GB2591826A

GB2591826A - Electrical interrupter with actuator

Info

Publication number: GB2591826A
Application number: GB2004270.1A
Authority: GB
Inventors: C Pande Manish; Mujawar Asad
Original assignee: Eaton Intelligent Power Ltd
Current assignee: Eaton Intelligent Power Ltd
Priority date: 2020-02-10
Filing date: 2020-03-24
Publication date: 2021-08-11
Also published as: WO2021160642A1; GB2607503A; GB202004270D0; GB202211718D0

Abstract

An electrical interrupter 100 comprises a housing 102 having a first sealed cavity 104 and a second cavity 106, a breakable conductor 108, and a pyrotechnic charge 116. The conductor comprises connection contacts 110a,b which extend through the housing, a curved section 130 between the contacts having an inside 134 and outside curved face 136, the inside curved face at least partly defining the first cavity. The curved section has first and second sections 112a,b which are supported on the outside face by the housing. A bridge section 114 connects the supported sections and separates the cavities. When actuated, the pyrotechnic charge releases gas into the first cavity and breaks the conductor at the bridge. Also disclosed is an interrupter 400 comprising an actuator 402, a housing 404 with cavity 406, and a breakable conductor 408. The conductor comprises connection contacts 412a,b, first and second sections 410a,b supported by the housing, a bridge 414 which defines at least part of the cavity, and a tension spring 416 coupled to the bridge. When the bridge is separated from the conductor by the actuator, the spring biases the bridge into the cavity to prevent accidental reconnection of the circuit.

Description

Electrical Interrupter with Actuator

Field

This relates to opening, or interrupting, a current conduction path. In particular, this relates to an electrical interrupter (such as an electrical isolator or switch disconnector) including an actuator for opening a current conduction path, and a method for operating an electrical interrupter.

Background

co Current conduction paths can be opened by breaking a continuous conductor along which a current conduction path is defined. One approach is to use an electrical interrupter comprising an actuator, in some examples a pyrotechnic based actuator, to break the continuous conductor.

It is desirable to provide an improved apparatus for 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 first electrical interrupter apparatus is provided as defined in appended independent apparatus claim 1, with optional features defined in the dependent claims appended thereto. In a second aspect, a method of operating the electrical interrupter of the first aspect is provided as defined in the first appended independent method claim, with optional features defined in the dependent claims appended thereto. In a third aspect, a second electrical interrupter apparatus is provided as defined in the second appended independent apparatus claim, with optional features defined in the dependent claims appended thereto.

In the following specification, an electrical interrupter for opening a current conduction path is described. The electrical interrupter comprises: a housing; a breakable conductor and a pyrotechnic charge. The housing has a first, sealed, cavity and a second cavity. The breakable conductor has connection contacts at either end. The connection contacts of the conductor extend through the housing. The conductor has a curved section extending between the connection contacts and having an inside curved face and an outside curved face. The inside curved face at least in part defines the first cavity. The curved section of the conductor comprises: first and second supported sections and a bridge section arranged to separate the first and second cavities. Each of the first and second supported sections (of the curved section) are connected to a respective one of the connection contacts and (partially or fully) supported along the outside curved face (i.e. along the outside curved face of the curved section) by the housing. The first and second supported sections are connected via the bridge section. The pyrotechnic charge is arranged, upon ignition, to release gas into the first cavity to break the conductor at the bridge section, and thereby to break a current conduction Iv path through (or along) the conductor.

A curved conductor section may experience both radial and hoop stresses at particular regions of the curved section, which stresses can be manipulated through the geometry of a conductor to facilitate faster breaking of the conductor and/or the breaking of the /5 conductor with less force. Faster breaking of the conductor results in faster opening of the current conduction path and hence faster electrical interruption. A rapid electrical interrupter may therefore be provided. Facilitating the breaking of the conductor with less force may facilitate the use of a less powerful pyrotechnic charge. Less powerful pyrotechnic charges may themselves be cheaper and smaller. Furthermore, less powerful pyrotechnic charges exert less force on the housing facilitating the use of thinner housing than may otherwise need to be used. A thinner housing may be cheaper to manufacture as less materials may be used, and/or may less expensive manufacturing processes may be used. A thinner housing may also facilitate the manufacturing of a smaller electrical interrupter.

Optionally, a thickness of the curved section, defined between the inside curved face and the outside curved face, may be variable. Optionally, a thickness and/or a width of the bridge section may be less than a thickness and/or a width of the first and second supported sections. This may more effectively concentrate radial and hoop stresses at the bridge section, meaning that the conductor more reliably breaks at the bridge section. By reliably breaking the conduction path at the unsupported bridge section, the ends and/or portions of the conductor proximate to the breakage maybe pushed into the second cavity and away from one another. This may result in more reliable electrical interruption, as the likelihood or extent of arcing and the probability of undesired reconnection of the current conduction path are reduced.

Optionally, the bridge section may-comprise at least one notched portion, and the bridge section maybe configured to break at the at least one notched portion. The use of notched portions may facilitate faster breaking of the conductor and/or breaking of the conductor with less force. Faster breaking of the conductor and/or the breaking of the conductor with less force may have the advantages previously outlined.

The notches may also ensure that the conductor reliably breaks at the same location. When the conductor reliably breaks at the same location, mechanical properties of the breakage are predictable. Examples of such mechanical properties include the manner, iv speed and extent to which the ends and/or portions of the conductor proximate to the breakage bend and/or are displaced into the second cavity. Electrical properties of the electrical interrupter are dependent on these mechanical properties. Therefore, the electrical properties of the electrical interrupter may be predictable. For example, the likelihood and/or extent of arcing may be predicted to allow, the reliable operation of is the electrical interrupter up to a specified current. The speed at which the electrical interrupter breaks the current conduction path may also be ensured.

Optionally, the pyrotechnic charge maybe configured to separate at least a portion of the bridge section from the first and second supported sections and displace the at least a portion of the bridge section into the second cavity to break/open the current conduction path. This may be advantageous as the bridge section is distanced from the first and second supported sections, reducing the extent or probability of arcing. Reducing the extent or probability of arcing may facilitate the reliable operation of the electrical interrupter at greater currents. The probability of undesired reconnection of the current conduction path may also be reduced facilitating more reliable operation of the electrical interrupter. A safer switch may also be provided.

Optionally, the bridge section may comprise a notched portion at or proximate either end of the bridge section and the portion of the bridge section may be bounded by the notched portions. These notches bounding the bridged section may facilitate faster separation of the portion of the bridge section and/or separation of the portion of the bridge section with less force. Faster separation of the portion of the portion of the bridge section may result in faster electrical interruption. The separation of the portion with less force may facilitate the use of a less powerful pyrotechnic charge which. has several advantages as previously outlined, such as a smaller switch. The double break -4 -of the conduction path with the two notched portions also acts to reduce the formation of electrical arcs between the broken conductor ends.

Optionally, at least a portion of the inside face of the curved section may be an inscribe sector of a circle, e.g. part-circular, optionally, at least the inside face of the bridge section is an inscribe sector of a circle, e.g. part-circular.

Optionally, a biasing member may be coupled to the bridge section and may be arranged to urge or bias the portion of the bridge section towards the second cavity Iv upon the separation of the portion of the bridge section from the first and second supported sections. This may facilitate faster separation of the portion of the bridge section, and allow for retention of the portion of the bridge section in the second cavity, Faster separation of the portion of the portion of the bridge section may result in faster electrical interruption. Retention of the portion of the bridge section in the second cavity may reduce the probability of undesired reconnection of the conduction path. By reducing the probability of undesired reconnection of the conduction path, the biasing member may facilitate the reliable operation of the electrical interrupter in circumstances where undesired reconnection of the current conduction path would otherwise be likely, e.g. where the electrical interrupter is rotated or is accelerated or decelerated. An orientation independent device may therefore be provided.

