GB2112587A - Insulator and support for bus bar system - Google Patents

Abstract

Bus bar runs 58 with droppers 67, 68, 69 are protected from the environment and insulated from inadvertent human contact by front and rear mouldings 1 or 73 and 13 or 70 respectively which snap engage together to separate and arc- proof e.g. three individual bus phases in their own ducts V1, V3, V5. The front moulding 1 has apertures 4, 5 and 6 through which the bus droppers 67, 68, 69 pass. The droppers 67, 68, 69 are attached to the bus bars via holes 63, 64, 65. The joints are protected by aperture covers 30 which fit detachably onto the front moulding 1. Slots (41 Fig. 7, not shown) formed between the bottom edges of the aperture covers and the front moulding 1 allow exit of the droppers. Only after such exit do the droppers need taping or such insulation. The mouldings 1, 13 are supported by the bus bar supports 43, which are also claimed. The mouldings 1, 13 may be of polycarbonate plastic, and the supports 43 may be of glass or filled or loaded polyester. <IMAGE>

Description

SPECIFICATION Insulator for bus bar system The present invention relates to the insulation of bus bar systems particularly at joints or dropper locations where an electrical connection has to be made with each bus bar. Such locations may be control bays. The existence of the electrical junction, which includes terminal soldering, or nuts, bolts or the like cause problems in insulation. Electrically live portions should not come in contact with each other, or with personnel or with external metal etc. There may be three conductors, each having a dropper leading away.

One known method of insulating the joints is to wind the bars, the joint sites and the lead-outs with insulating tape. This winding is time consuming and awkward, even more so if the insulation needs subsequently to be removed, eg. for an inspection of the joint.

The tape itself eventually starts to unwind and become detached. These objections can be overcome to some extent by shrink sleeving on the bars, but the joints themselves still have to be taped. Thus it would be desirable to have easily applied and removable insulation with any parts to be standard and massproducible. The insulation should be flameretardent and capable of cooperation with busbar supports.

Accordingly, the invention can be embodied either in busbar insulation mouldings or in busbar support mouldings, or in both in cooperation. The insulation mouldings presently preferred are clipped together and so resist vibrations. No adhesive is involved. The mouldings have front and rear portions, the latter defining individual channels for the eg.

three bus conductors and cooperating with shaped ridges on support mouldings. The attached front portions are individually apertured for the respective droppers, and detachable front covers cover the apertures while forming slits with the front portions for exiting dropper conductors.

Since the conductors usually exit downwards after a downward bend, they are technically droppers, but the exit slits may orient the joined conductors in another direction, which will usually be close to and parallel to the plane of the front portion.

It has been proposed (see US Patent 4,316,234, published on 16th February 1982) to use an insulating cover having three parallel channels for snugly fitting bus, bars.

Also French Patent 1,505,698 proposes easily removable insulating panels for each of plural bus bar runs. Such proposed features are not applied to demountable protection at junction sites.

The above and further objects, features and advantages of the invention will appear from the following description of embodiments thereof, given by way of example in conjunction with the drawings, in which: Figures 1 and 2 show side and front views of a front panel insulation member; Figures 3, 4 and 5 are side, front and a scrap plan view of a rear insulation member; Figure 6 shows a bus bar and insulation support moulding; Figures 7 and 8 show front and side view of an aperture cover fitting the front insulator member; and Figure 9 shows an exploded perspective view of a supported three-phase bus bar section at a dropper site, showing the insulation components in orientation for assembly.

Referring to Figs. 1 and 2, a transparent front moulded insulating member 1 extends in height, between bent over flanges 2 and 3, sufficiently to confront three installed bus bar conductors, eg. of a three-phase mains line.

Member 1 extends in width sufficiently to accommodate three joints to exit conductors or droppers which are to exit from the buses via apertures 4, 5 and 6 at the different heights of the buses and also horizontally spaced for ease in separating the joints, and in spacing the droppers which will extend downwards from each aperture 4, 5 or 6.

Spring fastener holes 7, 8, 9 and 10 (or other clearance or threaded holes) provide for securing the member 1 to the apices of two U Bends in a rear member described below.

