Field

This relates to opening, or interrupting, a current conduction path ln particular, this relates to a switch for opening a current conduction path, and a method for operating the switch.

Background

Current conduction paths can be opened by breaking a continuous conductor which defines the current conduction path. One approach is to use a pyrotechnic based switch to break the continuous conductor.

It is desirable to provide an improved apparatus for breaking a conductor and opening a current conduction path. Such an improved apparatus is desirable for applications which require reliable and rapid opening of a current conduction path, for example, batteries in electric vehicles or electrical overload mechanisms for industrial processes. Summary

In a first aspect, a switch is provided as defined in the appended independent apparatus claim, with optional features defined in the dependent claims appended thereto. In a second aspect, a method of operating the switch of the first aspect is provided as defined in the appended independent method claim.

In the following specification, a switch for opening a current conduction path is described. The switch comprises: an ignition chamber; a pyrotechnic actuator arranged to release gas into the ignition chamber upon ignition; a rotor comprising a rotor blade arranged within the ignition chamber, the rotor blade arranged to rotate from an initial position towards a final position in response to actuation by the pyrotechnic actuator; and a conductor (optionally located outside of the ignition chamber). The conductor comprises a first section, a second section, and a third section arranged between the first and second sections. The first and second sections comprise connection contacts and the first, second and third sections define a current conduction path. The third section is (rotationally) coupled to the rotor, such that rotation of the rotor blade causes a rotation of the third section (of the conductor) relative to the first and second sections of the conductor to open the current conduction path. At least part of the conductor may be located inside of the ignition chamber, or the conductor may be located outside of the ignition chamber.

Optionally, the rotor blade is arranged to rotate from an initial position towards a final position within the ignition chamber in response to actuation by the pyrotechnic actuator. Optionally the third section is located outside of the ignition chamber and coupled to the rotor such that rotation of the rotor blade causes a rotation of the third section relative to the first and second sections of the conductor to open the current conduction path.

Optionally, the rotor blade is arranged to rotate from an initial position towards a final position around an axis of rotation in response to actuation by the pyrotechnic actuator. Optionally, the conductor is offset from the rotor blade along the axis of rotation.

Optionally, the third section is directly coupled to the rotor. Previous pyrotechnic based switches (or automatic pyrotechnic based circuit breakers) relied on a linear arrangement to break a continuous conductor. For example, a linear displacement of a pyrotechnically actuated piston would cut the conductor into two segments under a wedge type action to interrupt the current. By using a rotary or rotational movement in accordance with the switch of the first aspect, an improved breaking of the conductor can be achieved. In particular, the rotation of the third section of the conductor relative to the first and second sections of the conductor (which are preferably fixed] provides for breaking of the conductor, and thus opening of the current conduction path defined by the conductor, in two places for one pyrotechnic actuation. The conductor is broken on both sides of the axis of rotation of the third section. Not only can this arrangement achieve a greater physical separation in the components of the conductor than a linear motion, but such separation can be achieved quicker. Improved breaking of the conductor, and opening of the current conduction path, is therefore provided by the rotary motion of the switch. In some arrangements, such a rotary switch may also be more compact than previous linear arrangements.

The separation of the conductor sections can also facilitate a reduction in the electric arc (or arc discharge] formed when the sections of the conductor separate from one other. In particular, the rotatory movement of the broken edges of the conductor (i.e. of the ends of the third section] can rapidly stretch the arc, increasing the arc resistance. An increased arc resistance causes a corresponding increase in arc voltage and a decrease in arc current (since electrical arcs exhibit negative resistance]. With the physical separation in conductor sections which is achievable with the rotary switch of the first aspect, the arc resistance can be quickly increased with time, and the current correspondingly reduced to such a value that heat formed by the current passing through the air is not sufficient to maintain the arc— the arc is thus extinguished. As such, a more effective interruption of the electrical arc can be provided. A safer and more robust switch may therefore be provided.

