EP0757367B1

EP0757367B1 - Switching system with terminal modules

Info

Publication number: EP0757367B1
Application number: EP19960202024
Authority: EP
Inventors: Jan Willem Hoekstra; Hilbert Gezienus Knol
Original assignee: Holec Holland NV
Current assignee: Danfoss Power Solutions II BV
Priority date: 1995-07-31
Filing date: 1996-07-16
Publication date: 2001-03-14
Anticipated expiration: 2016-07-16
Also published as: NZ299084A; AU6067396A; AU719989B2; DE69612043D1; NO963182D0; DE69612043T2; DK0757367T3; EP0757367A1; ES2154781T3; NO963182L; NO315015B1; NL1000906C2

Description

The invention relates to a switching system, in which in each case a number of switch elements are combined in a switch module having a predetermined power input side and power output side,provided with input and output terminals of the switch elements.
Such a switch system is known from EP 0 219 570. This system comprises a switch module having three switch elements and a terminal module. The switch module has an input side and an output side provided with terminals for connecting the switch elements. The terminals could be connected to incoming and outgoing leads by means of clamping devices in the terminal module, said devices pressing the switch elements terminals to the associated leads.
It is generally known that a switching system is housed in a switchbox, the switch elements of the switching system being grouped in switch modules. This is employed, for example, in a switchbox for supplying power to an installation. In this case the switch elements are switch contacts which comprise at least a fixed and a movable contact, or cartridges or a combination thereof, although the invention is suitable for any type of switch element. For three-phase power supply, for example, the switch contacts for the R, S and T phases are combined in a group or switch module, optionally supplemented by the neutral conductor. The switch contacts are placed in the switch module with their main directions parallel to one another, so that, in general, the location of the input and output sides of the module is determined by the orientation of the switch contacts and the location of the terminals thereof. In general, therefore, the incoming leads and outgoing leads will be located in the extension of one another and run parallel to or in line with the main direction of the switches.
It has been found that customers have a requirement to produce connections which are not in line with the main direction of the switch contacts but where, for example, the input and/or output cables or rails run perpendicular to the said main direction. With this arrangement the power input and/or power output side is not in the vicinity of the terminals of the switch contacts, whilst the plane thereof is also not perpendicular to the main direction of the switch contacts but can run parallel thereto. In this case, when the cables, which in the case of high currents are of large diameter, are installed they must be bent between the power input and/or power output side and the terminals of the switch contacts so that the cable lugs fixed to the ends of the cables can then be fixed on the appropriate terminals of the switch contacts. The connections here are at 90°.
The problem with this arrangement is that installation can not always be carried out equally easily, whilst, moreover, in the case of thick cables a great deal of space is lost because of the unavoidable large radii of curvature of the bends in the cables. Arranging the switch module turned through 90° could provide a solution. However, this is also associated with the disadvantage of loss of space in the lengthwise direction of the switchbox. Furthermore, the heat balance of the switch module is adversely affected as a consequence of the switch contacts running above one another, as a result of which a lower nominal current is permitted in the switch module (so-called derating).
The aim of the invention is to provide a switching system of the type mentioned in the preamble, with which a flexible choice of the position and orientation of the input and/or output side is possible and installation work is simplified. Furthermore, the aim is for as complete as possible utilisation of the available space in the switchbox and of the nominal load of the switch module.
Said aims are achieved according to the invention in that a connection module is added to the switch module which connection module has four sides, each side being arranged for receiving terminals for connecting incoming and outgoing leads and that the connection module is provided with connecting conductors for connecting the input and/or output terminals of the switch module to the terminals provided on at least one of the sides of the connection module.
By this means it is possible to produce both connections which are in line with the main direction of the switch elements and connections at 90°. Because the switch module is provided with connecting conductors, said module can be regarded as an adapter, by means of which the desired connection can be produced, that is to say the normal connections to the switch elements can be brought to the desired position via the adapter. For a so-called 90° connection, only three connecting conductors are needed for a three-phase power supply.