Further similar holes such as 11 and 1 2 beneath each aperture provide for fixings on the front member of aperture covers described below. The material is thin, transparent and flame-retardent and also slightly springy because bent over portions 2 and 3 can then be resiliently forced outward by slight pressure.

The rear insulator member is shown at 13, Figs. 3 and 4 and extends in height between bent over flanges 1 4 and 15, the exterior parts of which can be forced between the bent over edges 2 and 3 of the front member of Figs. 1 and 2 until bent over edges 1 6 and 1 7 of the flanges lodge against vertical portions of the front edges. This gives a reasonably unpassable pressure joint, and yet the two members are easily attached and detached from each other by the following arrangement.

The rear insulator member 1 3 comprises an upper vertical section V,, and is then bent along its width at right angles at 18, again bent on closely spaced width lines 1 9 and 20 in the opposite direction to form a U-bend and another vertical section V2, and then again bent in the first direction at 1 8A adjacent bend 1 8 to begin another vertical section V3 towards another similar right-angle and Ubend arrangement. These bends create another short vertical section V4, and another long vertical section V5 terminating at flange 1 5.

Thus there are short vertical sections V2 and V4 forward of the majority of the rear insulating member and formed between the bends of the U. There may be further short and long vertical sections formed by further right-angle and U-bendings if desired. In this embodiment, two are sufficient because, with the resulting horizontal sections H,, H2, H3 and H4 and the top and bottom flanges, three channels 21, 22 and 23 are formed which are destined to accommodate the three conductors of a three-phase mains power horizontal busbar run with vertical separation formed by the distances between H, and H2, and between H3 and H4.

The three channels 21, 22 and 23 are completed by attaching the front member 1 to the rear member 1 3 by the attachment means 7, 8, 9 and 10 on the front member, and 24, 25, 26 and 27 on the rear member. The attachment means may be holes tapped or clearance for nuts and bolts, or fasteners and sprung holes for quick fastening, anti-vibration mountings. Thus the U-bends provide not only the separated horizontal sections H,-H4 for the channels, but also the vertical sections V2, V4 against which the front section 1 rests and is attached. The vertical extent of V2, V4 is a compromise between giving enough separation to the busbar conductors if these are to be of very high voltages and for the attachment means 24-27, and yet maintaining rigidity of the whole structure.The conductors are thus enclosed in respective ducts by members 1 and 1 3 except for the apertures 4, 5, 6 and the entries and exits to the sides as viewed in Figs. 2 and 4. These are discussed later.

Cutaways 29 are (see Fig. 4) provided at the ends of the vertical sections V2 and V4 ie., at the outer ends of the U-bends. Cut-aways 28 (see Figs. 3 and 5) are located at the corners of each of the horizontal sections H1-H4 adjacent to, and indeed continuous with, the cut-aways 29. The cut-aways are discussed functionally hereinbelow in connection with Fig. 8.

Having provided ducts for the horizontal conductor lengths we must consider the junctions and the droppers or spur conductors, being local taps on the main lengths. We are not primarily concerned with the junctions themselves which will be horizontally spaced adjacent apertures 4, 5 and 6 to allow space for the droppers to be coplanar. The junctions will have some depth to allow terminal attachments, bolts etc, for which the depths of channels 21-23 will allow.

For each junction a flat conductor will run outward and through an aperture 4, 5 or 6 in the front panel, at which aperture it will be bent so as to run across the front member and close to it. In this embodiment the preferred directions of flexure and continuation of the conductors are into a vertically downward direction. Accordingly the following design of aperture cover not only stops metal objects and environmental ingress at the apertures, but also a cut-away in the cover provides with the front member a thin downwards exit slot for a respective dropper.

Referring to Figs. 6 and 7, the aperture covers 30 seen in front and side views include side flanges 31 and 32 to lie on the front member 1 each side of an aperture 4, 5 or 6, and attachment means 33, 34 for fastening or screwing to the front member 1. Such means may be clearance holes or spring fasteners cooperating with means 11, 1 2 below each aperture. A tongue 35 attached at the top of the cover is inserted under the top 36, Fig. 2, of the aperture before the cover is pivoted downwards to lay the flanges 31 and 32 against the front cover for attachment.