When the conductor is located outside of the ignition chamber, it may be easier to maintain a high pressure gas within the confined volume of the ignition chamber, which can facilitate more efficient breaking of the conductor due to the induced rotation. Optionally, at least the third section of the conductor is located inside a secondary chamber (physically separated from the ignition chamber]. In this arrangement, the electrical arc can be confined within the secondary chamber, which may allow for more effective suppression of the electric arc. Optionally, the switch further comprises a store of arc extinguishing media, the arc extinguishing media arranged to fill the secondary chamber when the third section of the conductor is rotated. Optionally, the arc extinguishing media is stored in the secondary chamber, wherein rotation of the third section of the conductor displaces the arc extinguishing media within the secondary chamber in order to fill the chamber. Alternatively, the store of arc extinguishing media can be external to the secondary chamber, the arc extinguishing media arranged to be released into the secondary chamber to fill the secondary chamber when the third section of the conductor is rotated. Use of arc extinguishing media can help to cool the arc and thus increase the resistance of the arc in order to improve interruption of the arc. As such, a safer and more robust switch may be provided. Optionally, the arc extinguishing media comprises silica, but any other suitable media may be used. Optionally, when the rotor blade is in the initial position, the first, second and third sections of the conductor are arranged at an angle of 0 degrees relative to one another. In other words, the conductor sections are aligned along a single axis. Optionally, when the rotor blade is in the final position, the third section of the conductor is arranged at an angle relative to the first and second sections. The angle may be between 45 and 90 degrees, optionally between 60 and 90 degrees, optionally between 75 and 90 degrees. Optionally, the angle is substantially 90 degrees (for example, 90 degrees plus or minus 10 degrees, optionally, 90 degrees plus or minus 5 degrees}. Alternatively, the third section of the conductor is arranged at any suitable angle relative to the first and second sections.

Optionally, in the initial position the rotor blade is arranged to form a seal to partition the ignition chamber. By partitioning the ignition chamber by way of a seal, improved transfer of force from the pyrotechnic actuator to the rotor blade may be achieved, which can led to a more efficient conversion between the actuating force and the torque generated by rotation of said rotor blade in turn, this may provide improved transfer of the force from the pyrotechnic actuator to the third section of the conductor coupled to the rotor. More efficient breaking of the conductor may therefore be provided.

Optionally, the pyrotechnic actuator is arranged to release gas into the ignition chamber in a direction tangential to an orientation of the rotor blade in the initial position. Such an arrangement can make use of the full charge of the pyrotechnic actuator and thus provide for a more efficient transfer of force from the pyrotechnic actuator to the rotor blade. Optionally, the ignition chamber comprises two chambers and the rotor comprises two rotor blades, one rotor blade arranged in each ignition chamber. In one group of examples, the two ignition chambers are fluidly coupled such that the pyrotechnic actuator is arranged to actuate the two rotor blades to cause the rotor blades to rotate in the same direction. In other words, force is applied to the two rotor blades from a single pyrotechnic charge.

In another group of examples, the two ignition chambers are isolated from one another, wherein the switch comprises two pyrotechnic actuators, each arranged to release gas into a respective ignition chamber. This arrangement can increase the force applied on the conductor in order to break the conductor, which can result in an improved breaking of the conductor. For example, physical separation of sections of the conductor may be quicker if two pyrotechnic actuators are used in place of one, which can increase the rate of arc suppression or interruption. Optionally, the pyrotechnic actuators are arranged to release gas into the respective ignition chambers in opposing directions to actuate the two rotor blades to cause the rotor blades to rotate in the same direction, optionally, wherein the directions in which the pyrotechnic actuators are arranged to release gas into are tangential to the orientation of the respective rotor blades. This arrangement may provide for the most effective transfer of force from the pyrotechnical actuators to the rotor in order to break the conductor. Optionally, in one group of examples, the conductor is formed as a single, continuous piece and the third section of the conductor is separated from the first section and/or the second section of the conductor by a section of conductor having a thickness less than a thickness of the third section of the conductor. For example, the third section may be delimited from the first and/or second sections by a notch in the conductor. Additionally or alternatively, the third section of the conductor is separated from the first section and/or the second section of the conductor by a section of conductor having a width less than a width of the third section of the conductor. For example, the third section may be delimited from the first and/or second sections by perforations along the width of the conductor; said perforations may be arranged to extend part or all of the way through a thickness of the conductor. Alternatively, in another group of examples, the first, second and third sections of the conductor are formed as separate pieces and are connected with a separate conductive material to form the conductor.

Such arrangements may make the conductor easier to break upon rotation of the third section by the rotor. As such, a smaller charge may be used for the pyrotechnic actuator (s). The pyrotechnic actuator(s) may therefore be smaller, which can result in a smaller and more compact switch device. The switch device may also be cheaper to manufacture due to the smaller pyrotechnic actuator.

