High current DC disconnector

Abstract

The present invention relates to a DC disconnector and parts thereof. An aspect of the disclosure provides a DC disconnector comprising: one or more static electrical contacts; one or more corresponding movable electrical contacts connected to a drive bar; wherein the drive shaft is configured to actuate the drive bar between: a first position wherein at least a portion of each of the one or more movable electrical contacts abuts one of the one or more static electrical contacts; and, a second position wherein each of the one or more moveable electrical contacts is vertically displaced by a vertical displacement from each of the one or more static electrical contacts; wherein the drive bar is configured to be operable in an air configuration in a first orientation and a vacuum configuration in a second orientation, wherein the separation between the one or more moveable electrical contacts and the static electrical contacts in the second position is greater in the air configuration than in the vacuum configuration.

Description

[0001] DC disconnector

[0002] Field of the invention

[0003] The present invention relates to a DC disconnector.

[0004] Background

[0005] Disconnectors are used in high current applications to provide fail-safe disconnection (offloading) and isolation of supply. Commonly disconnectors (or components thereof, for example, a drive bar and / or a cam for moving the drive bar) are suitable for use only in an air environment or in a vacuum environment.

[0006] Disconnectors comprise at a movable electrical contact and a static electrical contact. The disconnectors move the movable electrical contact out of contact with the static electrical contact to disconnect a circuit.

[0007] If a user needs to convert (e.g. retrofit) a disconnector suitable for use only in an air environment so that instead it may be used in a vacuum environment, then the user needs to purchase a number of replacement parts (e.g. drive bar, cams, drive link bars) to be able to convert the disconnector.

[0008] Typical disconnectors suitable for use in vacuum environments move the movable electrical contact out of contact with the static electrical contact by an arcing motion i.e. the movable electrical contact follows a curved line when moved out of contact from the static electrical contact.

[0009] Movable electrical contacts are connected to the drive bar by typical drive rod assemblies. Typical drive rod assemblies comprise a drive shield comprising a shed profile (e.g. a cross-sectional profile similar to a square wave, for example, a crenallated profile shape). It may be difficult to adjust the electrical creepage provided by drive shields with a shed profile. Drive shields with shed profiles may be difficult to manufacture.

[0010] Summary

[0011] Aspects of the disclosure are as set out in the independent claims and optional features are set out in the dependent claims. Aspects of the invention may be provided in conjunction with each other and features of one aspect may be applied to other aspects.

[0012] An aspect of the disclosure provides a drive bar for holding one or more movable electrical contacts in a DC disconnector, the drive bar comprising: a first end and a second end wherein the first end is separated from the second end in an x-direction; a first engagement portion and a second engagement portion at respective ends, wherein each of the first engagement portion and the second engagement portion are configured to engage respective drive link bars in a first configuration and in a second configuration, wherein the respective drive link bars are configured to couple to a drive shaft.

[0013] The first configuration may be configured to provide a first separation between the one or more moveable electrical contacts mounted on the drive bar and respective static electrical contacts of the DC disconnector when the drive bar is vertically displaced by a vertical displacement from each of the one or more static electrical contacts; and, the second configuration may be configured to provide a second separation between the one or more moveable electrical contacts mounted on the drive bar and respective static electrical contacts of the DC disconnector when the drive bar is vertically displaced by a vertical displacement from each of the one or more static electrical contacts, wherein the first separation is greater than the second separation.

[0014] Engagement of both the first drive link bar and the second drive link bar in the first configuration may provide an air spacing between the drive bar and the first cam engagement portion and an air spacing between the drive bar and the second cam engagement portion; and, engagement of both the first drive link bar and the second drive link bar in the second configuration may provide a vacuum spacing between the drive bar and the first cam engagement portion and a vacuum spacing between the drive bar and the second cam engagement portion, wherein the air spacing is less than the vacuum spacing.

[0015] When the drive bar is disposed in the second position and the drive bar and drive link bars arranged in the air configuration (e.g. the first orientation) then the distance between the drive bar and the drive shaft in the air configuration may be referred to herein as the air spacing or the air drive bar-to-drive shaft distance (air DBDS distance). When the drive bar is disposed in the second position and the drive bar and drive link bars arranged in the vacuum configuration (e.g. the second orientation) then the distance between the drive bar and the drive shaft in the vacuum configuration may be referred to herein as the vacuum drive bar-to-drive shaft distance (vacuum DBDS distance).

[0016] The air DBDS distance is less than the vacuum DBDS distance i.e. air DBDS distance < vacuum DBDS. By providing an air DBDS distance which is less than the vacuum DBDS distance, an air vertical displacement (i.e. the distance between the movable electrical contacts and corresponding static electrical contacts when the drive bar and drive link bars are arrange in the air configuration) may be provided which may be greater than a vacuum vertical displacement (i.e. the distance between the movable electrical contacts and corresponding static electrical contacts when the drive bar and drive link bars are arrange in the vacuum configuration).

[0017] A drive bar may be provided which can be configured for use in DC disconnector in an air environment and for use in a DC disconnector in a vacuum environment. Advantageously, if a DC disconnector needs to be converted to be used in a vacuum environment rather than in an air environment (or vice versa) then no further components are required i.e. a new drive bar is not needed. Furthermore, it may simplify obtaining parts (i.e. drive bars) for DC disconnector because a customer need only order the drive bar according to the disclosure rather than two different types of drive bar.

[0018] The first drive link bar may be configured to link the drive bar to a drive shaft via a first cam; and, the second drive link bar may be configured to link the drive bar to the drive shaft via a second cam; and, rotation of the drive shaft rotates the first cam and the second cam to thereby cause linear movement of the drive bar in a direction parallel to the longitudinal direction. In examples, only a first cam is required e.g. the second cam can be foregone.

[0019] The drive bar has a first side and a second side, wherein: each of the first side and the second side is disposed between the first end and the second end; and, the first side is opposite the second side; wherein the first engagement portion and the second engagement portion is disposed closer to the first side than the second side.

[0020] The drive bar may be in a vacuum configuration when the first side is disposed closer to the drive shaft than the second side. The drive bar may be in an air configuration when the second side is disposed closer to the drive shaft than the first side. Advantageously, the drive link bars may be engaged with the drive bar in two configuration (e.g. corresponding to orientations of the drive link bar relative to the drive bar e.g. the drive link bars pointing ‘up’ (e.g. the air configuration) or ‘down’ (e.g. the vacuum configuration), thereby permitting the air drive bar to be transitioned between an air configuration and a vacuum configuration.

[0021] An aspect of the disclosure provides a kit of parts for providing a DC disconnector comprising: a drive bar comprising: a first end and a second end wherein the first end is separated from the second end in a longitudinal direction of the drive bar; a first engagement portion at the first end, wherein the first engagement portion is configured to engage a first drive link bar in an air configuration and in a vacuum configuration, wherein the first drive link bar is configured to couple to a drive shaft; and, a second engagement portion at the second end, wherein the second engagement portion is configured to engage a second drive link bar in an air configuration and in a vacuum configuration, wherein the first drive link bar is configured to couple to the drive shaft; wherein: engagement of both the first drive link bar and the second drive link bar in the air configuration provides an air spacing between the drive bar and the drive shaft; and, engagement of both the first drive link bar and the second drive link bar in the vacuum configuration provides an vacuum spacing between the drive bar and the drive shaft, wherein the air spacing is less than the vacuum spacing the kit further comprising a first drive link bar configured to engage the first engagement portion of the drive bar; a second drive link bar configured to engage the second engagement portion of the drive bar; a first cam configured to connect the first drive link bar to the drive shaft; a second cam configured to connect the second drive link bar to the drive shaft.

