Load break switch

Abstract

Load break switch for controlled interruption of an electrical current, comprising: a switch blade for switching the electrical current; a blade support for supporting and operating the switch blade; a vacuum interrupter for controlled current interruption; and an actuator cam rotatable about a cam axis for operating the vacuum interrupter; wherein the switch blade is electricallyconductive and rotatable at a first blade end about a blade axis and wherein a second blade end is rotationally displaceable, in sequence, to electrically: connect the first blade end to a primary blade contact, connect the first blade end to a secondary blade contact, and disconnect the first blade end; wherein the vacuum interrupter is connected between the primary and secondary blade contacts to provide a shunt circuit for controlled current interruption; wherein the blade support is arranged, at the second blade end, to cause the rotation of the actuator cam to open the vacuum interrupter.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of electrical distribution systems, specifically focusing on medium voltage load break switches used in medium voltage switchgear and designed to improve the reliability, efficiency, and safety / security of electrical power distribution networks.BACKGROUND

[0002] Load break switches are well known in the state of the art. Medium voltage load break switches are essential components in electrical power distribution networks, typically handling voltages up to 52 kV and currents up to 1250 A. They are used to interrupt load currents, close load and fault currents and provide a means to isolate sections of a network for maintenance or during faults.

[0003] With increased awareness and concern over SF6 gas usage in switchgear, due to its extremely high global warming potential, medium voltage load break switch technology is moving away from SF6 gas towards alternative technologies. One such alternative technology is a shunt vacuum interrupter type switch that uses a vacuum interrupter bottle (VI) placed in a circuit parallel to the main circuit and to which current is transferred for circuit breaking operations.

[0004] Document US2773154A discloses an electric switch having a shunt device for making and breaking the load circuit or current wherein after the circuit is closed the shunt device carries no part of the load current

[0005] Document US2023187151A1 discloses a current switch comprising a main contact with an electrically conductive knife and an electrically insulating element, both mounted movably on a first portion of an electric line to alternate between open and closed positions. It also includes a shunt branch with a first part electrically connected to a second portion of the line and incorporating a vacuum interrupter, and a second part movable relative to the first part for actuating the interrupter. During the opening movement, the conductive knife actuates the second part to open the vacuum interrupter, while during the closing movement, the insulating element moves the second part without actuating the interrupter.

[0006] Document US2012048692A1 discloses a switch incorporating latching and locking systems configured to retain the rod of a vacuum interrupter in a defined open or closed position. These systems are actuated and controlled either by the same mechanism that drives the movable contact of the vacuum interrupter or by the disconnector itself, ensuring position retention without requiring independent actuators.

[0007] Document US2023230785 A1 discloses a medium voltage load break switch comprising a main contact and a knife blade that rotates about a pivot to engage or disengage from the main contact. The switch further includes a vacuum interrupter with fixed and movable contacts, wherein the movable contact is actuated along the vacuum interrupter axis by a shaft linked to a lever. The lever rotates about its own rotation point to drive the movement of the vacuum interrupter's movable contact.

[0008] The difficulty posed by such a switch relates to the implementation of a mechanism that enables both the current transfer to this parallel circuit with the shunt VI and the opening and closing of the VI at the appropriate time in a simple, economical, and reliable manner, and also meets the technical requirements of the making and breaking operations of the switch, under both normal and fault network conditions.

[0009] These facts are disclosed in order to illustrate the technical problem addressed by the present disclosure.GENERAL DESCRIPTION

[0010] The present invention provides a mechanism for the implementation of a medium voltage switch, that uses shunt vacuum interrupter (VI) type technology.

[0011] The solution of the present disclosure relates to a medium voltage switch incorporating a shunt vacuum interrupter (VI) mechanism with coordinated actuation. The system ensures efficient current transfer and VI operation, enhancing reliability, performance, and environmental compliance.

[0012] According to the present disclosure, the switch includes a housing, a rotating blade support, switch blades, and fixed contacts for line and earth circuit positions. A shunt VI is connected between the line contact (i.e. a primary contact) and a secondary contact in the path of the switch blades. As the switch blades rotate during an opening operation, current is transferred to the VI circuit, and the VI is then opened in a timed sequence.

