Armature for electromagnetic actuator, an electromagnetic actuator, a switch device and a method for manufacturing an armature

Abstract

An armature for an electromagnetic actuator, the armature including an armature body, at least one electrically conductive member configured for cooperation with a magnetic field generator of an electromagnetic actuator, and a connection end configured for connection of the armature to an apparatus operable by an electromagnetic actuator. The armature body also having a cellular structure. The armature may form part of an electromagnetic actuator, which in turn may be a component in a switch device. The armature may be manufactured by an additive manufacturing process.

Claims

1. An armature for an electromagnetic actuator, the armature comprising: an armature body comprising a cellular structure, a magnetic field generator including a repulsion coil, at least one electrically conductive member configured for cooperation with the magnetic field generator, a connection end configured for connection of the armature to an apparatus operable by an electromagnetic actuator, wherein the electrically conductive member is a separate member attached to the armature body, wherein the armature body comprises a connection part configured as a channel in the armature body and said channel having an opening at the connection end of the armature, wherein the connection part is configured for connection of the armature to the apparatus operable by the electromagnetic actuator, and wherein said channel has a channel wall that forms part of an armature housing.

2. The armature according to claim 1, wherein the cellular structure comprises cells, each cell defining a hollow area having a longitudinal dimension and a lateral dimension, wherein the longitudinal dimension extends in a direction away from the electrically conductive member.

3. The armature according to claim 2, wherein the cellular structure includes cellular walls configured to take up and/or distribute forces and stresses within the armature.

4. The armature according to claim 2, wherein the armature is configured to be movable in at least one direction of movement, and wherein the cellular structure includes cellular walls extending in the at least one direction of movement.

5. The armature according to claim 2, wherein the cellular structure is a honeycomb structure.

6. The armature according to claim 2, wherein the armature body includes the armature housing configured to at least partly surround the cellular structure.

7. The armature according to claim 6, wherein the at least one electrically conductive member is at least partly embedded in the armature housing.

8. The armature according to claim 2, wherein the armature body has a central axis and a delimiting external contour, and wherein, for at least a portion of the armature body, a distance between the central axis and the external contour decreases in an axial direction towards the connection end of the armature.

9. The armature according to claim 2, wherein the armature body has at least one side that has a flat portion that is perpendicular to a central axis of the armature and wherein the at least one electrically conductive member is located on or in said flat portion.

10. The armature according to claim 2, comprising two electrically conductive members configured for cooperation with the magnetic field generator, wherein the armature has two opposing sides that each have a respective flat portion perpendicular to a central axis of the armature, and wherein the two electrically conductive members are located on or in the respective flat portions.

11. The armature according to claim 3, wherein the armature is configured to be movable in at least one direction of movement, and wherein the cellular structure includes cellular walls extending in the at least one direction of movement.

12. The armature according to claim 3, wherein the cellular structure is a honeycomb structure.

13. The armature according to claim 3, wherein the armature body includes the armature housing configured to at least partly surround the cellular structure.

14. The armature according to claim 3, wherein the armature body has a central axis and a delimiting external contour, and wherein, for at least a portion of the armature body, a distance between the central axis and the external contour decreases in an axial direction towards the connection end of the armature.

15. The armature according to claim 3, wherein the armature body has at least one side that has a flat portion that is perpendicular to a central axis of the armature and wherein the at least one electrically conductive member is located on or in said flat portion.

16. An electromagnetic actuator comprising: an armature including: an armature body comprising a cellular structure, at least one electrically conductive member, a connection end configured for connection of the armature to an apparatus operable by the electromagnetic actuator, wherein the electrically conductive member is a separate member attached to the armature body, wherein the armature body comprises a connection part configured as a channel in the armature body and said channel having an opening at the connection end of the armature, wherein the connection part is configured for connection of the armature to the apparatus operable by the electromagnetic actuator, and wherein said channel has a channel wall that forms part of an armature housing, at least one magnetic field generator including a repulsion coil, wherein the electrically conductive member is configured for cooperation with the magnetic field generator, and an electricity source connectable to the magnetic field generator.