[0022] Advantageously, DC disconnectors may be retrofitted using the kit and may therefore be suitable for use in an air environment and a vacuum environment depending on the configuration of the drive bar and drive link bars (e.g. in a vacuum configuration or an air configuration).

[0023] The kit may comprise: two air cams configured to be the first cam and the second cam; and, two vacuum cams configured to be the first cam and the second cam; wherein using the two air cams as the first cam and second cam causes more linear movement in comparison to using two vacuum cams as the first cam and the second cam.

[0024] Each air cam may have an air eccentricity and each vacuum cam may have a vacuum eccentricity, wherein the air eccentricity is greater than the vacuum eccentricity.

[0025] The kit may comprise: at least one drive rod assembly for coupling a drive bar to a movable electrical contact, the drive rod assembly comprising: a first drive rod configured for connection to the drive bar; and, a second drive rod connected to the first drive rod, wherein the second drive rod is configured for connection to the movable electrical contact, and wherein the second drive rod is an electrical insulator. The drive rod assembly may further comprise: a drive screw connected to the first drive rod; and, a thrusting member disposed between a portion of the drive screw and the first drive rod, wherein the thrusting member is configured to thrust the first drive rod portion towards the second drive rod.

[0026] The drive rod assembly may further comprise: a setting nut configured for connection to the first drive rod; and, a locking nut configured for connection to the drive screw; wherein first drive rod and the drive screw are configured to be disposed at least partially within a tapped through hole in the drive bar and the setting nut and locking nut are arranged around the drive bar to thereby connect the drive bar to the drive rod.

[0027] An aspect provides a DC disconnector comprising: one or more static electrical contacts; one or more corresponding movable electrical contacts connected to a drive bar; wherein the drive shaft is configured to actuate the drive bar between: a first position wherein at least a portion of each of the one or more movable electrical contacts abuts one of the one or more static electrical contacts; and, a second position wherein each of the one or more moveable electrical contacts is vertically displaced by a vertical displacement from each of the one or more static electrical contacts; wherein the drive bar is configured to be operable in an air configuration in a first orientation and a vacuum configuration in a second orientation, wherein the separation between the one or more moveable electrical contacts and the static electrical contacts in the second position is greater in the air configuration than in the vacuum configuration.

[0028] The drive bar may have a longitudinal axis arranged parallel to the drive shaft; and, the drive bar may be switched from the first orientation to the second orientation by rotating the drive bar 180° about the longitudinal axis.

[0029] The drive bar may comprise: a first engagement portion at a first end; and, a second engagement portion at a second end, wherein the second end of the drive bar is separated from the first end in along the longitudinal axis thereof; wherein, the first engagement portion and the second engagement portion both respectively engage a first drive link bar and a second drive link bar in either an air configuration or a vacuum configuration, wherein the first drive link bar and the second drive link bar couple the drive bar to the drive shaft and wherein: engagement of the first drive link bar and the second drive link bar in the air configuration provides an air vertical displacement in the second configuration to thereby provide, electrical insulation of the one or more moveable electrical contacts from the one or more static electrical contacts in an air environment; and, engagement of the first drive link bar and the second drive link bar in the air configuration provides a vacuum vertical displacement in the second configuration to thereby provide, electrical insulation of the one or more moveable electrical contacts from the one or more static electrical contacts in a vacuum environment, wherein the air vertical displacement is greater than the vacuum vertical displacement.

[0030] The drive bar may have a first side and a second side, wherein: each of the first side and the second side is disposed between the first end and the second end; and, the first side is opposite the second side; wherein the first engagement portion and the second engagement portion are disposed closer to the first side than the second side.

[0031] The first drive link bar may be coupled to the drive shaft by a first cam and engaged to the first engagement portion of the drive bar; and, a second drive link bar coupled to the drive shaft by a second cam and engaged to the second engagement portion of the drive bar.

[0032] The first cam and the second cam in the air configuration may each be an air cam wherein the linear motion of the drive bar actuated by the drive shaft and air cams is greater than the linear motion of the drive bar actuated by the drive shaft and vacuum cams.

[0033] The longitudinal direction of the drive bar may be an x-direction as illustrated in Figures 2A and 2C.

[0034] An aspect of the disclosure provides a DC disconnector comprising: one or more static electrical contacts; one or more corresponding movable electrical contacts connected to a drive bar comprising; a drive shaft, coupled to the drive bar via at least one cam, wherein the shaft is configured to actuate the drive bar between: a first position wherein at least a portion of each of the one or more movable electrical contacts abuts one of the one or more static electrical contacts; and, a second position wherein each of the one or more moveable electrical contacts is vertically displaced by a vertical displacement from each of the one or more static electrical contacts, wherein the vertical displacement is configured to provide electrical insulation of the one or more moveable electrical contacts from the one or more static electrical contacts in an vacuum environment; wherein the drive shaft and at least one cam are configured to actuate linear movement of the drive bar between the first position and the second position. It is noted that typical disconnectors suitable for use in vacuum environments move the movable electrical contact out of contact with the static electrical contact by an arcing motion i.e. the movable electrical contact follows a curved line when moved out of contact from the static electrical contact. Mechanisms which permit this arcing motion wear more quickly compared to the mechanism described herein which permits linear movement. Therefore, advantageously, the DC disconnector provided according to an aspect of the disclosure is suitable for use in an vacuum environment and actuates linear motion of the drive bar between a first and second position. The DC disconnector provided herein may be less prone to wear (i.e. compared to typical ‘arcing motion’ air DC disconnectors). In such examples, the drive link bars bar may be fixed to the drive bar (e.g. they cannot be arranged in the vacuum configuration, only in the air configuration) and only air cams may be provided.

[0035] An aspect of the disclosure provides a drive rod assembly for coupling a drive bar to a movable electrical contact, the drive rod assembly comprising: a first drive rod configured for connection to the drive bar; and, a second drive rod connected to the first drive rod, wherein the second drive rod is configured for connection to the movable electrical contact, and wherein the second drive rod is an electrical insulator.

[0036] Movable electrical contacts are connected to the drive bar by typical drive rod assemblies. Typical drive rod assemblies do not electrically shield the drive bar from the movable electrical contact which can cause electrical leakage from the circuit. Advantageously, simplified drive rod assemblies may be provided which dispense with a drive shield comprising a shed profile (e.g. a cross-sectional profile similar to a square wave, for example, a crenallated profile shape). The electrical creepage provided by the drive rod assemblies provided herein may be more easily adjusted compared typical drive rod assemblies which comprise drive shields having a shed profile. The drive rod assemblies provided herein may be easier to manufacture than typical drive rod assemblies e.g. the drive shields of the drive rod assemblies described herein may be easier to manufacture than typical drive shields having a shed profile..

