AU729401B2

AU729401B2 - Electrical bus connector apparatus and method

Info

Publication number: AU729401B2
Application number: AU70135/98A
Authority: AU
Inventors: Allan Brownlie; David F Schwede
Original assignee: TOTALLY FLEXIBLE PRODUCTS Pty
Current assignee: Lai Switchboards Australia Pty Ltd
Priority date: 1997-04-17
Filing date: 1998-04-17
Publication date: 2001-02-01
Anticipated expiration: 2018-04-17
Also published as: AU7013598A

Description

WO 98/48496 PCT/AU98/00276 1 ELECTRICAL BUS CONNECTOR APPARATUS AND METHOD This invention relates to an electrical bus connector apparatus and method.

This invention has particular but not exclusive application to electrical bus connector apparatus and methods suitable for use in connecting a load circuit via a circuit breaker into a three phase AC bus, and for illustrative purposes reference will be made to such application. However, it is to be understood that this invention could be used in other applications, such as electrical bus connector apparatus and methods for connecting electrical components including switches or fuse blocks generally to a bus.

In industrial power switchboards, three phase power is distributed to circuits via fuses or circuit breakers. Fuses are relatively cheap but are a consumable. To replace a fuse it is necessary to remove power to the bus, or switch off at the fuse if provided for, unclamp the defective fuse (usually secured on terminal studs by four nuts), and replace it. This takes a considerable amount of time.

There are generally three fuses per circuit, one for each phase. Accordingly there is three times the likelihood of failure resulting in down time. This will generally affect more than just the circuit with the defective fuse. The studs mounting the fuses are necessarily conductive, intrusive into the stack space, and must be touched to remove the fuse.

Circuit breakers can be reset without powering down the bus. A circuit breaker is essentially an automatic three pole switch operable in response to a fault condition. However, to change or replace a circuit breaker, such as rerating a circuit or in the case of breaker failure, it is again necessary to remove power from the bus, or provide a separate three pole switch.

WO 98/48496 PCT/AU98/00276 2 Circuit breakers are also generally secured by threaded fixings to the front connected terminals, the mounting means being necessarily conductive and intrusive into the stack space, and must be touched to remove the breaker. This action also takes a considerable amount of time.

The present invention aims to alleviate at least one of the foregoing disadvantages and to provide an electrical bus connector apparatus and method which will be reliable and efficient in use.

With the foregoing and other objects in view, this invention in one aspect resides broadly in an electrical bus connector apparatus including: an insulated body adapted to engage and insulate a busbar and a take-off conductor and having an electrical component mounting surface; a supply side terminal located at said mounting surface and electrically connected to said busbar; a load side terminal located at said mounting surface in said body and electrically connected to said take-off side conductor; an insulated-case electrical component adapted to be secured to said mounting face and having poles adapted for press-in engagement with respective said supply and load side terminals.

The apparatus may be adapted for single or multipole use. Preferably, the apparatus is adapted for use on three phase AC power circuits or the like. Typically such circuits are rated from 0.16 to 630 amps.

The body member may be moulded about the busbars and takeoff bars and their respective terminals. As such the body member may be adapted to service a plurality of electrical components representing a multistack component array.

WO 98/48496 PCT/AU98/00276 3 Alternatively, the body member may comprise body elements adapted to be mechanically secured to the busbars and take-off bars. In the latter embodiment, a separate body member may be provided for each electrical component, whereby a selected number of body members may be formed into a stack.

The body member may be formed of any suitable insulative material known in the art to have the desired dielectric strength for the intended insulating performance.

Preferably, the material of the body member is selected to provide the mechanical separation of the busbars and takeoff bars to also function as restraining means capable of maintaining the respective conductors in their relative positions, thereby reducing the likelihood of a short circuit fault condition arising. Preferably, the body member material is a reinforced polymeric material. For example the body member may be formed of an approved material such as fire retarded glass filled polyester or nylon.