17. A switch device comprising: at least a first electric contact element and a second electric contact element which can be selectively connected and disconnected with each other such that when the first and second contact elements are connected the switch device is closed, and when the first and second contact elements are disconnected the switch device is opened, and wherein one of said contact elements is movable, an electromagnetic actuator including: an armature having: an armature body comprising a cellular structure, at least one electrically conductive member, po3 a connection end configured for connection of the armature to an apparatus operable by the electromagnetic actuator, wherein the electrically conductive member is a separate member attached to the armature body, wherein the armature body comprises a connection part configured as a channel in the armature body and said channel having an opening at the connection end of the armature, wherein the connection part is configured for connection of the armature to the apparatus operable by the electromagnetic actuator, and wherein said channel has a channel wall that forms part of an armature housing, at least one magnetic field generator including a repulsion coil, wherein the electrically conductive member is configured for cooperation with the magnetic field generator, and an electricity source connectable to the magnetic field generator, a pullrod having a first end connected to the connection end of the armature of the electromagnetic actuator and having a second end connected to the movable contact element such that opening or closing of the switch device is controllable by the electromagnetic actuator.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will now be described in more detail, with reference being made to the enclosed schematic drawings illustrating different aspects and embodiments of the invention, given as examples only, and in which:

(2) FIG. 1 shows a circuit breaker with a Thomson coil electromagnetic actuator according to prior art,

(3) FIG. 2 is a schematic perspective view showing a first example of an armature,

(4) FIG. 3 shows schematically a bottom side of the armature in FIG. 2,

(5) FIG. 4 illustrates schematically a cross-section of the armature in FIG. 2,

(6) FIG. 5 illustrates schematically a second example of an armature,

(7) FIG. 6 illustrates schematically a third example of an armature,

(8) FIG. 7 illustrates schematically a first example of a switch device with a first example of an electromagnetic actuator,

(9) FIG. 8 illustrates schematically a second example of a switch device with a second example of an electromagnetic actuator,

(10) FIGS. 9a and 9b illustrate schematically a third example of a switch device with a third example of an electromagnetic actuator, and

(11) FIG. 10 illustrates schematically another example of an armature.

DETAILED DESCRIPTION

(12) In FIG. 1 is schematically illustrated an example of a circuit breaker 1 as is known from prior art and in which a Thomson coil is used to generate a large impulsive force. It may for example be a HVDC breaker. The mechanical part of the circuit breaker comprises a contact system, a pullrod, an ultra-fast actuator (often also called drive) and a control unit. Normally the circuit breaker is enclosed in an enclosure containing an insulating medium. The contact system comprises a pair of current carrying contacts 2a, 2b, of which one is a movable contact 2b and one is a stationary contact 2a. A pullrod 4 connects the contact system to the actuator 5. The pullrod is made of an electrically insulating material in order to electrically insulate the contacts from the actuator. The actuator comprises an electrically conductive armature 7, an opening coil 6a and a closing coil 6b which are connected to an electricity source. The opening coil 6a would conventionally be connected to a capacitor bank 8, as an electricity source. The closing coil may also be connected to the capacitor bank. The coils are e.g. flat multi-turn spiral coils, such as Thomson coils. This is thus an example of an electromagnetic actuator. Spring biased bistable contacts 9 are used to keep the armature 7 in close contact with the opening coil 6a or the closing coil 6b.

(13) The armature 7 is made of an electrically conducting material. When a fault current occurs, the control unit is triggered so that the breaker's actuator can separate the contacts within a few hundreds of a microsecond. This is done by discharging the capacitor bank 8 connected to the opening coil 6a, which will result in a large current surge in the coil that in turn generates a substantial varying magnetic field. Eddy-currents are generated in the armature 7, in the opposite direction, which will result in an repulsive force impulse that will move the armature 7 away from the coil 6a, in a downwards direction shown by the arrow in FIG. 1. The contacts 2a and 2b will thus by separated when the movable contact 2b is moved downwards by the armature 7 and the pullrod 4. Since the circuit breaker in FIG. 1 is also provided with a closing coil 6b, the armature 7 will come to a stop against the closing coil. In order to close the contacts again, the closing coil 6b can be activated such that the armature 7 and the pullrod 4 moves upwards and thereby moves the movable contact 2b into contact with the stationary contact 2a and thereby closing the electric circuit.

