Compact Bus Bar Assembly with Insulating Ribs for UL 489 Compliance
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Solution Overview
Problem
Existing power distribution systems with bus bar assemblies and switching devices face challenges in meeting the stringent creepage distance and air gap requirements of UL 489 standards while maintaining compact dimensions, leading to larger footprints and increased space requirements.
Innovation Solution
A compact bus bar assembly with electrically conductive tracks covered by an insulating cover featuring ribs that extend the creepage distance without increasing terminal length, combined with a switching device having collars with ribs to enhance insulation and reduce overall dimensions, allowing compliance with UL 489 standards while minimizing footprint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional bus bar assemblies are designed to meet UL 489 creepage distance and air gap requirements, then safety compliance is improved, but the footprint and overall dimensions increase significantly
Solution Approach 1:
The bus bar assembly transitions from a planar arrangement to a three-dimensional configuration by stacking conductive tracks vertically within the insulating material. Multiple conductive tracks are arranged in different levels (first level, second level, third level) along the longitudinal axis, allowing creepage distance requirements to be met through vertical separation rather than horizontal spacing, thereby reducing the footprint.
Solution Approach 2:
The conductive tracks are nested within the insulating material, with each conductive track embedded in the insulating substance. The insulating material completely surrounds and embeds the conductive tracks, creating a compact nested structure where the insulation provides both mechanical support and electrical clearance, eliminating the need for separate clearance structures.
2Reliability
If independent adapter units with insulating elements are added to meet clearance requirements, then electrical insulation is improved, but the dimension across the bus bar assembly increases
Solution Approach 1:
The insulating material and conductive tracks are merged into a single integrated component. The insulating material is formed as one piece that completely surrounds and embeds the conductive tracks, eliminating the need for separate adapter units or independent insulating elements. This integration allows the bus bar assembly to meet clearance requirements without increasing the dimension across the assembly.
3Reliability
If larger spacing between terminals of opposite polarity is provided to meet UL 489 requirements, then compliance with stringent standards is improved, but the overall device size and fabrication costs increase
Solution Approach 1:
The design moves from horizontal spacing to vertical stacking to achieve required creepage distances. Conductive tracks are arranged in multiple levels (first level, second level, third level) separated by insulating material, allowing compliance with UL 489 spacing requirements while maintaining a compact horizontal footprint and reducing overall device volume.
Solution Approach 2:
The bus bar assembly uses a composite structure combining conductive tracks (copper or aluminum) with insulating material (thermosetting or thermoplastic resin). This composite construction allows the insulating material to provide both mechanical support and electrical clearance, enabling compact design that meets stringent UL 489 requirements without increasing device volume.
Data Source
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AI summary
The present invention relates to a contact bus bar assembly for supplying power to a load, and further pertains to a switching device which can be connected to such a compact bus bar assembly, and to a power distribution system The bus bar assembly comprises at least two electrically conductive tracks which are at least partly covered by an electrically insulating cover (108), said electrically conductive tracks each comprising at least one output terminal (106) to be connected to said load, wherein said output terminals (106) are formed as pin terminals having an electrically insulating sleeve (110) formed from the electrically insulating cover (108) and partly covering said terminals. An outer surface of said insulating cover (108) is provided with a plurality of ribs (112) arranged in a region connecting said pin terminals(106). The switching device may additionally comprise separating element (116) provided with a plurality of second ribs (118).