Optionally, arc extinguishing media may be arranged within the second cavity. This may reduce the extent and/or likelihood of arcing, which has several advantages as previously outlined. Optionally, the arc extinguishing media may be arranged within a capsule located inside the second cavity, and the capsule may be configured to release the arc extinguishing media upon rupture/breaking. The capsule may be ruptured by forces exerted on it due to the gas released upon ignition of the pyrotechnic charge. The use of the capsule may prevent the leakage of the arc extinguishing media prior to ignition of the pyrotechnic charge. Optionally, the outside curved face of the bridge section may comprise at least one puncturing means arranged to puncture the capsule upon contact with the capsule to release the arc extinguishing media. Use of such puncturing means may facilitate the use of a stronger material for the capsule, reducing the likelihood of unintentional rupture of the capsule prior to ignition of the pyrotechnic charge. Optionally, the arc extinguishing media may be a gelatinous arc extinguishing media, such as silica gel. The use of a gelatinous arc extinguishing may be -5 -beneficial since the high viscosity reduces the likelihood and/or amount of leakage of the arc extinguishing material out of the housing.

In some examples, a portion of the housing surrounding the second cavity comprises one or more vents extending at least partially through the housing for releasing gas from the second cavity. Optionally, the one or more vents extend only partially through the housing and the portion of the housing at the end of each vent is arranged to break upon release of gas from the pyrotechnic charge into the second cavity. Such vents extending only partially through the housing facilitate sealing of the second cavity prior /o to ignition of the pyrotechnic charge while enabling the release of gas upon ignition of the pyrotechnic charge. Furthermore, the breaking of the portion of the housing may be visible from the outside of the electrical interrupter, indicating that the pyrotechnic charge has been ignited to a user upon visual inspection. This may facilitate easier maintenance of apparatus comprising the pyrotechnic charge, as the electrical /5 interrupters should he replaced subsequent to ignition of the pyrotechnic charge.

Optionally, the vents may comprise one or more through holes. Tt may be relatively simpler to manufacture a housing having through holes as compared to other gas releasing means. Through holes may also release gas from the second cavity more quickly than other gas releasing means. Optionally, the one or more through holes may contain at least one of a mesh and a baffle. The mesh and/or baffle slow the release of gas from the second cavity. Therefore, through holes with a mesh and/or a baffle facilitate the release of gas from the second cavity while preventing high velocity jets of plasma and/or high temperature gases, which could potentially damage components and/or equipment in the vicinity of the switch and/or pose a safety risk, being emitted.

Optionally, the curved section may extend at least 120 degrees around the first cavity. The greater the angular span of the curved section, up to 180 degrees, around the first cavity, the greater the distance between the ends of the curved section reducing the risk of dielectric breakdown, hence, facilitating the use of the electrical interrupter at greater currents.

Optionally, the curved section may extend at least itI3o degrees around the first cavity. Optionally, the curved section may extend at least 270 degrees around the first cavity. In some examples, the conductor may be arranged in an "omega" shape, such that the curved section extends about 270 degrees, or more, and then straight portions extend in opposite directions away from the cu rved section. The greater the angular span of the curved section around the first cavity, the greater the proportion of the forces exerted from ignition of the pyrotechnic charge are experienced by the conductor rather than housing, e.g. the more the conductor shields the housing from the forces exerted from ignition of the pyrotechnic charge. The housing may, therefore, be made relatively thinner, which has several advantages, as previously outlined.

Optionally, the curved section may extend 350 degrees or less around the cavity.

Optionally, the housing may have a third cavity, and the breakable conductor may Iv comprise a second bridge section arranged to separate the first and third cavities. The first and second supported sections may be connected via the second bridge section. The pyrotechnic charge may be arranged to also break-the second bridge section to break the current conduction path through the conductor. Where the first and second bridge section are in series, the use of multiple bridge sections provides redundancy in is the breaking of the conduction path and consequently more reliable breaking of the conduction path. Where the First and second bfidge sections are in paralle:1,-the current through the current conduction path is distributed between the bridge sections. As the current through the current conduction path is distributed between the bridge sections, there is relatively less current through each of the bridge sections, facilitating a reduction in the thickness of the conductor. As the bridge sections are thinner', the bridge sections may be broken with less force. Facilitating the breaking of the conductor with less force may facilitate the use of a less powerful pyrotechnic charge. Less powerful pyrotechnic charges may themselves be cheaper and smaller. Furthermore, less powerful pyrotechnic charges exert less force on the housing, facilitating the use of thinner housing than may otherwise need to be used, which has several advantages, as previously outlined.

Optionally, the curved section extends around the first cavity such that the inside face of the curved section defines the first cavity, and the third cavity is arranged on an opposite side of the first cavity from the second cavity. By extending the conductor around the first cavity and consequently the pyrotechnic charge, the conductor shields the housing from the forces exerted from ignition of the pyrotechnic charge. The housing may, therefore, be made relatively thinner, which has several advantages, as previously outlined.

Optionally, the first cavity may be substantially circular. Optionally, the first cavity may have a semi-circular face opposite to the inside curve of the bridge section, the semicircular face formed by the housing. A substantially circular cavity and/or semi-circular faces formed by the housing may reflect shoekwaves of the explosion resulting from the ignition of the pyrotechnic charge toward the bridge sections, thereby multiplying the forces exerted on the bridge sections by the explosion. This may facilitate the use of a less powerful pyrotechnic charge, which has several advantages as previously outlined, such as facilitating the provision of smaller switch.

/0 In a second aspect of the specification, a method for operating an electrical interrupter is provided. The method is optionally a method for operating the electrical interrupter of the first aspect. The method comprises: igniting a pyrotechnic charge to release gas into a first sealed cavity of a housing; exerting, in dependence on the released gas, pressure on a bridge section of a curved section of a breakable conductor; and breaking, by the exerted pressure, the conductor at the bridge section to break a current conduction path through the conductor. The curved section has an inside curved face and an outside curved face section, the inside curved face at least in part de-fining the first cavity. The bridge section is arranged to separate the first cavity from a second cavity of the housing. First and second support sections of the curved section are electrically connected by the bridge section and (fully or partially) supported along their outside curved face by the housing.

Optionally, the method further comprises separating, by the exerted pressure, a portion of the bridge section from the first and second supported sections; and displacing, by at least the exerted pressure, the portion of the bridge section into the second cavity. This may be advantageous as -the bridge section is distanced from the first and second supported sections, reducing the extent or probability of arcing. Reducing the extent or probability of arcing may facilitate reliable electrical interruption at greater currents.

in a third aspect of the following specification, a second electrical interrupter for opening a current conduction path is described. The electrical interrupter comprises an actuator; a housing having a cavity; a breakable conductor; and a biasing member. The breakable conductor comprises: a first section and a second section, and a bridge section. The first and second sections comprise connection contacts, and at least a portion of each of the first and second sections is supported by the housing. The bridge section is arranged between the first and second sections to define a current conduction -8 -path. The bridge section also defines at least a portion of the cavity. The biasing member is connected to the bridge section. The actuator is configured, upon actuation, to exert a force on the bridge section in a first direction to separate a portion of the bridge section from the first and second conductor sections so as to open the current conduction path. The biasing member is arranged, upon the separation of the bridge section from the first and second sections to urge the portion of the bridge section in the first direction into the cavity.

