Description

The invention is related to a laminated busbar, comprising a base body composed of conducting layers and insulating materials to electrically insulate said conducting lay- ers from each other. .

Low voltage switchgear cabinets are commonly used as a housing of electrical components. Withdrawable modules or plug-in modules are commonly used to be connected with such cabinets.

Switchgear cabinets or sections are produced as single cabinets or sections and have to be connected electrically to do a switchgear line-up. The individual cabinets or sections have to be joint at the customer site. Also two separated laminated busbars may have to be connected electrically.

The object of the invention therefore is to ensure an easy arrangement of cabinets or sections and to realize a capable electrical connection of a laminated busbar with another conductor.

The object of the invention is achieved by means of the features of claim 1 .

According to this claim at least one conducting layer comprises a connection area which is free of insulating materials, whereas the said conducting layer has a bigger effective cross section in the connection area than in a sandwich area which is covered by an insulating material.

According to the invention the above mentioned laminated busbar can be used in- stead of a conventional busbar especially in a cabinet or section. To realize a capable electrical connection of two initially separated laminated busbars their conducting layers comprise connection areas. In those connection areas an effective cross section through which electrical current flows is increased.

A first conducting layer of a first laminated busbar may be connected electrically with a second conducting layer of a second laminated busbar in a capable manner. This can be done using a bridging element connecting both separated connection areas electrically. So a switchgear line-up is easily possible when laminated busbars are used. Neighbouring sections or cabinets can be connected electrically in a capable manner.

It was found that a laminated busbar is rated to a nominal current up to 6000 A and a short circuit current of 100 kA. A connection of laminated busbars of two cabinets or sections is adding additional resistance, which causes an increase of a conductor temperature during normal operation, but even more extreme in case of a short circuit.

The invention therefore describes an increasing of the effective cross section of the laminated busbar in its connection area to a neighboured section or cabinet. The increase of the effective cross section in a connection area will reduce the current density during short circuit and therefore the expected temperature rise will be reduced. Advantageously the conducting layer is folded in the connection area. A folding can be done without use of separate parts. A conducting layer has to be shaped only in a boundary area, namely in its connection area.

Further advantageously the bigger effective cross section is doubled or tripled relating to the smaller effective cross section in the sandwich area. A tripling, doubling or other multiplying of the effective cross section can be done by folding.

Advantageously the conducting layer is reinforced in the connection area by at least one strip. Strips or sheets can be added and so each thickness of the connection area can be adjusted according to the specific requirements. Preferably copper strips or sheets are added because the conducting layer is also made of copper.

Further advantageously at least one conducting layer has at least one pin to allow an electrical contact between the said conducting layer and a device. Hereby is ensured an easy arrangement of withdrawable modules or plug-in modules within a cabinet. The modules can be plugged on the pins and the laminated busbar can be designed as a replacement part. The laminated busbar can be designed according to the types and to the number of modules to be used.

Further advantageously the base body is formed like a wall and is flat. Hereby the busbar can be used as a protection or cover of a cabinet or within a cabinet.

A cabinet or section, comprising a housing, whereas the housing comprises at least a rear side, advantageously comprises a laminated busbar as mentioned above which is arranged on the rear side of the cabinet or section and/ or forms at least a part of a back wall of the housing. Thereby a cabinet or section can be covered by a laminated busbar. Advantageously the housing comprises a back wall which covers the laminated bus bar. Hereby the laminated bus bar is protected from unauthorized access.

Further advantageously the cabinet or section is a switchgear cabinet or section or is a low voltage switchgear cabinet or section. The cabinet or section advantageously comprises at least one module, in particular a low voltage switchgear module.

An arrangement, comprising two cabinets or sections as mentioned above, advantageously comprises at least one bridging element which connects the connection areas of the laminated busbars. Thereby two laminated busbars can be connected elec- trically.

A laminated busbar according to this invention may comprise insulating materials between the conducting layers, whereas the said insulating materials comprise separate prefabricated sheets and/ or whereas the insulating materials comprise a sub- stance which can be cast to form a solid block when the substance is cured. All the sheets may be composed of one substance or different sheets may be composed of different substances. The front side and the back side of the laminated busbar also may be insulated by insulating materials, namely by said sheets or by a substance which can be cast.

In the drawings:

Fig. 1 shows a laminated busbar comprising several conducting layers and sev- eral insulating sheets, whereas the conducting layers comprise pins, namely contact pins,

Fig. 2 shows above a connection area of a laminated bus bar in which the conducting layer is folded to double its effective cross section and shows be- low a connection area of the same laminated busbar in which another conducting layer is folded to triple its effective cross section, and

Fig. 3 shows schematically an arrangement of two cabinets which are connected electrically by a bridging element which grips two neighboured connection areas of two neighboured laminated bus bars and bridges a gap between them.