[0037] The drive rod assembly may comprise: a drive screw connected to the first drive rod; and, a thrusting member disposed between a portion of the drive screw and the first drive rod, wherein the thrusting member is configured to thrust the first drive rod portion towards the second drive rod. The drive rod assembly may comprise: a setting nut configured for connection to the first drive rod; and, a locking nut configured for connection to the drive screw; wherein first drive rod and the drive screw are configured to be disposed at least partially within a tapped through hole in the drive bar and the setting nut and locking nut are arranged around the drive bar to thereby connect the drive bar to the drive rod.

[0038] Brief description of drawings

[0039] Some examples will now be described, by way of example only, which reference to figures, in which:

[0040] Figure 1A illustrates perspective view of a DC disconnector;

[0041] Figure 1 B illustrates a cross-sectional plan view of the DC disconnector of Figure 1A;

[0042] Figure 2A illustrates a perspective view of a pair of drive link bars engaged to a drive bar in an air configuration;

[0043] Figure 2B illustrates a plan end view of a first or second end of the drive bar shown in Figure 2A;

[0044] Figure 2C illustrates a perspective view of the pair of drive link bars and drive bar of Figures 2A and 2B wherein the drive link bars are engaged to the drive bar in a vacuum configuration;

[0045] Figure 2D illustrates a plan end view of a first or second end of the drive bar shown in Figure 2C;

[0046] Figure 3A illustrates a perspective view of an air cam;

[0047] Figure 3B illustrates a perspective view of a vacuum cam;

[0048] Figure 4A illustrates a cross-sectional plan view of a DC disconnector arranged for use in an air environment, wherein the DC disconnector is in a first position;

[0049] Figure 4B illustrates a cross-sectional plan view of the DC disconnector illustrated in Figure 4A wherein the DC disconnector is in a second position;

[0050] Figure 5A illustrates a cross-sectional plan view of a DC disconnector arranged for use in a vacuum environment, wherein the DC disconnector is in a first position;

[0051] Figure 5B illustrates a cross-sectional plan view of the DC disconnector illustrated in Figure 5A wherein the DC disconnector is in a second position;

[0052] Figure 6 illustrates a cross-sectional plan view of a typical drive rod assembly for a DC disconnector;

[0053] Figure 7 illustrates a cross-sectional plan view of a drive rod assembly according to the present disclosure. In the drawings like reference signs indicate like elements.

[0054] Figure 1A illustrates a perspective view of a DC disconnector 100; Figure 1 B illustrates a cross-sectional plan view of the DC disconnector of Figure 1A. The DC disconnector 100 comprises: a plurality of static electrical contacts 110; a corresponding plurality of movable electrical contacts 120; drive rod assemblies 130; a drive bar 140; drive link bars 150; cams 160; a drive shaft 170.

[0055] The plurality of static electrical contacts 110 comprises: a first static electrical contact 111 ; a second static electrical contact 112; a third static electrical contact 113; and, fourth static electrical contact 114.

[0056] The plurality of movable electrical contacts 120 comprises: a first movable electrical contact 121 ; a second movable electrical contact 122; a third movable electrical contact 123; and, fourth movable electrical contact 124.

[0057] The static electrical contacts 110 are arranged opposite the movable electrical contacts 120. That is, the first static electrical contact 111 is arranged opposite the first movable electrical contact 121 , the second static electrical contact 112 is arranged opposite the second movable electrical contact 122 and so on.

[0058] Each of the movable electrical contacts 120 is connected to the drive bar 140 by a drive rod assembly 130. Provided is a first drive rod assembly 131 connecting the first movable electrical contact 121 to the drive bar 140, a second drive rod assembly 132 connecting the second movable electrical contact 122 to the drive bar 140, a third drive rod assembly 133 connecting the third movable electrical contact 123 to the drive bar 140, and a fourth drive rod assembly 134 connecting the fourth movable electrical contact 124 to the drive bar 140.

[0059] The drive bar 140 is connected to the drive link bars 150. Each drive link bar 150 is connected to a cam 160. The drive shaft 170 is connected to the cams 160. The drive shaft 170 is configured to rotate about a rotational axis X. Rotation of the drive shaft 170 rotates the cams 160. Rotation of the cams 160 actuates linear motion of the drive link bars 150, the drive bar 140, drive rod assemblies 130 and the movable electrical contact 120. This linear motion is in a direction parallel to the drive shaft 170. The drive bar 140 is movable between a first position and the second position.

[0060] Disposing the drive bar 140 in the first position at least a portion of each of the plurality of movable electrical contacts 120 abuts a corresponding one of the static electrical contacts 110. Specifically, in the first position, the first movable electrical contact 121 abuts the first static electrical contact 111 , the second movable electrical contact 122 abuts the second static electrical contact 112, the third movable electrical contact 123 abuts the third static electrical contact 113, and the fourth movable electrical contact 124 abuts the fourth static electrical contact 114. In the first position, a circuit is completed by the abutment (e.g. electrical contact) of each of the movable electrical contacts 120 with a corresponding static electrical contact 110.

[0061] Disposing the drive bar 140 in the second position each of the plurality of moveable electrical contacts 120 is vertically displaced by a vertical displacement from a corresponding one of the plurality of static electrical contacts 110. Specifically, in the second position, the first movable electrical contact 121 is separated from the first static electrical contact 111 by a vertical displacement, the second movable electrical contact 122 is separated from the second static electrical contact 112 by a vertical displacement, the third movable electrical contact 123 is separated from the third static electrical contact 113 by a vertical displacement, and the fourth movable electrical contact 124 is separated from the fourth static electrical contact 114 by a vertical displacement. The vertical displacement is configured to provide electrical insulation of the plurality of moveable electrical contacts 120 from the plurality of static electrical contacts 110. In the second position, a circuit is broken by the vertical displacement (e.g. lack of electrical contact) between the static electrical contacts 110 and the moveable electrical contacts 120.

[0062] The drive bar is configured to be operable in a first orientation (e.g. an air configuration) and a second orientation (e.g. a vacuum configuration). The separation between the one or more moveable electrical contacts and the static electrical contacts in the second position is greater when the drive bar is operated in the first orientation (e.g. in the air configuration) than when the drive bar is operated in the second orientation (e.g. the vacuum configuration).

[0063] The DC disconnector 100 can be disposed in either an air environment or in a vacuum environment. Without wishing to be bound by theory, the magnitude of the vertical displacement between the static and movable electrodes required to provide a sufficient break in the circuit is inversely proportional to the dielectric strength of the medium between the static and movable electrodes. Air has a dielectric strength of around 3 MV / m and vacuum has a dielectric strength of around 1012MV / m; all other variables being equal, a greater vertical displacement is required to insulate the electrical contacts in air in comparison to in vacuum. A greater vertical displacement is provided when the DC disconnector is disposed in an air environment in comparison to the vertical displacement provided when the DC disconnector is disposed in a vacuum environment. For example, for typical operating parameters of DC disconnectors (e.g. voltage), a suitable vertical displacement between the movable and static electrical contacts of DC disconnectors described herein may be around 3.5 mm in a vacuum environment and around 6.0 mm in an air environment.