(14) In FIGS. 2, 3, 4, 5 and 6 are schematically illustrated examples of an armature 10, 30, 50 according to the present disclosure. FIG. 4 shows a cross-section of the armature shown in FIG. 2, and FIGS. 5 and 6 show cross-sections of alternative examples of an armature. The armature may e.g. be an armature for an electromagnetic actuator, such as a Thomson coil actuator. The armature 10, 30, 50 comprises an armature body 12, 32, 52, at least one electrically conductive member 14, 34, 54, 64 configured for cooperation with a magnetic field generator of an electromagnetic actuator, and a connection end 26, 46, 66 configured for connection of the armature to an apparatus operable by an electromagnetic actuator. The armature body 12, 32, 52 comprises a cellular structure 13, 33, 53. In FIGS. 4, 5 and 6 is also schematically illustrated a magnetic field generator 110, 130, 150, 151 with which the respective electrically conductive member 14, 34, 54, 64 is configured to cooperate.

(15) Generally, the cellular structure 13, 33, 53 may comprise cellular walls 18, 38, 58 that are configured to take up and/or distribute forces and stresses within the armature 10, 30, 50. Forces and stresses are generated by the repulsive force impulse that results when the armature is used in an electromagnetic actuator and in e.g. a switch device, as described above.

(16) An example of a cellular structure 13, 33, 53 of the armature body 12, 32, 52 can be more clearly seen in the perspective view of FIG. 2. The illustrated cellular structure 13 is a partly open cellular structure. It may be described as comprising an array of hollow cells. The cellular structure may for example be a honeycomb structure. A honeycomb structure usually comprises hexagonal cells, but the thickness of the cellular walls may vary such that the cells can be close to having a circular shape. The armature body in any one of the examples in this disclosure can comprise such a cellular structure. Other geometric shapes of the cells may also be foreseen, even when the cellular structure itself has the general structure of a honeycomb structure.

(17) The armature 10, 30, 50 is configured to be movable in at least one direction of movement when the armature is mounted in an electromagnetic actuator. Since the repulsion forces that are generated upon activation of the electromagnetic actuator affect the armature to move in a certain direction of movement, it is an advantage if the cellular structure 13, 33, 53 comprises cellular walls 18, 38, 58 that extend essentially in the at least one direction of movement, in order to take up and/or distribute forces and stresses within the armature and have a strong cellular structure and a strong armature. In the examples illustrated in FIGS. 2, 4, 5 and 6, the armature 10, 30, 50 comprises a central axis A and the armature 10, 30, 50 is configured to be movable in a direction of the central axis, i.e. in the axial direction along the central axis, when the armature is mounted in the electromagnetic actuator. The cellular structure then comprises cellular walls 18, 38, 58 extending essentially in the axial direction. However, it may also be conceivable to have cellular walls that are somewhat inclined in relation to the direction of movement/the axial direction.

(18) In the shown examples of FIGS. 2-6, the armature 10, 30, 50 has at least one side 21, 40, 60, 61 that has an essentially flat portion 22, 43, 62, 63, which flat portion is essentially perpendicular to a central axis A of the armature, and the at least one electrically conductive member 14, 34, 54, 64 is located on or in said respective flat portion.

(19) In the example shown in FIG. 6, the armature 50 has two electrically conductive members 54, 56 configured for cooperation with a respective magnetic field generator of an electromagnetic actuator. The armature 50 then has two opposing sides 60, 61 that have a respective essentially flat portion 63, 62 perpendicular to a central axis A of the armature, and it has an electrically conductive member 54, 64 located on or in the respective essentially flat portion 63, 62.

(20) Generally, the armature can be described as having two main sides; a first side 20, 40, 60 on which is located the connection end 26, 46, 66 of the armature and which side may therefore be referred to as the connection side, and a second side 21, 41, 61 that is opposite the connection side. Based on the views in the figures, the first side 20, 40, 60 can also be referred to as the upper side and the second side 21, 41, 61 may then be referred to as the bottom side.

(21) In the shown examples, the at least one electrically conductive member 14, 34, 54, 64 is attached to the armature, or rather to the armature body 12, 32, 52. This can be achieved in many ways. For example the electrically conductive member may be sunken into the flat portion 22, 43, 62, 63. The flat portion may then comprise a recess made in the armature/armature body, and the shape of the recess is made such that the electrically conductive member will fit snugly in the recess. When the electrically conductive member has been secured at its location, the electrically conductive member will form part of the flat portion of the concerned side of the armature. The electrically conductive member may be secured by mechanical means or it may be bonded to it, e.g. at a molecular level. Alternatively, if the armature body 12, 32, 52 is made of an at least partly electrically conductive material the at least one electrically conductive member 14, 34, 54, 64 can be configured as an integral part of the armature body 12, 32, 52.