Optionally, the switch further comprises a housing enclosing at least the ignition chamber(s), pyrotechnic actuator(s), the rotor and rotor blade(s), and at least partially enclosing the conductor. For example, the third section and at least part of each of the first and second sections may be enclosed by the housing.

A system is provided comprising a switch as described above and a controller arranged to provide a signal to the pyrotechnic actuator to ignite the pyrotechnic actuator. Such a system may be used in any suitable application where a switch (or automatic circuit breaker, where an activation trigger is provided) is required, such as for overload in industrial applications, for example. A vehicle is provided comprising a switch as described above. Optionally, the vehicle may further comprise a controller arranged to provide a signal to the pyrotechnic actuator to ignite the pyrotechnic actuator. Optionally, the vehicle is an electric vehicle. The switch may be used, for example, to break a circuit in a battery of the vehicle in case of an accident. This may improve safety.

There is provided a method for opening a current conduction path by operating a switch as described above. The method comprises: igniting a pyrotechnic actuator; releasing, by the ignition, gas into an ignition chamber; and exerting, with the released gas, pressure on a rotor blade of a rotor, the rotor blade arranged in the ignition chamber. The rotor is (rotationally) coupled to a third section of a conductor (optionally located outside of the ignition chamber), the conductor comprising a first section, a second section, and a third section arranged between the first and second sections. The first, second and third sections define a current conduction path, and the first and second sections comprise connection contacts. The method further comprises: rotating the rotor blade between an initial position and a final position within the ignition chamber in response to the exerted pressure, thereby causing rotation of the third section of the conductor; and opening, by the rotation of the third section of the conductor, the current conduction path of the conductor.

Brief Description of the Drawings

The following description is with reference to the following Figures:

Figure 1A shows a schematic cross section of a first side of a switch in accordance with the first aspect;

Figure IB shows a schematic cross section of a second side of the switch of Figure 1A, the second side being opposite the first side;

Figure 2A illustrates a cross section of a first side of a switch in accordance with the first aspect when the rotor blade is in an initial position;

Figure 2B illustrates a cross section of a second side of the switch of Figure

2A, the second side being opposite the first side; Figure 3A illustrates a cross section of the switch of Figure 2A when the rotor blade is in a final position;

Figure 3B illustrates a cross section of the switch of Figure 2B when the rotor blade is in the final position;

Figure 4A illustrates a perspective view from a first side of a switch in accordance with the first aspect when the rotor blade is in an initial position;

Figure 4B illustrates a perspective view from a second side of the switch of Figure 4A, the second side being opposite the first side;

Figure 5 illustrates a vehicle comprising the switch of the first aspect; and Figure 6 illustrates a method in accordance with the second aspect.

Detailed Description

With reference to Figures 1A, 2A and 3 A, a switch 100 for opening a current conduction path defined by a conductor 112 is described.

Switch 100 comprises ignition chambers 104 and pyrotechnic actuators 106 arranged to release gas into the ignition chambers upon ignition. The switch further comprises a rotor 108 comprising rotor blades 110. The rotor blades 110 may be coupled to, or integrally formed with, a portion 108a of the rotor 108. The rotor blades 110 are arranged within respective ignition chambers 104 and are arranged to rotate from an initial position towards a final position in response to actuation by the pyrotechnic actuators 106. These components of switch 100 are enclosed within a housing 102. In the group of embodiments described with reference to Figures 1-3A, two pyrotechnic actuators 106a and 106b are used, each arranged to actuate respective rotor blades 110a, 110b arranged within respective ignition chambers 104a, 104b. However, it will be understood that only one pyrotechnic actuator 106 (with one or more corresponding ignition chambers] may be included. For example, a single pyrotechnic actuator may be provided with one associated ignition chamber, or provided in combination with two ignition chambers which are in fluid communication (or fluidly coupled). In this way, a single pyrotechnic actuator can be arranged to actuate two rotor blades arranged within two ignition chambers and cause the rotor blades to rotate.