Optionally, a thickness of the bridge section may be less than a thickness of the first and iv second sections. This may facilitate reliable separation of the portion of the bridge section from first and second conductor sections resulting in more reliable electrical interruption.

Optionally, the housing is configured to support the first and second sections in a /5 second direction opposite the first direction. This may increase the stresses on the bridge section, facilitating faster breaking and/or breaking with a less powerful actuator. Faster breaking may reduce the likelihood and/or the extent of arcing. Less powerful actuators may be smaller and/or cheaper than more powerful actuators, facilitating the construction of smaller and/or cheaper electrical interrupters.

It will be understood that any of the features described above with reference to the switch of the first aspect may be provided in any suitable combination. Moreover, any such features may be combined with any features of the method of the second aspect or the apparatus of the third aspect as appropriate.

Brief Description of the Dra

The following description is with reference to the following Figures: Figurer: Figures -IA shows a schematic cross-section of an example of an electrical interrupter in accordance with the first aspect, where the electrical interrupter is in a first, closed, position. Figure 113 shows a schematic illustration of an example breakable conductor used in the electrical interrupter, and Figure if shows on exploded view of an electrical interrupter in accordance with the first aspect; Figure 2: Figures 2A and 2B show schematic cross-sections of embodiments of an electrical interrupter in accordance with the first aspect, where the electrical interrupter is in a second, open, position; -9 -Figure 3: Figures 3A-3F show schematic cross-sections of further examples of electrical interrupters in accordance with the first aspect, Figure 4: Figures 4A-4D show schematic cross-sections of example breakable conductors usable in embodiments of electrical interrupters in accordance with the first aspect; Figure 5: Figure 5A shows a schematic cross-section of an example electrical interrupter in accordance with an embodiment of a third aspect, where the electrical interrupter is in a first, closed, position, and Figure 5B shows a schematic cross section of the electrical interrupter of Figure 5A in a second, open, position; and It) Figure 6: Figures 6A and 6B illustrate a vehicle comprising an electrical interrupter as described herein.

Detailed Description

With reference to Figure 1 (Figures 1A-1C), an electrical interrupter 100 for opening a current conduction path is described. The current conduction path is defined along a conductor io8, which conductor is configured to break under pressure from an actuator or pyrotechnic charge 116 to open the current conduction path and interrupt current flow through an electrical circuit.

Electrical interrupter 100 corrrprises a breakable conductor 108 (i.e. a conductor which is configured to break under force) arranged within a housing 102. Portions of the conductor 108 extend through the housing 102 of the electrical interrupter 100 for connection of the electrical interrupter to an external electrical circuit; these portions are herein called connection contacts noa, nob. As can be seen in Figure 1C, the housing 102 is configured with slots into which the connection contacts may be fitted to extend out of the housing such that the connection contacts can be electrically connected to the external circuit.

The connection contacts non, nob are arranged at either end of the conductor 108, and a curved section 130 of conductor 108 is arranged between the two connection contacts. The curved section may extend the entire way between the two connection contacts, or the conductor 108 may comprise one or more intermediate sections or portions (such as portions 132a, 132b) arranged between the curved section and the connection contacts no, nob (as is illustrated in Figureth). In the examples shown herein the intermediate portions 132 are straight, but the intermediate section( s) or -10 -portion(s) may be any suitable geometry, depending on the size and shape of the device 100.

The curved section 130 of the conductor to8 has an inside curved face 134 and an outside curved face 136 (the face on the inside of the curve and the face on the outside of the curve, respectively). The curved faces 134 and 136 extend along the entire length of the curved section of the conductor and are here shown as smooth faces, though it ill be understood that the faces may be discontinuous in some examples, such as where the conductor is not formed as an integral component, as will be discussed in iv more detail below.

The housing of the electrical interrupter 100 is arranged such that, when the conductor 108 is arranged within the housing 102, the housing is configured to support portions of the curved section -1.3o of the conductor 108 to form a first supported section 112a is and a second supported section 1121) of the conductor. The housing (partially or full)') supports each of the supported sections 112 along their outside curved face; in other words, the housing is arranged to support the outside curved face of the carved section of ti-re conductor to form supported regions of the curved conductor section 130. The first supported section n2a is electrically connected to a first of the connection contacts, noa. The second supported section 112b is electrically connected to a second of the connection contacts, nob. As shown in Figure 1, the supported sections tr2a, rub are integral with the connection contacts configured to extend outside of the housing 102, but the supported sections 112 may be formed separately from, and electrically connected to (via any suitable means), the connection contacts to define the current conduction path along or through the conductor.

The first supported section 112a and the second supported section 112b are also electrically connected via a bridge section 114 of the curved section 130 of conductor 108, which bridge section 114 is unsupported by the housing. In the example of Figure 1 the bridge section 114 is illustrated as being integral with the supported sections 112 of the conductor, but it will be understood that the bridge section maybe mechanically and electrically coupled to each of the supported sections in order to electrically connect the two supported sections via the bridge section. For example, the bridge section may be welded, brazed or joined with an electrically conducting adhesive in order to connect or couple the bridge section n4. to the first and second supported sections 112a, Frith. in such examples, the curved faces 134 and 136 of the curved section 130 may be discontinuous in the areas around the joins/coupling.

As shown in Figure 1C, the housing components 102a, 1021) may each contain a single cavity 138. When the electrical interrupter 100 is assembled, the conductor 108 can be arranged within the housing such that the bridge section 114 is not supported by the housing but is arranged to span the cavity 138 (i.e. to bridge the cavity 138 in the housing such that the supported regions 112 of the conductor either side of the cavity are connected via the bridge section 114). When the electrical interrupter is assembled, Iv the bridge section 114 of the curved section 130 is arranged to separate the single cavity 138 to form a first cavity 104 and a second cavity 106 of the housing, such that the inside curved face 134 of the bridge section 114 at least partly defines the first cavity 104 of the housing 102. it Will be understood that, in other examples of device 100, the housing maybe, configured in any suitable manner such that the bridge section is is arranged to separate the first and second cavities. The outside curved face of the bridge section may define part of the second cavity 106, depending on the particular arrangement of the switch (and depending on which other components maybe present in the second cavity).

In the examples described herein, the inside curved face of the portion of the conductor making up the bridge section 114. defines part of the first cavity 104, but other arrangements are possible. in particular, the inside curved face 134 of the bridge conductor section at least partially defines a circumference of the first cavity 104. In some examples, the circumference of the first cavity 104 may be completely defined by the inside curved face in the radial direction, such that the conductor is arranged in a cylinder, or cylindrical, shape; the first cavity 104 is within the cylinder, defined by the inside volume of the cylinder (see e.g. Figure 3F). Where only a portion of the cavity 104 is defined by the inside curved face 134 of the curved section 1.30 of conductor 108, one or more faces of the first cavity 104 may be defined by the housing 102. The face(s) of the housing maybe curved; depending on the particular device design, the face(s) defining the cavity may be substantially semi-circular, semi-circular, substantially hemispherical or hemispherical. The conductor 108 and housing 102 are thus arranged such that a substantially cylindrical first cavity 104 is formed within the housing. End portions of the substantially cylindrical shaped first cavity 104 are formed by the housing 102, and/or one or more sealing members, to form a sealed first cavity 104.

This arrangement can be seen in more detail in Figure PC, which shows the flat end portion of the inside cavity 104being defined by housing component 102b.

