WO1993002497A1

WO1993002497A1 - Support arrangement for busbar assembly

Info

Publication number: WO1993002497A1
Application number: PCT/AU1992/000348
Authority: WO
Inventors: Richard De Laeter
Original assignee: Harwald Industries Pty Ltd
Current assignee: Harwald Industries Pty Ltd
Priority date: 1991-07-17
Filing date: 1992-07-13
Publication date: 1993-02-04
Anticipated expiration: 1994-01-17
Also published as: CN1069602A

Abstract

A busbar support arrangement for supporting two sets of busbars (11 and 12), which are supported by a support member (13) whereby the two sets of busbars are disposed at an angle to each other. The arrangement comprises said support member having two substantially opposed faces which support the sets of busbars at the region of intersection of the two sets of busbars. The support member is formed of an insulating material, and the busbars of each set are supported on the respective opposed faces of the support member in spaced parallel relationship. An opening (22) is formed in the support member at the intersection of pairs of the busbars of each set and extends between the faces. A conductive spacer (23) is located in the opening to be in face to face engagement with the busbars, and a clamping means (24) is provided between the pairs of busbars at the point of intersection to clamp the pairs of busbars and spacers together.

Description

SUPPORT ARRANGEMENT FOR BUSBAR ASSEMBLY

THIS INVENTION relates to switchboard design and support arrangements which are provided for busbar assemblies which can be used in association with switchboards.

According to conventional practice busbars which are used for the distribution of electrical power to switchboards generally comprise two sets of busbars where the busbars of each set present a separate phase. It is general practice that the two sets of busbars are arranged to be perpendicular to each other whereby provision is made for interconnection between appropriate pairs of the busbars of each set at zones of intersection between the busbars. It is general practice not to insulate each of the busbars by providing a wrapping or covering to each of the busbars due to the need to have access to the surface of the busbars for interconnection between sets of busbars and for plug-in devices on the vertical bars. Therefore it is usual practice that the busbars are exposed.

The insulation which is provided between the busbars is effected by separating each of the busbars from each other by an appropriate air gap. The magnitude of the air gap is determined by the maximum anticipated electrical voltage for the busbars and the environment in which the busbars are located. Furthermore the separation must be sufficient to avoid short circuiting between busbars as a result of "tracking" which will occur across surfaces of insulators which interconnect the busbars especially in the presence of a deposition of dust or like particles which under certain circumstances may become conductive.

Therefore, in systems where there are two sets of busbars the busbars of each set are connected to a separate phase and thus there are at least three busbars to each set which must be contained in spaced relation to • each other and three busbars from the second set which must also be arranged in spaced relation to each other. Both sets of busbars are usually offset perpendicularly to each other. In order to maintain the appropriate separation by an air gap between the busbars and to meet appropriate safety requirements it is usual to utilise three-dimensional space. As a result large volumes of space will be utilised in the electrical distribution system merely as a result of the need to provide for the appropriate insulating space between the busbars which are providing the distribution of electricity for electrical circuit power components in a switchboard.

In addition a means must be provided to support of each of the busbars in their spaced relationship and for providing the appropriate electrical interconnection between each of the busbars. It is usual that much of the support which is provided for at least one set of the busbars derives from the connectors which are supported from the other set of busbars. As indicated above it is generally required that the sets of busbars be arranged in a three-dimensional array whereby busbars are in spaced parallel relation to each other and the one set of busbars extend in a third dimension perpendicular to the plane of the other set of busbars. Therefore connectors must extend out of the plane of the other set of busbars and must have sufficient rigidity to be able to not only support the weight of the busbar but be able to withstand the stresses that may be induced under fault conditions.

In instances where the busbar assembly is associated with a high load such as in the event of a short circuit or like instance the electromagnetic forces which are exerted upon the busbars can result in considerable mechanical forces on each of the busbars and this force must be withstood by the support provided for each of the busbars. Such support can be particularly difficult to maintain in the light of the requirement that it is necessary to contain the bus bars in spaced relation to each other and that any support provided for the busbars must be able to withstand "tracking" .

In addition the interconnection between each busbar becomes particularly complicated and generally requires that each of the connectors be customised according to the particular location. As a result the assembly of a power distribution system utilising busbars can be extremely time consuming and labour intensive.