For the manufacturer, the invention has the advantage that the production line is simplified because fewer components are needed. Stocks can be reduced because one switch module can be used with one connection module in several terminal configurations and there is therefore no need to keep a separate switch module in stock for each individual configuration.
The invention also offers the advantage of simple assembly because only the connection module has to be adapted for a specific terminal configuration.
For the user or installer, the invention has the advantage that connection is simplified by the freedom in the direction of connection. Moreover, the required space for non-standard connection directions is reduced and no derating has to be employed. An additional factor is the reduction in price as a result of modularity and, consequently, the less expensive production and stockholding.
The European patent application 0 188 258 discloses a switch housing or module having terminals for connecting cables. The connection of a side termination is possible by bending the terminal connections. As it appears from figure 10 the terminal connection 77, 78 and 79 are provided at one side of the switch housing. These terminal connections are floating, because of which there is a risk of short circuit between said connections. Furthermore, if as usually, thick cross sections are required for passing high currents, additional space is required at one side of the switch housing for the bending of the terminal connections.
Please note that this prior art switch housing has no connection module, so that the terminal connections are floating. A further difference should be seen in the position of the conductors of the connection module according to the invention. The conductors of the connection module according to the invention are bent in the space under the switch housing and such that the plane of bending remains within the respective dimension of the switch housing.
From the British patent 529,968 a T-shaped contact for a distribution pillar is known. Two kinds of T-shaped contacts are suggested, one having a downwards extending socket for receiving an electrical connection of a cable and the second one having an upwards extending socket. Because the T-shaped contact is reversible four positions of the sockets, left downward, left upward, right downward and right upward are possible. This flexibility has nothing to do with the situation as described in the present patent application with switch elements and the connection with cables or busbars running perpendicular thereto.
The French patent application 2,353,946 relates to connection members 30, 32 on the support 16 of a switch 10. By positioning the connecting members perpendicular mounting directions are possible, however, both directions are in the plane of the switch 10, in particular one of the directions is downwards . Also in this prior art solution no connection module is used.
The connecting conductors can be insulated cables, but preferably the connecting conductors are in the form of electrically conducting connecting bars. Said bars can be of circular or rectangular cross-section and can be manufactured in the factory, it being possible to apply an extensive degree of standardisation. The aim of said standardisation is to select the shape of the conductors in such a way that a minimum number of standard conductors can suffice. The conductors to be used can be chosen in accordance with the requirements of the customer and fitted in the connection module. At the time of installation all that is then necessary is to connect the cables to the connection and/or switch module, without bending being necessary.
In this context it is advantageous that the connection module has a housing of insulating material and the connecting bars are arranged on the base of the connection module housing, electrically insulated from one another.
Preferably, the base of the connection module housing is provided with an upright partition of insulating material, by which means the base is divided into two regions, it being possible for the connecting conductors running essentially perpendicular to the main direction of the switch elements to the associated power input or power output side to be arranged in the one region and for the connecting conductors to the opposite side to be arranged in the other region. By this means a symmetry is obtained, as a result of which the same connecting conductors can be used for both sides, with the advantage of yet more extensive standardisation and reduction in the number of different connecting conductors in stock.
In order to obtain an arrangement of the connecting conductors which is as compact as possible and in which, at the same time, the conductors are reliably electrically insulated from one another, the base of the connection module housing is provided with a number of upright partitions of insulating material to form channels in which connecting conductors can be laid.
In a further embodiment, the connection module is provided with terminal modules on the power input and the power output side.
As a consequence it is possible to dispense with the use of cable lugs, as a result of which the terminal points, especially in the side at 90° to the main direction of the switch contacts, can be placed closer together, so that the so-called fill factor in a panel of a switchbox increases by 40 %. On the other hand, by using a specific type of terminal module, a simple and rapid electrical connection can be produced by plugging into, for example, a rail system.
In a further development of the invention, at least one of the terminal modules consists of a screw terminal module for clamped connection of a connecting conductor and corresponding cable conductor. A preferred embodiment of the screw terminal module comprises an outer housing inside which an electrically conducting inner housing is movably accommodated, the distance of movement being greater than the thickness of the connecting conductor and a plate, which is movable in the same direction as the inner housing by means of a screw which is supported in the outer housing and can be screwed in and out, being accommodated in the inner housing for simultaneously clamping a cable conductor between the plate and the wall of the inner housing facing said plate.