[0013] In an embodiment, the switch employs two actuator cams that engage with the blade support via protrusions and rotate to operate the VI. The cams feature a slot that engages a pin coupled to the VI's movable contact. The geometry of the slot controls the timing of the VI operation, introducing a delay to ensure safe transfer before interruption. Additional features in the slot geometry accommodate VI wear and retain the open and closed positions.

[0014] In an embodiment, a moveable secondary contact is included, pivoted by the blades during opening to increase isolating distance, and spring-returned after blade disengagement. The blades engage a pin in the secondary contact causing it to rotate. The pin is positioned in a slot in the secondary contact allowing the pin to escape and clear the blades during closing.

[0015] In an aspect of the present disclosure, the switch comprises a housing, a rotating blade support, switch blades a blade axis common contact, and fixed contacts for both line and earth circuit positions. For the parallel shunt VI circuit, there is the shunt VI with one of its contacts connected to the line circuit contact and the other connected to a secondary contact, positioned in line with the trajectory of the end of the switch blades. During an opening operation, the switch blades rotate and the circuit transfers from the main line contact to the secondary contact. The mechanism of the present invention provides a way to coordinate the movement (opening and closing) of the shunt VI contact with the movement of the switch blades.

[0016] In an embodiment, the disclosed mechanism comprises two actuator cams that rotate about and are supported by an axis on each side of the VI support structure. The axis is perpendicular to the axis of the shunt VI and VI support structure. The set of cams rotate together and are operated by the switch blade isolating support as it engages with protrusions on these cams. The switch blade isolating support rotates together with the switch blades during switch movement and has a specific geometry near the end of the switch blades to engage and rotate the two actuator cams in a smooth and even manner by maintaining a good force transmission angle. These cams are rotated in one direction during opening and in the opposite direction during closing. The geometry of the switch blade isolating support used during opening is inclined with a rounded extremity and engages the first set of protrusions of the cams. The geometry of the switch blade isolating support used during closing is straight with a rounded extremity and engages the second set of protrusions on the cams.

[0017] In an embodiment, the two actuator cams have a slot that engages a pin connected to the moveable contact of the shunt VI, that is guided by the VI support structure such as to operate (open and close) the shunt VI along its axis as the cams rotate, in one direction, and then the other. The shunt VI movement is always biased to close due to the pressure difference on the moveable contact. The slot geometry allows control over the opening and closing movement of the shunt VI and includes a delay between the initial movement of the cams, during an opening operation, and the effective opening of the shunt VI. This is achieved, for example, by means of an initial section of the slot with a constant radius or other slot shape that provides this delay.

[0018] In an embodiment, the assembly allows the synchronized movement of the shunt VI contact with the rotational position of the switch blades. During the opening movement of the switch blades, the opening of the shunt VI happens only after the switch blades transition to the shunt VI circuit secondary contact and no longer contacts the line contact. Note that when the cams and shunt VI are in the final open position, the cam protrusions, which were engaged during opening, are now positioned so as not to be engaged during closing. During the closing movement of the switch blades, the closed position of the VI happens only after the switch blades contact the main circuit contact.

[0019] In an embodiment, the geometry of the slot on the two actuator cams accounts also for VI contact erosion during the equipment life, that results in additional closing stroke accommodated by means of a wider initial part of the slot. The geometry of the slot on the two actuator cams also preferably includes means to maintain the final open position of the VI (and cams) until being operated again during a closing operation. This is also accomplished by the geometry of the slot which includes a small additional opening stroke followed by a recess to retain the final open position.

[0020] It is disclosed a load break switch for controlled interruption of an electrical current, comprising: a switch blade for switching the electrical current; a blade support for supporting the switch blade; a vacuum interrupter (VI) for controlled current interruption; and an actuator cam rotatable about a cam axis for operating the vacuum interrupter; wherein the switch blade is electrically-conductive and rotatable at a first blade end about a blade axis and wherein a second blade end is rotationally displaceable, in sequence, to electrically: connect the first blade end to a primary blade contact, connect the first blade end to a secondary blade contact, and disconnect the first blade end; wherein the vacuum interrupter is connected between the primary and secondary blade contacts to provide a shunt circuit for controlled interruption of a main circuit electrical current between the first blade end and the primary blade contact; wherein the blade support is arranged, at the second blade end, to cause the rotation of the actuator cam to open the vacuum interrupter when the second blade end is connected to the secondary blade contact and moving in sequence from the primary blade contact to the secondary blade contact.