The electrical interrupter 100 comprises a pyrotechnic actuator/charge ii6 arranged within the First cavity 104. The pyrotechnic charge is placed into the first cavity during manufacture, and the first cavity is then sealed around the charge by appropriate means, for example using 0-rings, rubberized sealant and/or overmoulding of the. Where rubberized sealant is used to seal the housing, the rubberized sealant may be a rubber solution applied during manufacture which then solidifies to provide sealing.

xv The pyrotechnic charge is configured, upon ignition, to release gas into the first cavity; because the first cavity is sealed 104, the pressure increases within the cavity, and the force exerted on the inside curved face 134 of the curved conductor sectiont3o as a result of the increased pressure eventually causes the conductor to8 to break, thereby opening the current conduction path.

Efficient breaking of the conductor is facilitated by the particular geometry of the conductor m8 and the housing 102. For example, due to the curvature of the curved section 130 of the conductor t08, the portion of the inside face of the curved section 120 which at least partially defines the first cavity 104 of the housing 102 experiences both radial and hoop stresses when the charge u6 is ignited from the increased pressure within the cavity. These stresses can combine to cause the conductor 108 to break. Radial stress is stress in directions coplanar with, but perpendicular to, the symmetry axis, Hoop (or circumferential) stress is the value of stress in the tangential direction (e.g. the stress exerted circumferentially, perpendicular to the axis and radius of the cylinder), which is defined in Equation i below. Since the curved section 130 is unconfined in the axial direction (into the page in Figure IA), axial forces are not experienced by the conductorro8 in these examples (though they may be experienced by the housing 102).

Equationt hoop stress = Force, exerted circurnferentiallypn an area nf cylinder (radial thickness of area of cylinder * axial length of area of cylinder) In the example described with reference to Figure i, the conductor 08 has a variable thickness, where the thickness 142 is defined between the curved outer face and the curved inner face. In particular, the thickness 142 of the bridge section 114 is less than a thickness of the supported sections 112a, 112b of the curved section 130 in these examples. This change in thickness increases the hoop stresses in the bridge section (see Equation 1, a smaller thickness means greater stresses for the same force), leading to concentration of the forces in that region of the conductor, and thus breaking of the conductor at the bridge section.

Moreover, as can be seen with reference to Figure IC, in some examples a 'length' of the cylinder (here defined across a width 140 of the conductor) is reduced in the bridge section 114 as compared to the rest of the conductor 108. This acts to increase hoop iv stresses in the bridge section (see Equation 1, a shorter length means greater stresses for the same force), again leading to concentration of the forces in that region and thus breaking of the conductor at the bridge section 114. 11 will be understood that the conductor may have the same thickness and width across the entire length of the conductor (extending between the two connection contacts), or that a thickness and/or is a width of the conductor may be variable at least in the curved section 130, optionally, when the thickness in the curved section is variable, a thickness and/or a width of the conductor may be less in the bridge section 114 than in the supported sections 112a, n2b.

In order to further facilitate breaking of the conductor 108 only at the bridge section 114, the housing 102 is arranged to be sufficiently strong to withstand the significant forces which arise from the increased pressure in the sealed first cavity 104 after ignition of the pyrotechnic charge 116 (e.g. to withstand the axial forces and any radial forces on the confined/retained supported sections 112 of the curved section of conductor 108, which may also at least partially define the first cavity 104, see Figure lA), For example, the housing may be formed of plastic, optionally glass-reinforced thermoset polyester. The housing may be formed in any suitable manner, such as compression moulding. Alternatively, any other suitable material or method of manufacture may be used, provided the housing 102 is able to retain/support the supported sections 112 of the conductor 108 after ignition of the charge 116, Examples of other suitable materials include filled polymers, unfilled polymer, and any other nonconductive material. Examples of other suitable manufacturing processes include injection moulding and transfer moulding.

Upon ignition of the pyrotechnic actuator, the expanding gas will exert a pressure in all directions on the wails of cavity 104. However, the shape of the first cavity 104 may -14 -cause the shock-waves from the explosion to be reflected toward the bridge section 114, multiplying the forces exerted on the bridge section 14 by the explosion. For example, where the one or more faces of the first cavity 104defined by the housing 102 are curved, substantially semi-circular, semi-circular, substantially' hemispherical or hemispherical, shockwaves may be reflected back to the unsupported bridge section 114., which will increase the force exerted on the bridge section in response to the Even in the absence of a conductor with a variable width and/or thickness (i.e. where nt the conductor has the same cross--section throughout the curved section 130), the device is configured such that exerted forces from the charge H6 can break the current conduction path through the conductor 108 by causing the conductor 108 to break at the bridge section 114. In particular, the release of gas into the first cavity 104 causes a large pressure differential between the first cavity 104 and the second cavity 106; this is pressure differential will push the unsupported bridge section 114 towards the second cavity, leading to breaking of the conductor 108 at the bridge section (since the supported sections 112 are retained or supported by the housing along the outside curved face, in the opposite direction to that in which the force from the actuator is acting on the bridge section).

With reference to Figure 2 (Figures 2A and 213), opening of the current conduction path is described in more detail. Operation of the device comprises igniting the pyrotechnic charge n6 to release gas into the first sealed cavity 104 and exerting, in dependence on the released gas, pressure on the bridge section 114. The exerted pressure causes breaking of the conductor at the bridge section to open the current conduction path through the conductor 108. In the examples of Figure 2, a portion of the bridge section is broken away from the rest of the conductor in order to break the conductor and open the current conduction path, thereby stopping or interrupting current flow around the external circuit to which device 100 is connected (as will be described below in more detail with reference to the examples of Figures 313-31-0, However, it will be understood that the bridge section may instead break at only a single point, causing the unsupported parts of the bridge section. either side of the break/opening to be pushed into the second cavity in response to the forces from ignition of the charge 116 (see for example the embodiments of Figures 3A, 4A and 4B).

Figure 2A is an illustration of an example of the electrical interrupter 100, subsequent to the ignition of the pyrotechnic charge n6 and the resultant breaking of at least a portion 118 of the bridge section 114 of the conductor 108 and the opening of the current conduction path. As is illustrated, the portion 118 of the bridge section has been pushed to the end of the second cavity 106 furthest from/opposite to the first cavity 104 by the forces from the ignited charge 116. Figure 2B is an illustration of another example of the electrical interrupter 100 subsequent to the ignition of the pyrotechnic charge 116, in Which the portion u8 of the bridge section has again been displaced to the end of the second cavity 106 and is retained in that position by a xv biasing member 120. This approach can prevent accidental closing of the current conduction path due to movement of the portion 148, since the portion n8 cannot come back into electrical contact with the rest of the conductor 108 due to the urging of the biasing member in a direction away from the conductor 108. This arrangement may therefore facilitate provision of a more reliable disconnectorlinterrupter device. This is arrangement can also provide an orientation independent device, since the portion 118 will not fall back towards the first cavity in response to gravity, for example.

The displacement of the portion 118 of the bridge section in the manner described herein can also facilitate a reduction in the electric arc for arc discharge) formed when the portion 118 of the bridge section 114 is broken away from the supported sections.

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 between the portion and the remainder of the conductor 108, 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 by the displacement of the bridge section, which interruption may be further improved by the use of biasing member 120 to accelerate the portion n8 of the bridge section into the second cavity 126. A safer and more robust switch may therefore be provided.

As illustrated in Figure J.C, the electrical interrupter may include a capsule 122 including arc extinguishing media. Further details of the capsule and the arc extinguishing media are described in relation to Figure 3D, but it will be understood that, subsequent to the ignition of the pyrotechnic charge 146 and the resultant breaking of a portion n8a of the bridge section 114 of the conductor 108, the capsule 122 may be broken or ruptured and the arc extinguishing media contained within released into the second cavity. The presence of the arc extinguishing media can further improve the interruption of the electrical arc, providing a safer and more robust electrical interrupter.