Furthermore, regular maintenance of the busbar assemblies is required which involves checking to determine that all of the interconnections between the assemblies are tight. This maintenance can become extremely difficult due to poor physical access which can be provided to some the interconnection points once the system has been installed.

It is an object of the present invention to at least alleviate some of the disadvantages of existing power distribution systems described above.

In one form the invention resides in a busbar support arrangement comprising two sets of busbars, supported one from the other by a support member whereby the two sets of busbars are disposed at an angle to each other, the arrangement comprising said support member providing two opposed substantially^' opposed surfaces and supporting the sets of busbars at the region of intersection of the two sets of busbars, said support member being formed of an insulating material, the busbars of each set being supported on the respective surfaces of the support member in spaced parallel relationship, an opening formed in the support member at the point of intersection of pairs of busbars of each set and extending between the faces, a conductive spacer located in the opening to be in face to face engagement with the busbars, and clamping means provided between the pairs of busbars at the point of intersection to clamp the pairs of busbars and spacers together.

According to a preferred feature of the invention the support member further supports at one side a housing which encloses one set of busbars in at least the region of intersection of the two sets of busbars.

According to a preferred feature of the previous feature the support member on said one side is formed with a plurality of separate zones whereby each zone accommodates a busbar of the one set whereby the busbars of the one set are isolated from each other.

According to a preferred feature of the invention the other set of busbars are sleeved with an insulating material except in the region of intersection.

According to a preferred feature of the previous feature a removable insulating cover is supported from the support to overlie exposed portions of the other set of busbars in the region of intersection.

According to a preferred feature of the invention the busbars of the other set comprise substantially flat conductive strips.

According to a preferred feature of the invention the busbars of the one set of busbars are formed of conductive channel sections where the entry to said channels are defined by a flange along at least one side of the entry, the entry face of the channel being in opposed relation to the other set of busbars and said clamping means engaging the flange of the one set of busbars. According to a preferred feature of the invention said support arrangement is associated with a control housing which is adapted to accommodate circuit control elements whereby said support member defines one face of the control housing.

According to a preferred feature of the previous feature the interior of the control housing is separated from the one set of busbars by an intermediate wall, said intermediate wall being formed with removable panels to enable access to each busbar of the one set of busbars.

According to a preferred feature of the previous feature each of the busbars of the one set of busbars is formed with a flat strip shaped portion directed edgewise towards said intermediate wall.

According to a preferred feature of the invention the support member is associated with a housing which comprises a web supported in substantially parallel spaced relation to the support member whereby each of the busbars of the one set of busbars are supported between the support member and the web.

According to a preferred feature of the invention described above the web which is provided in association with the support member comprises the intermediate wall of the control housing referred to above.

According to a preferred feature of the previous feature the support member and web are interconnected by transverse walls which extend between the support member and web to each side of each of the busbars to define separate zones in which each busbar is accommodated and isolated from the other busbars of the set. According to a preferred feature of the invention the face of the support member which accommodates the other set of busbars is formed with a pair of parallel ribs which are to be located adjacent each side of each busbar of the other set of busbars.

The invention will be more fully understood in the light of the following description of one specific embodiment. The description is made with reference to the accompanying drawings of which;

Figure 1 is an isometric view of a busbar support arrangement according to the embodiment;

Figure 2 is a cross-section of the point of intersection between a pair of busbars of the embodiment shown at Figure 1;

Figure 3 is a sectional view along the line 3-3 of Figure 2;

Figure 4 is a cross-sectional view of a point of intersection of a set of busbars where the busbars of the one set take a different form from those shown in relation to Figures 1, 2 and 3;

Figure 5 is a cross-sectional view along the line 5-5 of Figure 4;

Figure 6 is a front isometric view of the support arrangement of the first embodiment associated with appropriate control housings; and

Figure 7 is a rear isometric view of the support arrangement of the embodiment associated with support housings as shown at Figure 6. The embodiment shown in the drawings relates to a support arrangement which is provided for a power distribution system which incorporates a set of busbars. The busbars comprise a first set 11 of three busbars where each busbar is associated with a separate phase and a second set 12 of three busbars where the second set of busbars are disposed substantially horizontally and are connected to the source of electrical power. The one set of busbars 11 are arranged substantially vertically and are intended to be connected to the circuit elements which are to be driven by the electrical power.