Fig. 1 shows a laminated busbar 1 ', comprising a flat base body 2 composed of conducting layers 3a-d and insulating materials 4a-c to electrically insulate said conduct- ing layers 3a-d from each other, whereas at least one conducting layer 3a-d has at least one pin 5a-d to allow an electrical contact between the said conducting layer and a device.

Fig. 1 shows an example of a laminated busbar 1 '. Fig. 1 also shows schematically one possible method to produce such a laminated busbar 1 '. Each conducting layer 3a-d has four pins 5a-d. Some of the conducting layers 3a-d and some of the insulating materials comprise spaces 6 or cavities 7 to allow a reach-through of a pin 5a-d. Further the spaces 6 or cavities 7 can be filled with a resin 8 to fix or mechanically connect conducting layers 3a-d and the insulating materials 4a-c. Each conducting layer 3a-d is a flat sheet and is current-carrying. Electrical current can be introduced by a pin 5a-d which is electrically connected with its associated conducting layer 3a-d. For example pin 5d is associated with conducting layer 3d.

Fig. 2 in extracts shows another example of a laminated busbar 1 . Fig. 2 shows a laminated busbar 1 , comprising a base body 2 composed of conducting layers 3c, 3d and an insulating material 4c to electrically insulate said conducting layers 3c, 3d from each other.

At least one conducting layer 3c, 3d comprises a connection area 18a, 18b which is free of insulating materials, whereas the said conducting layer 3c, 3d has a bigger effective cross section 19a, 19b in the connection area 18a, 18b than in a sandwich area 2a which is covered by an insulating material 4a-c.

The conducting layer 3c is folded in the connection area 18a. The bigger effective cross section 19a is tripled relating to the smaller effective cross section in the sandwich area 2a. The conducting layer 3d is folded in the connection area 18b. The bigger effective cross section 19b is doubled relating to the smaller effective cross section in the sandwich area 2a.

Fig. 3 shows that the base body 2 is formed like a wall and is flat.

Fig. 3 shows at least one cabinet 13, comprising a housing 14, whereas the housing 14 comprises at least a rear side 15. A laminated busbar 1 according to Fig. 1 or 2 is arranged on the rear side 15 of the cabinet 13. The cabinet 13 is a switchgear cabinet.

Fig. 3 shows an arrangement, comprising two cabinets 13, whereas at least one bridging element 20 connects the connection areas 18a of the laminated busbars 1 . A connection of laminated busbars with copper sheets with a thickness of a fraction of a millimeter to several millimeters, in particular of 0.5 - 5 mm between two sections or cabinets of a switchgear lineup is shown. The base body 2 is formed like a wall and is flat. The laminated busbar 1 is a 4 pole or may also be a 3 pole fully insulated sandwich of copper sheets with a thickness of a fraction of a millimeters to several millimeters, in particular of 0.5 - 5 mm thickness, with insulation sheets between the phases as well as on the front and back side. The conducting layers 3a-d of Fig. 1 insofar are copper sheets and the insulating materials 4a-c of Fig. 1 are insofar insulation sheets between the copper sheets. The laminated busbar 1 is equipped with contact pins 5a-d to allow a pluggable

connection to withdrawable modules or also plug-in modules.

Fig. 3 shows a cabinet 13, comprising a housing 14, whereas the housing 14 com- prises at least a rear side 15, whereas a laminated busbar 1 is arranged on the rear side 15 of the cabinet 13, whereas the said laminated busbar 1 , comprises a base body 2 composed of conducting layers 3a-d and insulating materials 4a-c to electrically insulate said conducting layers 3a-d from each other, whereas at least one conducting layer 3a-d has at least one pin 5a-d to allow an electrical contact between the said conducting layer 3a-d and a device.

The cabinet 13 comprises a module. A module described here may be embodied as a withdrawable module, a plug-in module or a fixed module or fixed device. The scope of the respective claim covers all the aforementioned embodiments of a mod- ule.

The cabinet 14 is a switchgear cabinet and is a low voltage switchgear cabinet. It is described a laminated main busbar system which is located at the back side or rear side 15 of a low voltage switchgear cabinet. The insulation of the laminated busbar 1 is forming the segregation to the module area. Since the laminated busbar 1 is fully insulated it is at the same time forming the segregation to a module.

Nevertheless Fig. 1 shows casting resin, the invention described here is not limited to casting. Embodiments of laminated busbars fabricated without casting are also pos- sible and are also kept in the scope of the claims.

All layers and insulating materials or sheets may be fixed and/ or coated by any possible mechanical or chemical method, especially with or without casting, with or without glueing or with or without epoxy coating.

Reference numbers