[0021] The blade support is preferably arranged, at the second blade end, to cause the rotation of the actuator cam to close the vacuum interrupter when the second blade end is connected to the primary blade contact and moving in sequence from the secondary blade contact to the primary blade contact.

[0022] The load break switch may comprise an actuator pin mechanically coupled to the vacuum interrupter for actuating said vacuum interrupter, and wherein the actuator cam comprises a slotted path for guiding the actuator pin between a closed location, where the vacuum interrupter is closed, and an open location, where the vacuum interrupter is open, as the actuator cam rotates.

[0023] The secondary blade contact may be electrically connected to a movable contact of the vacuum interrupter.

[0024] The slotted path is preferably a curvilinear path.

[0025] The slotted path may comprise, at one or both of ends of the slotted path, a pressure retainer for non-permanent retention of the actuator pin, in particular the pressure retainer comprising a moulded pressure clip for non-permanent retention of the actuator pin.

[0026] The actuator cam may comprise a concave surface for receiving the rotating blade support for the actuator cam to operate the vacuum interrupter.

[0027] The secondary blade contact may be pivotable for increasing distance to the primary blade contact, when the second blade end is moving from the primary blade contact to the secondary blade contact.

[0028] The secondary blade contact may comprise a spring for decreasing distance to the primary blade contact, when the second blade end is not moving from the primary blade contact to the secondary blade contact.

[0029] The secondary blade contact may comprise a displaceable pin arranged to be: engaged by the blade support to pivot the secondary blade contact for increasing distance to the primary blade contact, when the second blade end is moving from the primary blade contact to the secondary blade contact; and not engaged by the blade support, when the second blade end is moving from the secondary blade contact to the primary blade contact.

[0030] The secondary blade contact may comprise a slot and the displaceable pin is arranged to be displaceable along said slot, in particular wherein the secondary blade contact comprises a spring for returning the displaceable pin to a rest position.

[0031] The load break switch may comprise an additional actuator cam rotatable about the cam axis for operating the vacuum interrupter, wherein the two rotatable cams are mechanically coupled to each other, wherein the vacuum interrupter is arranged between the two rotatable cams, and wherein the blade support is arranged, at the second blade end, to cause the rotation of the additional actuator cam to open the vacuum interrupter when the second blade end is connected to the secondary blade contact and moving in sequence from the primary blade contact to the secondary blade contact [i.e. the rotatable cams are arranged to reduce bending loads], in particular the blade support is arranged, at the second blade end, to cause the rotation of the additional actuator cam to close the vacuum interrupter when the second blade end is connected to the primary blade contact and moving in sequence from the secondary blade contact to the primary blade contact.

[0032] The load break switch may comprise a first and a second electrical terminals, wherein the first blade end is connected to the first electrical terminal at said blade rotation axis thus being a blade axis contact, and the primary blade contact is connected to the second electrical terminal.

[0033] The load break switch may comprise a ground terminal, in particular the load break switch comprising a housing electrically connected to the ground terminal.

[0034] The cam axis may be arranged in a region defined by the primary and secondary blade contacts and the second electrical terminal [i.e. the cam rotating axis is between or at one of these reference points.

[0035] The the blade support may comprise one or more protuberances at the second blade end for pushing the actuator cam to cause rotation of the actuator cam.

[0036] The vacuum interrupter may comprise first and second connections, wherein the first connection is connected to the second electrical terminal, and wherein the second connection is connected to the secondary blade contact.

[0037] The load break switch is preferably a medium voltage load break switch, in particular the medium voltage is 5 kV to 60 kV, preferably from 10 kV to 36 kV.

[0038] The actuator cam is preferably electrically-isolating.

