Electrical Switch Permanent Magnet Arc Control

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Solution Overview

Problem

Existing electrical switches face challenges in effectively directing and extinguishing arcs, particularly due to the limitations of permanent magnet placement and the risk of re-ignition during the opening sequence, which can lead to damage and reduced switch performance.

Innovation Solution

Positioning a permanent magnet after the extinguishing apparatus in the opening direction of the movable contact, away from the hottest contact point, to effectively direct the arc into the extinguishing plates and prevent re-ignition, while maintaining the magnet within a safe temperature range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the permanent magnet is positioned near the fixed contact to direct the arc, then the arc direction control is improved, but the permanent magnet is exposed to excessive temperature and may be damaged

Engineering Contradiction:

Improvearc direction controlVSAvoidpermanent magnet temperature

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

Instead of positioning the permanent magnet before the extinguishing apparatus (conventional approach), the patent inverts the sequence by positioning the permanent magnet after the extinguishing apparatus in the opening direction. This allows the magnet to direct the arc while being protected from excessive heat by the extinguishing plates that are positioned between the contact and the magnet.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The extinguishing apparatus serves as an intermediary element between the arc source (fixed contact) and the permanent magnet. It absorbs and dissipates the thermal energy of the arc before the magnet is exposed to it, thereby protecting the magnet from thermal damage while still allowing the magnet to exert its arc-directing function.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Temperature

If the permanent magnet is positioned after the extinguishing apparatus, then the permanent magnet is protected from excessive heat, but the arc direction control may be weakened

Engineering Contradiction:

Improvepermanent magnet temperatureVSAvoidarc direction control

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The patent inverts the conventional sequence of components. By placing the permanent magnet after the extinguishing apparatus rather than before it, the system achieves both thermal protection for the magnet and effective arc direction control, as the magnet can still influence the arc path through the extinguishing plates.

Inventive Principle:

Principle #13The other way round (Inversion)

3Reliability

If conventional arc extinguishing methods are used, then the arc is extinguished, but re-ignition may occur during the opening sequence causing damage

Engineering Contradiction:

Improvearc extinguishmentVSAvoidre-ignition damage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The permanent magnet is positioned to exert its arc-directing function during the entire opening sequence, including the critical period when re-ignition could occur. By maintaining continuous arc direction control through the extinguishing plates, the system prevents re-ignition before the arc is fully extinguished, thereby protecting the switch from damage.

Inventive Principle:

Principle #10Preliminary action

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 enhances arc direction and extinguishment efficiency, preventing re-ignition and maintaining the permanent magnet within its maximum working temperature, thus providing a compact and cost-effective solution for electrical switches handling DC currents up to 1600 amperes and 1500V.

Implementation Method 1

one or more permanent magnets positioned after the extinguishing apparatus in an opening direction of the movable contact

Methodology Applied

Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

The electromagnetic force moves and stretches the electric arc in a direction perpendicular to the breaking plane regardless of the polarity of the magnet and/or of the current

Methodology Applied

Scientific EffectElectromagnetic force: Lorentz Force

Data Source

PatentEP3561837B1An electrical switch

Publication Date: 2022.12.21 ABB (SCHWEIZ) AG

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AI summary

The electrical switch comprises at least one fixed contact (100, 200), a movable contact (300) contacting the fixed contact, and at least one extinguishing apparatus (14A, 14B) positioned after the fixed contact (100, 200) in an opening direction of the movable contact. A permanent magnet (510, 520) is further positioned after the extinguishing apparatus in the opening direction of the movable contact.