(22) As schematically shown in FIGS. 2-6, the armature body 12, 32, 52 may comprise an armature housing 15, 35, 55 configured to at least partly surround the cellular structure 13, 33, 53. Preferably, the armature body 12, 32, 52 will comprise an armature housing 15, 35, 55 at the locations where the electrically conductive member 14, 34, 54, 64 is located. An electrically conductive member may be located on either one of the above described first connection side or the second side, or on both sides. Preferably, the armature housing comprises a first wall part 15a, 35a, 55a that covers at least a part of the cellular structure 13, 33, 53 at the second side 21, 41, 61 of the armature. In most cases, and as illustrated in FIGS. 4-6, it would be preferable that the first wall part 15a, 35a, 55a covers the entire cellular structure at the second side of the armature. The armature housing then preferably also comprises a second wall part 15b, 35b, 55b, connected to the first part, and which second wall part covers the lateral sides of the cellular structure 13, 33, 53, i.e. the sides that are essentially extending in the axial direction and which connect the first side with the second side at the outer rim of the armature. The armature housing may also, or as an alternative to the second wall part on the second side, comprise a third wall part 35c, 55c that covers at least a part of the cellular structure on the first, connection side 40, 60 of the armature, as is illustrated in FIGS. 5 and 6. In FIGS. 2 and 4 is illustrated an example where the connection side 20 is not covered by a housing wall, but instead the cellular structure is open. The armature housing 15, 35, 55 will have a stabilizing and/or reinforcing effect and it may very well be manufactured in one piece with the cellular structure. The armature housing usually has thicker walls than the cellular walls 18, 38, 58 of the cellular structure. E.g. at a ratio of approximately 10:1. The armature housing 15, 35, 55 is designed to hold and/or support the cellular structure 13, 33, 52, and it may also be designed to hold the electrically conductive member 14, 34, 54, 64, when this member is located where there is a housing. The housing will then contribute to transmitting the high forces and stresses, generated upon activation of the actuator, to the cellular structure.

(23) The at least one electrically conductive member 14, 34, 54, 64 may be at least partly embedded in the armature housing 15, 35, 55. It may be embedded by forming an integral part of the housing or as a separate part embedded in the housing as will be explained later.

(24) The first, connection side 20, 40, 60 of the armature may have a special shape, of which an example is illustrated in the FIGS. 2, 4-6. The armature body 12, 32, 52 has a central axis A and a delimiting external contour 25, 45, 65, and, as an example, for at least a portion of the armature body, a distance d between the central axis A and the external contour 25, 45, 65 decreases in the axial direction and in a direction towards the connection end 26, 46, 66 of the armature. The external contour may be curved. At least part of the delimiting surface in the axial direction may then be a negatively curved surface as illustrated in the figures. The curve may e.g. be part of a parabolic curve or hyperbolic curve.

(25) The armature may have different geometrical shapes depending on the chosen manufacturing process and depending on the design of the cellular structure. In an alternative way of describing the armature body, the armature body 12, 32, 52 has a central axis A and is shaped as a rotational symmetry body with a radius extending from the central axis to a delimiting curve of the rotational symmetry body, and wherein at least a portion of the armature body has a delimiting curve with a radius that decreases in the axial direction and in a direction towards the connection end 26, 46, 66 of the armature body. The curve may e.g. be part of a parabolic curve or hyperbolic curve. Generally, an advantageous shape of the armature body, and in particular the delimiting curve or contour, can be determined by using numerical techniques, such as the Finite Element Method (FEM), in which the mechanical stresses can be computed based on an initial current impulse given by the Thomson coil.

(26) It should also be mentioned that the armature could e.g. have a basically square shape.

(27) The armature described in the examples above can form part of an electromagnetic actuator 100. Such an electromagnetic actuator would also comprise at least one magnetic field generator 110, 130, 150, 151 and an electricity source 105 that is connectable to the magnetic field generator. Examples of an electromagnetic actuator 100 are schematically shown in FIGS. 7, 8, 9a and 9b, in which it is shown as a part of a switch device 200 that represents an apparatus operable by the electromagnetic actuator. The electricity source 105 may for example comprise a capacitor bank.