The body member may be substantially solid throughout, with moulded-in recesses to allow the body member portions to lay over and locate about the terminals and bars. However, in order to reduce the amount of material in the moulding, the body member may comprise substantially hollow box portions having integrally moulded therein such support structures as may be desirable to locate about and separate the busbars and provide support for the terminals and their lead bars against distortion in use.

The body member may be adapted for use with vertical busbars, whether top fed, bottom fed or both, or may be adapted for use with horizontal busbars. The body member may also be selected for use with any direction of orientation of the take-off bars.

WO 98/48496 PCT/AU98/00276 4 Where the body member comprises an assembly of body elements, these may be secured about the respective conductors by any suitable means, including bonding means, or fixing means such a through bolts. Preferably, the body member elements are provided with complementary channels and bracing elements in the mating surfaces whereby the busbars and take-off bars respectively may be located positively and clamped therebetween. The body elements are preferably configured such that they locate and are retained one to the other with precision.

If desired, the body member elements may be configured whereby in assembly the incoming or supply side components are substantially isolated from the load side components by an ionization barrier. An ionization barrier supplements the dielectric barrier provided by air or other insulating gas in the body member by providing a solid dielectric barrier to arcing should the air or gas become ionized and thus conductive in a fault condition. In addition, the body members may be vented to conventional chimneys in a supporting switchboard structure to prevent cascade dielectric breakdown in the switchboard during a fault condition.

The supply terminal preferably comprises a three phase set each connected by any suitable means to its respective busbar. For example, the supply terminals may each be brazed, silver soldered or bolted to its respective busbar via an integral intermediate bar, the respective intermediate bars being preferably formed up to shape to locate the supply terminals in a selected spaced relation which may or may not correspond to the spacing or orientation of the busbars. Alternatively, the intermediate bars may be provided with threaded outer ends whereby replaceable supply terminals may be affixed thereby.

The supply terminals may be flush with or recessed behind the mounting WO 98/48496 PCT/AU98/00276 surface such that the terminals do not intrude into the mounting space for the electrical component. Alternatively, the supply terminals may be slightly proud of the mounting surface and adapted to form a locating engagement with a corresponding insulative portion associated with the electrical component.

The load side terminals may be integrally formed with the take off bars, although it is envisaged that the intermediate bars may be provided with threaded outer ends whereby replaceable load side terminals may be affixed thereby. The load side terminals may be flush with or recessed behind the mounting surface such that the terminals do not intrude into the mounting space for the electrical component.

Alternatively the load side terminals may be proud of the surface to cooperate with corresponding recesses in an insulative mounting portion of the electrical component as per the supply side terminals.

The insulated-case electrical component may comprise a circuit breaker, switch, meter or the like adapted to be secured to said mounting face and having poles adapted for press-in engagement with respective said supply and load side terminals. The poles are preferably protuberant and of a form adapted to engage complementary recesses in the respective supply and load side terminals. If it is desired to retain conventional HRC fuses, then these may be advantageously formed up into a three phase fuse pack on an insulated support and having poles adapted to engage the supply and load side terminals respectively.

For example, the supply and load side terminals may comprise a set of spring clamps adapted to receive a respective spade pole. Alternatively, the terminals each may be configured as a plain or tapered bore adapted to receive poles configured as a plain or tapered spigot. In a yet further alternative the terminals may comprise a WO 98/48496 PCT/AU98/00276 6 mechanical terminal such as the type having an annular arrangement of terminal segments retained against the spigot in use by an annular spring.

Where a tapered spigot and bore arrangement is used, the insulated-case electrical component may be configured with taper disengaging means. For example, insulated-case electrical component may be provided with the threaded stud or studs adapted to be driven against the mounting surface and thereby bias the insulated-case electrical component out of engagement with the tapered bore terminals. If desired, the taper disengaging means may form part of the securing means adapted to mount the insulated-case electrical component to the mounting surface.

