HV Switch Bushing Interference Fit Cost Reduction
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Solution Overview
Problem
Current medium or high voltage switches require costly materials like cycloaliphatic epoxy for bushings, making repair and replacement difficult, and there is a need for a switch that uses lower cost materials while meeting environmental and operational requirements.
Innovation Solution
A medium or high voltage switch design featuring a bottle assembly with contacts housed in a bushing, where the bottle assembly and bushing have an interference fit, allowing for the use of lower-cost materials and facilitating repair by providing a mechanical joint that does not rely on chemical bonding, using materials like high-density polyethylene and polyurethane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cycloaliphatic epoxy is used for the bushing, then the switch meets environmental and operational requirements, but the material cost increases and repair becomes prohibitively difficult
Solution Approach 1:
The bushing is divided into two separate components: an inner bushing component that interfaces with the interrupter and an outer bushing component that provides environmental protection. This segmentation allows each component to be optimized independently - the inner component can use materials compatible with the interrupter while the outer component uses cost-effective, environmentally resistant materials like polyurethane, thereby reducing overall material cost and enabling selective replacement during repairs.
Solution Approach 2:
A bonding agent or adhesive is introduced as an intermediary between the inner and outer bushing components. This intermediary allows the use of lower-cost materials in both components while maintaining the structural integrity and environmental sealing requirements previously achieved only with expensive cycloaliphatic epoxy, thus resolving the contradiction between material cost and reliability.
2Reliability
If the interrupter is mechanically installed in cycloaliphatic epoxy with polyurethane bonding, then the switch meets operational requirements, but the complexity of installation and repair increases
Solution Approach 1:
The bushing assembly is segmented into removable components with standardized interfaces. The inner bushing component can be independently removed and replaced without affecting the outer bushing component or requiring complete disassembly of the switch, thereby simplifying repair procedures while maintaining operational reliability through proper component design.
3Reliability
If costly materials like cycloaliphatic epoxy are used, then the switch meets environmental requirements, but the ease of repair deteriorates
Solution Approach 1:
The bushing is designed as separate components where the inner component containing the interrupter interface can be independently accessed and replaced. This eliminates the need to work with or replace expensive cycloaliphatic epoxy during routine interrupter repairs, significantly improving ease of repair while maintaining environmental protection through the outer bushing component.
Solution Approach 2:
The expensive cycloaliphatic epoxy material is extracted from the repair process entirely. Instead, lower-cost materials such as polyurethane are used in the outer bushing component that provides environmental protection without requiring expensive materials for routine maintenance operations, thereby improving ease of repair while maintaining environmental requirements.
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
The design reduces production costs, allows for easier servicing and repair of the switch, and maintains electrical integrity with a mechanical joint that is reversible, thus addressing the need for cost-effective and environmentally suitable solutions.
Implementation Method 1
The bottle assembly and the bushing have an interference fit
Data Source
AI summary
A medium or high voltage switch is provided. The medium or high voltage switch includes a bottle assembly and a bushing. The bottle assembly includes a bottle formed of a first material and defining a chamber. The bottle assembly further includes a plurality of contacts for selectively opening and closing an electrical circuit, the plurality of contacts disposed within the chamber. The bushing is formed of a second material and defines a cavity configured to receive the bottle assembly. The bottle assembly and the bushing have an interference fit.