Busbar Connection Device with Flexible Dielectric Shielding

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Solution Overview

Problem

The connection interface between a bar and a bushing in electrical switching devices is prone to premature damage due to ionization from electric fields and exposure to pollutants, leading to accelerated aging, especially in polluted environments, and existing solutions do not facilitate the installation of additional devices like dividers or capacitors.

Innovation Solution

A connection device with a conical and flared bushing design, featuring a conductive deflector overmolded with flexible material, which provides a snap-fastening mechanism for capacitive or resistive dividers and capacitors, ensuring dielectric sealing and resistance to aging without requiring specific bushing profiles, and allowing for the installation of additional devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a deflector and sheathing are provided to protect the triple point, then dielectric performance is improved, but the bars are exposed to accelerated aging in polluted atmospheres

Engineering Contradiction:
Improvedielectric performanceVSAvoidaccelerated aging of bars
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies a flexible silicone rubber sheath that completely encloses the bar at the connection interface, creating a protective barrier against polluted atmospheres. This flexible shell design allows for effective sealing while accommodating thermal expansion and contraction, preventing accelerated aging of the bar in harsh environments while maintaining dielectric performance.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The invention uses composite material construction combining the conductive bar, insulating deflector, and flexible silicone rubber sheath. This multi-material approach creates a layered protective structure where each material performs its specific function: the deflector provides initial dielectric protection at the triple point, while the silicone rubber sheath provides environmental sealing, together preventing both dielectric breakdown and accelerated aging.

Inventive Principle:
Principle #40Composite materials

2Reliability

If a sleeve with opening closed by plug is used to mask access to electrical connection, then dielectric performance is improved, but the profile must be adapted to the bushing making it less versatile

Engineering Contradiction:
Improvedielectric performanceVSAvoidadaptability to different bushing profiles
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The flexible silicone rubber sheath design provides universal adaptability to different bushing profiles without requiring custom-matched components. The material's flexibility and elastic properties allow it to conform to various bushing geometries, eliminating the need for profile-specific sleeve designs while maintaining effective dielectric protection and environmental sealing.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention utilizes the changeable physical parameters of silicone rubber, particularly its flexibility and elastic recovery, to create a universal fitting solution. The material can be compressed during installation to fit different bushing profiles, then returns to its original shape to provide consistent protective performance across various configurations.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If existing connection devices are used, then simple connection is achieved, but installation of additional devices such as dividers and capacitors is not facilitated

Engineering Contradiction:
Improveconnection device simplicityVSAvoidinstallation of additional devices
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The connection device is segmented into distinct functional zones: the deflector for dielectric protection, the silicone rubber sheath for environmental sealing, and the integrated mounting structure for additional devices. This segmentation allows the basic connection function to remain simple while providing dedicated spaces and attachment points for dividers, capacitors, and other auxiliary components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The design enables nesting of additional devices within or alongside the connection structure. Dividers, capacitors, and measurement devices can be installed within the bushing or attached to the external structure, creating a nested configuration where the simple connection device serves as the base structure and additional functionality is layered upon it.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 solution enhances dielectric resistance to aging in challenging environments by providing effective dielectric sealing and screening, facilitating the installation of additional devices without modifying existing equipment, and maintaining compact shapes while ensuring standardized pressure distribution and heat evacuation.

Implementation Method 1

a deflector (4) forming a conductive screen, placed around the connection zone (5)

Methodology Applied
Scientific EffectElectric field screening: Faraday Cage

Implementation Method 2

said deflector (4) being overmolded with a flexible material over substantially all of its outer surface

Methodology Applied
Scientific EffectDielectric insulation: Dielectric

Implementation Method 3

the aforementioned flexible material is an elastomer or a TPE, for example silicone or EPDM

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP2333801B1Device for the electrical connection of a busbar with an isolated electric feedthrough to a circuit breaker
Publication Date: 2016.05.04 SCHNEIDER ELECTRIC IND SAS
  • EP2333801B1 patent drawingFigure 1
  • EP2333801B1 patent drawingFigure 2
  • EP2333801B1 patent drawingFigure 3

AI summary

The device has a screw (10) with a screw head (10a) that is in support against a part (4b) of a deflector (4), after screwing of the screw in a conductive insert (3). The deflector is interposed between the screw head and an end part (2a) of a bar (2), where the end part of the bar is in support against an end part of the insert. An edge of an upper part (6b) of a sleeve (6) is bent towards an axis (Y) of the sleeve and towards the interior of an electrical cut-off apparatus along a surface of the deflector, to form a tubular opening (7) allowing the passage of the screw head.