The insulated-case electrical component may be mounted to the mounting surface by any suitable means. In conventional switchboards, it is desirable to presentthe apparatus as a relatively conventional stack, wherein each stack component is housed in a metal case having the requisite fault chimney vents, front covers, operating knobs and the like. Accordingly, in this application it is preferred that the mounting means incorporate such a component housing.

In one embodiment the insulated case electrical component may be mounted with its poles passing through slots in a metal enclosure of the conventional type, the enclosure being mounted to the mounting surface with set screws after the poles are engaged with their respective terminals. Alternatively, the mounting means may mount the insulated case electrical component directly to the mounting surface, such as by set screws or the like, and an enclosure be mounted thereover.

In such cases, and particularly where the supply and take-off terminals protrude from the mounting surface, the electrical component may form part of an assembly comprising a conventional metal case having an insulative mounting end WO 98/48496 PCT/AU98/00276 plate to which the insulated case electrical component is secured and through which the component terminals protrude. The insulative mounting may include locating means adapted to accurately align the assembly with the mounting surface, or at least align the terminals to the extent that the engagement thereof will safely occur. As such an assembly is pushed home, the protruding portions of the supply and take off terminals may then be adapted to engage corresponding counterbores in the insulative mounting end plate.

As a yet further alternative, the pole to terminal interaction may comprise the mounting means.

The respective poles and terminals are preferably formed of highly conductive materials, and in keeping with industry standards are preferably of copper or brass alloy, and may be silver or gold plated.

In one embodiment of the present invention, supply terminal assemblies are affixed to the busbars. Take off bar/load side assemblies are fitted to a first body element including the mounting face and having channels adapted to receive a portion of the busbars and take-off bars, and bracing pads for at least the longer of the take-off and supply terminal bars. This assembly is then offered up to the busbars with the supply terminals extending through passages to the mounting surface, whereupon a second body element having moulded-in channels for the busbars, supply terminal bars and take-off bars is bolted to the first element to clamp the assembly to the busbars. The busbars may support the assembly while the assembly maintains the spatial integrity of the busbars.

In order that this invention may be more readily understood and put into practical effect, reference will now be made to the WO 98/48496 PCT/AU98/00276 8 accompanying drawings which illustrate a preferred embodiment of the invention and wherein: FIG. I is a hidden detail top front perspective view of apparatus in accordance with the present invention in use; FIG. 2 is a hidden detail side view of the apparatus of FIG. 1; FIG. 3 is a front view of the apparatus of FIG. 1, without the electrical component mounted; FIG. 4 is a plan view of the apparatus of FIG. 1, without the electrical component mounted; FIG. 5 is a front view of the apparatus of FIG. 1, without the electrical component mounted and with front cover removed; FIG. 6 is an end elevation of the apparatus of FIG. 1; FIG. 7 is the section A-A through the apparatus of FIG. 1 as indicated in FIG.

3; FIG. 8 is the section B-B through the apparatus of FIG. I as indicated in FIG.

3; FIG. 9 is the section C-C through the apparatus of FIG. I as indicated in FIG.

3; FIG. 10 is the section D-D through the apparatus of FIG. I as indicated in FIG.

3; FIG. 11 is the section E-E through the apparatus of FIG. I as indicated in FIG.

4; FIG. 12 is the section F-F through the apparatus of FIG. 1 as indicated in FIG.

4; WO 98/48496 WO 9848496PCT/AU98/00276 9 FIG. 13 is a horizontal section through an alternative embodiment of apparatus in accordance with the present invention; and FIG. 14 is a front view of the apparatus of FIG. 13 with the body element comprising the mounting surface removed.

In the figures there is provided electrical connector apparatus generally indicated as 10 adapted to provide removable connection between a moulded case electrical component, in this example a circuit breaker 11, and a three phase electrical supply, in this example illustrated by the three vertical busbars 12, 13, 14.

The apparatus 10 generally comprises a moulded plastic casing comprising a front moulding 16 and a rear moulding 17, formed of fire retarded glass filled polyester.