[0064] The present disclosure provides a DC disconnector and components thereof which can be arranged in an air configuration (i.e. it can be used in an air environment and provide a sufficient vertical displacement between the movable and static electrodes to break the circuit) and in a vacuum configuration (i.e. it can be used in a vacuum environment and provide a sufficient vertical displacement between the movable and static electrodes to break the circuit). The DC disconnector is arranged in the air configuration when the drive bar and drive link bars are arranged in a first orientation and air cams are used. The DC disconnector is arranged in the vacuum configuration when the drive bar and drive link bars are arranged in a second configuration and vacuum cams are used.

[0065] That is, the same drive bar 140 and drive link bars 150 can be arranged in both an air configuration and a vacuum configuration. Different cams (e.g. air cams 160A and vacuum cams 160V respectively, described in more detail herein) may be used in the air configuration and vacuum configuration.

[0066] When arranged in the air configuration, an air vertical displacement (air VD) is provided between the static and movable electrical contacts when in the second position. When arranged in the vacuum configuration, a vacuum vertical displacement (vacuum VD) is provided between the static and movable electrical contacts when in the second position. The air VD is greater than the vacuum VD i.e. air VD > vacuum VD.

[0067] The air cam 160A has a greater eccentricity than the vacuum cam 160V which allows it to move the drive bar through a greater distance than the vacuum cam 160 (i.e. for a given rotation of the drive shaft) thereby moving the electrical contacts into abutment. Figure 2A illustrates a perspective view of a pair of drive link bars 150 engaged to a drive bar 140 in an air configuration; Figure 2B illustrates a plan end view of a first or second end of the drive bar 140 shown in Figure 2A. Figure 2C illustrates a perspective view of the pair of drive link bars 150 and drive bar 140 of Figures 2A and 2B wherein the drive link bars 150 are engaged to the drive bar 140 in a vacuum configuration; Figure 2D illustrates a plan end view of a first or second end of the drive bar shown 140 in Figure 2C.

[0068] The drive bar 140 has a cuboid shape i.e. it has three pairs of faces. The drive bar 140 comprises: a first end 145 and a second end 146 (i.e. a pair of opposite faces); and, a first side 147 and a second side 148 (i.e. another pair of opposite faces). The drive bar has an x-direction, which in use is parallel to the rotational axis X of the drive shaft 170, as well as a y-direction and z-direction which are each perpendicular to the x-direction and to each other, x, y, and z axes are shown on Figures 2A to 2D to indicate the x-, y-, and z-directions respectively.

[0069] The first end 145 is separated from the second end 146 in the x-direction. The first side 147 is separated from the second side 148 in the z-direction.

[0070] The drive bar 140 comprises four tapped through holes 141 to 144, namely, a first tapped through hole 141 , a second tapped through hole 142, a third tapped through hole 143, a fourth tapped through hole 144. Each of the tapped through holes has an opening on the first side 147 of the drive bar 140 and an opening on the second side 148 of the drive bar 140. Each of the tapped though holes are configured to receive a drive rod there through. Each of the tapped through holes 141 to 144 comprises an internal thread. The internal thread of a given tapped through hole is configured to engage an external thread of a drive screw.

[0071] In examples described herein, the drive bar comprises four tapped through holes wherein each tapped through hole corresponds to a respective movable electrical contact (which in turn corresponds to a respective static electrical contact because the movable and static electrical contacts are provided in pairs: one static and one movable electrical contact). However, it will be readily appreciated by those skilled in the art that the number of pairs of movable and static electricals (and a corresponding number of tapped through holes; one through hole for each pair of electrical contacts) may be any number, for example preferably, 2 tapped through holes, 3 tapped through holes, 4 tapped through holes, five tapped through holes or six tapped through holes.

[0072] The drive bar 140 comprises a first engagement portion 140-1 disposed at the first end 145 and a second engagement portion 140-2 disposed at the second end 146. The first engagement portion 140-1 is configured to engage the first drive link bar 150-1 and the second engagement portion 149-2 is configured to engage the second drive link bar 150- 2.

[0073] The first and second engagement portions 149 are disposed closer to the first side 147 than to the second side 148. Each of the first engagement portion 149-1 and the second engagement portion 149-2 is spaced by a distance zi from the first side 145 and spaced by a distance z2from the second side 146 wherein the distance zi is greater than the distance z2.

[0074] The first engagement portion 149-1 and the second engagement portion 149-2 comprise a plurality of screw holes 149 configured to engage screws 151-1 & 151-2 from the first drive link bar 150-1 and the second drive link bar 152 respectively. The mean position of the screw holes 149 is closer to the second side 148 than the second side 147 e.g. the mean position of the screw holes 149 is located a distance zi from the first side 147 and a distance z2from the second side 148 wherein the distance zi is greater than the distance z2.

[0075] The first drive link bar 150-1 comprises: an engagement means 151-1 (e.g. screws for engaging the screw holes 149 on the drive bar 140); and, a cam engagement portion 152- 1 displaced from the engagement means 151-1. Similarly, the second drive link bar 150-2 comprises: an engagement means 151-2 (e.g. screws for engaging the screw holes 149 on the drive bar 140); and, a cam engagement portion 152-2 displaced from the engagement means 151-2. The cam engagement portions 152 are configured to engage cams 160 (either air cams 160A or vacuum cams 160V).

[0076] The first engagement portion 149-1 can engage the first drive link bar 150-1 in two different orientations, either the cam engagement portion 152-1 of the first drive link bar 150-1 projects beyond the first side 147 (i.e. is closer to the first side 147 compared to the second side 148) or the cam engagement portion 152-1 of the first drive link bar 150-1 projects beyond the second side 148 (i.e. is closer to the second side 148 compared to the first side 147). Likewise, the second engagement portion 149-2 can engage the second drive link bar 150-2 in two different orientations, either the cam engagement portion 152-2 of the second drive link bar 150-2 projects beyond the first side 147 (i.e. is closer to the first side

[0077] 147 compared to the second side 148) or the cam engagement portion 152-2 of the second drive link bar 150-2 projects beyond the second side 148 (i.e. is closer to the second side

[0078] 148 compared to the first side 147).

[0079] The air configuration comprises engaging the first drive link bar 150-1 with the first engagement portion 149-1 so the cam engagement portion 152-1 projects beyond the first side 147 and engaging the second drive link bar 150-2 with the second engagement portion 149-2 so the cam engagement portion 152-2 projects beyond the first side 147. Engagement of both the first drive link bar 150-1 and the second drive link bar 150-2 in the first configuration may provide an air spacing between the drive bar 140 and the first cam engagement portion 152-1 and an air spacing between the drive bar 140 and the second cam engagement portion 152-2. The air spacing may be the defined as the distance between a side of the drive bar closest to the cam engagement portions and each cam engagement portion (e.g. a line perpendicular to the side of the drive bar closest to the cam engagement portion joining the side of the drive bar and the cam engagement portion).

[0080] The vacuum configuration comprises engaging the first drive link bar 150-1 with the first engagement portion 149-1 so the cam engagement portion 152-1 projects beyond the second side 148 and engaging the second drive link bar 150-2 with the second engagement portion 149-2 so the cam engagement portion 152-2 projects beyond the second side 148.

