GB2052877A - Improvement in or relating to low-voltage electric switching systems - Google Patents

Abstract

An electric low-voltage switching system comprises a cabinet containing inserts 11 in a number of tiers. Power is supplied by vertical busbars 7 each connected by plugs 420 to a horizontal distribution bar 42, which has plugs 421 for each counter-plug 4210 of each insert 11 in the tier in question. The distribution bars 42 are secured via insulated spacers 41 to a bearing plate 40 of an assembly unit 4 which is pre-assembled by wiring at the factory. The assembly unit also bears plugs 43 which co-operate with the insert plugs 430 in order to transmit the power output and control current from the insert to the cabinet. The plugs 43 are connected at the factory by wiring 44 to the terminals 45, 46, to which the output lines 50 are connected. <IMAGE>

Description

SPECIFICATION Improvements in or relating to low-voltage electric switching systems The invention relates to a low-voltage electric switching system.

Low-voltage electric switching systems are known which comprise a cabinet having a space for connection with terminals for the power output and the control current, adjacent a space containing inserts disposed in a number of tiers and bearing electric appliances and plugs at the back for the power input. The power output and the control current, counter-contacts for the power output and control currents, wired to the correspondingly named terminals, are disposed behind the inserts in the cabinet, and the device also has a three-phase group of vertical busbars for the power input which are adapted to receive plugs.

A system of this kind is known from German Offenlegungsschrift 25 1 5 1 52. Its main disadvantage is that the terminals in the space for connections must be wired in the cabinet to the plugs in the rear insertion space, which of course is very complicated.

An object of the invention is to provide an economic, advantageous low-voltage electric switching system wherein the wiring work is simpler and more economic.

According to the present invention there is provided a low-voltage electric switching system comprising a cabinet having a space for connections with terminals for the power output and the control current, adjacent a space containing inserts disposed in a number of tiers and bearing electric appliances and plugs at the back for the power input, the power output and the control current, counter-contacts for the power output and control currents, wired to the correspondingly named terminals, being disposed behind the inserts in the cabinet, and the device also comprising a three-phase group of vertical busbars for the power input, adapted to receive plugs, characterised in that the counter-plugs for the power output and the control current, the associated terminals and the corresponding wiring per tier, which can be produced in the factory, are disposed on a prefabricated assembly unit mounted in the cabinet.

Since the asembly unit can be pre-assembled and wired in the factory, outside the cabinet and then only has to be secured in the cabinet, the assembly work is greatly reduced and also made more pleasant.

It is thus possible to assemble the cabinet simply by using plug and screw connections, since welding work, for example, can be done at the factory. This makes assembly at the place of use more advantageous.

If a number of independent appliances or groups thereof are in the same insert or a number of inserts are on the same tier then, according to a preferred embodiment of the invention, it is not necessary to provide a corresponding number of groups of vertical busbars, but the assembly unit in question can have a group of horizontal distribution bars disposed between the insert and the vertical busbars and each adapted to be connected by plugs to a busbar and to each independent appliance or each insert.

Another advantage of the invention is that the assembly unit can form the back wall of the insert space and the connection space, behind which the vertical busbars can extend, which in turn are in front of the leads. For example, the leads for a number of cabinets can be disposed in a back plane, the vertical busbars in a plane further to the front, and the assembly unit and horizontal distribution bars in a plane still further to the front.

Advantageously the distribution bars have rear plugs engaging the busbars and front plugs engaging the counter plugs of the inserts or individual appliances.

The invention will be described now by way of example only with reference to the drawings in which: Figure 1 shows part of a parallel projection of a cabinet disposed at the end of a row of cabinets; Figure 2 is a parallel projection of an assembly unit on a larger scale than in Fig. 1; Figure 3 is a partial plan view of a tier of a cabinet with two inserts, on the same scale as Fig. 2, and Figure 4 is a parallel projection on substantially the same scale as Figs. 2 and 3, showing the co-operative action of leads, busbars and distribution bars.

In the drawing the proportions may be distorted, for ease of drawing, and most parts, for simplicity, are shown in outline only.

Fig. 1 shows a cabinet comprising a vertical space 1 for receiving inserts adjacent a vertical space 2 for connections and separated therefrom by a partition 3 (shown by a broken line).

The back wall of spaces 1 and 2 is made up of assembly units 4, one of which is shown on a larger scale in Figs. 2 and 3.