A forwardly projecting area 37 then covers and nearly encloses the aperture and terminal bolts likely to be projecting from the busbar union; the base of projecting area 37 is formed by a bend 38 and horizontal transition 39 to a less projecting vertical area 40 which eventually will confront the first part of the dropper after flexure parallel to the front member, in this embodiment in a vertically downward direction. The flexure will occur at or near the same level as the horizontal portion 39 of the aperture cover, and a slot 41 is provided by a cut-away or absent horizontal section 42 in the bottom of the cover 30 for exiting into the external world of the dropper.

Afterwards the dropper may be shielded by a shrunk-on sheath, insulating tape or other protection with which we are not concerned, which eventually will confront the first part of the dropper after flexure parallel to the front member, in this embodiment in a vertically downward direction. The flexure will occur at or near the same level as the horizontal portion 39 of the aperture cover, and a slot 41 is provided by a recess or cut-away in, or indeed totally absent, horizontal section 42 in the bottom of the cover 30 for exiting into the external world of the dropper. Afterwards the external parts of the dropper may be shielded by a shrunk on sheath, insulating tape or other protection irrelevant to this invention.

The above aperture cover thus is able to provide attachability to the front member for establishing physical contact virtually all round the aperture, but for cut-away 41. This arrangement completes environmental protection for the whole bus bar section at the locality of front member 1, while allowing frequent (if desired) inspections of the dropper joint and its vicinity without in any way dismantling the joint. The projecting portion 37 not only can house projecting portions of the joint, but allows easy handling to disengage and re-engage the aperture cover, specifically the tongue 35 thereof, with the front member at the aperture, without disturbing the joint or dropper. The fasteners 33, 34 are meanwhile unfastened.

Therefore an aperture cover may include flanges (31, 32) for seating on a front member (1) at least partly surrounding an aperture (eg. 4), an aperture closure member (37) and a dropper cover member (40) attached between the flanges, front member attachment means (33, 34) on the flanges, which flanges and aperture closure member (37) provide contact with the front member substantially all around the aperture (4) of the front member, with a cut-away of the dropper cover member (40) providing limited non-contact with the front member for egress of a conductor eg.

(vertical) dropper.

Referring now to Fig. 8 which is a side view of a bus bar support 43, which may have a flat front surface 44 and a flat rear surface 45, a composite ridge patterning 46 comprises three rectangles with two short sides 47, 48 which are each common to two rectangles. The three rectangles are nearly complete, except that ridge portions are missing at 49 at the ends of the rear long sides.

The other hidden side of the support member 43 may be similar except the rear and front would be oppositely illustrated. The support member 43 does not only provide local support for bus bar conductors passing through the H-shaped through-holes 50, 51, 52 which appear within the rectangles, but the ridge patterning provides good support for the insulating members of the preceding drawings. The patterning is shaped not only to provide this good support, but also to cooperate with the members to allow minimum atmospheric or indeed human accidental interactions with the three bus bar conductors and the housed dropper joints. The atmospheric interactions may cause dust or moisture ingress and corrosion. The human factor includes the dropping of metal tools, nuts, bolts etc leading to short-circuitings; or manual contactings of live conductors and other dangers.The support member 43 like those of Figs. 1-7 is of moulded flame-retardent thermosetting plastics. Support member 43 is of robust construction in view of its supporting role.

Referring to Fig. 8 and Fig. 3, the dropper insulator moulding rear member 1 3 is set in position first by placing the vertical portions V1, V3, V5 of the latter against the incomplete vertical rectangle sides 53, 54, 55 to the left of Fig. 8 as viewed. The horizontal lengths H,-H4 of Figs. 3 and 4 will rest against the common short sides 47 and 48 of the ridge pattern, these ridge sections pressing H, and H2, also H3 and H4 siightly apart. The bends 18, 1 8A etc of Fig. 3 are accommodated by the gaps 49 in the ridge pattern. The cutaways 28, 29 (see Figs. 4 and 5) allow the short vertical sections V2 and V4 to be pushed forward nearly adjacent the front side of the ridge section 46 of Fig. 8.

The cut-aways 28 and 29 need not be present if there are further missing portions similar to 49 but in the front side and short sides of the ridge pattern of Fig. 8. Also the missing portions 49 may be replaced by further cut-aways each side of the rear of the rear member 13, ie., at the ends of the rightangle bend portions 1 8 etc.