[0081] Engagement of both the first drive link bar 150-1 and the second drive link bar 150-2 in the second configuration may provide a vacuum spacing between the drive bar 140 and the first cam engagement portion 152-1 and a vacuum spacing between the drive bar 140 and the second cam engagement portion 152-2. The vacuum spacing may be the defined as the distance between a side of the drive bar closest to the cam engagement portions and each cam engagement portion (e.g. a line perpendicular to the side of the drive bar closest to the cam engagement portion joining the side of the drive bar and the cam engagement portion). The air spacing is less than the vacuum spacing.

[0082] So by simply selecting the orientation of the drive link bars 141 144, the drive bar 130 can be arranged in either an air configuration or a vacuum configuration i.e. the vertical displacement between respective static and movable electrical contacts can be changed from the air vertical displacement to the vacuum vertical displacement (and vice versa). Figure 3A illustrates a perspective view of an air cam 160A; Figure 3B illustrates a perspective view of a vacuum cam 160V.

[0083] In the air configuration two air cams 160A are used. The air cams 160A comprise a through hole 161 A for receiving and engaging the drive shaft 170. When the drive shaft is disposed within the through hole 161 A, rotation of the drive shaft 170 enacts a corresponding rotation of the air cam 160A. The two air cams 160A have an air eccentricity (e.g. a measure of the offset of the through hole 161 A from a centre of the cam - the greater the eccentricity then the greater this offset).

[0084] The air cams 160A may be identical or may be have a chiral relationship i.e. a first air cam is the mirror image of a second air cam. When the air cams 160A are rotated by the drive shaft 170 they actuate linear motion of the drive bar 140 (and the movable electrical contacts 120 connected thereto). The minimum distance through which the drive bar 140 moves due to the linear motion is the air vertical displacement (air VD). The linear motion actuated by the drive shaft 170 and air cams 160A moves the drive bar 140 from the second position to the first position, therefore, the linear motion closes the distance between the static electrical contacts 110 and movable electrical contacts 120 from a maximum (i.e. the air vertical displacement) a minimum of zero (i.e. abutment between the contacts). The linear motion of the drive bar 140 is perpendicular to the rotational axis X of drive shaft 170.

[0085] In the vacuum configuration two vacuum cams 160V are used. The vacuum cams 160V comprise a through hole 161V for receiving and engaging the drive shaft 170. When the drive shaft is disposed within the through hole 161V, rotation of the drive shaft 170 enacts a corresponding rotation of the vacuum cam 160V. The two vacuum cams 160V have a vacuum eccentricity (e.g. a measure of the offset of the through hole 161 A from a centre of the cam - the greater the eccentricity then the greater this offset). The vacuum eccentricity is less than the air eccentricity (e.g. for a given DC disconnector and / or drive bar).

[0086] The vacuum cams 160V may be identical or may be have a chiral relationship i.e. a first vacuum cam is the mirror image of a second vacuum cam. When the vacuum cams 160V are rotated by the drive shaft 170 they actuate linear motion of the drive bar 140 (and the movable electrical contacts 120 connected thereto). The minimum distance through which the drive bar 140 moves due to the linear motion is the vacuum vertical displacement (vacuum VD). The linear motion actuated by the drive shaft 170 and vacuum cams 160V moves the drive bar 140 from the second position to the first position, therefore, the linear motion closes the distance between the static electrical contacts 110 and movable electrical contacts 120 from a maximum (i.e. the vacuum vertical displacement) a minimum of zero (i.e. abutment between the contacts). The linear motion of the drive bar 140 is perpendicular to the rotational axis X of drive shaft 170.

[0087] The air cams 160A actuate linear movement of the drive bar 140 over a greater minimum distance, (e.g. the air vertical displacement) than the vacuum cams 160V (which may actuate a minimum linear movement of the drive bar by e.g. the air vertical displacement). The actuated linear movement may be greater than that described above, for example, the drive rod assemblies 130 may comprise urging members (e.g. springs) which may be compressed when the movable electrical contacts 120 abut the static electrical contacts 110.

[0088] The DC disconnector and the drive bar which can be configured in an air and vacuum configuration is described in more detail below.

[0089] Figure 3A illustrates a perspective view of an air cam 300A; Figure 3B illustrates a perspective view of a vacuum cam 300V;

[0090] When the drive bar and the drive link bars are arranged in the air configuration, air cams are disposed in the cam engagement portions 143 and 146. When the drive bar and the drive link bars are arranged in the vacuum configuration, vacuum cams are disposed in the cam engagement portions 143 and 146.

[0091] The two air cams are configured to receive the drive shaft, for example, each air cam is configured to engage the drive shaft and rotate in response to rotation of the drive shaft. The two air cams have an air eccentricity. When the air cams are rotated by the drive shaft they actuate linear motion of the drive bar. The minimum distance through which the drive bar moves due to the linear motion is the air vertical displacement. The linear motion of the drive shaft moves the drive bar from the second position to the first position, therefore, the linear motion closes the distance between the static and movable electrical contacts from a maximum (i.e. the air vertical displacement) a minimum of zero (i.e. abutment between the contacts). The two vacuum cams are configured to receive the drive shaft, for example, each vacuum cam is configured to engage the drive shaft and rotate in response to rotation of the drive shaft. The two vacuum cams have a vacuum eccentricity. When the vacuum cams are rotated by the drive shaft they actuate linear motion of the drive bar. The minimum distance through which the drive bar moves due to the linear motion is the vacuum vertical displacement. The linear motion of the drive shaft moves the drive bar from the second position to the first position, therefore, the linear motion closes the distance between the static and movable electrical contacts from a maximum (i.e. the vacuum vertical displacement) a minimum of zero (i.e. abutment between the contacts).

[0092] The linear motion of the drive bar 170 is perpendicular to the drive shaft.

[0093] Therefore, the DC disconnector may be arranged in an air configuration by disposing the drive bar and drive link bars in the air configuration and providing air cams (e.g. cams having the air eccentricity) and the DC disconnector may be arranged in a vacuum configuration by disposing the drive bar and drive link bars in the vacuum configuration and providing vacuum cams (e.g. cams having the vacuum eccentricity).

[0094] Figure 4A illustrates a cross-sectional plan view of the DC disconnector 100A arranged for use in an air environment, wherein the DC disconnector is in a first position; Figure 4B illustrates a cross-sectional plan view of the DC disconnector 100A illustrated in Figure 4A wherein the DC disconnector is in a second position.

[0095] The DC disconnector 100A comprises: a plurality of static electrical contacts 110; a corresponding plurality of movable electrical contacts 120; drive rod assemblies 130; a drive bar 140; drive link bars 150; air cams 160A; a drive shaft 170. These features are arranged in the manner described herein with reference to Figures 1A and 1 B.

[0096] Importantly, in DC disconnector 100A, air cams 160A are used (i.e. in place of the generic cams 160 described in Figures 1A and 1 B). The air cams 160A are described with reference to Figure 3A. Also, it is noted that in DC disconnector 100A, the drive link bars 150 and the drive bar 140 are arranged in the air configuration. The air configuration of the drive link bars 150 and the drive bar 140 is described in detail in Figures 2A and 2B.