Behind units 4 there is a busbar space 5 containing horizontal leads 6 and vertical busbars 7, shown in Figs. 3 and 4. As shown in Fig. 4 each lead 6 is connected to a busbar 7 at places 70. Each lead 6 and each busbar 7 corresponds to one of three phases of the unit power.

Fig. 4 shows four complete tiers 10, the top containing two inserts 11, the next from the top containing three inserts 12, the bottom containing one insert 13 and the next from the bottom containing four inserts 14.

With reference to Figs. 2, 3 and 4 the tier with two inserts 11 will be discussed.

Assembly unit 4 (Figs. 2 and 3) has a metal bearing plate 40 to which three distribution bars 42 are secured via spacers 41 (Fig. 3) made of insulating material. Plate 40 also bears two multiple plugs 43 connected at the factory by wiring 44 to terminals 45, 46 secured to plate 40 in the connecting part of unit 4. Terminals 45 provide a power output and are connected by wiring 44 to the interior of each plug 43.

As Fig. 3 shows, counter-plugs 430 of inserts 11 engage plugs 43 when the inserts are inserted as shown.

If there was only one insert on the tier in question there would be no need of bars 42 on unit 4, because the input power could be directly taken from bars 7 by plugs. In the present case, however, the tier has two inserts 11, each of which must be supplied with the input power. This is supplied to them by the distribution bars 42 which are disposed on plate 40 in the manner described. Accordingly, bars 42 each have a rear plug 420 which is plugged to a busbar 7 in the manner shown in Figs. 3 and 4 when unit 4 is inserted into the appropriate tier in the cabinet. Each bar 42 has a front plug 421 for each insert to be connected thereto. Plugs 421 are accessible in unit 4 behind windows 47 (Fig. 2) of plate 40, so that they can engage the counter-contacts 4210 (Fig. 3) of the inserts 11 when they are inserted.

The windows 47 for introducing the counter-contacts 4210 can have a known protection against electric shock hazard. An automatic protection device of this kind contains at least one protective slide (omitted from the drawings for simplicity) which, when an insert is inserted, opens window 47 for countercontact 4210, the window remains closed when the insert is removed.

Accordingly, each assembly unit 4 can be manufactured by wiring in the factory in accordance with the exact requirements of the particular tier and can then be secured ready for use in the cabinet by plugging contacts 420 into bars 7 and by screwing flanges 48 (Figs. 2 and 3) to parts 49 (Fig. 3) of the cabinet. It is then only necessary to put in the inserts, which will immediately be properly connected if suitably constructed. The cabinet can then be operated at the place of use, simply by connecting the output lines 50.

This avoids all the complicated, risky operations of wiring the plugs and terminals in known switching systems, which are mounted in the cabinet.

In addition to the advantage of more efficient work and lower risk of error in assembly at the factory, there is the advantage that, in factory assembly, production means can be used which are unsuitable or difficult in the case of wiring in a cabinet.

Claims (6)

1. A low-voltage electric switching system comprising a cabinet having a space for connections with terminals for the power output and the control current, adjacent a space containing inserts disposed in a number of tiers and bearing electric appliances and plugs at the back for the power input, the power output and the control current, counter-contacts for the power output and control currents, wired to the correspondingly named terminals, being disposed behind the inserts in the cabinet, and the device also comprising a three-phase group of vertical busbars for the power input, adapted to receive plugs, characterised in that the counter-plugs for the power output and the control current, the associated terminals and the corresponding wiring per tier, which can be produced in the factory, are disposed on a prefabricated assembly unit mounted in the cabinet.

2. An electric switching system according to claim 1, characterised in that at least one assembly unit is provided and also bears horizontal lead-in bars between the vertical busbars and at least one insert associated with the corresponding tier, the lead-in bars being connected by plugs each to a vertically extending busbar and to each insert on the same tier.

3. An electric switching system according to claim 1 or claim 2, characterised in that the assembly unit forms the back wall of the insert space and the space for connections.

4. An electric switching system according to any one of claims 1 to 3, characterised in that the distribution bars have rear plugs which each engage in a vertical busbar and front plugs co-operating with insert plugs.

5. An electric switching system according to any one of claims 1 to 4, characterised in that the cabinet is fitted together by means of screw and plug connections only.

6. An electric switching system substantially as hereinbefore described with reference to and as shown in the accompanying draw ings.