With reference to Figures 3 and 4, different example arrangements of the electrical interrupter 100 and its optional features are described; these features may be combined in any suitable manner with features from other examples, even if that combination is not explicitly illustrated.

With references to Figures 3A and 4A, in some examples of the electrical interrupter 100 the conductorro8 has a curved section comprising a bridge section 14 which is thinner than the supported sections, but there is a smooth variation in thickness 142 along the length of the conductor 108. The conductor to8 may reliably break at the bridge section 1.14 due to that region of the conductor being unsupported by the housing and due to the relativelythinnercross section of the bridge section of this example compared to the supported sections 112a, 1121), Such an arrangement of conductor 108 may be relatively cheap and simple to manufacture, as compared to more complex conductor geometries.

During breaking of the bridge section 114., one or more portions 1_18 of the bridge section may be blOAAM out or broken away from the conductor 108 as a result of the ignition of the charge 116. Alternatively, the bridge section may break at a single point, causing the ends of the portions of the bridge section either side of the single break to be pushed_ outwards into the second. cavity due to the actuating forces. These portions remain electrically and physically coupled to the supported sections 11.2a, 112b (the dashed lines indicate the boundaries of the supported sections of the conductor 108), but the physical gap between the ends causes the current conduction path to open.

With reference to Figure 4B, breaking of the conductor at a single point may be further facilitated by the presence of one or more notched portions 140 (illustrated within the dotted circle of Figure 4B) Within bridge section 114, in particular, Figure 4B shows a close-up illustration of a breakable conductor 108 having a curved section with a bridge section 114 With a single notched portion 140. The dashed lines indicate the boundaries of the supported sections of the conductor 108. The presence of the single notched portion facilitates reliable breaking of the bridge section 114 at that notched portion in response to the forces exerted on the bridge section 114 from ignition of tbe pyrotechnic charge 116 because the notch thins the conductor cross section at that region, thereby leading to higher stresses vvi thin the conductor in the areas at and around the notch. The single notched portion 140 may include a notch on the inside curved face, a notch on the outside curved face, or two notches: a notch on the inside curved face and on the outside curved face. The use of a notched portion thus reduces the force required to break the conductor, allowing a smaller, lower powered actuator to be used. A cheaper and smaller switch may therefore be provided.

There may also be cuts, e.g. rectangular cuts, and/or dents, e.g. triangular dents, from Iv both edges or one edge of the curved section of the conductor at the notched portion 140. These cuts and/or dents reduce force required to break the conductor, at least because the width of the conductor at the notched portion is reduced further concentrating forces at the notched portion 140.

The notched portion 140 of this example may be positioned approximately at the centre of the bridge section 114 or at the centre, such that the notched ponLion is at the apex of the curve of the conductor. After breaking of the conductor, the forces exerted on the bridge section 114 cause the portions of the bridge section 114 either side of the notched portion 140 to bend away from each other and into the second cavity, as is described above with reference to Figure 4A; the physical gap between the ends of this portions causes opening of the current conduction path.

As illustrated in Figures 3B-3E, with reference to Figure 4C, in some embodiments of the electrical interrupter 100 the conductor 108 has a curved section having a bridge section 114 with two notched portions. Each of the two notched portions may include a notch on the inside curved face, a notch on the outside curved face, or two notches: a notch on the inside curved face and on the outside curved face. There may also be cuts, e.g. rectangular cuts, and/or dents, e.g. triangular dents, from both edges or one edge of the curved section of the conductor at each of the notched portions. These cuts and/or dents reduce force required to break the conductor, at least because the width of the conductor at the notched portions is reduced further concentrating forces at the notched portion 140.

The two notched portions are proximate either end of the bridge section 114 and bound a portion n8 of the bridge section 114. The bridge section 114 is configured to break at each of the two notched portions upon the exertion of pressure on the bridge section -18 - 114, due to the reduced thickness 142 in these areas. The portion 118 bounded by the two notched portions is configured to be separated from the rest of the bridge section and from supported sections n2a, 11.2h on the exertion of pressure from the pyrotechnic charge n6, and to be displaced into the second cavity 106.

In some examples, the portion n8 may comprise all of the bridge section 114, or only a portion of the bridge section, depending on the position of the notch portions 140. Where the portion n8 comprises the whole of the bridge section 114, the notched portions may be positioned right at the edge of the bridge section, proximate the xv housing supporting the supported sections 112a, 112b. Where the portion 118 comprises a portion of the bridge section, the notched portions may be positioned equidistant from the edges of the bridge section such that the portion n8 is at the centre of the bridge section. By using two notched regions in this manner, double breaking of the conductor 108 can be achieved. This can reduce arc formation and allow circuits with higher current ratings to be interrupted using the device 100 described herein.

Where the portion 118 comprises a portion of the bridge section, the portion 118 may comprise at least 20%, at least 50% or at least 80% of the bridge section. The larger the portion n8 of the bridge section separated from the rest of the bridge section, the greater the distance between the remaining portions of the bridge section, which may reduce the likelihood of dielectric breakdown allowing circuits with higher current ratings to be interrupted. The smaller the portion n8 of the bridge section separated from the rest of the bridge section, the faster the portion 118 is displaced, wit ch may reduce arc formation.

More notched portions may be used, as discussed below, to achieve two double breaks which may further arrest arc formation.

As illustrated in Figures 3C and 3D, in some embodiments of the electrical interrupter a biasing or urging member 120 is coupled to the bridge section n4, between the two notched portions, and arranged to urge the portion 118 of the bridge section towards the second cavity 106. The biasing member may be a resiliently deformable member. The resiliently deformable member may be a spring. Alternatively or additionally, the resiliently deformable member may be formed from an elastic material, such as rubber, elastic or another elastomer. The resilient deformable member is placed under tension -19 - (i.e. it may be a tensioned spring) when the device is in the closed position, such that it urges the portion n8 of the bridge section towards the second cavity 106 upon breaking of the at least a portion 118 of -the bridge section. The biasing member 120 may be coupled to the bridge section 114 at the centre of the portion 11.8. The biasing member 120 maybe coupled to the housing 102 at an end of the second cavity 106 opposite to the outer curved face of the bridge section 114. The biasing member 120 may be coupled to each of the bridge section 114 and the housing 102 by lugs. The forces exerted on the bridge section 114 by the biasing member 120 cause a quicker separation of the portion n8 of the bridge section 114 from the supported sections n2a, 112b, and iv a faster displacement of the portion 118 toward the second cavity 106. The biasing member /20 also retains the portion n8 in the second cavity 106, thereby preventing any unwanted reestablishment of the current conduction path due to movement of the portion n8. An orientation independent device may therefore be provided.

As illustrated in Figure 3D, in some embodiments 100 of the electrical interrupter, arc extinguishing media is arranged within the second cavity 106 in a capsule 122 The arc extinguishing media maybe in liquid, gel or powder form. As an example, the arc extinguishing media maybe silica gel. The use of silica gel, or another gelatinous arc extinguishing media, may be beneficial as gelatinous materials are penetrable by the displaced portion 118 of the bridge section 114 during opening of the current path and interrupting of the circuit. At the same time, due to their high viscosity, the likelihood and/or amount of leakage of the are extinguishing material out of the housing 102 is reduced.