When one or more switch elements have to be connected to a power rail, it is advantageous that the associated terminal modules are made up of a plug terminal module for connecting the switch element or a connecting conductor to the power rail. To this end, the plug terminal module can be a spring contact which engages around the rail, but the plug terminal module is preferably accommodated in a housing of insulating material which is a snap fit on a wall of the connection module and in which knife or scissor contacts are located for accommodating the power rail between them in a clamping manner.
The invention will be explained in more detail below with reference to the drawings, in which:
Figs 1a-1f show, diagrammatically, the possible terminal configurations for the connection module according to the invention;
Fig. 2 shows a side view of a switching system according to the invention;
Fig. 3 illustrates a bottom view of the embodiment in Fig. 2;
Fig. 4 shows a side view of another embodiment of the invention;
Fig. 5 is a bottom view of the embodiment in Fig. 4;
Fig. 6 illustrates yet a further embodiment of the switching system according to the invention;
Fig. 7 is a bottom view of the embodiment in Fig. 6;
Fig. 8 shows an embodiment of a plug terminal module according to the invention;
Fig. 9 shows a preferred embodiment of a plug terminal module according to the invention;
Fig. 10 shows the embodiment in Fig. 8 with dismantled components;
Fig. 11 shows a screw terminal module according to the invention.
The switching system comprises switch elements, of which in each case a number, in general three, are combined or grouped to form a switch module. The switch elements can be, for example, switch contacts, cartridges, a combination thereof or other elements having a switch function.
The invention will be described below with the aid of embodiments which contain switch contacts for a three-phase switching system. A system of this type comprises the switch contacts for the phases R, S and T, the switch contacts of which are, for reasons of clarity, not shown in Figures 1a-1f. However, the terminal points R1, R2, S1, S2, T1 and T2 of the switch contacts of the three-phase system are shown. The switch contacts are combined to form a switch module of three sets of switch contacts, to which a connection module 1 has been added.
The main directions of the switch contacts in Figures 1a-1f are in the direction of R1-R2, etc. When, as in Fig. 1a, the terminal points L1a, L2a and L3a of the cables have to be made in line with the main direction of the switch contacts, few problems are experienced in practice. However, in practice it has been found that customers purchasing the switching system, and installers, have a requirement not only for the conventional connections which are in line with the main direction of the switch contacts but also for a facility for making connections which are not in line with, but at an angle of, for example, 90° to the said main direction. Examples of the latter are shown in Figs 1b-1f.
In Fig. 1b the terminal points L1b, L2b and L3b shown at the bottom of the connection module 1 are in line with the main direction of the switch contacts. Said terminal points are located, for example, on the power input side. The power output side is in this case on the left side of the connection module 1. The terminal points L1a, L2a and L3a of said power output side are connected, by means of the connecting conductors 2, which are drawn diagrammatically and in broken lines, to the respective terminal points R1, S1 and T1 of the switch contacts. In Fig. 1c the terminal points L1a, L2a and L3a of, for example, the power input side are shown at the top of the connection module 1 and are connected to the terminals R1, S1 and T1 of the switch contacts. In Fig. 1c the terminal points L1b, L2b and L3b of the power output side, which are connected to the terminals R2, S2 and T2 of the switch contacts, are arranged on the right-hand side of the connection module 1. The connecting conductors 2 between the terminals R2, S2 and T2 of the switch contacts and the terminal points L1b, L2b and L3b of the power output side on the right-hand side of the switch module have been drawn in broken lines. In Fig. 1d both the power input side and the power output side have been chosen such that they are at 90° with respect to the main direction of the switch contacts. In this case also, the connecting conductors 2 are shown in broken lines. It is pointed out that the power input side can be the power output side, and vice versa.