Each pyrotechnic actuator 106a, 106b is arranged to release gas into the ignition chamber in a direction tangential to an orientation of the rotor blades 110 when arranged in their initial position. In particular, the pyrotechnic actuators are arranged to release gas into the respective ignition chambers 104a, 104b in opposing directions to actuate the two rotor blades 110a, 110b to cause the rotor blades to rotate in the same direction and transmit torque through the rotor 108. This illustrated arrangement can provide for the most efficient transfer of force from the pyrotechnic actuators 106 to the rotor blades 110. However, any other suitable arrangement of pyrotechnic actuators relative to the rotor blades may be employed. Each pyrotechnic actuator 106a, 106b comprises connector pins 118 and an igniter 116. The connector pins 118 activate a charge inside the igniters 116 upon receipt of an ignition signal. The pyrotechnic actuators 106a, 106b are arranged to, upon activation or ignition of their charge, expel gas into the ignition chambers 104. The high-pressure gases which are expelled into the ignition chambers 104 produce actuating forces which act on the rotor blades 110 and cause rotation of the rotor blades 110 from their initial position (shown in Figures 1A and 2A) towards their final position (shown in Figure 3A). In the group of embodiments described with reference to Figures 1-3A, the rotor blades rotate until they reach a stop 114, the position of which defines their final position. In the particular orientation of the switch 100 illustrated in Figures 1-3 A, the rotor blades 110 are arranged to rotate in an anticlockwise direction around an axis 124.

In some arrangements, each rotor blade 110 is arranged to form a seal across the ignition chamber when in the initial position in order to partition the ignition chamber 104 (i.e. to prevent gas expelled by pyrotechnic actuator 106 escaping past the sides of the rotor blades into the ignition chamber 104 without actuating the rotor blades 110). This arrangement can provide for an improved transfer of force from the pyrotechnic actuators to the rotor blades, which force is transferred to the rotor 108 in the form of torque.

Improved transfer of torque may also be provided by the use of an ignition chamber which is hermetically sealed, which can maximise the amount of force applied by the expelled gases to the rotor blades 110 and prevent hot gases being vented into the environment of the switch. Alternatively, a vent may be provided on an opposite side of the rotor blade to the pyrotechnic actuator (when the rotor blade is in the initial position), wherein any excess gas within the portion of the ignition chamber 104 into which the rotor blades 110 are to rotate could be expelled through the vent by the displacing force of the rotor blades as the rotor blades rotate. This could allow pyrotechnic actuators with smaller charges to be used, since a lack of air resistance may reduce the force required to rotate the rotor blades.

As described with reference to Figures IB, 2B and 3B, switch 100 further comprises a conductor 112 provided outside of the ignition chamber. Conductor 112 comprises three sections: a first section 112a, a second section 112b, and a third section 112c. The third conductor section 112c is arranged between the first and second conductor sections 112a, 112b. The first and second sections 112a, 112b of the conductor comprise connection contacts for connection of the switch 100 to an external electrical circuit. The first, second and third sections define a current conduction path through which current flows when the connection contacts are connected to an electrical circuit. As can be seen Figures 1-3B, the first and second conductor sections may extend outside of housing 102 in order to provide easier connection of the connection contacts of switch 100 to external electrical circuits.

The third section of the conductor 112c is rotationally coupled to a portion 108b of the rotor 108, i.e. is coupled such that rotation of the rotor blades 110 causes a rotation of the third section relative to the first and second sections of the conductor 112b, 122c due to the torque transferred through the rotor 108. In other words, switch 100 operates to open the current conduction path defined by the conductor 112 and prevent the flow of current by mechanically breaking the conductor 112 through rotation of a portion of the conductor 112 relative to the remainder of the conductor. In the particular orientation of the switch 100 illustrated in Figures 1-3B, the third conductor section 112c is arranged to rotate in an anticlockwise direction around axis 124.

The two rotor portions 108a and 108b may be directly and rigidly coupled, such that the rotor 108 is rigidly coupled to the third section of the conductor and the third section rotates at the same speed (and time) as the rotor blade 110. The rotor blades 110 and the third section of the conductor 112c can also be arranged to rotate about a common axis 124. Both of these arrangements can provide for more efficient torque transfer, and a quicker opening of the current conduction path may therefore be provided in one example, the two rotor portions 108a, 108b may be integrally formed, or may comprise two separate components rigidly coupled to form the rotor 108. Alternatively, the coupling between the two portions may not be a rigid coupling, or may be an indirect coupling, for example using a geared arrangement such as a planetary gear. ln the group of embodiments described with reference to Figures 1A-3B, the first, second and third sections of the conductor 112 are arranged at an angle of (substantially) 0 degrees relative to one another when the rotor blades 110 are in the initial position. In other words, the conductor sections are aligned along a single axis and, in this group of embodiments, are aligned also with the rotor blades 110. Due to the coupling between the rotor 108 and the third section 112c of the conductor, as the rotor blades 110 rotate around axes 124, the third section of the conductor rotates relative to the first and second sections 112a, 112b such that, when the rotor blades 110 are in the final position, the third section of the conductor is arranged at an angle relative to the first and second sections. This relative rotation of the conductor sections causes the conductor to break. The angle of the rotor blades 110 relative to the first and second sections of the conductor 112 is substantially 90 degrees in this final position, but stop 114 may be provided to stop rotation of the rotor blades when the conductor section 112c is at any other suitable angle relative to the first and second conductor sections 112a, lib. As described herein, conductor 112 is formed as a continuous piece material, and the third conductor section 112c is separated from the first and the second sections of the conductor by a conductor section 122 having a thickness less than a thickness of the third section of the conductor. This arrangement provides a mechanical weakness in the conductor, which makes the conductor easier to break upon rotation of the rotor 108. The conductor section 122 which introduces the mechanical weakness to the conductor 112 can comprise a notch, as shown in Figures IB and 2B, for example.