The arc extinguishing media may be arranged, e.g. enclosed, within capsule 1.22 located.

in the second cavity 106. The capsule 122 may be formed from plastic, such as polyvinyl chloride (PVC) or nylon, or any other suitable material, e.g. paper or metallic foil. The use of the capsule 122 may prevent leakage of the arc extinguishing media prior to the ignition of the pyrotechnic charge n6. The capsule 122 is configured to release the arc extinguishing media upon breaking or rupture of the capsule to help attenuate the electric arc that may form around or between the broken ends of the conductor 108. The capsule 122 may be ruptured by forces (e.g, compressive forces) exerted on the capsule 122 by contact with the portion 118 of the bridge section 114 upon displacement of the portion n8 into the second cavity 106 after ignition of the pyrotechnic charge n6. The portion n8 may optionally include one or more puncturing means arranged to puncture the capsule 122 upon contact with the capsule.

-20 -The puncturing means may, for example, be a needle, spike, sharp fin, or a thin cylindrical protrusion. In some embodiments, the capsule 122 is sufficiently strong to not rupture by the forces exerted on it before puncturing, but may be sufficiently weakened by the puncture to be ruptured, torn, burst, and/or broken by these forces subsequent to puncturing.

As illustrated in Figure 3E, in some embodiments 100 of the electrical interrupter, the portion of the -housing 102 surrounding the second cavity 106 has one or more gas releasing means 124a, 124b, 126, 128, which may be used to release the gas generated Iv upon ignition of the pyrotechnic charge il6 from the second cavity 106.

The gas releasing means may include breakable wall vents 124a, 124h. The breakable wall vents 124a, 124b extend partially through the housing 102 with a portion of housing 102 at each end of each of the breakable wall vents 124a, 124b The portions of is housing 102 at each end of each of the breakable wail vents. 124a, 124b, which may be referred to as breakable walls, are configured to break upon release of gas from the pyrotechnic charge 116 into the second cavity 106. Breakable wall vents 124a. 124b facilitate sealing of the second cavity prior to ignition of the pyrotechnic charge no while enabling the release of gas upon ignition of the pyrotechnic charge 116 to prevent damage to the electric interrupter 100. Furthermore, the breaking of the breakable walls may be visible from the outside of the electrical interrupter, acting as a visual indicator that the pyrotechnic charge 116 has been ignited and that the current conduction path has been opened. This may facilitate easier and cheaper maintenance and inspection for a user.

The gas releasing means may additionally or alternatively include one or more through holes 126 extending completely through the housing 102. It may be simpler to manufacture a housing 102 having through holes as compared to other gas releasing means, facilitating the provision of a cheaper switch. Through holes may also release gas from the second cavity 106 more quickly than other gas releasing means, improving the gas release process and reducing the likelihood of damage to the housing. The one or more through holes 126 may, in some examples, include a rubber plug; the rubber plug may be ejected from the through hole on the release of gas into the second cavity, providing a visual indicator that the pyrotechnic charge n6 has been ignited. The gas releasing means may additionally or alternatively include one or more through holes containing either or both of a mesh and/or a baffle 128. The mesh and/or baffle slow the release of gas from the second cavity. Therefore, through holes with a mesh and/or a baffle facilitate the release of gas from the second cavity while preventing high velocity jets of plasma and/or high temperature gases being emitted. Such high velocity jets could potentially damage components and/or equipment in the vicinity of the switch and/or pose a safety risk.

As illustrated in Figure 3F, in some embodiments 100 of the electrical interrupter the housing 102 has a third cavity io6b, where the second cavity is herein referred to as cavity 106a. The conductor 108 also has a second bridge section 11.4b arranged to iv separate the first cavity 104 from the third cavity 106b. A first supported section 112a and a second supported section 112b are electrically connected via the first bridge section 114a and the second bridge section 114h. The pyrotechnic charge 116 is arranged to break the second bridge section 114b, in addition to the first bridge section ima, to break the current conduction path through the conductor 108. The second is bridge section 1146 may also have two notched portions, where the two notched portions are proximate either end of the bridge section 1141) and bound a portion 118b of the bridge section 114b. The portion 118b bounded by the two notched portions is configured to be physically and electrically separated from the supported sections 112a, 1126 on the exertion of pressure from the pyrotechnic charge no; for example, the portion 118b may he broken away from the rest of conductor 108 and displaced into the third cavity 106b. The operation of opening the current conduction path through bridge section pi4b is identical to the process described above for bridge section 114 more generally.

In the example shown in Figure 3F, the sections 114a and 114b are arranged in parallel.

In this example, the curved section of the conductor 108c may extend around the first cavity 104, e,g. extend 360" around the first cavity 104 such that the inside curved face of the curved section completely defines the circumference of the first cavity 104. The inside face of the curved section of the conductor 108c may be circular or substantially circular. By extending the conductor 108 completely around the first cavity, and consequently around the pyrotechnic charge 116, the conductor 108 shields the housing 102 from some of the forces exerted on the housing when the pyrotechnic charge 116 is ignited. The housing may, therefore, be made relatively thinner than for other interrupter devices. A thinner housing may be cheaper to manufacture as less materials are used, which may in turn reduce the cost and/or allow for less expensive manufacturing processes. A thinner housing may also facilitate the manufacturing of a smaller electrical interrupter. The inside curved face of the second bridge section 114b may define part of the first cavity io4. opposite to the part defined by the inside curved face of the first bridge section 1.14a, Na it will be understood that the cavitiesm6a, 1.06b, and bridge secti onsti4a, 114b may not be arranged opposite one another.

An alternative arrangement in which the two bridge sections may be arranged in series is described with reference to Figure 4D. In particular, Figure 4D shows a close-up illustration of a breakable conductor m8 having a curved section with two bridge sections wta, wth and several notched portions. Pairs of notched portions define Iv portions ll8a,n8b of the bridge sectionsll4a,114b, which are configured to be separated from the conductor 108 in response to the forces exerted from ignition of the pyrotechnic charge. Another supported section 112C is located between the two bridge sections iti4a,114b, each of which spans a cavity m6a,w6b into which the respective portion of the bridge section may be displaced when the current conduction path is Is opened. A benefit of such a conductor is that by having a plurality of separable portions 118a, it8b in series, there are multiple points at which the conduction path along the conductor 108 may be broken. This can provide redundancy in the breaking of the conduction path and consequently more reliable breaking of the conduction path, and hence more reliable electrical interruption by the electrical interrupter mo. Moreover, the increased number of conductor breaking points can reduce arc formation.

In any of these arrangements, a biasing or urging member as described may also be used, with respective biasing members urging the respective portions n8a, 118b of the respective bridge sections n4a.,114b into the respective cavities 106a, m6b. Arc extinguishing media as described above may also be used with these example embodiments, with arc extinguishing media arranged in either or both of the second cavitynia and the third cavity mob, optionally within capsules 122.

With reference to Figure 5 (Figures 5A and 5B), an electrical interrupter 400 for opening a. current conduction path is described. The current conduction path is defined along a breakable conductor 408 extending through a housing 404. of the electrical interrupter 400.

Electrical interrupter 400 comprises a breakable conductor 408 (i.e. a conductor which is configured to break under force) arranged within a housing 404. Portions of the conductor 408 extend through the housing 402 of the electrical interrupter 400 for -23 -connection of the electrical interrupter to an external electrical circuit; these portions are herein called connection contacts 412a, 412b. The housing 402 is configured with slots into which the connection contacts may be Fitted such that the connection contacts can be connected to the external circuit.

