GB2134726A - Terminal connector assembly for an electric control device - Google Patents

Abstract

The terminal connector assembly comprises an elongate, shell-like insulating housing (100) and, supported therein, several terminal connectors (93) which are isolated from each other by means of arc-propagation preventing barriers, including insulating barriers (102, 103) between the terminal connectors. The assembly is for use with electric control devices, such as drawout-type switchgear, motor controllers. <IMAGE>

Description

SPECIFICATION Terminal connector assembly for an electric control device This invention relates to a terminal connector assembly for connecting an electric control device to a power distribution system comprising several conductors.

More particularly, the invention relates to a terminal connector assembly which is especially well suited for use with drawout-type switchgear, motor controllers, and similar control devices adapted to be physically and mechanically connected to bus bars, such as employed for instance in the kind of motor control center disclosed in Applicant's U.K. patent specification No. 1,554,645. As described in the latter, the feeder bus bars to which the control devices, circuit interrupters or the like are connected are sheathed in insulation which isolates the various bus bars from each other so as to prevent the propagation of electric arcs during fault conditions.The control devices employ clip-type terminal connectors adapted, when the control devices are moved into operating position, to slide into contact engagement with bare blade portions of the bus bars which are accessible through openings formed in the insulation sheathing the bus bars. The terminal connectors of each such device are supported in a shell-like insulating housing, preferably in a floating manner enabling them to self-align with the respective blade portions of the bus bars, as described in Applicant's U.K. patent specification No.

1,554,582.

It has been found that whilst arc propagation at the bus bars will be effectively suppressed due to the sheathing of the latter, it is still possible for it to occur at the conventional terminal connectors, a problem which the invention has for its principal object to solve.

The invention accordingly resides in a terminal connector assembly comprising an elongate insulating housing mounted or adapted to be mounted on an electric control device, and, supported in the housing, a plurality of terminal connectors for connecting the control device to a power distribution system comprising several conductors, characterized in that said insulating housing has formed therein insulating barriers disposed between the terminal connectors and electrically isolating the latter from one another.

Preferably, the insulating housing is a composite structure consisting of separate housing sections joined together, with each of said insulating barriers including first and second labyrinth-forming means disposed on the respective housing sections and meshing with one another so as to form a labyrinth preventing the passage of ionized gases. Furthermore, the housing sections preferably are provided, along peripheral edge portions thereof, with similar intermeshing labyrinth-forming means which connect with the labyrinth-forming means of the barrier so as to provide substantially total isolation of the individual terminal connectors.

A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of an electrical control center; Fig. 2A is a front elevational view of the upper half of a left-hand portion of the control center, with the front doors open; Fig. 2B is a front elevational view of the lower half of said left-hand portion of the control center, with two of the doors open; Fig. 3 is a horizontal sectional view taken along the line Ill-Ill of Fig. 2B and showing a control unit as it is being inserted into place; and Fig. 4 is a plan view of a section of a terminal connector housing embodying the invention.

The electric control center illustrated in the drawings is of the type disclosed in U.K. patent specification No. 1,554,645, to which reference may be had for a fuller description. Briefly, the control center, generally designated in the drawings with reference numeral 13, comprises a metal cabinet having a plurality of compartments 15, 17, 19 and 21 (see Figs. 2A-B) arranged one above the other and separated from each other by horizontal shelves 23. The compartments 1 5, 1 7, 19 and 21 have access doors 25, 27, 29 and 31, respectively, which are shown as provided with openings 33 for operating handles 35, 37 of the control units within the compartments, and for indicator-light panels 39.

The cabinet 1 3 comprises a rectangular steel framework consisting of U-shaped corner posts 41 (Fig. 3), horizontal interconnectors 43, 45 at upper and lower ends, vertically spaced horizontal braces, such as braces 47, upright posts 49, and two support posts 51 and 53 adjacent opposite side wall panels 55 and 57 of the cabinet. As seen best from Fig. 3, in the particular embodiment shown herein, the cabinet 13 has compartments similar to compartments 1 5-21 formed therein at the rear as well as the front thereof, and it contains vertical bus bars 59, 61 and 63 which are disposed between the front and rear compartments in such manner that electric control units, as indicated at 65, can be connected to the bus bars from both sides.The vertical bus bars 59, 61 and 63 are connected, adjacent their upper ends, to separate horizontal main or through buses 77, 79 and 81, respectively, by means of suitable fasteners, such as bolts 83. A wiring compartment 67 with a door 73 extends adjacent the side wall panel 57 vertically alongside the front compartments 1 5, 17, 19 and 21, from which it is separated by a partition 69, another partition 71 being provided to separate the wiring compartment from the central area containing the bus bars. A similar wiring compartment 75 adjacent the other side wall panel 55 is provided for the rear compartments 15,17,19 and 21.The two wiring compartments accommodate electrical wiring (not shown) leading from the control units 65 in the various compartments 15, 17, 1 9 and 21, as known in the art.