(28) The switch device 200 comprises at least a first electric contact element 201 and a second electric contact element 202. These contacts can be selectively connected and disconnected such that when the first and second contact elements are connected the switch device 200 is closed, and when the first and second contact elements are disconnected the switch device is opened. In order to achieve this, at least one of the contacts is movable. In the illustrated examples the second contact element 202 is movable. The switch device further comprises an electromagnetic actuator 100 as described below, and having an armature as described in any one of the examples above. The switch device also comprises a pullrod 107 having a first end 108 connected to the connection end 26, 46, 66 of the armature of the electromagnetic actuator and having a second end 109 configured for connection to the movable second contact element 202 such that the opening or closing of the switch device is controllable by the electromagnetic actuator. Thus the armature 10, 30, 50 is connectable to the switch device via the pullrod 107. The pullrod 107 is made of a non-electrically conducting material. A switch device would normally also include some type of control unit that would control the activation of the electromagnetic actuator, but such a control unit can be of any known type and is not shown in the figures.

(29) In FIG. 7 is shown a switch device 200 as described above and having an electromagnetic actuator 100 comprising an armature 10 as shown in FIG. 4, and said armature having an electrically conductive member 14 on its bottom side 21. The actuator 100 further has a magnetic field generator 110, e.g. Thomson coil. When a repulsive impulse is generated by the magnetic field generator 110, the armature 10 is moved upwards and the second contact element 202 is then moved upwards such that the contacts 201, 202 are opened and the circuit is broken.

(30) In FIG. 8 is shown a switch device 200 as described above and having an electromagnetic actuator 100 comprising an armature 30 as shown in FIG. 5, and said armature having an electrically conductive member 34 on what is referred to as its upper side 40 above; i.e. the connection side facing towards the contacts 201, 202. The actuator 100 further has a magnetic field generator 130, e.g. Thomson coil. When a repulsive impulse is generated by the magnetic field generator 130, the armature 30 is moved upwards and the second contact element 202 is then moved upwards such that the contacts 201, 202 are opened and the circuit is broken.

(31) In FIGS. 9a and 9b is shown a switch device 200 as described above and having an electromagnetic actuator 100 comprising an armature 50 as shown in FIG. 6. The armature has two electrically conductive members 54, 64. One electrically conductive member 54 on what is referred to as its upper side above; i.e. the connection side facing towards the contacts 201, 202, and one electrically conductive member 64 on its bottom side. The actuator 100 further has two magnetic field generators 150, 151, e.g. Thomson coils. One coil 150 for opening the contacts 201, 202 of the switch device 200 and thus opening/breaking the electric circuit, and another coil 151 that is used for closing the contacts 201, 202 of the switch device 200 and thus closing the electric circuit. When a repulsive impulse is generated by the magnetic field generator 150, the armature 50 will move downwards, as indicated by the arrow in FIG. 9a, and the second contact element 202 will then move downwards such that the contacts 201, 202 will open and the circuit will be broken, as is illustrated in FIG. 9b. When a repulsive impulse is generated by the magnetic field generator 151, the armature 50 will move upwards, as indicated by the arrow in FIG. 9b, and the second contact element 202 will then move upwards such that the contacts 201, 202 will close and the circuit will be closed again, as is illustrated in FIG. 9a.

(32) In FIGS. 7 and 8 is not illustrated any device for closing the contacts again. Since the closing of the contacts, and closing of the circuit, is not an operation that will have to be executed in an extremely short time, other types of devices than a Thomson coil may be used for the closing function. The actuators in FIGS. 7-9 may also be provided with bistable contacts in order to provide close contact between the electrically conductive member of the armature and the magnetic field generator, e.g. a Thomson coil, or other types of devices with similar function.

(33) In addition to the elements and features described above, the following individual elements and features, as described below, may be individually added and combined with anyone of the above described elements and features taken separate or in combination.