After the rear member 1 3 has been pushed into position, the end flanges 1 6 and 1 7 thereof will snap into locating recesses 56, 57 in the ridge pattern of Fig. 8, so that the relative positioning is stable. The front insulating member 1 is now applied against the front vertical ridge 46 and attached to the rear member 1 3 with fastening means 24-27 and 11, 12. The apertures 4, 5 and 6, Fig. 2, will be opposite the joint positions in the bus bar runs.

It is assumed that in the usual case, there will be another support member 43 on the other side of the insulating members 1 and 1 3 for their symmetrical support, location and protection of the insulating members 1 and 1 3 of the joints and bus bars from the atmosphere.

The joints are now made by appropriate electrical attachments and the exiting droppers bent downwards or otherwise across the outside of the front member.

The aperture covers 30 are now fitted and as mentioned above may be removed and replaced with easy convenience whenever inspection, testing and repairs are required.

The bus bars, conductors, joints and exit conductors are not illustrated as forming no part of the invention, which relates to the support members 43 of Fig. 8 and to the insulating front and rear members of Figs.

1-5. The aperture covers of Fig. 6 and 7 are preferred designs. The invention is not restricted to any finite number of conductors, apertures 4-6 or rectangular channels and ridging. Three is a likely number because of the frequency of occurrence of three phase bus bar supplies.

The material of the protector mouldings should be flame retardent, self-extinguishing if ignited, and desirably vacuum moulded, somewhat resilient, anti-vibrational and transparent. An ideal plastics is a polycarbonate moulding. The support member(s) may be of glass, filled or loaded polyester D.M.C.

It will have been appreciated that the cutaways at the ends of each U-turn of the rear dropper protector member are to avoid continuities in the vertical ridge of the support member. Therefore we can have both vertical ridges continuous if we provide cut-aways also at the ends of the rearwards perpendicular bends of the rear member. Alternatively we need no cut-aways in the rear member if there are suitable interruptions in both vertical ridges.

There will only be one horizontal support ridge if only two bus bar conductors are in question, and two channels in the rear protector member, but three is the usual number required. The design can obviously easily be extended to encompass four or more bus bar conductors.

Referring now to the exploded view of Fig.

9, two spaced support members 43A, 43B can be seen similar to member 43 of Fig. 8, having front and rear sides 44 and 45 and apertures 50, 51 and 52. Most other reference numerals in Fig. 9 correspond to those of Figs. 1 to 8 except for new items. Supported by the two support members is an intermediate bus bar three-phase section 58, the bars of which pass through apertures 50, 51 and 52, and an array of three droppers 59. The distal ends 60, 61 and 62 of the individual droppers are, when installed, joined tightly by attaching holes such as 63, 64 and 65 to the bus bars for making good electrical junctions.

The three droppers are mounted on a rectangular insulating frame 66, or may be installed individually. Cranked portions 67, 68, 69 can be seen near the distal ends, and these portions pass through the apertures 4, 5 and 6 in the front panel. The aperture covers 30 then snap onto the panel, and the lower vertical portions of droppers 59 pass through slots 41 (see Figs. 6 and 7) which are formed between the panel and the lower edges of the aperture covers 30.

As previously described, the front panel 1 has fasteners which snap engage with the short vertical sections V, and V2 of the rear moulded member 13, thereby enclosing the bus bars, with the members 1 and 1 3 in position abutting supports 43A and 43B.

The bus bars continue in joined up sections, and at intervals where no droppers are required, no aperture covers 30 will be needed which project outwards to accommodate the cranked, exiting dropper portions. Accordingly, although at these intervals without droppers, the bus bars are housed in channels in rear mouldings which may be identical to mouldings 13, the front panel 71 is different.

It needs no apertures and covers unless it is required occasionally to attend to the bus bar.

In this case apertures 73, 74 elongated in height to provide access to all three bus bars may be present, and easily removable aperture covers 75, 76 may cover these apertures, eg again using snap connectors 77.

Therefore the invention provides a complete environmental and electrical protection for a bus bar system having dropping bays and bays without droppers, where the protection is easily and quickly removed. Such removal can be either incompletely, using snap mounted aperture covers, or completely, by disconnecting snap mountings of moulded front panels on double or U-bent moulded rear panels.