The connection module 1 is to be regarded as an adapter. As a result of the use thereof, the direction of connection can be freely chosen when connecting a switching system in a switchbox, without the cables which have to be connected for the various phases having to be bent or the switching system having to be turned. Furthermore, a saving in space is achieved because no account has to be taken of the size of the radii in the bends of the cables. The connection module is thus a highly advantageous solution with which both connections in line with a main direction of the switch contacts and connections at 90° are possible without any problem. The switch module also has the abovementioned advantages for the manufacturer and the user, as well as for the installer and/or customer.
The neutral conductor is not shown in Figs 1a-1f and it is clear that more configurations are possible with said neutral conductor, and especially when the sequence of the connections L1, L2 and L3 can be changed, as can be seen from Figures 1e and 1f.
Figs 2 and 3 show an embodiment of a part of a switching system according to the invention. Said part consists of a switch module 3, in which the switch contacts 4, 5 and 6 for the three-phases have been combined or grouped. The switch contacts 4, 5 and 6 have been arranged with their main directions parallel to one another. The connecting conductors for the connection of the terminals R2, S2 and T2, which are located on one side of the switch contacts 4, 5 and 6, to the power side 8 are shown as pre-formed connecting strips 9, 10 and 11. However, said conductors can also be cables or connecting conductors having a circular cross-section. Said connecting strips 9, 10 and 11 are arranged such that they are insulated from one another, for example by means of air, on the base of the connection module 1 made of insulating material and are fixed to said base by screws 30. The connection module 1 has two side walls 12 and 13, but can also have a side wall on the remaining sides. The base of the connection module 1 is provided with a partition 14 made of insulating material, which runs diagonally and has been cast as an integral whole with the connection module 1. Said partition 14 divides the base into two regions. The partition 14 is to be regarded as a plane of symmetry of the connection module 1. The effect achieved by introducing symmetry is that when it is desired that the power side 7 is not at the top of the connection module 1 in Fig. 3 but at the right-hand side, connecting conductors of the same shape as the connecting conductors 9, 10 and 11 can be used for the connection to the terminals of the switch contacts at the other side thereof. In this context reference is made to Fig. 5. The number of different connecting conductors has been reduced as a result of this measure, which is advantageous from the standpoint of production engineering and for stockholding.
In the embodiment in Figs 2 and 3, the upper terminals of the switch contacts 4, 5 and 6 have been fed to the outside via short terminal strips outside the wall 12 of the connection module 1. Terminal modules 18, 19 can be arranged at the end of said short terminal strips 15, 16, 17. Connection of the cable ends to the terminal strips 15 and 16 is effected by means of the screw terminal modules 18 and 19. Connection of a cable to the terminal strip 17 can be effected by means of a cable lug and screw. Of course, the screw terminal modules 18 and 19 are preferable to said cable lug and screw connection.
The free ends of the connecting strips 9, 10 and 11 are likewise provided with terminal modules 20, 21 and 22. Because cable lugs in general take up a great deal of space, an appreciable saving in space is achieved by the use of the terminal modules in which the exposed cable ends can be connected directly to the strips, because said narrow side 8 of the connection module 1 does not have to be made wider.
Should it be desired that the power side 8 must be at the opposite side of the switch contacts, it will be possible to use the same connection module 1, it then being possible to turn the connection module 1 through 180° with respect to the switch contacts.
Figs 4 and 5 show an embodiment in which both the power input side and the power output side are oriented in a direction perpendicular to the main direction of the switch contacts 4, 5 and 6 of the switch module 3. In Fig. 5 the connecting strips 9, 10 and 11 for connecting the terminals R2, S2 and T2 of the switch contacts 4, 5 and 6 to the terminal modules 20, 21 and 22 are shown on the power input side 8 of the connection module 1. For the power output side 7, the connecting strips 23, 25, 26 are arranged on the base of the connection module 1, one end of said strips being connected to the associated terminals R1, S1 and T1 of the switch contacts, whilst the free ends thereof are provided with the terminal modules 27, 28 and 29. The connecting strips 9, 10 and 11 are fixed to the base of the connection module 1 by means of screws 30, and the connecting strips 23, 25 and 26 are fixed to the base of the connection module 1 by means of screws 31. The connecting strips 9/26, 10/25 and 11/23 are identical to one another and the latter are electrically insulated from one another with the aid of the partition 14, instead of by means of air.