(34) The armature may comprise a connection part 16, 36, 56 for connection of the armature to an apparatus operable by an electromagnetic actuator, e.g. for connection of a pullrod. The connection part of the armature can be configured as a channel 16, 36, 56 in the armature body, with a centrally located opening 16a, 36a, 56a at the connection end 26, 46, 66 of the armature, into which opening a pullrod 107 can be inserted and secured. The wall 17, 37, 57 of the channel may form part of the armature housing 15, 35, 55. The channel wall will then be connected to the armature housing at the connection side 20, 40, 60 of the housing or at the opposing second side 21, 41, 61 of the housing, or on both sides. The channel may then extend all the way through the armature body, from the connection side to the opposing second side. As mentioned before with regard to the housing, the channel would then be configured with thicker walls than the cellular walls 18, 38, 58 of the cellular structure. E.g. at a ratio of 10:1. The channel preferably has a shape corresponding to the shape of the pullrod 107 and it should connect firmly to the pullrod. There may also be a particular connection device located in the channel by means of which the pullrod can be connected to the armature. A common connection arrangement for this purpose would be a screw/thread arrangement. The channel wall may very well be manufactured in one piece with the cellular structure, and will have a stabilizing and/or reinforcing effect.

(35) As shown in particular in FIG. 3, the electrically conductive member 14 can have the shape of a plate and in particular a plate having an annular shape. This is also applicable to all examples of the electrically conductive member 14, 34, 54, 56. When the electrically conductive member is located in a part of the armature housing or other part of the armature body, it has a free outwards directed surface that faces the magnetic field generator. The electrically conductive member may e.g. be made of copper or silver. In the example shown in FIG. 3, the electrically conductive member 14 is located in the housing part 15a of the bottom side 21 of the armature 10, as also shown e.g. in FIG. 4.

(36) The magnetic field generator 110, 130, 150, 151 of the electromagnetic actuator is preferably a repulsion coil, such as a Thomson coil. It is preferably a flat multi-turn spiral coil.

(37) Generally, the cellular structure may be an at least partly open cellular structure, as shown in FIGS. 2 and 4, or it may be a closed structure, being surrounded by external walls, e.g. walls of the armature housing, as shown in FIGS. 5 and 6. It may also be described as an array of hollow cells. It has also been illustrated, as an example, as being a honeycomb structure. However, also other cellular structures may be contemplated, e.g. lattice structure, mesh structure. The cells of the structure may have many different geometrical shapes, e.g. polygonal, triangular, circular, etc.

(38) At least a part of the armature body is advantageously manufactured by using an additive manufacturing process, such as 3D printing, and from that method other cellular structures may be possible. For example a manufacturing process involving selective laser melting may be used. The armature body with the cellular structure may be made using titanium or a titanium alloy as a suitable material. Other materials may include graphene and polymers.

(39) The cellular structure may comprise cells having a diameter of 2 mm-20 mm. Preferably 4 mm-10 mm.

(40) The cellular structure may comprise cells having a wall thickness of 0.05 mm-1.0 mm. Preferably of 0.1 mm-0.5 mm. The walls of the cells may have a thickness that increases at the intersection of walls.

(41) The cellular structure may have a density of cells of between 0.5 cells/cm.sup.2 and 6 cells/cm.sup.2.

(42) The generated repulsion force results in forces and stresses that are distributed in the armature not only in the axial direction, or direction of movement, but there are usually also components of the forces and stresses in a direction perpendicular to the direction of movement, i.e. radial components when the direction of movement is axial. As schematically illustrated in FIG. 10, and in order to provide reinforcement in the radial direction, the cellular structure 13 of the armature body 12 may comprise intermediate walls 28 extending in an essentially perpendicular direction in relation to the previously described cellular walls 18. The cellular structure can then be described as a layered structure where the intermediate walls divide the cellular structure, having mainly vertical/axial cellular walls, into horizontal layers. The variant of cellular structure shown in FIG. 10 is based on the armature example shown in FIGS. 2-4, but it would also be possible to use as cellular structure in the other examples of FIGS. 5 and 6.

(43) The disclosure also concerns a method for manufacturing an armature 10, 30, 50 as described above, comprising an additive manufacturing process step of at least a part of the armature.

(44) The disclosure also concerns a method for manufacturing an armature for an electromagnetic actuator, comprising an additive manufacturing process step of at least a part of the armature. This method can be used for many other types of armatures then the armature described in detail in the present disclosure.

(45) The disclosure above has mainly been related to high voltage application. It should however be realized that it is not limited to this field of application. The armature and the actuator may for instance be used also for low or medium voltage applications. Further, the armature and the actuator are not limited to use in switch devices such as circuit breakers or current interrupters, but may also be used in e.g. the field of robotics, safety applications in the car industry, etc.