The front moulding 17 includes a component mounting surface 20 through which protrude supply terminals 21 and load terminals 22.

The internal detail of the apparatus 10, best illustrated in Figs 5 to 12, comprises integrally moulded busbar guide channels 23 formed up by the cooperation of respective front channel mouldings 24 and rear channel mouldings 25 integrally formed with the front moulding 16 and rear moulding 17 respectively.

The supply terminals 21 are connected to their respective left 12 center 13 and right 14 busbars by respective link bars 26, 27, 30. The connection of the supply terminals 21 is best illustrated in Figs 7, 8 and 9.

In these figures, the left busbar 12 is drilled to accept the left link bar 26 by virtue of bolted connection 31. The supply terminal comprises a generally tubular terminal portion 32 secured to the left link bar by threaded extension 33 and nut 34.

The center 13 and right 14 busbars are similarly secured to their respective supply terminals 21. The supply terminals 21 are partially supported towards their outer end WO 98/48496 PCT/AU98/00276 by integrally moulded spigot portions 35 formed in the front moulding 16. In order to provide bracing for the right link bar 30, the longest of the link bars, the front 16 and rear 17 mouldings have complementary bracing portions 36, 37, best seen in Fig 9, adapted to support the link bar 30 adjacent its connection to its supply terminal 21.

Whilst the supply terminals 21 and their respective link bars 26, 27, 30 form a relatively rigid assembly with the busbars 12, 13, 14, the load terminals 22 require a more insular system of support. For each of the three phases, the load terminals 22 again comprising a generally tubular portion 40 and threaded portion 41 are assembled to take-off bars 42, in this embodiment extending through the rear and side of the moulded plastic casing 15 to provide alternative points of connection to a circuit to be supplied. The take-off bars 42 are securely located in the rear moulding 17 by integrally formed web 43 and nut and bolt assembly 44. Again, the generally tubular portion 40 of the load terminals 22 are partially braced at the component mounting surface 20 by integrally formed spigot portion The circuit breaker 11 is mounted to an insulative support 46 of thickness substantially the same as the protrusion of the supply 21 and load 22 terminals beyond the mounting surface 20 of the moulded plastic casing 15. Terminal pins 47 are affixed to the working terminals 50 of the circuit breaker 11 and protrude through the insulative support 46. The insulative support 46 includes aligning lugs 5 1 adapted to engage arcuate corresponding channels 52. The insulative support 46 mounts a metal housing 53 of the conventional stack type, having a front door 54 upon which is mounted a manual breaker switch 55 operating the breaker 11 via remote control rod 56.

The insulative support 46, metal case 53 and circuit breaker II form a WO 98/48496 PCT/AU98/00276 11 removable assembly. In use the assembly is offered up such that the lugs 51 engage the channels 52 thereby substantially aligning the pins 47 with their respective terminals 21, 22. The assembly may thereafter be pushed home to make effective electrical contact with the bus. The assembly may then be secured by removable fixings (not shown) adapted to pass through the insulative support 46 through cut-outs 57 to engage complementary captive fixings 60 provided in the sides of the moulded plastic casing In the embodiment of FIGS. 13 and 14, there is also provided electrical connector apparatus generally indicated as 10 adapted to provide removable connection between a moulded case electrical component and a three phase bus. In this embodiment the front moulding 16 and the rear moulding 17 cooperate to form an ionization barrier 61. The load side take off bars 42 are mutually isolated within the housing by webs 62. The front moulding 17 includes, in lieu of the spigot portions 35, 45 of the previous embodiment, moulded sleeves 63, 64 which are adapted to provide clearance for the supply terminals 21 and load terminals 22. This clearance is required since this embodiment utilises expanding mechanical terminals recessed behind the mounting surface 20 and having an insulative locating pin adapted to cooperate with corresponding bores in the connecting pins of the electrical component.