The support between the two sets of busbars is provided by a support member 13 which is formed of a plastics insulation material which has an appropriate insulation capacity and is able to withstand temperatures which are most likely to be experienced under extreme load conditions. Suitable plastics material have been found to comprise a form of polycarbonate.

The support member 13 primarily comprises a rear wall 14 which presents a pair of opposed parallel faces against which each set of busbars 11 and 12 are supported. The support member 13 further comprises a set of transverse walls 15 located in spaced parallel relation across the rear wall 14 and which are substantially perpendicular to the rear wall 14. The transverse walls define channel shaped zones 16 whereby each zone 16 accommodates a busbar of the one set 11. The support member further comprises a front wall 17 which extends across the forward edges of the transverse walls 15 to enclose the zones 16. The transverse walls 15 are formed integrally with the rear wall 14 while the front wall 17 is removably supported from the support member and is held in engagement with the support member 13 by appropriate fixing means. As shown at Figures 1 and 2 the front wall 17 is formed on its internal face with a set of spaced abutments 40 which extend inwardly into each of the zones 16 and which are spaced from each other such that they will receive the leg portion of each busbar of the one set 11 to rigidly retain the busbar in position within the zone and resist flexural movement of the busbar within the zone.

The outer face of the rear wall 14 is formed with a set of pairs of horizontal ribs 18 which have a spacing corresponding to the width of the busbars of the other set of busbars 12 which are formed as flat strips of conductive material. The spacing between each pair of the ribs 18 is such that the busbars are snugly received between the respective pair of ribs 18.

The support member 13 is formed as a set of modules whereby each module A, B and C supports one busbar of the other set of busbars 12. As stated above each busbar of the other set of busbars 12 are formed of lengths of flat strip material and the lengths are sleeved with a suitable insulation 28. Two lengths are supported from the support in end to end relationship at a point of intersection with a busbar of the one set 11 to which the busbar of the other set is to be associated. Both ends of the lengths which form each busbar of the one set are clamped to the support in a manner which will be described below. Before being placed in position the end portions of the abutting ends of the busbars of the other set have the insulation material removed therefrom such that they are exposed.

Each busbar of the one set 11 are formed as T-shaped members where the cross member of the section is formed as a channel section 19 having an open face 20 defined by a flange 21 extending inwardly from each side of the channel 19 such that the open face has a reduced width. Where a pair of busbars from each set are to be electrically interconnected such interconnection is effected by an opening 22 through the rear wall 14 of the support member 13 at the point of intersection of the pair of busbars. The opening 22 accommodates a spacer 23 formed of an electrically conductive material which is held in abutting face to face engagement with the opposed faces of the pair of busbars 11a and 12a by the clamping means.

The clamping means comprises a pair of threaded bolts 24 which are received through the space provided between the abutting ends 26 of the busbar 12a of the other set of busbars. The bolts pass through an aperture provided through the spacer and into the entry 20 provided in the channel 19 of the one busbar 11a. The threaded bolts are each associated with a washer plate 25 which bears against the exterior face of the exposed end portions of each of the other busbars 12a. The threaded bolts are further associated with a plate 27 having a pair of threaded apertures. The plate is received within the channel 19 to be supported by the flanges 21 of the channel. As shown at Figure 1 the pair of threaded bolts 24 are used to provide the clamping engagement between the pair of busbars 11a and 12a. The washer plate 25 is further provided with an outwardly extending threaded spigot 29 formed of an electrically insulating material and an insulating cover 30 is receivable over the exposed end portions of the other busbar 12a and has an aperture which is receivable over the insulated threaded spigot 29 whereby a suitable nut 31 can be applied to the threaded spigot to retain the insulating cover in position over the exposed end portions of the other busbars.