Additionally and/or alternatively, the conductor section 122 can comprise a series of perforations along the width of the conductor 122 in order to provide the mechanical weakness at the edges of the third section 112C. The perforations may be arranged to extend part or all of the way through a thickness of the conductor 112 in order to delimit the third section 112C from the first and second conductor sections 112A, 112B and ease breaking of the conductor to open the current conduction path. Alternatively, the first, second and third sections of the conductor can be formed as separate conductor pieces; the conductor 112 may then be formed by connecting the three separate conductor sections 112a, 112b, 112c with additional conductive material to form the conductor. For example, the conductor 112 may be formed by connecting the three conductor sections with conductive adhesive. Alternatively, pressure may be applied to the conductor where the separate conductor sections join in order to maintain electrical contact between the three sections and provide a current conduction path. *

As described further with reference to Figures 1-3B, breaking of conductor 112 and the subsequent opening of the current path can lead to formation of an arc 128 between the ends of the third conductor section 112c and the first and second conductor sections. This phenomenon can occur whenever portions of a conductor physically separate from one another. The rotary movement of the third conductor section relative to the rest of the conductor 112 can facilitate a reduction in this electric arc (or arc discharge) by rapidly stretching the arc, thereby increasing the arc resistance. An increased arc resistance causes a corresponding increase in arc voltage and a decrease in arc current (since electrical arcs exhibit negative resistance). Rotary motion can act to increase the physical separation of the respective conductor sections quicker than with previous linear approaches, leading to more effective interruption of the electrical arc. A safer and more robust switch may there be provided.

Arc interruption or extinguishing can be further improved through the use of arc extinguishing media. As described further with reference to Figures 1-3B, at least the third section 112c of the conductor is located outside of the ignition chamber within a secondary chamber 126. The secondary chamber may also enclose the rotor portion 108b to which the third conductor section is coupled, or this rotor portion may be provided within a housing and physically separated from the interior of the secondary chamber. In this group of embodiments, the secondary chamber 126 is filled with an arc extinguishing media 120. As the third conductor section rotates in response to rotation of the rotor blades 110, the media 120 is displaced around the secondary chamber 126 to fill the secondary chamber 126 by the third conductor section. Alternatively, a store of arc extinguishing media can be provided external to the secondary chamber and can be released into the secondary chamber 126 to fill the chamber. The arc extinguishing media 120 can comprise silica in any suitable form. Alternatively, any other suitable media may be used.

As described with reference to Figures 4A and 4B, a radial extent of the third section (as measured relative to the axis of rotation 124 around which both the third section and the rotor blades 110 rotate) is less than a radial extent of a rotor blade 110a or 110b. This difference in radial extent can provide a mechanical advantage in breaking the conductor 112, since the torque transferred through the rotor then exerts a comparatively greater force on the third section than the force exerted on the rotor blades 110 by the ignition of the pyrotechnical actuators 106. Alternatively, the radial extend of the third section may be equal to or greater than that of the rotor blades 110. lt can be seen from Figures 4A and 4B that the force generation arrangement of the switch 100 (the pyrotechnical actuators 106, the ignition chamber 104, rotor portion 108a and the rotor blades 110) is offset from the conductor breaking arrangement (rotor portion 108b and conductor 112) along the axis of rotation 124 (represented by the dotted line). This offset arrangement can provide for an efficient transfer of torque between the rotor blades 110 and the third conductor section 112C via rotor portions 108a and 108b. However, any other suitable arrangement may be provided.