The connection contacts 412a, 412b are arranged at either end of the conductor 408, and are respectively part of a first section 410a and a second section 410b of the conductor. While described as being part of the first section 4.10a and the second section 4 lob, the first section 410a and the second section 410b may be formed Iv separately from, and electrically connected to (via any suitable means), the connection contacts to define the current conduction path through the conductor 408.

The housing 404 of the electrical interrupter 400 is arranged such that, when the conductor 408 is arranged within the housing 402, the housing 404 supports at least a /5 portion of each of the first section 410a and the second section 4101). Tn particular, the housing supporting the first section 410a and the second section 410b may support the housing in a direction opposite to that in which an actuator 402 is arranged to exert a force (the arrow representing actuator 402 illustrates the direction of force exerted by the actuator in these examples).

The first section 410a and the second section 410b are also electrically connected via a bridge section 414 of the conduckor108, where bridge section 414 is unsupported by the housing, 'The bridge section 414 defines at least a portion of a cavity 406 in the housing 404; in some examples, the cavity 406 may be a cuboid with five faces of the cavity defined by the housing 404 and the other face defined by the bridge section 414. In the example of Figure 5, the bridge section 414 is illustrated as being integral with the conductor 408, but it will be understood that the bridge section may be mechanically and electrically coupled to the first and second sections 410a, 4101) in order to electrically connect the first and second sections 41.0a, 4101) to form a conduction path along the conductor. For example, the bfidge section maybe welded, brazed. or joined with an electrically conducting adhesive in order to connect the bridge section 414 to the first and second sections 410a, 410b, 'the bridge section 414 may be thinner than the first section 410a and the second section 410b. The bridge section 414 may have notched portions bounding a separable portion of the bridge section which is configured to separate from the rest of conductor 408 to open the current conduction path.

In operation, actuator 402 is configured to exert a force on at least a portion of the conductor in a direction towards the second cavity 406 in order to break the conductor 408 and displace at least a portion of the bridge section 414 into the second cavity 406. The actuator may be arranged directly opposite to the cavity 406, with the bridge section arranged between the actuator and the cavity. As described herein, actuator 402 may he any suitable type of actuator. in some examples actuator 402 is a pyrotechnic charge nt of the type explained in relation to the electrical interrupter 1.00 with respect to Figure 1. However, another form of electrically actuated actuator, or a Iv manually operated actuator, may be used to break the conductor. it will be understood that the type of actuator used may be dependent on a thickness of the conductor 408, since this thickness affects the force required to be applied to break the bridge section 414 and open the current conduction path.

is A biasing member 416 may optionally be connected to the bridge section 414 and arranged to urge the bridge section into the cavity 406 in the same direction in which the actuator exerts a force. The biasing member may be a resiliently deformable member. The resiliently deformable member may be a spring, e.g. a tensioned spring. Alternatively or additionally, the resiliently deformable member may be formed from an elastic material, such as rubber, elastic or another elastorner. The resilient deformable member is tensioned such that upon separation of the portion of the bridge section 414 the restoring force of the biasing member acts to urge or bias the portion into the cavity 406. The biasing member 416 may be coupled to the bridge section 414 at the centre of the bridge section 414 and the other end may be coupled to the end of the cavity 406. The biasing member 416 may be coupled to the bridge section 414 and the housing 402 by respective lugs. The forces exerted on the bridge section 414 by the biasing member 120 cause a quicker separation of the portion of the bridge section 414 from the first and second sections 410a, 410b and a faster displacement of the portion toward the cavity 406. The biasing member 416 also retains the portion in the cavity 406, thereby preventing any unwanted. reestablishment of the current conduction path due to movement of the portion. An orientation independent device may therefore be provided.

Figure 5A illustrates the state of the electrical interrupter 400 prior to actuation of the actuator 402. Upon actuation of the actuator 402, the actuator 402 exerts forces on the bridge section 414 in a given direction. The exerted forces act to break the conductor -25 -and separate at least a portion of the bridge section 414 from the first section 410a and the second section 410b of the conductor 408. Where there is a separable portion of the bridge section 414 bounded by notched portions, the portion separated by the exerted forces may be this separable portion. In some examples the separable portion is the entire bridge section, depending on the positioning of the notches or notched portions. Upon separation of the bridge section 414, the biasing member 416 urges the bridge section 414 into the cavity 406. As discussed above, the use of the biasing member 416 may result in a quicker breaking of the conductor 408 and faster displacement of the bridge section, which acts to reduce arc formation. The biasing Iv member also facilitates the separation of the portion from the conductor with less force, allowing for the use of smaller actuators, and thus a smaller device.

In order to facilitate breaking at the bridge section 414 only, the housing 404 may be sufficiently strong to withstand significant forces acting on the rest of the conductor is 408, e.g. pressure forces resulting from actuation of a pyrotechnic actuator.

Compression moulding is an example of a suitable method for manufacturing a sufficiently strong housing. The housing 404 may be formed from plastic, optionally a glass-reinforced thermoset polyester. A thinner housing maybe used when different types of actuators 4.02 are used that do not exert significant pressure forces on the housing 404. A housing may be formed using any suitable manufacturing methods, e.g. injection moulding. A thinner housing may be cheaper to manufacture as less materials are used, which may in turn reduce the cost and/or allow for less expensive manufacturing processes. A thinner housing may also facilitate the manufacturing of a smaller electrical interrupter. Any suitable material or method of manufacture may be used., provided the housing 404 is able to withstand the forces from the actuator during breaking of the conductor to retain the supported portions of the first section 410a and the second section 410 after actuation of the actuator. Figure 5B illustrates the state of the electric interrupter 400 subsequent to actuation of the actuator 402. in this example, the entire bridge section 414 has been urged into the cavity 406 by the biasing member 416 and is retained in the cavity 406 by the biasing member.

The electrical interrupter such as device 100 or 400 comprising a biasing member has several advantages, as previously outlined. Faster separation of the at least a portion of the bridge section may result in faster electrical interruption. Retention of the separated portion in the cavity 406 may also reduce the probability of undesired reconnection of th.e conduction path. A safer switch may therefore be provided.

Moreover, by reducing the probability of undesired reconnection of the conduction path, the biasing member may facilitate the reliable operation of the electrical interrupter in circumstances where undesired reconnection of the current conduction path would otherwise be likely, e.g. where the electrical interrupter is rotated or is accelerated or decelerated (for example, in a vehicle). The use of the biasing member 416 can prevent accidental closing of the current conduction path due to movement of the at least a portion of the bridge section 414 back into electrical contact with the rest of the conductor 408, and may facilitate provision of a more reliable electrical disconnector or interrupter device. This arrangement can also provide an orientation xv independent device, since the portion will not fall back towards the conductor in response to gravity, for example.

The displacement of the portion of the bridge section 414 in the manner described herein can also facilitate a reduction in the electric arc (or arc discharge) formed when the portion of the bridge section 414 is broken away from the supported sections. 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 between the portion and the remainder of the conductor 408, 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 by the displacement of the portion of the bridge section 414. In particular, biasing member 416 accelerates the displacement of the portion of the bridge section 414 into the cavity 406, reducing arc formation. A safer and more robust switch may therefore be provided.

With reference to Figure 6, example uses of an electrical interrupter 100/400 are described. In the example of Figure 6A, electrical interrupter 100/400 is incorporated within a powertrain 220. In particular, powertrain 220 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,), 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 220 also includes battery-230 and an electric motor, for example. :Electrical interrupter 100/400 may be connected, via the connection contacts 110a/412a,n0b/412b of the breakable conductor 108/408, to an electrical circuit 250 within vehicle 500, which electrical circuit may optionally include the battery 230. Alternatively, in the example of Figure 6B, electrical interrapter 100/4.00 is employed for another use within vehicle 500, which maybe an electrical vehicle.