[0039] The blade support is preferably electrically-isolating.

[0040] The disclosure includes a triphasic load break switch comprising three load break switches according to any of the described load break switches.

[0041] Further particular and preferred aspects are set out in the accompanying independent and dependent claims. Features of the dependent claims may be combined with features of the independent claims as appropriate, and in combinations other than those explicitly set out in the claims.

[0042] Where an apparatus feature is described as being operable to provide a function, it will be appreciated that this includes an apparatus feature which provides that function or which is adapted or configured to provide that function.BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The following figures provide preferred embodiments for illustrating the disclosure and should not be seen as limiting the scope of invention. Figure 1: Schematic representation of an embodiment of a complete three-phase switch assembly. Figure 2: Schematic representation of an embodiment of a complete three-phase switch assembly (with transparent housing for viewing hidden components). Figure 3: Schematic representation of an embodiment of the disclosure illustrating a single-phase switch assembly (with transparent housing for viewing hidden components). Figure 4: Schematic representation of an embodiment of the disclosure illustrating a Shunt VI assembly in the open position (with transparent VI support and transparent actuator cam for viewing hidden components). Figure 5: Schematic representation of an embodiment of the disclosure illustrating a Shunt VI assembly in the closed position (with transparent VI support and transparent actuator cam for viewing hidden components). Figure 6: Schematic representation of an embodiment of the disclosure illustrating a single-phase switch assembly in the line closed position (with transparent blade support, VI support and transparent actuator cam for viewing hidden components). Figure 7: Schematic representation of an embodiment of the disclosure illustrating a single-phase switch assembly in an intermediate opening position just before starting to open the VI (with transparent blade support, VI support and transparent actuator cam for viewing hidden components). Figure 8: Schematic representation of an embodiment of the disclosure illustrating a single-phase switch assembly in an intermediate opening position with the VI fully open (with transparent blade support, VI support and transparent actuator cam for viewing hidden components). Figure 9: Schematic representation of an embodiment of the disclosure illustrating a single-phase switch assembly in the open and sectionalized position (with transparent blade support, VI support and transparent actuator cam for viewing hidden components). Figure 10: Schematic representation of an embodiment of the disclosure illustrating a single-phase switch assembly in an intermediate closing position before starting to close the VI (with transparent blade support, VI support and transparent actuator cam for viewing hidden components). Figure 11: Schematic representation of an embodiment of the disclosure illustrating a single-phase switch assembly in the earthed position (with transparent blade support, VI support and transparent actuator cam for viewing hidden components). Figure 12: Schematic representation of an embodiment of the disclosure illustrating a complete three-phase switch assembly. Figure 13: Schematic representation of an embodiment of the disclosure illustrating a complete three-phase switch assembly (with transparent housing for viewing hidden components). Figure 14: Schematic representation of an embodiment of the disclosure illustrating a single-phase switch assembly (with transparent housing for viewing hidden components). Figure 15: Schematic representation of an embodiment of the disclosure illustrating a shunt VI assembly in the open position (with transparent VI support and transparent actuator cam for viewing hidden components). Figure 16: Schematic representation of an embodiment of the disclosure illustrating a Shunt VI assembly in the closed position (with transparent VI support and transparent actuator cam for viewing hidden components). Figure 17: Schematic representation of an embodiment of the disclosure illustrating a shunt VI assembly in the open position (with no transparent or hidden components). Figure 18: Schematic representation of an embodiment of the disclosure illustrating a shunt VI assembly in the closed position (with no transparent or hidden components). Figure 19: Schematic representation of an embodiment of the disclosure illustrating a single-phase switch assembly in the line closed position (with transparent blade support, VI support and transparent actuator cam for viewing hidden components). Figure 20: Schematic representation of an embodiment of the disclosure illustrating a single phase switch assembly in In an intermediate opening position with the switch blades transitioning to the stationary secondary contact and with the VI still closed (with transparent blade support, VI support and transparent actuator cam for viewing hidden components). Figure 21: Schematic representation of an embodiment of the disclosure illustrating a single phase switch assembly in an intermediate opening position with the switch blades fully transitioned to the secondary contact which is also now moving with the blades and also the VI is starting to open (with transparent blade support, VI support and transparent actuator cam for viewing hidden components). Figure 22: Schematic representation of an embodiment of the disclosure illustrating a single-phase switch assembly in an intermediate opening position with the VI fully open (with transparent blade support, VI support and transparent actuator cam for viewing hidden components). Figure 23: Schematic representation of an embodiment of the disclosure illustrating a single-phase switch assembly in the open and sectionalized position (with transparent blade support, VI support and transparent actuator cam for viewing hidden components). Figure 24: Schematic representation of an embodiment of the disclosure illustrating a single-phase switch assembly in the earthed position (with transparent blade support, VI support and transparent actuator cam for viewing hidden components). Figure 25: Schematic representation of an embodiment of the disclosure illustrating a single-phase switch assembly in an intermediate closing position before sliding the secondary contact pin along the secondary contact slot - the VI remains open (with hidden blade support, transparent VI support and transparent actuator cam for viewing hidden components). Figure 26: Schematic representation of an embodiment of the disclosure illustrating a single-phase switch assembly in an intermediate closing position after sliding the secondary contact pin along the secondary contact slot - the VI remains open (with hidden blade support, transparent VI support and transparent actuator cam for viewing hidden components). Elements referenced in the drawings