With reference to Figure 5, a powertrain 540 comprising switch 100 is described. In particular, powertrain 540 can be a powertrain for a vehicle 500. In regard to a vehicle (e.g. a motor vehicle, a ship or boat, or a plane, etc.), a powertrain encompasses the main components that generate power and deliver it to the road surface, water, or air. This includes the engine, transmission, drive shafts, and the drive wheels (or other drive mechanism, such as a propeller). In an electric or hybrid vehicle, the powertrain 500 also includes battery 560 and an electric motor, for example. Switch 100 may be connected, via the connection contacts of the first and second conductor sections, to an electrical circuit 550 within vehicle 500, which electrical circuit may optionally include the battery 560. Alternatively, vehicle 500, which may be an electrical vehicle, can comprise switch 100 in the absence of powertrain 540, as illustrated in Figure 5.

An ignition signal may be provided to connectors 118 of the pyrotechnical actuators 106 from a remote controller or a remote power distribution unit 570 within the vehicle 500. Such an ignition signal may be issued in response to an external event. For example, when the switch 100 is connected to a battery 560 installed in the vehicle 500, an ignition signal may be sent to the pyrotechnic actuators 106 in response to a collision of the vehicle; activation of the charge inside the igniter 116 can cause the conductor 112 to be broken, as described above, in order to open the electrical circuit 550 and prevent the flow of current through the battery 560. Such an arrangement can improve safety in the event of a collision. Alternatively, switch 100 and remote controller 570 can be deployed in any other application where such breaking of a circuit is required.

With reference to Figure 6, a method 600 for opening a current conduction path is described. At step 610, the method comprises igniting a pyrotechnic actuator, optionally in response to a collision or other external event triggering an ignition signal which is received by the pyrotechnic actuator. Any other trigger can be used for ignition of the pyrotechnic actuator. Upon ignition of the pyrotechnic actuator, at step 620, high-pressure gas is released into the ignition chamber. This released gas exerts (step 630) a pressure on a surface of a rotor blade orientated to face the pyrotechnic actuator. The rotor blade is arranged within the ignition chamber in accordance with a switch of the first aspect.

At step 640, the rotor blade is rotated between an initial position and a final position. The rotor blade is part of a rotor coupled to a portion of a conductor (i.e. the third section of the conductor, as described above), optionally located outside of the ignition chamber. The conductor defines a current conduction path through which current flows. Rotation of the rotor blade at step 640 in response to the pressure exerted at step 630 causes a corresponding rotation of the portion of the conductor to which the rotor is coupled, due to the transfer of torque through the rotor. This rotation of the coupled portion of the conductor relative to the rest of the conductor (and the subsequent breaking of the conductor due to the relative rotation) results in opening (step 650) of the current conduction path of the conductor.

Optionally, at step 660, an electrical arc formed upon separation of the conductor portion from the remainder of the conductor is suppressed, or interrupted. This interruption may be achieved solely by the relative rotation of the conductor portion, or by the release of arc extinguishing media, for example, a media comprising silica. Also described herein is an arrangement where the conductor is broken directly (rather than indirectly through the transfer of torque). A switch for opening a current conduction path is described, the switch comprising: an ignition chamber; a pyrotechnic actuator arranged to release gas into the ignition chamber upon ignition; a rotor coupled to a portion of a conductor arranged within the ignition chamber, the portion of the conductor arranged to rotate from an initial position towards a final position in response to actuation by the pyrotechnic actuator; wherein rotation of the conductor portion causes breaking of a conductor and opening of a current conduction path defined by the conductor. In other words, a portion or section of a conductor is provided within the ignition chamber and directly actuated (and thus rotated) by the pyrotechnic actuator to break the conductor and open the current conduction path.

There is also provided a method for opening a current conduction path by operating a switch as described above. The method comprises: igniting a pyrotechnic actuator; releasing, by the ignition, gas into an ignition chamber; and exerting, with the released gas, pressure on a portion of conductor coupled to the rotor, the conductor portion arranged in the ignition chamber. The method further comprises: rotating the conductor portion within the ignition chamber relative to the rest of the conductor in response to the exerted pressure, thereby causing breaking of the conductor; and opening, by the rotation of the conductor portion, the current conduction path of the conductor.

It is noted herein that while the above describes various examples of the isolating switch of the first aspect, these descriptions should not be viewed in a limiting sense. Rather, there are several variations and modifications which may be made without departing from the scope of the present invention as defined in the appended claims.