[0097] The DC disconnector 100A is configured for use in an air environment i.e. it comprises a drive bar 140 and drive link bars 150 arranged in an air configuration and comprises air cams 160A.

[0098] In use, the DC disconnector 100A is arranged in the first position (shown in Figure 4A) wherein the movable electrical contacts 120 abut the static electrical contacts 110 to close a circuit.

[0099] When the drive bar 140 of the DC disconnector 100A is in the first position (shown in Figure 4A) and the circuit needs to be broken, the drive shaft 170 is rotated about its axis X (e.g. in response to a signal either sent automatically by a machine or sent by a human user). Rotation of the drive shaft 170 causes a corresponding rotation of the air cams 160A. The air cams 160A actuate linear movement of the drive link bars 150 and drive bar 140 perpendicular to and towards the rotational axis X of the drive shaft 170 to the second position (shown in Figure 4B). The linear movement of the drive bar 140 results in corresponding linear motion of the drive rod assemblies 130 and the movable electrical contacts 120 connected thereto. When the drive bar 140 is in the second position (shown in Figure 4B) the minimum distance between the movable electrical contacts 120 from their corresponding static electrical contacts 110 is the air vertical displacement (air VD). The air VD electrically isolates the movable electrical contacts 120 from the corresponding static electrical contacts 110 thereby breaking the circuit and preventing a discharge across the gap between the contacts. The drive shaft 170 is typically rotated through 90° but the total rotation required depends on the geometry of the air cams used i.e. the rotation required to move the drive bar the air VD.

[0100] When the drive bar 140 of the DC disconnector 100A is in the second position (shown in Figure 4B) and the circuit needs to be broken, the drive shaft 170 is rotated about its axis X (e.g. in response to a signal either sent automatically by a machine or sent by a human user). Rotation of the drive shaft 170 causes a corresponding rotation of the air cams 160A. The air cams 160A actuate linear movement of the drive link bars 150 and drive bar 140 perpendicular to and away from the rotational axis X of the drive shaft 170 to the first position (shown in Figure 4A). The linear movement of the drive bar 140 results in corresponding linear motion of the drive rod assemblies 130 and the movable electrical contacts 120 connected thereto. When the drive bar 140 is in the first position (shown in Figure 4A) the movable electrical contacts 120 contact the corresponding static electrical contacts 110 which completes a circuit. The drive shaft 170 is typically rotated through 90° in the opposite direction that that required to break the circuit, but the total rotation required depends on the geometry of the air cams used i.e. the rotation required to move the drive bar the air VD. Also it will be appreciated that the drive shaft might be rotated through the remainder of a turn (e.g. 270°) to return the cam to its initial rotational position.

[0101] It is noted that typical disconnectors suitable for use in vacuum environments move the movable electrical contact out of contact with the static electrical contact by an arcing motion i.e. the movable electrical contact follows a curved line when moved out of contact from the static electrical contact. Mechanisms which permit this arcing motion wear more quickly compared to the mechanism described herein which permits linear movement. Therefore, advantageously, a DC disconnector suitable for use in an air environment is provided which is less prone to wear. It will be noted that in such examples, the drive link bars bar be fixed to the drive bar (e.g. they cannot be arranged in the vacuum configuration, only in the air configuration) and only air cams are provided.

[0102] Figure 5A illustrates a cross-sectional plan view of the DC disconnector 100V arranged for use in a vacuum environment, wherein the DC disconnector 100V is in a first position; Figure 5B illustrates a cross-sectional plan view of the DC disconnector 100V illustrated in Figure 5A wherein the DC disconnector 100V is in a second position.

[0103] The DC disconnector 100V comprises: a plurality of static electrical contacts 110; a corresponding plurality of movable electrical contacts 120; drive rod assemblies 130; a drive bar 140; drive link bars 150; vacuum cams 160V; a drive shaft 170. These features are arranged in the manner described herein with reference to Figures 1A and 1 B.

[0104] Importantly, in DC disconnector 100V, vacuum cams 160V are used (i.e. in place of the generic cams 160 described in Figures 1A and 1 B). The vacuum cams 160V are described with reference to Figure 3B. Also, it is noted that in DC disconnector 100V, the drive link bars 150 and the drive bar 140 are arranged in the vacuum configuration. The vacuum configuration of the drive link bars 150 and the drive bar 140 is described in detail in Figures 2C and 2D.

[0105] The DC disconnector 100V is configured for use in a vacuum environment i.e. it comprises a drive bar 140 and drive link bars 150 arranged in a vacuum configuration and comprises vacuum cams 160V.

[0106] In use, the DC disconnector 100V is arranged in the first position (shown in Figure 5A) wherein the movable electrical contacts 120 abut the static electrical contacts 110 to close a circuit.

[0107] When the drive bar 140 of the DC disconnector 100V is in the first position (shown in Figure 4A) and the circuit needs to be broken, the drive shaft 170 is rotated about its axis X (e.g. in response to a signal either sent automatically by a machine or sent by a human user). Rotation of the drive shaft 170 causes a corresponding rotation of the vacuum cams 160V. The vacuum cams 160V actuate linear movement of the drive link bars 150 and drive bar 140 perpendicular to and towards the rotational axis X of the drive shaft 170 to the second position (shown in Figure 5B). The linear movement of the drive bar 140 results in corresponding linear motion of the drive rod assemblies 130 and the movable electrical contacts 120 connected thereto. When the drive bar 140 is in the second position (shown in Figure 5B) the minimum distance between the movable electrical contacts 120 from their corresponding static electrical contacts 110 is the vacuum vertical displacement (vacuum VD). The vacuum VD electrically isolates the movable electrical contacts 120 from the corresponding static electrical contacts 110 thereby breaking the circuit and preventing a discharge across the gap between the contacts. The drive shaft 170 is typically rotated through 90° but the total rotation required depends on the geometry of the vacuum cams used i.e. the rotation required to move the drive bar the vacuum VD.

[0108] When the drive bar 140 of the DC disconnector 100V is in the second position (shown in Figure 5B) and the circuit needs to be broken, the drive shaft 170 is rotated about its axis X (e.g. in response to a signal either sent automatically by a machine or sent by a human user). Rotation of the drive shaft 170 causes a corresponding rotation of the vacuum cams 160V. The vacuum cams 160V actuate linear movement of the drive link bars 150 and drive bar 140 perpendicular to and away from the rotational axis X of the drive shaft 170 to the first position (shown in Figure 5A). The linear movement of the drive bar 140 results in corresponding linear motion of the drive rod assemblies 130 and the movable electrical contacts 120 connected thereto. When the drive bar 140 is in the first position (shown in Figure 5A) the movable electrical contacts 120 contact the corresponding static electrical contacts 110 which completes a circuit. The drive shaft 170 is typically rotated through 90° in the opposite direction that that required to break the circuit, but the total rotation required depends on the geometry of the vacuum cams used i.e. the rotation required to move the drive bar the vacuum VD. Also it will be appreciated that the drive shaft might be rotated through the remainder of a turn (e.g. 270°) to return the cam to its initial rotational position. When the DC disconnector is arranged with the drive bar in the vacuum configuration, the vertical displacement (i.e. the vacuum VD) between the movable electrical contacts 120 and the static electrical contacts 110 in the second position may be 3.5 mm.

