element 10 functions as a switching state transformer. The second unit also contains a cooling element 13 for the semiconductor switching element 12. Terminal blocks 14 are arranged outside the housing.The two components 1, 8 of the electronic switching device can be arranged in one housing or largely separately in different housings.

[0039] Fig. 2 shows the partial section of the electronic switching device. Fig. 1 From above. In this illustration, the first component 1 is shown with the control element 2, the energy storage device 3, the magnetic release 4, the contact arrangement 5, and terminal connections 15. The second component 8 is essentially represented as the printed circuit board 9, on which various functional modules are arranged. The functional modules include a control circuit 16 for the semiconductor switching element 12, a current evaluation unit 17, a short-circuit / overload current evaluation circuit 18, a voltage monitoring circuit 19, a pre-charging circuit 20, an EMC component 21, a communication module 22, and a power supply 23.

[0040] In Fig. 3 The interaction of the control unit 24 with the control element 2 of the electronic switching device with a rotary-angle position-sensing element 25 in the initial position is shown. The control unit 24 comprises the control element 2, which is mounted on a cylindrical body 26. The control unit 24 is flanged to one end of the cylindrical body 26, and a projecting collar 27 is flanged to the other end of the cylindrical body 26. The projecting collar 27 acts upon the rotary-angle position-sensing element 25 when the control unit 2 is rotated accordingly. The rotary-angle position-sensing element 25 has a component 28, preferably designed to be movable in one plane, which is preferably pressed into a housing 29 when acted upon by the projecting collar 27. The rotary-angle position-sensing element 25 is preferably resiliently mounted in the housing 29. Fig. 3 The operating unit 24 is shown in its initial position at an angle of 0° to the installation plane of the magnetic trigger.

[0041] Fig. 4 The figure shows in an enlarged partial section the position of the protruding collar 27 on the cylindrical body 26 or of the control element 24 in relation to the rotation angle position querying element 25.

[0042] In Fig. 5 The interaction of the control element 24 of the electronic switching device with the rotary angle position sensing element 25 in the trip position is shown. The control element 2 is now at an angle of 90° to the mounting plane of the magnetic trip 100, 200, 300. The projecting collar 27 of the cylindrical body 26 can preferably be designed with a recess.

[0043] Fig. 6 The figure shows, in an enlarged partial section, the position of the control element relative to the rotation angle position querying element 25 in the trigger position with an angle of 90° between control element 2 and the mounting plane of the magnetic trigger.

[0044] In Fig. 7 The interaction of the control element 24 of the electronic switching device with the rotary angle position sensing element 25 is shown in the movement from the trip position to the initial position. This position is characterized by an angle of 72° between the control element 2 and the mounting plane of the magnetic trip. The opening movement of the galvanic switching point is coupled to this position.

[0045] Fig. 8 The figure shows, in an enlarged section, the position of the control unit relative to the rotation angle position querying element 25 in the movement from the trigger position to the starting position.

[0046] In Fig. 9 Figure 1 shows a partial section of an electronic switching device according to the invention with a magnetic trigger and its electronic connection in the initial position.

[0047] Fig. 10 shows a partial section of the electronic switching device according to the invention with a magnetic release and its electronic connection in the release position according to Fig. 4 and 4a.

[0048] Fig. 11 Figure 1 shows a first embodiment of a magnetic release 100 without flux amplification by a ferromagnetic yoke, featuring a magnetic remanence system in the initial state. The magnetic release 100 comprises a release spring 30, which acts on a plunger 31 in the release direction, and a coil 32, wherein a current flow through the coil 32 generates a magnetic flux H in the event of release. The plunger 31 is connected to a latching point 33, and the latching point 33 is connected to a switching kinematic mechanism 34. The switching kinematic mechanism 34 is mechanically connected to current-carrying main contacts 35, which are closed in the initial state and open in the event of release. A magnetic remanence system 36 in the form of a pole piece is arranged in the coil 32. The diagram below this arrangement shows a current-versus-time plot, which displays the magnetizing current pulse H2 for the initial state.