[0044] 1 - Switch Housing 2 - Blade Support 3 - Line contact 4 - Common Contact 5 - Earth Contact 6 - Switch Blades 7 - VI Support 8 - Actuator Cam (8A & 8B) 8C - Actuator Cam Slot 8D - Actuator Cam Axis 8E - Actuator Cam Opening Protrusion 8F - Actuator Cam Closing Protrusion 8G - Actuator Cam Slot Open Retaining Clip 8H - Actuator Cam Slot Closed Retaining and Contact Pressure Clip 9 - Secondary Contact 9A - Secondary Contact Axis 9B - Secondary Contact Spring 9C - Secondary Contact Pin 9D - Secondary Contact Pin Slot 10 - Moveable Contact Pin 11 - Shunt VI DETAILED DESCRIPTION

[0045] The present disclosure relates to a medium voltage load break switch comprising a coordinated shunt vacuum interrupter (VI) mechanism designed to enhance electrical power distribution reliability and environmental compliance. The switch comprises a rotatable blade assembly, fixed line and earth contacts, and a shunt VI circuit connected between the line contact and a secondary contact. An actuation mechanism with preferable dual cams, each having a profiled slot engaging a pin linked to the VI's movable contact, ensures precise timing of VI opening and closing. The system preferably includes geometry to delay VI actuation until after current transfer, and features to retain the VI in stable open or closed positions. A pivoting secondary contact optionally provides increased isolation distance during breaking and automatically resets via a torsion spring. The present disclosure facilitates efficient current interruption and safe switch operation while enabling compact, SF 6 -free switchgear design with a surprisingly effective and practical setup.

[0046] In an embodiment, to allow for higher voltage ratings of the load break switch, a larger distance between the line contact (3 ) and the secondary contact (9 ) during breaking may be necessary. On the other hand, the transition of the switch blades (6 ) between the line contact (3 ) and the secondary contact (9 ) needs to maintain a close distance to avoid arcing. To simultaneously achieve these conditions, and comply with the requirements for higher voltage ratings, a moveable secondary contact system was included in which the secondary contact (9 ) pivots around an axis (9A ) and is rotated by the switch blades when these contact a pin (9C ) with lateral protrusions assembled in a slot (9D ) in the secondary contact. The secondary contact (9 ) is rotated (dragged) by the switch blades (6 ) during the opening operation, achieving a much higher isolating distance during VI switching. The secondary contact (9 ) returns to its initial position, by means of a torsion spring (9B ), after the switch blades (6 ) leave the secondary contact (9 ).

[0047] In an embodiment, during the closing operation the secondary contact pin (9C ) would collide and block the switch blades movement and so a slot (9D ) exists in the secondary contact and is designed to allow the pin (9C ) to slide out of the path of the switch blades (6 ) during a closing operation (demonstrated in fig. 25 and fig. 26). The pin (9C ) then returns to its initial position, by means of a spring within the secondary contact, after the blades have passed.