New dropper bays, can be provided for by susbtituting panels 1 and aperture covers 30 for items 71 and 75, 76. Danger in old installations of electric shock by drying and cracking off of old insulating tape from bus bar droppers is avoided, and yet installation is extremely rapid to carry out with unskilled personnel, with full insulation also between the two, three or more bus bar phases. Personnel working alongside the bays will be protected with much more certainty from danger of electric shock or arcing burns etc.

Claims (12)

1. An insulator moulding for protecting a bus bar dropper, comprising; a generally flat front member having height and width, and plural apertures of different height positions and different width positions on the front member, aperture covers detachably mountable to the front member so as to cover respective apertures except that an exit slot is provided by a cutaway in each aperture cover at an edge adjacent the front member; and a rear member of generally similar height and width to the front member and being formed rearwards with bends and frontwards with approximate U-turns at given heights so as to form spatially separated horizontal channels; wherein said front member at heights intermediate between said apertures is detachably securable to said U-turns of said rear member, whereon the bottom and top edge portions of the front and rear members are then arranged to approach each other and to complete at least top and bottom insulating ducts for buses, said aperture covers providing individual and covered exits for droppers joined individually to bus bars housed in the separated channels.

2. A moulding according to claim 1 wherein the front and/or rear protector member is transparent.

3. A moulding according to claim 1 or 2 wherein the rear member comprises cut-aways at each end of said U-turns.

4. A bus bar support member for supporting a bus bar at a horizontal location, and for supporting a bus bar dropper insulator moulding on at least one side of the location; said member being apertured at plural spaced height intervals for the passage of respective supported buses; a vertical front ridge on the member extending past all the bus bar apertures forwardly thereof; A vertical rear ridge on the member extending past all the bus bar apertures rearwardly thereof; a horizontal ridge between each bus aperture; wherein one of the vertical ridges is interrupted at intervals proximate free ends of the horizontal ridge(s); and the other of the vertical ridges is tee-ed into by each of the horizontal ridges and is thus commoned therewith; whereby said commoned composite ridge and said interrupted ridge can provide support for attached together front and rear insulation mouldings on said one side of said location.

5. A support member according to claim 4 supporting insulator protector mouldings according to claim 1, 2 or 3, and a bus bar with droppers exiting via said mouldings, on at least one side of said location.

6. A support member according to claim 4, when supporting the protector mouldings claimed in claim 3 wherein the interrupted vertical ridge is the rear ridge, the interruptions accommodate said rearwards bends, and said cut-aways at ends of the U-turns accommodate the T-junctions of the horizontal ridges with the continuous front vertical ridge.

7. A support member according to claim 6 modified in that not one but both of the vertical ridges are thus interrupted at intervals, and in that neither of the vertical ridges is tee-ed into by each horizontal ridge; whereby the protecting insulator rear member does not require cut-aways at each end of said Uturns.

8. A support member according to claim 6, but modified in that neither of said vertical ridges are thus interrupted; wherein both of the vertical ridges are tee-ed into by the horizontal ridge (if only one is present) or by all the horizontal ridges; and the rear protector member has cut-aways not only at each end of the U-turns but also at each end of the rearward bends, for engaging the ridges of the support member and yet avoiding the vertical ridges in the vicinities of the teed-in horizontal ridges.

9. A support member according to claim 4 wherein one vertical ridge has top and bottom recesses to accommodate and iocate snapping-in of tongue-edges of a protector member when this has been pushed into a cooperating position.

1 0. A support member, either for supporting or actually supporting a bus bar and protective moulding, the support member being arranged substantially as hereinbefore described with reference to Fig. 8.

11. An insulator moulding according to any of claims 1 to 3, wherein the rear member has, attached to top and bottom flanges thereof forming walls of the top and bottom channels, top and bottom bent over extensions or tongues, for locating into recesses of a support member ridge pattern.

12. A bus bar and dropper protection moulding substantially as hereinbefore described with reference to Figs. 1 to 7.

1 3. A protection moulding and support system, substantially as hereinbefore described with reference to Figs. 1 to 8, or Fig. 9.