[0109] When the DC disconnector is arranged with the drive bar in the air configuration, the vertical displacement (i.e. the air VD) between the movable electrical contacts 120 and the static electrical contacts 110 in the second position may be 6.0 mm.

[0110] The arrangement described in Figures 1A to 5B can use any type of drive rod assembly. A typical drive rod assembly is shown in Figure 6. Figure 7 illustrates an improved drive rod assembly according to the present disclosure.

[0111] A drive rod assembly connects a movable electrical contact 120 to the drive bar 140. The drive bar 140 comprises a tapped through hole for attaching each of the movable electrical contacts 120 to the drive bar 140. In the examples shown in Figures 1A, 1 B, 2A to 2D, and 4A to 5B the drive bar 140 comprise four tapped through holes: a first tapped through hole 141 ; a second tapped through hole 142; a third tapped through hole 143; and, a fourth tapped through hole 144. The first tapped through hole 141 receives a first drive rod assembly for attaching a first movable electrical contact, the second tapped through hole 142 receives a second drive rod assembly for attaching a second movable electrical contact and so on.

[0112] Figure 6 illustrates a cross-sectional plan view of a typical drive rod assembly 600 for a DC disconnector. The typical drive rod assemblies 600 may be used in the arrangements described herein although the drive rod assembly 160 (described herein and shown in cross-section in Figure 7) is preferred for reasons set out herein.

[0113] The typical drive rod assembly 600 comprises a: drive rod 601 ; a drive shield 602; a thrust plate 603; a spring 604; a setting nut 605; and a grub screw (not shown in Figure 6). The drive rod 601 , thrust plate 603, spring 604, setting nut 605 and grub screw are made of a conductor such as metal. The drive shield 602 is formed of plastic.

[0114] The drive rod 601 is disposed through a through hole 141 in a drive bar 140. The setting nut 605 and grub screw are connected to the drive rod 601 to thereby prevent the drive rod 601 from exiting the through hole 141. The drive shield 602 is disposed around the drive rod 601 and is configured to electrically shield the drive bar 140 from the movable electrical contact 120. The drive shield 602 comprises a shed profile (e.g. a cross-sectional profile similar to a square wave, for example, a crenallated profile shape) to provide a preselected electrical creepage. The thrust plate 603 is disposed opposite the movable electrical contact 120. A spring 604 is disposed between the thrust plate 603 and the movable electrical contact 120. The thrust plate 603 and spring 604 force the movable electrical contact 120 towards a static electrical contact (not shown in Figure 6) to remove any tolerance in the arrangement and provide electrical contact between the movable electrical contact and the static electrical contact.

[0115] Figure 7 illustrates a cross-sectional plan view of a drive rod assembly 130 according to the present disclosure. The drive rod assembly 130 shown in Figure 7 is shown in the DC disconnector in Figures 1 A & 1 B, 4A & 4B, and, 5A & 5B. Each movable electrical contact 120 is connected to the drive bar 140 by a drive rod assembly 130.

[0116] Each drive rod assembly 130 comprises: a drive rod insert 131 ; a drive rod 132; a drive screw 133; a thrusting member 134 (e.g. comprising a disc spring and thrust washer); a setting nut 135; a locking nut 136.

[0117] The drive rod insert 131 is connected to the drive rod 132 (e.g. the drive rod insert is bonded to the drive rod). The drive rod insert 131 is disposed through, for example, a tapped through hole 141 in the drive bar 140. The drive rod insert 131 is disposed within the drive screw 133 and connected to the drive screw 133 and drive bar 140.

[0118] The drive rod 132 is connected to the movable electrical contact 120 e.g. either directly or indirectly via a drive plate. In examples, the drive rod 132 is bonded to the drive plate. The setting nut 135 is connected to the drive rod 132 and the locking nut 136 is connected to the drive screw 133. The drive bar 140 is disposed between the setting nut 135 and the locking nut 136The drive bar 140 is attached (e.g. locked) to the locking nut. The drive screw 133 is fixed within the tapped through hole 141 .

[0119] The thrusting member 134 is disposed in a region between a longitudinal face of the drive screw 163 and a longitudinal face of the drive rod insert 131. The longitudinal face of the drive screw 133 and thrusting member 134 force the movable electrical contact 120 towards a static electrical contact (not shown in Figure 7) to remove any tolerance in the arrangement and provide electrical contact between the movable electrical contact and the static electrical contact. The drive screw 163 comprises an external thread configured to engage the internal thread of the tapped through hole 141. The relative position of the drive screw 163 within the tapped through hole 141 can be selected by screwing the drive screw 163 into or out of the tapped through hole 141. The relative position of the drive screw 163 in the tapped through hole 141 determines the compression of the thrusting member 134. The greater the compression of the thrusting member 134 the greater the thrusting force provided by the thrusting member 134; therefore, adjusting the relative position of the drive screw 163 in the tapped through hole 141 determines the thrusting force of the thrusting member 134.

[0120] The drive rod 132 is an electrical insulator. The drive rod 132 provides an electrical clearance between the drive rod insert 131 (typically formed of a conductor e.g. metal) and the movable electrical contacts 120. In other words, the drive bar 140 is electrically shielded from the movable electrical contact by the second drive rod 132.

[0121] Herein the terms air configuration, first configuration, first orientation refer to the same particular orientation of the drive link bars and drive bar. Herein the terms vacuum configuration, second configuration, second orientation refer to the same particular orientation of the drive link bars and drive bar.

[0122] It will be appreciated that any number of static electrical contacts may be provided, for example, one static electrical contact, two static electrical contacts, three static electrical contacts, four static electrical contact or any other number thereof. A corresponding number of movable electrical contacts may be provided, for example, if four static electrical contacts are provided then four movable electrical contacts are provided. Therefore provided is a one-to-one correspondence between the set of static electrical contacts and the set of movable electrical contacts e.g. so that the first movable electrical contact abuts (i.e. contacts) the first static electrical contact, the second movable electrical contact abuts the second electrical contact and so on.

Claims

Claims1. A DC disconnector comprising: one or more static electrical contacts; one or more corresponding movable electrical contacts connected to a drive bar; wherein the drive shaft is configured to actuate the drive bar between: a first position wherein at least a portion of each of the one or more movable electrical contacts abuts one of the one or more static electrical contacts; and, a second position wherein each of the one or more moveable electrical contacts is vertically displaced by a vertical displacement from each of the one or more static electrical contacts; wherein the drive bar is configured to be operable in an air configuration in a first orientation and a vacuum configuration in a second orientation, wherein the separation between the one or more moveable electrical contacts and the static electrical contacts in the second position is greater in the air configuration than in the vacuum configuration.

2. The DC disconnector of claim 1 , wherein: the drive bar has a longitudinal axis arranged parallel to the drive shaft; and, the drive bar is switched from the first orientation to the second orientation by rotating the drive bar 180° about the longitudinal axis.

