GB2178605A - Electrical bus-bar take-off assemblies - Google Patents

Abstract

A bus-bar assembly comprises a plurality of flat elongate conductors (22, 23, 24) separated by insulating layers (25, 26) and power take-off connectors in the form of insulated flexible conductive tapes (Fig. 2 not shown) or lugs (21, 27), wherein an edge of each conductor (22, 23, 24) is reduced in thickness and the connectors are soldered to respective reduced edges, the combined thickness of a connector and a reduced edge being less than the thickness of the main part of the conductor. <IMAGE>

Description

SPECIFICATION Electrical bus-bar assemblies The present invention relates to electrical busbar assemblies. Such bus-bar assemblies are utilised in the distribution of electrical power throughout electrical apparatus, for example.

One form of bus-bar assembly comprises a plurality of flat elongate conductors separated by insulating layers. Each of the conductors forms a separate bus-bar and may carry a different potential. Provision is made for connection to the conductors at positions along their lengths to enable power to be taken from the conductors at those points.

It has previously been proposed to integrally form lugs or projections on the conductors at required positions to which power take-off connectors are bolted. The lugs have previously been formed by taking a conductor of a width greater than is required and removing excess metal to leave the lugs extending from the conductor. A disadvantage with this form of manufacture, however, is that a considerable amount of metal is wasted.

The present invention overcomes this disadvantage and results in a bus-bar assembly which is cheaper to manufacture.

According to the present invention a busbar assembly includes: a plurality of elongate conductive members separated by interposed insulating layers, each conductive member having a first portion and a second portion of reduced thickness compared to the first portion; and a plurality of power take-off connectors secured in electrical contact to said second portions, the combined thickness of each distribution member and the second portion being no greater than the thickness of said first portion.

An electrical bus-bar assembly will now be described, by way of example, with reference to the accompanying drawing, in which: Figure 1 shows part of a typical prior art bus-bar assembly.

Figure 2 shows part of a bus-bar assembly incorporating one embodiment of the present invention, and, Figure 3 shows an end view of a further embodiment of the invention.

Referring to Fig. 1 of the drawing, a conventional electrical bus-bar assembly 1 comprises three conductors 2, 3 and 4. The conductors are formed from a material having good electrical conductivity such as copper, for example. Insulating layers 5 and 6 separate the conductors 2, 3 and 4 from one another and the conductors and insulating layers are bonded together to form the assembly. Lugs 7, 8 and 9 are integrally formed with the conductors 2, 3 and 4 respectively.

The lugs may be turned through 90" as are the lugs 7 and 9 or may project vertically as in the case of the lug 8. Holes 10 are provided in the lugs to facilitate electrical connection thereto by, for example, a nut and bolt.

Referring now to Fig. 2, a bus-bar assembly 11 according to the present invention is shown. The assembly 11 comprises three conductors 12, 13 and 14 separated by insulating layers 15 and 16. The conductors 12, 13 and 14 are reduced in thickness along the whole length of their upper edges as indicated at 17. Power take-off connectors are provided by flexible copper tapes 18 enclosed within an insulating layer 19. The layer 19 leaves the ends of the tapes 18 exposed to allow electrical connection thereto. One end of each of the tapes 18 is soldered to the reduced portion 17 of one of the conductors 12, 13 or 14. The combined thickness of a tape 18 and the reduced portion 17 of a connector after soldering is less than the thickness of the main part of the conductor.

A number of the flexible tapes 18 are soldered to the conductors at positions along their lengths from which power is to be taken.

The free ends of the tapes are left extending vertically from the conductors 12, 13 and 14 and the assembly is encapsulated, using a known insulating encapsulant, leaving the flexible tapes extending outside. After the bus-bar assembly has been installed in the apparatus of which it forms a part, the flexible tapes 18 may be formed and cut to length to enable the required connections to be made. Alternatively, the tapes may be cut to length before they are soldered to the conductors.

It will be realised that the described arrangement provides significant advantages over the prior art in that it enables a flexible connection to be made directly on to a bys-bar without the use of a terminal thereby resulting in improved reliability and a reduction in cost. Furthermore, elimination of any form of terminal enables the density of possible connections to be increased, for example, connections may be made to adjacent bus-bars at the same point along the length of the assembly. It has also been found that wiring errors are reduced with this arrangement.

Fig. 3 shows another embodiment of the invention in which conductive lugs 21 replace the flexible tapes 18 of the embodiment of Fig. 2. The lugs 21 are attached to the conductors 22, 23 and 24 in the same manner as the tapes 18 of the embodiment of Fig. 2 are attached to the conductors 12, 13 and 14.

However, in this embodiment the lugs 21 also have portions of reduced thickness which extend across one end and are arranged to mate with the reduced portions of the conductors 22, 23 and 24. In this case the combined thickness of the reduced portions of the conductors and the lugs after soldering is less than the thickness of the main part of the conductor. Insulating layers 25 and 26 separate the conductors 22, 23 and 24 and holes 27 are formed in the lugs 21 to facilitate con nection thereto. The lugs 21 may be turned through 90" or left straight as desired. The assembly is finally encapsulated as before as indicated by broken lines 28 leaving the lugs extending outside the-encapsulation.

This embodiment, although not providing all of the advantages of the previously described embodiment provides a power take-off connector that will carry heavier currents than the flexible tapes. Thus, it need only be employed when heavy currents are drawn from or fed intq the bus-bar. In a typical arrangement the majority of take-off connectors would be in the form of flexible tapes and relatively few would comprise conductive lugs.

Claims (7)

1. A bus-bar assembly including: a plurality of elongate conductive members separated by interposed insulating layers, each conductive member having a first portion and a second portion of reduced thickness compared to the first portion; and a plurality of power take-off connectors secured in electrical contact to said second portions, the combined -thickness of each distribution member and the second portion being no greater than the thickness of said first portion.

2. A bus-bar assembly as claimed in claim 1, in which said second portions of reduced thickness extend along the whole length of an edge of the elongate conductive members.

3. A bus-bar assembly as claimed in claim 1 or 2, in which the power take-off connectors are secured to the conductors by soldering.

4. A bus-bar assembly as claimed in claim 1, 2 or 3, in which the power take-off connectors are provided by insulated flexible conductive tapes.

5. A bus-bar assembly as claimed in claim 1, 2, 3 or 4, in which the power take-off connectors include a portion of reduced thickness for mating with the second portions of the conductive members.

6. A bus-bar assembly as claimed in any preceding claim, in which the conductive members and the interposed insulating layers are encapsulated in insulating material.

7. A bus-bar assembly constructed substantially as hereinbefore described with reference to Figs. 2 and 3 of the accompanying drawing.