A further embodiment of the invention is shown in Figs 6 and 7. In this case also the switch contacts 4, 5 and 6 are combined to give a switch module 3, to which a connection module 1 has been added. The base of said connection module 1 is provided with partitions 32 to 36, as a result of which the connecting strips can be placed closer together and the whole is kept more compact. Symmetry is maintained in this embodiment as well, so that the number of different connecting strips has been restricted to a minimum, i.e. three. The connecting strips 23, 25 and 26 are connected at one side to the terminals R1, S1 and T1 of the switch contacts 4, 5 and 6 at one side thereof, whilst the free ends of said connecting strips are provided with the terminal modules 27, 28 and 29. The strips 23, 25 and 26 are fixed to the base of the connection module 1 by means of screws 31. The effect achieved by the use of the partitions 32, 33 and 34 of insulating material is not only a more compact construction, but also that the connecting strips are never able to make contact with one another even when subjected to rough treatment, whilst the position of the connecting strips is also more or less fixed at the time of assembly.
The embodiment shown in Figs 6 and 7 is particularly suitable for connecting the terminals of the switch contacts on one side to associated rails. For this purpose terminal modules 37, 38 and 39 are used, which are slid onto the wall 13 and fixed thereto by means of, for example, a snap fitting connection. The modules 37, 38 and 39, which are constructed as plug terminal modules, clamp around the rails and provide the electrical connection between the rails and the terminals R2, S2 and T2 of the switch contacts.
Fig. 8 shows a possible embodiment of a plug terminal module 56. Said module 56 comprises the contacts 57 and 58 for clamping around a rail. The clamp contacts 57 and 58 merge into a body 59 which has the flat parts a, b and c. The body 59 is connected to the lip 61, in which there is a hole 60 which serves for connection to a terminal point of an associated connecting strip of the connection module or a terminal point of the associated switch contact.
Said plug terminal module can be arranged or fixed directly on the connection module. However, said fixing can also take place by means of a block 62 made of insulating material, which is provided with snap fitting elements, which are not shown, which interact with snap fitting elements of the connection module, which likewise are not shown. The flat parts a, b and c of the body 59 fit in recesses 63, intended for this purpose, in the block 62.
In Fig. 9 a preferred terminal module is shown with a partially cut-away housing and in Fig. 10 said module is shown with disassembled components.
The plug terminal module 37 comprises a housing 40, preferably made of insulating material. A metal base plate 41, which is provided with a disc 42, is located in the housing. The base plate 41 is also provided with a strip 43, by means of which a terminal of a switch contact can be connected. The knife or scissor contacts 45 and 46 are held in a predetermined position by means of a resilient element 44, the distance between the free ends of the knife contacts 45 and 46 being less than the thickness of the rail to be inserted between them. When the rail is pushed between the knife contacts 45 and 46, said knife contacts 45 and 46 bear against the rail under pretension. The housing 40 of said plug terminal module is also provided with a recess 47 for sliding said housing on the wall of a connection module, in which recess snap fitting elements, which are not shown, are located which interact with snap fitting elements on the wall of the connection module 1.
Fig. 11 shows a terminal module in the form of a screw terminal module. Said screw terminal module consists of a metal outer housing 48, inside which an electrically conducting inner housing 49 is movably accommodated. The inner housing 49 can be moved inside the outer housing 48 over a distance which is greater than the thickness of the associated connecting strip, so that the connecting strip 52 fits in the gap between two opposing walls 53, 54 of the outer and inner housings. A movable plate 50 is located in the inner housing 49. The plate 50 can be moved in the inner housing 49 by means of the screw 51. When the connecting strip has been accommodated between the walls 53, 54 of the outer and inner housings respectively and an exposed cable conductor 55 has been brought between the plate 50 and the opposing wall 54 of the inner housing 49, the connecting strip and the end of the cable conductor are clamped simultaneously by tightening the screw 51, an excellent electrical connection between end 55 of the cable conductor and connecting strip 52 being produced, which takes up little space.