3. The DC disconnector of claim 2, wherein: drive bar comprises: a first engagement portion at a first end; and, a second engagement portion at a second end, wherein the second end of the drive bar is separated from the first end in along the longitudinal axis thereof; wherein, the first engagement portion and the second engagement portion both respectively engage a first drive link bar and a second drive link bar in either an air configuration or a vacuum configuration, wherein the first drive link bar and the second drive link bar couple the drive bar to the drive shaft and wherein: engagement of the first drive link bar and the second drive link bar in the air configuration provides an air vertical displacement in the second configuration to thereby provide, electrical insulation of the one or more moveable electrical contacts from the one or more static electrical contacts in an air environment; and, engagement of the first drive link bar and the second drive link bar in the air configuration provides a vacuum vertical displacement in the second configuration to thereby provide, electrical insulation of the one or more moveable electricalcontacts from the one or more static electrical contacts in a vacuum environment, wherein the air vertical displacement is greater than the vacuum vertical displacement.

4. The DC connector of claim 3, wherein: the drive bar has a first side and a second side, wherein: each of the first side and the second side is disposed between the first end and the second end; and, the first side is opposite the second side; wherein the first engagement portion and the second engagement portion are disposed closer to the first side than the second side.

5. The DC disconnector of claim 4, wherein: the first drive link bar coupled to the drive shaft by a first cam and engaged to the first engagement portion of the drive bar; and, a second drive link bar coupled to the drive shaft by a second cam and engaged to the second engagement portion of the drive bar.

6. The DC connector of claim 5, wherein: the first cam and the second cam in the air configuration are each an air cam wherein the linear motion of the drive bar actuated by the drive shaft and air cams is greater than the linear motion of the drive bar actuated by the drive shaft and vacuum cams.

7. A drive bar for holding one or more movable electrical contacts in a DC disconnector, the drive bar comprising: a first end and a second end wherein the first end is separated from the second end in a longitudinal direction of the drive bar; a first engagement portion and a second engagement portion at respective ends, wherein each of the first engagement portion and the second engagement portion are configured to engage respective drive link bars in a first configuration and in a second configuration, wherein the respective drive link bars are configured to couple to a drive shaft.

8. The drive bar of claim 7, wherein: the first configuration is configured to provide a first separation between the one or more moveable electrical contacts mounted on the drive bar and respective static electricalcontacts of the DC disconnector when the drive bar is vertically displaced by a vertical displacement from each of the one or more static electrical contacts; and, the second configuration is configured to provide a second separation between the one or more moveable electrical contacts mounted on the drive bar and respective static electrical contacts of the DC disconnector when the drive bar is vertically displaced by a vertical displacement from each of the one or more static electrical contacts, wherein the first separation is greater than the second separation.

9. The drive bar of claim 8, wherein: engagement of both the first drive link bar and the second drive link bar in the first configuration provides an air spacing between the drive bar and the first cam engagement portion and an air spacing between the drive bar and the second cam engagement portion; and, engagement of both the first drive link bar and the second drive link bar in the second configuration provides a vacuum spacing between the drive bar and the first cam engagement portion and a vacuum spacing between the drive bar and the second cam engagement portion, wherein the air spacing is less than the vacuum spacing.

10. The drive bar of claim of any of claims 7 to 9, wherein: the first drive link bar is configured to link the drive bar to a drive shaft via a first cam; and, the second drive link bar is configured to link the drive bar to the drive shaft via a second cam; and, rotation of the drive shaft rotates the first cam and the second cam to thereby cause linear movement of the drive bar in a direction parallel to the longitudinal direction.

11. The drive bar of claim 10, wherein: the drive bar has a first side and a second side, wherein: each of the first side and the second side is disposed between the first end and the second end; and, the first side is opposite the second side; wherein the first engagement portion and the second engagement portion is disposed closer to the first side than the second side.

12. The drive bar of claim 11 , wherein: the drive bar is in a vacuum configuration when the first side is disposed closer to the drive shaft than the second side; the drive bar is in an air configuration when the second side is disposed closer to the drive shaft than the first side.

13. A kit of parts for providing a DC disconnector comprising: the drive bar of any of claims 7 to 12; a first drive link bar configured to engage the first engagement portion of the drive bar; a second drive link bar configured to engage the second engagement portion of the drive bar; a first cam configured to connect the first drive link bar to the drive shaft; a second cam configured to connect the second drive link bar to the drive shaft.

14. The kit of claim 13 comprising: two air cams configured to be the first cam and the second cam; and, two vacuum cams configured to be the first cam and the second cam; wherein using the two air cams as the first cam and second cam causes more linear movement in comparison to using two vacuum cams as the first cam and the second cam.

15. The kit of claim 14 wherein: each air cam has an air eccentricity; each vacuum cam has a vacuum eccentricity, wherein the air eccentricity is greater than the vacuum eccentricity.

16. The kit of claim 15 comprising: at least one drive rod assembly for coupling a drive bar to a movable electrical contact, the drive rod assembly comprising: a first drive rod configured for connection to the drive bar; and, a second drive rod connected to the first drive rod, wherein the second drive rod is configured for connection to the movable electrical contact, and wherein the second drive rod is an electrical insulator.

17. The kit of claim 16, wherein: the drive rod assembly further comprises:a drive screw connected to the first drive rod; and, a thrusting member disposed between a portion of the drive screw and the first drive rod, wherein the thrusting member is configured to thrust the first drive rod portion towards the second drive rod.

18. The kit of claim 17, wherein: the drive rod assembly further comprises: a setting nut configured for connection to the first drive rod; and, a locking nut configured for connection to the drive screw; wherein first drive rod and the drive screw are configured to be disposed at least partially within a tapped through hole in the drive bar and the setting nut and locking nut are arranged around the drive bar to thereby connect the drive bar to the drive rod.

19. A DC disconnector comprising: one or more static electrical contacts; one or more corresponding movable electrical contacts connected to a drive bar comprising ; a drive shaft, coupled to the drive bar via at least one cam, wherein the shaft is configured to actuate the drive bar between: a first position wherein at least a portion of each of the one or more movable electrical contacts abuts one of the one or more static electrical contacts; and, a second position wherein each of the one or more moveable electrical contacts is vertically displaced by a vertical displacement from each of the one or more static electrical contacts, wherein the vertical displacement is configured to provide electrical insulation of the one or more moveable electrical contacts from the one or more static electrical contacts in an vacuum environment; wherein the drive shaft and at least one cam are configured to actuate linear movement of the drive bar between the first position and the second position.

20. A drive rod assembly for coupling a drive bar to a movable electrical contact, the drive rod assembly comprising: a first drive rod configured for connection to the drive bar; and, a second drive rod connected to the first drive rod, wherein the second drive rod is configured for connection to the movable electrical contact, and wherein the second drive rod is an electrical insulator.21 . The drive rod assembly of claim 20, comprising: a drive screw connected to the first drive rod; and, a thrusting member disposed between a portion of the drive screw and the first drive rod, wherein the thrusting member is configured to thrust the first drive rod portion towards the second drive rod.

22. The drive rod assembly of claim 21 , comprising; a setting nut configured for connection to the first drive rod; and, a locking nut configured for connection to the drive screw; wherein first drive rod and the drive screw are configured to be disposed at least partially within a tapped through hole in the drive bar and the setting nut and locking nut are arranged around the drive bar to thereby connect the drive bar to the drive rod.

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