WO1998048496A1

WO1998048496A1 - Electrical bus connector apparatus and method

Info

Publication number: WO1998048496A1
Application number: PCT/AU1998/000276
Authority: WO
Inventors: David F. Schwede; Allan Brownlie
Original assignee: Totally Flexible Products Pty. Ltd.
Priority date: 1997-04-17
Filing date: 1998-04-17
Publication date: 1998-10-29
Also published as: AUPO627797A0

Abstract

Electrical connector apparatus (10) provides removable connection between a circuit breaker (11), and three phase busbars (12, 13, 14), the apparatus (10) comprising front (16) and rear (17) mouldings. The front moulding (17) has a mounting surface (20) through which protrude supply (21) and load (22) side terminals. The mouldings (16, 17) comprise integrally moulded busbar guide channels (23), the supply side terminals (21) being connected to their respective busbars by link bars (26, 27, 30) and each comprising a tubular terminal portion (32) secured to the link bar by threaded extension (33) and nut (34) and supported in the front moulding (16) by integrally moulded spigot portions (35). The load terminals (22) comprise tubular portions (40) and threaded portions (41) assembled to take-off bars (42) extending through the rear and side of the moulded casing (15) to provide alternative points of connection to a load circuit. The take-off bars (42) are located in the rear moulding (17) by web (43) and nut and bolt assembly (44), the load terminals (22) being braced by spigot portion (45). The circuit braker (11) includes a support (46) adapted to pass over the supply (21) and load (22) terminals, terminal pins (47) of the cirucit breaker (11) protruding through the support (46) to engage respective terminals (21, 22). The assembly may thereafter be pushed home to make effective electrical contact with the bus.

Description

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. 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 tenriinals. As such the body member may be adapted to service a

plurality of electrical components representing a multistack component array. 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. 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 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 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

present the 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 temiinals. 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 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 accompanying drawings which illustrate a preferred embodiment of the invention and

wherein:

FIG. 1 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. 1 as indicated in FIG.

FIG. 9 is the section C-C through the apparatus of FIG. 1 as indicated in FIG.

3;

FIG. 10 is the section D-D through the apparatus of FIG. 1 as indicated in FIG.

3;

FIG. 1 1 is the section E-E through the apparatus of FIG. 1 as indicated in FIG.

4;

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

4; 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 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 45.

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 51 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 1 1 via remote control rod

56.

The insulative support 46, metal case 53 and circuit breaker 1 1 form a 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 15.

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 65

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 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 1 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.

5. 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.

10. Electrical bus connector apparatus according to any one of the preceding

Claims 1 to 8, wherein said insulated-case electrical component comprises a HRC 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.

15. 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 terminals protrude.

16. Electrical bus connector apparattis 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.