[0049] In Fig. 12 The magnetic trigger 100 with flux amplification by a ferromagnetic yoke 37 with a magnetic remanence system 36 is shown in its initial state. The diagram below this arrangement shows a current-versus-time plot, which displays the magnetizing current pulse H2 for the initial state.

[0050] Fig. 13 Figure 1 shows the electromagnetic trigger 100 with flux amplification by a ferromagnetic yoke 37 with a magnetic remanence system 36 in the event of triggering. The diagram below this arrangement shows a current-versus-time plot, which displays the current pulse for the coercive field strength H5 during the triggering state.

[0051] Fig. 14 Figure 2 shows a second embodiment of a magnetic release 200 with an angled design, in the switched state when the magnetic force is greater than the spring force and the coil is de-energized. The magnetic release 200 for switching devices comprises an armature 38, which has a plunger attachment 39 at one end and a plunger end region 40 at the other end, a permanent magnet 41 and an intermediate yoke 42, which are partially surrounded by an outer yoke 43, a coil 44, which surrounds the intermediate yoke 42, and a return spring 45, which surrounds the plunger end region 40 of the armature 38. The armature 38 is positioned in the magnetic release 200 such that the direction of movement of the armature 38 is parallel to the orientation of the coil windings of the coil 44. For this purpose, the plunger end region 40 of the armature 58 is mounted in a gap 46 between the intermediate yoke 42 and the outer yoke 43.

[0052] In Fig. 15 is the embodiment according to Fig. 15 This is shown in the circuit state when the spring force is greater than the sum of the magnetic force and the force of the coil 44. In this case, the piston end region 40 of the armature 38 increases its distance to the intermediate yoke 42.

[0053] Fig. 16 shows, based on the exemplary embodiment from the Fig. 15 and 16 the magnetic trigger 200 according to the invention with angled construction, wherein the coil windings of the coil 44 are positioned in the area of ​​the intermediate yoke 42 on a circuit board 47.

[0054] Fig. 17 Figure 3 shows a third embodiment of an electromagnetic release 300. The magnetic release 300 has a yoke 48 in which a permanent magnet 49 and a coil 50 are arranged, and an armature 51 which is positioned on the yoke 48 by means of a pre-tensioned return spring 52. When current flows through the coil 50, the movement of the armature 51 is formed as a rotational movement by the pre-tensioned return spring 52, preferably a torsion spring. Simultaneously, this bifunctional armature 51 can also be arranged as a latch lever within the switching kinematics of a switch lock.

[0055] In Fig. 18 The armature 51 of the magnetic release 300 is shown in the switching state of a de-energized coil 50. In this case, the magnetic force is greater than the spring force.

[0056] In Fig. 19The armature 51 of the magnetic release 300 is shown in the switching state of a current-carrying coil 50. In this case, the spring force is greater than the sum of the magnetic force and the force of the coil.

[0057] The electronic switching device according to the invention is characterized by the fact that, through the advance switching of the pressure switch and the function-coupled deactivation of the semiconductor switching point, the galvanic opening point can be opened without current, thus allowing it to be dimensioned significantly smaller. Therefore, the arc-conducting and arc-quenching devices in the switching device can be omitted due to the current-free opening, resulting in a space-optimized design. Reference symbol list

[0058] 1 First component 2 Control element 3 Energy storage 4 Magnetic release 5 Contact arrangement 6 Contact bridge 7 Contact bridge 8 Second component 9 Circuit board 10 Element 11 Control unit 12 Semiconductor switching element 13 Cooling element 14 Terminal connection 15 Terminal connection 16 Control circuit 17 Current evaluation unit 18 Short-circuit / overload current evaluation circuit 19 Voltage monitoring 20 Pre-charging circuit 21 EMC component 22 Communication module 23 Power supply 24 Control unit 25 Rotation angle position sensing element 26 Cylindrical body 27 Protruding collar 28 Component 29 Housing 30 Release spring 31 Plunger 32 Coil 33 Latching point 34 Switching kinematics 35 Main contact 36 Magnetic remanence system 37 Yoke 38 Armature 39 Punch attachment 40 Punch end area 41 Permanent magnet 42 Intermediate yoke 43 Outer yoke 44 Coil 45 Return spring 46 Gap 47 Circuit board 48 Yoke 49 Permanent magnet 50 Coil 51 Armature 52 Return spring 100 Magnetic release 200 Magnetic release300 Magnetic Trigger