In use the modules A, B and C of the support member 13 are fixed in abutting end to end relationship and the busbars of the one set 11 are supported to extend throughout the length of the support member 13 and beyond the support member 13. The other set of busbars 12 are mounted to the exterior face of the support member 13 and are each insulated by an insulating coating 28 which is applied to each busbar in all areas where electrical contact is not required as described above. In order to effect electrical contact the busbars of the other set of busbars are formed as discrete lengths whereby the end portions of each length have the insulating material removed such that they are exposed and it is those end portions which are maintained in electrical contact with the respective busbar of the one set through the clamping arrangement. In addition, the exposed portions of the end portions of the busbars are enclosed by an insulated housing. As a result each of the busbars of the other set are insulated by either the insulating sleeving 41 and by the support member 13 together with the insulating cover 30 which is applied to the exposed ends of the busbar.

The busbars of the one set 11 are each accommodated within a separate zone 16 within the support member such that each is electrically isolated from each of the other busbars of the one set. As a result of this arrangement there is a reduction in volume of the space for the support arrangement of the embodiment compared to the volume of the space which is conventionally required. This is effected by a reduction in the spacing which conventionally needs to be provided between the busbars of a distribution arrangement due to the conventional reliance upon the air gap between busbars which are generally not insulated or provided with any form of protective covering to isolate one busbar from the other. Furthermore, accommodation of one set of busbars 11 within an enclosed zone where they are separated from another set of busbars 12 which are located outside the zones 16 and results in a reduced likelihood of short circuiting by "tracking" between the sets of busbars. Furthermore the arrangement of the present embodiment reduces the volume which would normally be occupied by the busbar arrangement by significantly reducing the third dimension which conventionally needs to be provided to ensure a sufficient air gap exists between the busbars of the each of the sets. In addition the support for each busbar of each set, is such that in the event of an excessive mechanical or electrical load being placed upon the distribution system the mechanical stresses which result from the vibration of the busbars due to the electromagnetic forces exerted thereon can be accommodated to prevent undue flexing of the busbars which can result in short circuiting.

In addition, the maintenance of the support assembly is simplified in that the clamping means for interconnection between each busbar is readily accessible and such access is available with a significantly reduced likelihood of contact with other busbars of the distribution system during such maintenance program when compared with conventional systems.

Furthermore, by utilisation of a channel section as the busbars of the one set of busbars the current loading which is available for the busbars is increased while the overall dimensions of the busbar can be reduced. This is as a result of the increased cross-sectional area which is provided by the channel section. Furthermore, the channel section provides for a greater mechanical strength against flexural movement of the busbars which can occur under high electromagnetic load when compared to the flat sections which are conventionally used.

As shown at Figures 4 and 5 the busbars of the one set may vary in form from those described in relation to Figures 1, 2 and 3. The busbars of the one set shown in Figures 4 and 5 each comprise a double channel section 19 and 19a having opposed entries 20 and 20a which are directed in opposite directions to each other. However in all other respects the arrangement of the form of the first embodiment shown at Figures 4 and 5 is identical with the form of the first embodiment described in relation to Figures 1, 2 and 3. The only exception relates to the method by which the busbars 11a of the one set are connected to the electrical componentry with which the busbars are to be associated.

The busbars of the one set 11 of the form of the embodiment shown at Figures 1, 2 and 3 are intended to be connected to electrical componentry by means of a clip-on connector 45 which is snugly receivable over the leg portion of the T- shaped busbar. In the case of the form of the embodiment shown at Figures 4 and 5 the connector 46 is fixed to the busbar by a clamping arrangement which utilises a threaded bolt 47 which extends between the connector 46 and a threaded nut or a plate having a plurality of threaded apertures 48 which bears against the inner faces of the flanges 21a. Conductive spacers 49 are also provided between the channel 19a of the busbar of the opposed face of the conductor and the connector 46.

As shown at Figures 6 and 1 the embodiment is intended to be used with a control housing 50 which provides support for the circuit control elements with which the busbar is to be associated. The control housing 50 is formed of a plurality of preformed panels which comprise a set of side panels 51 and a set of floor panels 52. The panels are each formed with edges which provide for locking inter- engagement between the abutting edges of the panels. In addition adjacent of the side panels 15 may be lockingly inter-engaged in abutting edge to edge relationship by use of a suitable interconnecting members (not shown) without the need to provide a floor panel. As a result the control housing 15 shown at Figures 6 and 7 may comprise a set of three separate boxes each having an upper and lower wall defined by the floor panels 52 or alternatively one or more of the floor panels may be deleted to provide for a larger space. The front face of each of the control housing 50 is enclosed by a front panel 53 having a door 54 which provides access into the interior of each of the control housings.