With respect to the electrical interrupter 100, in both. Figure 6A and 6B an ignition signal may be provided to actuator 116, 420 from a remote controller, or a remote power distribution unit, 210 within the vehicle 500. Such an ignition signal may be issued in response to an external event. For example, when the electrical interrupter 100 is connected to a battery 230 installed in the vehicle 500, an ignition signal may be fo sent to the actuator n6, 420 in response to a collision of the vehhie; ignition of the pyrotechnic charge 116 or actuation of the actuator can cause the breaking of the conductor to8, 408 in order to open the electrical circuit 250 and prevent the flow of current through the battery 230.

Such arrangements can improve safety in the (sent of a collision. Alternatively, electrical interrupter 100 or electrical interrupter 400, and remote controller 210 can form a system which can be deployed in any other application where such breaking of a circuit is required.

It is noted herein that while the above describes various examples of the electrical interrupter 100 and the electrical interrupter 400, 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. in particular, it should be noted that features described in relation to the electrical interrupter 100 may be incorporated into the electrical interrupter 400. For example: arc extinguishing media may be arranged in the cavity 406, optionally in a capsule; and/or the conductor 408 may take any of the forms 108 described with respect to electrical interrupter 100.

Claims

Claims 1. An electrical interrupter comprising: a housing (102) having a first, sealed, cavity (104) and a second cavity (l06); a breakable conductor (108) comprising: connection contacts (t tea, tick) at either end, the connection contacts of the conductor extending through the housing; and a curved section (130) arranged between the connection contacts and having an inside curved face (134) and an outside curved face (136), the inside curved face at least in part defining the first cavity, wherein the curved section in of the conductor comprises: first and second supported sections (112a, 122b), wherein each supported section is coupled to a respective one of the connection contacts and is supported along the outside curved face by the housing, and a bridge section (114) arranged to separate the first and second cavities, the first and second supported sections connected via the bridge section; and a pyrotechnic charge (116) arranged, upon ignition, to release gas into the first cavity to break the conductor at the bridge section to break a current conduction path 20 through the conductor.
2. The electrical interrupter of claim 1, wherein a thickness of the curved section, defined between the inside curved face and the outside curved face, is variable, 3. The electrical interrupter of claim 2, wherein a thickness of the bridge section is less than a thickness of the first and second supported sections.The electrical interrupter of any preceding claim, wherein the bridge section comprises at least one notched portion (118), wherein the bridge section is configured to break at the at least one notched portion, The electrical interrupter of any preceding claim, wherein the pyrotechnic charge is configured to separate a portion of the bridge section from the first and second supported sections and displace the portion of the bridge section into the second cavity to break the current conduction path. 4. 5. :356. The electrical interrupter of claim 5, wherein the bridge section comprises a notched portion proximate either end of the bridge section, wherein the portion of the bridge section is bounded by the notched portions.7. The electrical interrupter of any preceding claim, wherein at least a portion of the inside face of the curved section is an inscribe sector of a circle, such as a semicircle, optionally, wherein at least the inside face of the bridge section is an inscribe sector of a circle, such as a semi--circle.Iv 8. The electrical interrupter of any preceding claim, further comprising a biasing member (20) coupled to the bridge section and arranged to urge the portion of the bridge section towards the second cavity upon the separation of the/portion of the bridge section from the first and second supported sections, /5 9, The electrical interrupter of any preceding claim, further comprising arc extinguishing media arranged within the second cavity.10. The electrical interrupter of claim 9, wherein the are extinguishing media is arranged within a capsule (122) located inside the second cavity, the capsule configured to release the are extinguishing media upon rupture.it The electrical interrupter of claim 9 or claim to, wherein the outside curved face of the bridge section comprises at least one puncturing means arranged to puncture the capsule upon contact with the capsule to release the arc extinguishing media.12. The electrical interrupter of ny one of claims 9-il. wherein the arc extinguishing media is silica gel.13. The electrical interrupter of any preceding claim, wherein the portion of the housing surrounding the second cavity comprises one or more vents (124a, 124b, 126, 128) extending at least partially through the housing for releasing gas from the second cavity, 14. The electrical interrupter of claim 13, wherein the one or more vents (124a, 124b) extend only partially through the housing and the portion of the housing at the end -30 -of each vent is arranged to break upon release of gas from the pyrotechnic charge into the second cavity.15. The electrical interrupter of claim 13, wherein the vents (126,128) comprise one or niece through holes, optionally, wherein the one or more through holes contain at least one of a mesh and a baffle.16. The electrical interrupter of any preceding claim, wherein the curved section extends at least 120 degrees around the first cavity, optionally at least 180 degrees, It) optionally at least 270 degrees, optionally wherein the curved section extends 350 degrees or less around the first cavity.17. The electrical interrupter of any preceding claim, he housing has a third cavity (i06b), and wherein the breakable conductor comprises a second bridge section (.14b) arranged to separate the first and third cavities, the first and second supported sections connected via the second bridge section, and wherein the pyrotechnic charge is arranged to also break the second bridge section to break the current conduction path through the conductor.18. The electrical interrupter of claim 17, wherein the curved section extends around the first cavity such that the inside face of the curved section defines the first cavity, and wherein the third cavity is arranged on an opposite side of the first cavity from the second cavity.19. The electrical interrupter of claim i8, wherein the first cavity is substantially circular.20. The electrical interrupter of any of claims ito 17, wherein the first cavity has a semi-circular face opposite to the inside curve of the bridge section, the semi-circular face formed by the housing.21. A method for operating an electrical interrupter 000, comprising: igniting a pyrotechnic charge (i.16) to release gas into a first sealed ca vity (104) of a housing 004; -31 -exerting, in dependence on the released gas, pressure on a bridge section (tri4) of a curved section (130) of a breakable conductor (108), wherein the curved section has an inside curved face (134) and an outside curved face (136), the inside curved face at least in part defining the first cavity, and wherein first and second supported sections 112b) of the curved section are supported along the outside curved face by the housing and connected via the bridge section, the bridge section arranged to separate the first cavity from a second cavity (106) of the housing; and breaking, by the exerted pressure, the conductor at the bridge section to open a current conduction path through the conductor.22. The method of claim 21, further comprising: separating, by the exerted pressure, a portion (418) of the bridge section from the first and second supported sections; and displacing, by at least the exerted pressure, the portion of the bridge section into the second cavity.23. A electrical interrupter comp si an actuator (4.02); a housing (404) having a cavity (406); a breakable conductor (408) comprising: a first section (410a) and a second section (4 rob), the first and second sections comprising connection contacts (412a, 412b), wherein at least a portion of each of the first and second sections is supported by the housing, and a bridge section (414) arranged between the first and second sections to define a current conduction path, wherein the bridge section is configured to define at least a portion of the cavity; and a biasing member (416) coupled to the bridge section, wherein the actuator is configured, upon actuation, to exert a force on the bridge section in a first direction to separate a portion of the bridge section from the first and second conductor sections so as to open the current conduction path, and wherein, upon the separation of the portion of the bridge section from the first and second sections, the biasing member is arranged to urge the portion of the bridge section in the first direction into the cavity.24. The electrical interrupter of claim 23, wherein a thickness of the idge section is less than a thickness of the first and second sections.25. The electrical interrupter of claim 23 OF Claim 24, wherein the housing is configured to support the first and second sections in a second direction opposite the first direction.