Angled Stabs for Busway Plug-in Units
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Solution Overview
Problem
Current busway systems face challenges in meeting Underwriters Laboratories (UL) clearance requirements for uninsulated stabs, which often necessitate labor-intensive and expensive epoxy insulation, and can result in uneven thickness and cracks, especially around corners and bends.
Innovation Solution
The busway system incorporates angled uninsulated stabs with an insulation sheet to achieve the required clearances, eliminating the need for costly epoxy insulation and allowing retrofitting to existing equipment without redesigning jaw locations, while improving thermal efficiency by eliminating air gaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If epoxy insulation is applied on all surfaces of the busbars to meet UL clearance requirements, then the insulation reliability is improved, but the manufacturing complexity and cost increase significantly
Solution Approach 1:
The patent extracts the insulation function from the busbar surface coating and relocates it to separate insulation sheets positioned between adjacent busbars. This eliminates the need for complex epoxy coating processes on all busbar surfaces while maintaining the required insulation reliability.
Solution Approach 2:
The patent introduces insulation sheets as intermediary elements between adjacent busbars. These sheets serve as the insulation medium, separating the electrical conductors and meeting UL clearance requirements without requiring the busbars themselves to be coated with insulation material.
2Reliability
If epoxy insulation is applied to meet UL clearance requirements, then the insulation reliability is improved, but the manufacturing time and cost increase
Solution Approach 1:
The insulation sheets are pre-cut and prepared before assembly, with insulation flanges already formed to the correct dimensions. This preliminary preparation eliminates time-consuming on-site insulation application processes and allows for rapid assembly of the busway system.
Solution Approach 2:
The patent uses simple, inexpensive insulation sheets that can be quickly installed and replaced if necessary, rather than investing in complex, time-consuming epoxy coating processes. The insulation function is achieved through simple dielectric materials that meet the clearance requirements.
3Reliability
If epoxy insulation is applied on busbar surfaces, then the insulation reliability is improved, but the manufacturing precision deteriorates due to cracks and uneven thickness
Solution Approach 1:
The patent extracts the insulation function from the busbar surface and places it in separate, pre-manufactured insulation sheets. This eliminates the manufacturing precision problems associated with applying uniform epoxy coatings on complex busbar geometries, as the insulation sheets are manufactured separately with controlled dimensions.
Solution Approach 2:
The insulation sheets are positioned only where needed between adjacent busbars, providing localized insulation exactly where the UL clearance requirements are needed. This avoids the complexity of coating entire busbar surfaces and allows for precise placement of insulation material.
4Ease of manufacture
If standard vertical stabs are used in busway plug-in units, then the manufacturing simplicity is maintained, but the UL clearance requirements cannot be met
Solution Approach 1:
The patent angles the stabs relative to the busbar length rather than having them perpendicular. This asymmetric configuration allows the stabs to be positioned such that they clear the insulation sheets and housing, meeting UL over-surface and over-air clearance requirements while maintaining simple manufacturing processes.
Solution Approach 2:
The patent resolves the clearance issue by changing the angular dimension of the stabs rather than increasing the horizontal spacing. By angling the stabs, the vertical clearance over the housing surface is increased, meeting UL requirements without complicating the manufacturing process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration ensures compliance with UL clearance requirements, reduces costs and assembly complexity, and enhances thermal efficiency by direct heat conduction, resulting in significant copper savings and improved system performance.
Implementation Method 1
enhances thermal efficiency by direct heat conduction
Data Source
AI summary
A busway system includes a plurality of busbars arranged in a flat stacked configuration. The system further includes at least one uninsulated stab having a base in direct contact with one of the busbars at a first length portion of the busbars. The stab also has a tip extending away from the base and angled at the length of the busbars such that the tip is positioned at least in part at a second length portion of the busbars. The stab is insulated from other stabs via one or more of a MYLAR® sheet and a wall of a plug-in opening base.