Claims

1. Switching device having: - a first separable switching point which is to be actuated manually by means of an operating device (24), wherein a change in the rotation angle of the operating device (24) is to be determined by a rotation angle position sensing element (25), whereby at a particular rotation angle a signal is generated which is passed on to an evaluation and control unit, and - a second switching point which acts in a circuit-disconnecting manner temporally ahead of the first switching point, wherein galvanic isolation is brought about in a contact arrangement (5) in the first switching point temporally subsequently by means of a switching state transformer, characterized in that - the operating device (24) comprises an operating element (2) which is mounted on a cylindrical body (26) and wherein the operating element (2) is flanged to one end region of the cylindrical body (26) and a projecting collar (27) is flanged to the other end region on the cylindrical body (26) and wherein the projecting collar (27) acts upon the rotation angle position sensing element (25) in the case of a corresponding rotation movement of the operating device (2).

2. Switching device according to Claim 1, characterized in that the switching device has evaluation electronics which have a circuit for controlling a semiconductor switching element (12) .

3. Switching device according to either of Claims 1 and 2, characterized in that the switching device has a short-circuit overcurrent evaluation circuit (18).

4. Switching device according to one of Claims 1 to 3, characterized in that the evaluating function module is the semiconductor switching element (12) or an additional one.

5. Switching device according to one of Claims 1 to 4, characterized in that the switching device is designed as a modular switching device.

6. Switching device according to Claim 5, characterized in that the operating device (24), the magnetic trigger (100, 200, 300) and the contact arrangement (5) are formed in a first housing and the power electronics are formed in a second housing.

7. Switching device according to one of Claims 1 to 6, characterized in that the switching device has an element (10) having a function as a switching state transformer, which converts an electrical signal into a force / displacement transfer in the magnetic trigger (100, 200, 300).

8. Switching device according to one of Claims 1 to 7, characterized in that the switching device has a mechanical return apparatus which resets the magnetic trigger (100, 200, 300) after the latter has been triggered.

9. Switching device according to one of Claims 1 to 8, characterized in that the rotation angle position sensing element (25) is designed as an electric pressure switch or as an inductive proximity switch or as a Hall sensor having a magnetic encoder or is in the form of a printed circuit board-mountable light barrier solution on a printed circuit board.

10. Switching device according to one of Claims 1 to 9, characterized in that the switching device has a communication module (22) for a communication environment in the field.

11. Switching device according to one of Claims 1 to 10, characterized in that the switching device has an external power supply (23).

12. Switching device according to one of Claims 1 to 11, characterized in that the magnetic trigger (100) has a plunger (31) which is acted upon by a trigger spring (30) in the trigger direction, and a coil (32), wherein a current flow through the coil (32) generates a magnetic flux Hcoil in the case of triggering and wherein the plunger (31) in a first retracted switching position is held in the switching position by a magnetic flux Hremanence caused by a magnetic remanence system (36).

13. Switching device according to one of Claims 1 to 12, characterized in that the magnetic trigger (200) has an armature (38), a permanent magnet (41) and an intermediate yoke (42) which are partially surrounded by an outer yoke (43), a coil (44) which surrounds the intermediate yoke (42), and a return spring (45) which surrounds the armature (38), wherein the direction of movement of the armature (38) is formed parallel to the orientation of the coil windings of the coil (44).

14. Switching device according to one of Claims 1 to 12, characterized in that the magnetic trigger (300) has a yoke (48) in which a permanent magnet (49) and a coil (50) are arranged, and an armature (51) which is positioned on the yoke (48) above a preloaded return spring (52), wherein when current flows through the coil (50) the movement of the armature (51) is in the form of a rotation movement by way of the preloaded return spring (52).