As shown in Fig. 3, the bus bars 59, 61, 63 are preferably Z-shaped in cross-section, each of them comprising a main or intermediate portion 91 lying in a plane substantially parallel to the front and rear sides of the cabinet, and connecting portions or blades 87, 89 which are spaced apart in the transverse direction of the main portion 91 and extend from the latter in opposite directions toward the compartments 1 5-21 in the front and rear of the cabinet 13 so as to be engageable with terminal connectors or clips 93 of the control units as the latter are inserted into the respective compartments.

The terminal connectors 93 of each control unit 65 form part of a terminal connector assembly including also a shell-like elongate housing 100 which is suitably secured to the control unit, e.g.

by means of bolts (not shown) extending through openings in end portions 101 of the housing 100, and in which housing the terminal connectors 93 are supported, preferably so as to permit selfalignment, and thereby to assure proper engagement thereof with the respective bus bars 59-61. Preferably, the construction of the terminal connectors, and the manner of their support in the housing 100, are as disclosed in Applicant's U.K. patent specification No.

1,554,582 to which reference should be had for a more detailed description. The connector housing 100 likewise is similar to the connector housing described in GB-PS 1,554,582, insofar as it is formed of a suitable insulating material having adequate dielectric and structural strength, and is composed of separate sections or halves fit and secured together, e.g. by the above-mentioned bolts, so as to form the shell-like housing 100 including hollow or tubular projections 1 05 which surround stem and contact portions of the respective terminal connectors 93.

As distinct from the connector housing described in GB-PS 1,554,582, the connector housing embodying the invention is provided with means forming labyrinth-type barriers which electrically isolate the terminal connectors 93 associated with different phases 1, y2 and (p3 (Fig. 4) from one another. More specificaliy, and with particular reference to Fig. 4 showing one section or half of the shell-like insulating housing 100, it is seen therefrom that the housing section has formed therein, and preferably molded integral therewith, barrier portions 102 and 103 which extend across the housing section interiorly thereof and between the regions which accommodate the terminal connectors 93 when the housing sections are joined together and the connector assembly is complete.As indicated at 110, each barrier portion 102 or 103 is provided with a first of two labyrinth-forming means, the second one of which is formed on the other housing section (not shown). Upon assembly of the two housing sections, the first and second labyrinth-forming means on the respective barrier portions mesh with one another to form insulating barriers which electrically isolate the terminal connectors 93 associated with the different phases (p1, q)2 and (p3 from one another and, due to the labyrinths formed in the barriers, will force ionized gases tending to pass between different phase regions to lose their charge, thereby preventing arc propagation between adjacent phase regions.The first and second labyrinthforming means of the preferred embodiment described are grooves and tongues which, when intermeshed, form labyrinths each having four right-angle bends thereacross.

As apparent from Fig. 4, the housing sections (only one being shown) of the connector housing 100 are provided, along peripheral edge portions thereof, with similar labyrinth-forming means which mesh with one another and connect with the respective labyrinth-forming means of the insulating barriers 1 02 and 103 so as to provide substantially total isolation of each terminal connector 93 from the others.

Likewise as seen from Fig. 4, the connector housing 100 is provided with openings 106, 107 and 108 for the usual cables connected to the various terminal connectors 93 to extend therethrough. Each of these openings preferably has a size and configuration such as to cause its wall to firmly engage the cable extending therethrough, thereby, together with the cable, forming a barrier to the passage of ionized gases.

Claims (6)

1. A terminal connector assembly comprising an elongate insulating housing mounted or adapted to be mounted on an electric control device, and, supported in the housing, a plurality of terminal connectors for connecting the control device to a power distribution system comprising several conductors, characterized in that said insulating housing has formed therein insulating barriers disposed between the terminal connectors and electrically isolating the latter from one another.

2. A terminal connector assembly according to claim 1, wherein said insulating housing is composed of two housing sections joined to each other, characterized in that each of said insulating barriers includes first and second labyrinthforming means formed on the respective housing sections and meshing with one another.

3. A terminal connector assembly according to claim 2, characterized in that the two housing sections are provided, along peripheral edge portions thereof, with first and second, respectively, labyrinth-forming means which mesh with one another and connect, respectively, with the first and second labyrinth-fprming means of the insulating barriers to provide substantially total isolation of the terminal connectors.

4. A terminal connector assembly according to claim 2 or 3, characterized in that said first and second labyrinth-forming means form four rightangle bends thereacross.

5. A terminal connector assembly according to claim 2, 3 or 4, characterized in that said first and second labyrinth-forming means are grooves and tongues, respectively.

6. A terminal connector assembly according to any of the preceding claims, wherein the insulating housing has formed therein openings for cables connected to the terminal connectors to extend therethrough, characterized in that each of said openings has a size and configuration such that the walls thereof engage the cable and, together therewith, form a barrier to the passage of ionized gas.