Roll-Element Switch Layout for Arc Extinction During Opening

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Solution Overview

Problem

Existing electrical switches are ineffective in extinguishing electric arcs during the opening event, leading to potential harm and prolonged conductivity issues.

Innovation Solution

An electrical switch design featuring a movable contact with contact portions on opposite sides of a center plane, an isolator system, and an arc extinguisher plate system to create a large clearance angle and prevent arc transfer between breaking zones, ensuring effective arc extinction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the clearance angle between stationary contact and movable contact is increased to extinguish electric arcs more effectively, then arc extinguishing capability is improved, but the device complexity increases due to the need for isolator systems and multi-zone breaking structures

Engineering Contradiction:
Improvearc extinguishing capabilityVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The electrical switch is divided into multiple breaking zones (first breaking zone and second breaking zone) separated by an isolator system. Each breaking zone handles arc extinction independently, allowing the clearance angle to be optimized for arc extinction while the segmentation manages the complexity of the overall structure. The movable contact is also segmented into first and second contact portions located on opposite sides of a center plane, enabling independent arc management in each zone.

Inventive Principle:
Principle #1Segmentation

2Reliability

If the movable contact portions are positioned on opposite sides of the center plane to achieve large clearance angle, then the clearance angle exceeds 350° improving arc extinction, but the manufacturing precision requirements increase

Engineering Contradiction:
Improveclearance angleVSAvoidcontact portion positioning precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The movable contact is designed with asymmetric positioning of its contact portions relative to the center plane. The first contact portion and second contact portion are located on opposite sides of the center plane, creating an asymmetric configuration that enables the clearance angle to exceed 350°. This asymmetric design allows optimization of arc extinction performance while distributing the manufacturing precision requirements across symmetric reference features like the center plane and rotation axis.

Inventive Principle:
Principle #4Asymmetry

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 achieves a clearance angle greater than 350° between stationary and movable contacts in the OFF-state, effectively extinguishing arcs and ensuring a non-conducting state, thereby enhancing the switch's operational reliability and safety.

Implementation Method 1

an isolator system electrically isolating a first breaking zone from a second breaking zone, the centre plane passing through the isolator system, and wherein the isolator system is adapted to prevent transfer of electrical arcs from one side of the isolator system to the other

Methodology Applied
Scientific EffectElectrical insulation: Dielectric

Implementation Method 2

During an opening event, an electric arc may be formed between a stationary contact and a movable contact moving away from the stationary contact. The electric arc conducts electricity

Methodology Applied
Scientific EffectElectric arc conduction: Electric Arc

Data Source

PatentEP3916745B1Electrical switch
Publication Date: 2024.03.13 ABB (SCHWEIZ) AG
  • EP3916745B1 patent drawingFigure 1
  • EP3916745B1 patent drawingFigure 2a~3b
  • EP3916745B1 patent drawingFigure 4a~6

AI summary

An electrical switch comprising a frame (2), a first stationary contact (31), a second stationary contact (32), a roll element (4) and a movable contact mounted to the roll element (4). The roll element (4) is rotatable around a rotation axis between a first position and a second position relative to the frame (2). The movable contact comprises a first contact portion (51) and a second contact portion (52). In the first position of the roll element (4), the movable contact electrically conductively connects the first stationary contact (31) to the second stationary contact (32), and in the second position of the roll element (4) the first stationary contact (31) is electrically disconnected from the second stationary contact (32). The first contact portion (51) and the second contact portion (52) are located on opposite sides of a centre plane perpendicular to the rotation axis.