Circuit Breaker Conductor Assembly with Magnetic Arc Control

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Solution Overview

Problem

Existing circuit breakers are ineffective in disconnecting direct-current short-circuited currents due to the absence of a 'zero-off' phenomenon, which hinders arc extinguishing, unlike in alternating-current circuits.

Innovation Solution

A conductor assembly for circuit breakers incorporating a magnetic member with permanent magnets arranged adjacent to the movable and stationary contacts, generating a magnetic field that directs the arc towards an arc chute for extinguishing, enhancing the breaking capability for direct-current short-circuited currents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the same circuit breaker structure is used for both alternating-current and direct-current circuits, then the alternating-current breaking performance is good, but the direct-current breaking performance is unsatisfactory

Engineering Contradiction:
Improvebreaking effectVSAvoidapplicability to different current types
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent introduces a magnetic member with specific magnetic polarity arrangement adjacent to the contact points. This local magnetic field generation creates different arc control effects for alternating-current and direct-current circuits, allowing the same circuit breaker structure to achieve reliable breaking performance for both current types through localized quality enhancement at the arc extinction region

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the physical parameter of magnetic field generation by introducing permanent magnets with specific polarity arrangements. This parameter change enables the circuit breaker to generate appropriate magnetic forces for arc control in both alternating-current and direct-current scenarios, improving adaptability while maintaining breaking effectiveness

Inventive Principle:
Principle #35Parameter changes

2Reliability

If conventional conductor assemblies are used without magnetic members, then the structure is simple, but arc extinguishing capability for direct-current is insufficient

Engineering Contradiction:
Improvearc extinguishing capabilityVSAvoidconductor assembly structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces a magnetic member as an intermediary element between the contact points and the arc. This magnetic member generates magnetic fields that act on the arc plasma, directing it toward the arc chute for effective extinguishing. The intermediary magnetic field provides the necessary force to control direct-current arcs without requiring complex mechanical structures

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces potential complex mechanical arc control mechanisms with a magnetic field-based system. By using permanent magnets to generate magnetic forces, the circuit breaker achieves effective arc control and extinguishing capability through electromagnetic interaction rather than mechanical means, maintaining structural simplicity while improving performance

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 magnetic field effectively pushes the arc towards the arc chute, improving the circuit breaker's ability to disconnect direct-current short-circuited currents and prevent damage to load equipment, achieving reliable disconnection even in direct-current scenarios.

Implementation Method 1

a magnetic member having a pair of permanent magnets disposed on lateral sides of the second contact end, and viewing the movable contact from the stationary contact, the N poles of the pair of permanent magnets are oriented towards each other

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

generating a magnetic field that directs the arc towards an arc chute for extinguishing

Methodology Applied
Scientific EffectLorentz force: Lorentz Force

Data Source

PatentEP3772078B1An electrode for a circuit breaker and the circuit breaker
Publication Date: 2023.05.03 EATON ELECTRIC INC
  • EP3772078B1 patent drawingFigure 1
  • EP3772078B1 patent drawingFigure 2
  • EP3772078B1 patent drawingFigure 3

AI summary

A conductor assembly 2 for a circuit breaker, wherein the conductor assembly comprises: an electrical terminal 20 configured to input and output electrical power to the electrode; a stationary contact 22 electrically connected to the electrical terminal 20 and fixed to the electrical terminal; a movable contact 21 configured to rotatably engage the stationary contact 22; an arc chute 23 arranged on the electrical terminal and adjacent to the stationary contact; and a magnetic member 24 arranged to generate a magnetic field force when the movable contact 21 is disconnected from the stationary contact 22 so as to push an arc formed between the movable contact 21 and the stationary contact 22 towards the arc chute 23.