The abovedescribed embodiments of the present invention provides plug-in configurations which makes it possible to extract and rapidly replace a circuit breaker without having to touch any connections within a metal enclosure which are live when power is connected to the bus. Circuit downtime by virtue of failure of the connected device, or the fuse or breaker replacement component of a service for WO 98/48496 PCT/AU98/00276 12 appliance failure or maintenance, is greatly reduced. The reduction in service times also contributes to an economic advantage in fitting circuit breakers in place of the current standard HRC fuses.

It will of course be realised that while the foregoing has been given by way of illustrative example of this invention, all such and other modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of this invention as defined in the claims appended hereto.

Claims

1. Electrical bus connector apparatus including: an insulated body adapted to engage and insulate a supply bus and a take-off conductor and having an electrical component mounting surface; a supply side terminal located at said mounting surface and electrically connected to said busbar; a load side terminal located at said mounting surface in said body and electrically connected to said take-off side conductor; an insulated-case electrical component adapted to be secured to said mounting face and having poles adapted for press-in engagement with respective said supply and load side terminals.

2. Electrical bus connector apparatus according to Claim 1, wherein said supply bus comprises a three phase AC power bus.

3. Electrical bus connector apparatus according to any one of Claims I and 2, wherein said insulated body comprises body elements adapted to be mechanically secured to the busbars and take-off bars.

4. Electrical bus connector apparatus according to Claim 3, wherein said body elements comprise substantially hollow box portions having integrally moulded therein support structures adapted to locate about and separate said supply bus and said take off bars, and adapted to provide support for said terminals.

WO 98/48496 PCT/AU98/00276 14 Electrical bus connector apparatus according to Claim 4, wherein said respective terminals are supported in respective spigots formed integrally with one said body element.

6. Electrical bus connector apparatus according to Claim 4, wherein said terminals are supported by their respective bus or take off conductor in respective insulative sleeves formed integrally with one said body element.

7. Electrical bus connector apparatus according to any one of the preceding Claims, wherein said body elements are configured whereby in assembly the supply bus and a take-off conductor and their respective terminals are substantially isolated one from the other by an ionization barrier.

8. Electrical bus connector apparatus according to any one of the preceding Claims, wherein said respective terminals are flush with or recessed behind the mounting surface.

9. Electrical bus connector apparatus according to any one of the preceding Claims, wherein said insulated-case electrical component comprises a circuit breaker assembly adapted to be secured to said mounting face and having poles adapted for press-in engagement with respective said supply and load side terminals.

Electrical bus connector apparatus according to any one of the preceding Claims 1 to 8, wherein said insulated-case electrical component comprises a HRC WO 98/48496 PCT/AU98/00276 fuse assembly comprising a conventional HRC fuse on an insulated support and having poles adapted to engage said supply and load side terminals respectively.

11. Electrical bus connector apparatus according to any one of the preceding Claims 6 to 10, wherein said terminals comprise a mechanical terminal having an annular arrangement of terminal segments retained by an annular spring.

12. Electrical bus connector apparatus according to any one of the preceding Claims, wherein said electrical component includes a case adapted to present as a conventional stack in a multiple-component switchboard.

13. Electrical bus connector apparatus according to Claim 12, wherein said case includes features selected from fault chimney vents, front covers, operating knobs and the like.

14. Electrical bus connector apparatus according to Claim 13, wherein said insulated case electrical component is mounted with its poles passing through slots in a metal said case, the enclosure being mounted to the mounting surface with set screws after the poles are engaged with their respective terminals.

Electrical bus connector apparatus according to Claim 13, wherein said insulated case electrical component forms part of an assembly comprising a conventional metal case having an insulative mounting end plate to which the insulated case electrical component is secured and through which the component WO 98/48496 PCT/AU98/00276 16 terminals protrude.

16. Electrical bus connector apparatus according to Claim 15, wherein said insulative mounting includes locating means adapted to align the assembly with the mounting surface to align the component poles with the terminals to the extent that the engagement thereof will safely occur.