[0048] In an embodiment, the geometry of the slot (8C ) on the two actuator cams (8A, 8B ) includes an additional means to maintain the final open position of the VI (and cams) until being operated again during a closing operation. This is accomplished by a retaining clip (8G ) molded into the geometry of the slot (8C ) (operating as a press-fit retainer) and that adds additional resistance and retention in the final open position.

[0049] In an embodiment, the geometry of the slot (8C ) on the two actuator cams (8A, 8B ) includes also an additional means to maintain the final closed position of the VI (and cams) until being operated again during an opening operation while also applying additional contact force to stabilize the VI in the closed position. This is accomplished by a retaining and contact pressure clip (8H ) molded into the geometry of the slot (8C ) (operating as a press-fit retainer). The geometry of the clip has a spring lever to provide the contact pressure and then a final recess to provide retention in the final closed position.

[0050] In an embodiment, the opening operation of the switch from line position comprises the transition from the position represented in Figure 6 to that of Figure 7, then to that of Figure 8 then to that of Figure 9, and finally to that of Figure 11.

[0051] In an embodiment, the closing operation of the switch into line position comprises the transition from the position represented in Figure 11 to that of Figure 10 and then finally to that of Figure 6.

[0052] In an embodiment, the closing operation of the switch into earth position comprises the transition from the position represented in fig. 9 to that of fig. 11.

[0053] In an embodiment, the opening operation of the switch from earth position comprises the transition from the position represented in fig. 11 to that of fig. 9.

[0054] Where a feature is described as being rotatably displaceable, it will be understood that this includes a feature which is capable of displacement along a rotation path or which is adapted or configured to undergo displacement along a rotation path.

[0055] Where an apparatus feature is described as being operable to provide a function, it will be appreciated that this includes an apparatus feature which provides that function or which is adapted or configured to provide that function.

[0056] Where elements are described as being electrically connected or connectable, they may be directly or indirectly connected. Where elements are described as being mechanically coupled or couplable, they may be directly linked or linked by one or more intervening or interposing elements.

[0057] Notably, the figures and examples above are not meant to limit the scope of the present disclosure to a single implementation, as other implementations are possible by way of interchange of some or all the described or illustrated elements. Moreover, where certain elements of the present disclosure can be partially or fully implemented using known components, only those portions of such known components that are necessary for an understanding of the present disclosure are described, and detailed descriptions of other portions of such known components are omitted so as not to obscure the disclosure. In the present specification, an implementation showing a singular component should not necessarily be limited to other implementations including a plurality of the same component, and vice-versa, unless explicitly stated otherwise herein. Moreover, applicants do not intend for any term in the specification or claims to be ascribed an uncommon or special meaning unless explicitly set forth as such. Further, the present disclosure encompasses present and future known equivalents to the known components referred to herein by way of illustration.

[0058] The disclosure should not be seen in any way restricted to the embodiments described and a person with ordinary skill in the art will foresee many possibilities to modifications thereof. The above-described embodiments are combinable. The following claims further set out particular embodiments of the disclosure.

Claims

1. Load break switch for controlled interruption of an electrical current, comprising: a switch blade for switching the electrical current; a blade support for supporting and operating the switch blade; a vacuum interrupter (VI) for controlled current interruption; and an actuator cam rotatable about a cam axis for operating the vacuum interrupter; wherein the switch blade is electrically-conductive and rotatable at a first blade end about a blade axis and wherein a second blade end is rotationally displaceable, in sequence, to electrically: connect the first blade end to a primary blade contact, connect the first blade end to a secondary blade contact, and disconnect the first blade end; wherein the vacuum interrupter is connected between the primary and secondary blade contacts to provide a shunt circuit for controlled interruption of a main circuit electrical current between the first blade end and the primary blade contact; wherein the blade support is arranged, at the second blade end, to cause the rotation of the actuator cam to open the vacuum interrupter when the second blade end is connected to the secondary blade contact and moving in sequence from the primary blade contact to the secondary blade contact.