Claims

Switching system, in which in each case a number of switch elements are combined in a switch module having a predetermined power input side and power output side, provided with input and output terminals (R1,S1,T1 respectively R2,S2,T2) of the switch elements, characterised in that a connection module (1) is added to the switch module, which connection module has four sides, of which two sides opposite to each other extend parallel to the power input and output sides and the remaining two sides extend perpendicular to the input and output sides of the switching module, that each side of the connection module being arranged for receiving terminals (L1a,L2a,L3a) respectively L1b,L2b,L3b) for connecting incoming and outgoing leads and that the connection module is provided with connecting conductors (2) for connecting the input and/or output terminals (R1,S1,T1 or R2,S2,T2) of the switch module to the terminals provided on at least one of the sides of the connection module.
Switching system according to Claim 1, characterised in that the connecting conductors (2) are in the form of electrically conducting connectors.
Switching system according to Claim 2, characterised in that the connection module comprises a housing of insulating material and in that the connectors are formed by rectangular connecting strips (9, 10, 11, 23, 25, 26) which are arranged on the base of the connection module housing, insulated from one another.
Switching system according to one of Claims 1, 2 or 3, characterised in that the base of the connection module housing is provided with an upright partition (14), by means of which the base is divided into two regions, it being possible to arrange the connecting conductors to the one power input or power output side in the one region and the connecting conductors to the opposite side in the other region.
Switching system according to one of Claims 1, 2, 3 or 4, characterised in that the base of the connection module housing is provided with upright partitions (33, 34, 35, 36) of insulating material to form channels in which the connecting conductors (23, 25, 26) can be laid.
Switching system according to one of Claims 1-5, characterised in that the connection module is provided with terminal modules (18-22) at the power input and/or power output side.
Switching system according to Claim 6, characterised in that one or more of the terminal modules is a screw terminal module (18-19) for clamped electrical connection of a connecting conductor to a corresponding cable conductor.
Switching system according to Claim 7, characterised in that the screw terminal module has an outer housing (48) inside which an electrically conducting inner housing (49) is movably accommodated, the distance of movement being greater than the thickness of the connecting strip (52), and in that a plate (50), which is movable in the same direction as the inner housing (49) by means of a screw (51) which is supported in the outer housing (48) and can be screwed in and out, is accommodated in the inner housing (49) for simultaneously clamping a cable conductor (55) between the plate (50) and the wall of the inner housing (49) facing said plate.
Switching system according to one of Claims 6, 7 or 8, characterised in that one or more of the terminal modules is a plug terminal module for connecting a switch element or connecting conductor to a power rail.
Switching system according to Claim 9, characterised in that the plug terminal module has a housing of insulating material which is a snap fit on a wall of the connection module and in which contacts are arranged for clamping the power rail between them.
Switching system according to one of the preceding claims, characterised in that the connection module has a housing of insulating material and in that the connecting conductors are arranged on the base of the connection module housing, insulated from one another.
Switching system according to Claim 11, characterised in that the base of the connection module housing is provided with an upright partition, by means of which the base is divided into two regions, it being possible to arrange the connecting conductors to the one power input or power output side in the one region and the connecting conductors to the opposite side in the other region.
Switching system according to Claim 11 or 12, characterised in that the base of the connection module housing is provided with upright partitions of insulating material to form channels in which the connecting conductors can be laid.
Switching system according to one of the preceding claims, characterised in that the terminals are provided by screw terminal modules having an outer housing inside which an electrically conducting inner housing is movably accommodated, the distance of movement being greater than the thickness of the connecting strip, and in that a plate which is movable in the same direction as the inner housing by means of a screw which is supported in the outer housing and can be screwed in and out, is accommodated in the inner housing for simultaneously clamping a cable conductor between the plate and the wall of the inner housing facing said plate.
Switching system according to one of the preceding claims, characterised in that the terminals are provided by plug terminal modules having a housing of insulating material which is a snap fit on a wall of the connection module and in which contacts are arranged for clamping the power rail between them.