The control housing is adapted to be mounted to the front wall 17 of the support member 13 such that the front wall 17 of the support member provides the rear face of the control housing. The front wall 17 is provided with panels 55 (see Figures 2 and 4) opposite each of the busbars of the one set which can be removed to enable access to each of the zones 16 and thus to the busbar accommodated in that zone. As a result each busbar can be accessed from within the control housing as required while the remaining busbars remain isolated from the interior of the control housing if not required.

It should be appreciated that the scope of the present invention need not be limited to the particular scope of the embodiment described above.

Claims

THE CLAIMS defining the invention are as follows:-

1. A busbar support arrangement comprising two sets of busbars, supported one from the other by a support member whereby the two sets of busbars are disposed at an angle to each other, the arrangement comprising said support member having two substantially opposed faces which support the sets of busbars at the region of intersection of the two sets of busbars, said support member being formed of an insulating material, the busbars of each set being supported on the respective opposed faces of the support member in spaced parallel relationship, an opening formed in the support member at the intersection of pairs of the busbars of each set and extending between the faces, a conductive spacer located in the opening to be in ace to face engagement with the busbars, and clamping means provided between the pairs of busbars at the point of intersection to clamp the pairs of busbars and spacers together.

2. A busbar support arrangement as claimed at claim 1 wherein the support member further supports at one ace a housing which encloses one set of busbars in at least the region of intersection of the two sets of busbars.

3. A busbar support arrangement as claimed at claim 2 wherein the support member at said one face is formed with a plurality of separate zones whereby each zone accommodates a busbar of the one set and whereby the busbars of the one set are isolated from each other.

4. A busbar support arrangement as claimed at claim 1, 2 or 3 wherein the other set of busbars are sleeved with an insulating material except in the region of intersection.

5. A busbar support arrangement as claimed at claim 4 wherein a removable cover is supported from the support to overlie exposed portions of the other set of busbars in the region of intersection.

6. A busbar support arrangement as claimed at any one of the preceding claims wherein the busbars of the other set comprise substantially flat conductive strips.

7. A busbar support arrangement as claimed at any one of the preceding claims wherein the busbars of the one set of busbars are formed of conductive channel sections where the open face of said channel section is defined by a flange extending along at least one side of the open face and wherein the open face of the channel section is in opposed relation to the other set of busbars and said clamping means engages the flange of the one set of busbars.

8. A busbar support arrangement as claimed at any one of the preceding claims wherein said support arrangement is associated with a control housing which is adapted to accommodate circuit control elements whereby said support member defines one face of the control housing.

9. A busbar support arrangement as claimed at claim 8 wherein the interior of the control housing is separated from the one set of busbars by an intermediate wall, said intermediate wall being formed with removable panels to enable access to each busbar of the one set of busbars.

10. A busbar support arrangement as claimed at claim 8 or 9 wherein each of the busbars of the one set of busbars is formed with a flat portion directed edgewise towards said intermediate wall.

11. A busbar support arrangement as claimed at claim 8 or 9 wherein each of the busbars of the one set of busbars is formed with a second channel having a second open face directed towards the intermediate wall.

12. A busbar support arrangement as claimed at any one of claims 8, 9, 10 or 11 wherein the support member is associated with a housing which comprises a web supported in substantially parallel spaced relation to the support member whereby each of the busbars of the one set of busbars are supported between the support member and the web.

13. A busbar support arrangement as claimed at claim 11 as dependent on claim 9 wherein the web which is provided in association with the support member comprises the intermediate wall of the control housing.

14. A busbar support arrangement as claimed at claim 11 or 12 wherein the support member and web are interconnected by transverse walls which extend between the support member and web to each side of each of the busbars to define separate zones in which each busbar is accommodated and isolated from the other busbars of the set.

15 A busbar support arrangement as claimed at any one of the preceding claims wherein the face of the support member which accommodates the other set of busbars is formed with a pair of parallel ribs which are to be located adjacent each side of each busbar of the other set of busbars.

16. A busbar support arrangement as claimed at any one of the preceding claims wherein the busbars are disposed substantially perpendicular to each other.

17. A busbar support arrangement substantially as herein described.