2. Load break switch according to the previous claim wherein the blade support is arranged, at the second blade end, to cause the rotation of the actuator cam to close the vacuum interrupter when the second blade end is connected to the primary blade contact and moving in sequence from the secondary blade contact to the primary blade contact.

3. Load break switch according to any of the previous claims comprising an actuator pin mechanically coupled to the vacuum interrupter for actuating said vacuum interrupter, and wherein the actuator cam comprises a slotted path for guiding the actuator pin between a closed location, where the vacuum interrupter is closed, and an open location, where the vacuum interrupter is open, as the actuator cam rotates, in particular the secondary blade contact is electrically connected to a movable contact of the vacuum interrupter, further in particular wherein the slotted path is a curvilinear path.

4. Load break switch according to the previous claim wherein the slotted path comprises, at one or both of ends of the slotted path, a pressure retainer for non-permanent retention of the actuator pin, in particular the pressure retainer comprising a moulded pressure clip for non-permanent retention of the actuator pin.

5. Load break switch according to any of the previous claims wherein the actuator cam comprises a concave surface for receiving the rotating blade support for the actuator cam to operate the vacuum interrupter.

6. Load break switch according to any of the previous claims wherein the secondary blade contact is pivotable for increasing distance to the primary blade contact, when the second blade end is moving from the primary blade contact to the secondary blade contact, in particular wherein the secondary blade contact comprises a spring for decreasing distance to the primary blade contact, when the second blade end is not moving from the primary blade contact to the secondary blade contact.

7. Load break switch according to the previous claim wherein the secondary blade contact comprises a displaceable pin arranged to be: engaged by the blade support to pivot the secondary blade contact for increasing distance to the primary blade contact, when the second blade end is moving from the primary blade contact to the secondary blade contact; and not engaged by the blade support, when the second blade end is moving from the secondary blade contact to the primary blade contact.

8. Load break switch according to the previous claim wherein the secondary blade contact comprises a slot and the displaceable pin is arranged to be displaceable along said slot, in particular wherein the secondary blade contact comprises a spring for returning the displaceable pin to a rest position.

9. Load break switch according to any of the previous claims comprising an additional actuator cam rotatable about the cam axis for operating the vacuum interrupter, wherein the two rotatable cams are mechanically coupled to each other, wherein the vacuum interrupter is arranged between the two rotatable cams, and wherein the blade support is arranged, at the second blade end, to cause the rotation of the additional actuator cam to open the vacuum interrupter when the second blade end is connected to the secondary blade contact and moving in sequence from the primary blade contact to the secondary blade contact, in particular the blade support is arranged, at the second blade end, to cause the rotation of the additional actuator cam to close the vacuum interrupter when the second blade end is connected to the primary blade contact and moving in sequence from the secondary blade contact to the primary blade contact.

10. Load break switch according to any of the previous claims comprising a first and a second electrical terminals, wherein the first blade end is connected to the first electrical terminal at said blade rotation axis thus being a blade axis contact, and the primary blade contact is connected to the second electrical terminal, in particular the cam axis is arranged in a region defined by the primary and secondary blade contacts and the second electrical terminal.

11. Load break switch according to any of the previous claims comprising a ground terminal, in particular wherein the second blade end is rotationally displaceable, in sequence, to electrically: connect the first blade end to a primary blade contact, connect the first blade end to a secondary blade contact, disconnect the first blade end, and connect the first blade end to the ground terminal, further in particular the load break switch comprising a housing electrically connected to the ground terminal.

12. Load break switch according to any of the previous claims wherein the vacuum interrupter comprises first and second connections, wherein the first connection is connected to the second electrical terminal, and wherein the second connection is connected to the secondary blade contact.

13. Load break switch according to any of the previous claims wherein the load break switch is a medium voltage load break switch, in particular the medium voltage is 5 kV to 60 kV, preferably from 10 kV to 36 kV.

14. Load break switch according to any of the previous claims wherein the actuator cam is electrically-isolating and / or the blade support is electrically-isolating.

15. Triphasic load break switch comprising three load break switches according to any of the previous claims.

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